SEEHD CALIFORNIA STATE UNIVERSITY, CHICO

SEEHD CALIFORNIA STATE UNIVERSITY, CHICO 15 January 2009 Mr. Marcos Yanes Municipality of Tela Atlántida, Honduras SOLID WASTE LANDFILL AND DUMP CLO...
Author: Derek Quinn
8 downloads 0 Views 13MB Size
SEEHD CALIFORNIA STATE UNIVERSITY, CHICO

15 January 2009 Mr. Marcos Yanes Municipality of Tela Atlántida, Honduras

SOLID WASTE LANDFILL AND DUMP CLOSURE DESIGNS FOR TELA NUEVA, ATLÁNTIDA HONDURAS

Dear Mr. Yanes: On behalf of the Municipality of Tela, Atlántida Honduras, the California State University, Chico student group Sustainable Engineering and Environmental Health for Development (“SEEHD”) is pleased to present Solid Waste Landfill and Dump Closure Designs for Tela, Atlántida, Honduras. This document is submitted as a compliance item for landfill design and operation standards delineated in Manual de Diseño y Operacíon de Rellenos Sanitarios en Honduras (2005) and the United Nations Environmental Programme’s (UNEP’s) Solid Waste Management (2005). The open dump where most of the waste generated in Tela is currently disposed is proposed to be closed in 2009, at which time a sanitary landfill will need to open in another location. A description of the current conditions at the Tela open dump is included in this document, as are designs for a sanitary landfill to serve the community of Tela through 2023. Two possible landfill designs are compared and contrasted: the semi-mechanized trench method, and the fully mechanized area/canyon method. Waste characteristics and estimates of waste generation, site selection, landfill capacity and useful life, leachate production, personnel requirements, and operating costs for each proposed landfill method are considered in detail in this report. The existing Tela open dump poses numerous health hazards that are also addressed. The engineering solutions described in this document will help to ensure that the current dump is closed properly, and that the proposed landfill designs will be is feasible and sustainable, and that they ensure the safety of employees and the residents of Tela. This report also addresses the economic, sustainability and cultural concerns and challenges unique to developing countries, resulting in technologically appropriate recommendations that will help to ensure human and ecological health. Without prompt action on the part of the Municipality of Tela, the lack of a sanitary method of managing solid wastes will lead to serious environmental and human health problems in the near future as the population continues to grow.

Marcos Yánes Municipality of Tela, Honduras

Solid Waste Landfill and Dump Closure 15 January 2009

Thus it is recommended that both the construction of a sanitary landfill to serve Tela, as well as closure of the Tela open dump, be initiated as soon as possible. If you have any questions or comments regarding the contents of Solid Waste Landfill and Dump Closure Designs for Tela, Atlántida Honduras, please feel free to contact the undersigned. Sincerely,

Louise Fox Co-President

Benjamin Forte Co-President

SOLID WASTE LANDFILL AND DUMP CLOSURE DESIGNS FOR TELA NUEVA, ATLÁNTIDA HONDURAS

SEEHD Sustainable Engineering and Environmental Health for Development California State University, Chico Student Chapter

15 January 2009

Prepared for: Municipality of Tela Tela, Atlántida, Honduras C.A.

ACKNOWLEDGMENTS SEEHD Contributors:

Kara E. Scheitlin Design and Contributing Writer, AutoCAD Drawings [email protected] Peter A. Harvey Design and Contributing Writer [email protected] J. Mike Magrey Design and Contributing Writer [email protected] Benjamin L. Bryant, AutoCAD Drawings [email protected]

Report Editors:

Jeremy L. Lazarus Andrew L. Lindeman Matthew M. Cook Michelle N. Lockhart Natasha Jacob Richard A. Foss Julian T. Storelli Tyler A. Bodnar Robert A. Greene

Faculty Advisor:

Stewart Oakley, PhD. Contributing Writer/Editor [email protected] Department of Civil Engineering California State University, Chico

Municipality of Tela Collaborator:

Marcos Yanes

TABLE OF CONTENTS

EXECUTIVE SUMMARY ............................................................ I   PROJECT BACKGROUND ...................................................................... I   PROJECT DESCRIPTION ....................................................................... I   DESIGN VALUES .................................................................................... I   COST ANALYSES ................................................................................. II   Landfill Costs ......................................................................................................................II   Dump Closure Costs ......................................................................................................... III  

SOLID WASTE LANDFILL DESIGN ........................................... 1   POPULATION AND WASTE GENERATION PROJECTIONS................... 1   POPULATION PROJECTION ........................................................................................................ 1   MASS OF WASTE GENERATED.................................................................................................. 2   VOLUME OF WASTE GENERATED ............................................................................................. 3   Uncompacted Waste............................................................................................................ 3   Mechanically Compacted Waste......................................................................................... 4   MUNICIPAL SOLID WASTE COMPOSITION ................................................................................ 6   RESOURCE RECOVERY ............................................................................................................. 9   SPECIAL AND HAZARDOUS WASTE .......................................................................................... 9   TRENCH METHOD LANDFILL DESIGN .............................................. 10   WASTE AUTO-COMPACTION AND DECOMPOSITION ............................................................... 13   DAILY CELL DESIGN .............................................................................................................. 13   TRENCH LANDFILL DESIGN .................................................................................................... 18   Trench Design Calculations ............................................................................................. 19   Cover Design Calculations ............................................................................................... 21   Filling Plan ....................................................................................................................... 22   EQUIPMENT SELECTION ......................................................................................................... 25   Trench Excavation Calculations....................................................................................... 25   LEACHATE PRODUCTION ........................................................................................................ 26   TRENCH METHOD LANDFILL COST ANALYSIS ....................................................................... 28   Required Personnel........................................................................................................... 28   Equipment ......................................................................................................................... 28   Operational Costs of Trench Method Landfill.................................................................. 29   POST-LIFETIME TRENCH LANDFILL GENERAL CLOSURE PLAN .............................................. 29   CANYON/AREA METHOD LANDFILL DESIGN.................................... 32   DAILY CELL DESIGN .............................................................................................................. 32   CANYON LANDFILL DESIGN ................................................................................................... 37   Landfill Capacity and Useful Life..................................................................................... 37   Cover Design Calculations ............................................................................................... 38   Filling Plan ....................................................................................................................... 39   EQUIPMENT SELECTION ......................................................................................................... 39  

TABLE OF CONTENTS (CONTINUED) Travel Distances and Material Quantities........................................................................ 39   Equipment Options............................................................................................................ 40   LEACHATE PRODUCTION ........................................................................................................ 50   CANYON METHOD LANDFILL COST ANALYSIS ...................................................................... 50   Required Personnel........................................................................................................... 50   Operational Costs of Canyon Method Landfill................................................................. 53   OPERATIONAL COSTS OF A CONTRACTOR ...................................... 54   HEALTH RISKS & OCCUPATIONAL PLAN FOR SCAVENGERS ......... 54   LANDFILL DESIGN RECOMMENDATIONS ......................................... 57   SITE SELECTION ..................................................................................................................... 57   COMPARISON OF TRENCH AND CANYON METHOD LANDFILLS .............................................. 57   Land Requirements ........................................................................................................... 57   Environmental Impact....................................................................................................... 58   Operational Costs per Ton of Waste................................................................................. 58   Feasibility ......................................................................................................................... 58  

DUMP CLOSURE DESIGN ....................................................... 61   GOALS OF DUMP CLOSURE ................................................................ 61   POPULATION AND WASTE GENERATION ESTIMATES ..................... 63   CURRENT CONDITIONS AT THE TELA OPEN DUMP ......................... 63   SITE CHARACTERISTICS ......................................................................................................... 63   Surface Area...................................................................................................................... 63   Volume of Waste on Site ................................................................................................... 64   Landfill Capacity .............................................................................................................. 64   Per-Capita Waste Generation Calculation and Comparison........................................... 65   CLOSURE DESIGN AND CONSTRUCTION .......................................... 66   FINAL CAP ............................................................................................................................. 66   Final Cap Design.............................................................................................................. 66   Final Cap Cost Analysis ................................................................................................... 67   Grading Plan .................................................................................................................... 76   LEACHATE PRODUCTION AND REMEDIATION ......................................................................... 76   Post-Closure Leachate Production................................................................................... 78   Leachate Management ...................................................................................................... 80   GAS PRODUCTION AND REMEDIATION ................................................................................... 80   Post-Closure Methane Gas Production ............................................................................ 80   Methane Management....................................................................................................... 80   POST-CLOSURE ACTIVITIES AND RECOMMENDATIONS .......................................................... 81   Safety Precautions ............................................................................................................ 81   Monitoring ........................................................................................................................ 81   Site Uses............................................................................................................................ 81  

TABLE OF CONTENTS (CONTINUED) DUMP CLOSURE DESIGN RECOMMENDATIONS ............................... 82   REFERENCES ....................................................................................... 83  

TABLES Table 1: Population and Waste Generation, 2008-2023 ................................................................. 5   Table 2: Composition of MSW in La Ceiba, Honduras (1996)...................................................... 7   Table 3: Special and Hazardous Waste Management................................................................... 10   Table 4: Volume of Auto-Compacted-Decomposed Waste, 2008-2023 ...................................... 13   Table 5: Summary of Daily Cell Dimensions, 2008 and 2023 ..................................................... 16   Table 6: Design Calculations for Trenches and Cover Material................................................... 23   Table 7: Expansion Factors for Clay ............................................................................................ 26   Table 8: Trench Method Leachate Production, 2008.................................................................... 27   Table 9: Operational Costs of a Trench Method Landfill............................................................. 29   Table 10: Optimal Daily Cell Dimension Calculations, 2008, 2015 and 2023 ............................ 37   Table 11: Canyon Method Site Capacity Analysis ....................................................................... 38   Table 12: Cover Material Availability and Requirement Analysis .............................................. 39   Table 13: Option 1 Daily Usage Requirements ............................................................................ 42   Table 14: Option 1 Hourly Owning and Operating Cost Estimate............................................... 43   Table 15: Option 2 Daily Usage Requirements ............................................................................ 44   Table 16: Option 2 Hourly Owning and Operating Cost Estimate............................................... 45   Table 17: Option 3 Daily Usage Requirements ............................................................................ 46   Table 18: Option 3 Hourly Owning and Operating Cost Estimate............................................... 47   Table 19: Canyon/Area Method Leachate Production, 2008........................................................ 50   Table 20: Canyon Method Landfill Options Lifetime Personnel Costs ....................................... 53   Table 21: Operational Costs of Canyon Method Landfill ............................................................ 53   Table 22: Cost of Contracting Landfill Operations ...................................................................... 54   Table 23: Occupational Health and Safety Plan Matrix ............................................................... 56   Table 24: Population and Waste Generated by Mass and Volume, 1997-2008 ........................... 63   Table 25: Final Cover Source Cost/Benefit Matrix ...................................................................... 68   Table 26: Cover Layer Material Cost Estimates at Various Layer Depths................................... 69   Table 27: Cost of Material for Various Options at Possible Layer Depths .................................. 71   Table 28: Total Cost for Application and Compaction at Various Layer Depths ........................ 73   Table 29: Total Dump Closure Project Cost for Various Options................................................ 74   Table 30: Monthly Leachate Production (Sloped and Flat Surfaces) ........................................... 79   Table 31: Closed Dump Gas Production ...................................................................................... 80  

FIGURES Figure 1: Projected Population for Tela, Atlántida, Honduras, 2008 to 2023 ................................ 2   Figure 2: Cumulative Mass of Waste Generated in Tela, 2008-2023............................................. 3   Figure 3: Cumulative Volume of Generated Waste, 2008-2023 .................................................... 6   Figure 4: Percent by Volume of Waste Components as Generated (Uncompacted)...................... 8   Figure 5: Percent by Volume of Waste Components as Generated (Compacted).......................... 8   Figure 6: Exposed Area and Dimensions of Daily Cell for Trench Method ................................ 14   Figure 7: Exposed Area of Daily Cell as a Function of Trench Width......................................... 17   Figure 8: Exposed Area of Daily Cell as a Function of Trench Depth......................................... 17   Figure 9: Top Surface Area (m2) of Daily Cell as a Function of Trench Depth........................... 18   Figure 10: Total Trench System Design Diagram ........................................................................ 19   Figure 11: Total Trench System Design Diagram ........................................................................ 26   Figure 12: Exposed Area and Dimensions of Daily Cell for the Canyon Method ....................... 33   Figure 13: Cell Dimension Relationships, 2008 ........................................................................... 35   Figure 14: Cell Dimension Relationships, 2015 ........................................................................... 35   Figure 15: Cell Dimension Relationships, 2023 ........................................................................... 36   Figure 16: Basic Design of a Final Cap System ........................................................................... 66   Figure 17: Final Cover Material Costs at Various Layer Depths ................................................. 70   Figure 18: Total Project Cost for Option 1 (Purchased Material) ................................................ 75   Figure 19: Total Project Cost for Option 2 (Locally Excavated Material) ................................... 75   Figure 20: Total Project Cost for Option 3 (Purchased Barrier/Excavated Soil Material)........... 76  

EXHIBITS Exhibit 1: Site Location Map Exhibit 2: Trench Method Landfill Plot Plan Exhibit 3: Canyon Method Landfill Site Topographic Map Exhibit 4: Canyon Method Landfill Lift Area Plan Exhibit 5: Canyon Method Landfill Final Surface Plot Plan Exhibit 6: Canyon Method Landfill Cover Material Platform Surfaces Plan Exhibit 7: Canyon Method Landfill Section Views Exhibit 8: Canyon Method Landfill Existing and Final Surface Plans Exhibit 9: Dump Closure Site Surface Plan, 1996 Exhibit 10: Dump Closure Site Surface Plan, 2008 Exhibit 11: Dump Closure Site Section View 1-1 Exhibit 12: Dump Closure Site Section View 2-2 Exhibit 13: Dump Closure Grading Plan Exhibit 14: Dump Closure Gas Vent Location Section 1-1

EXECUTIVE SUMMARY PROJECT BACKGROUND The California State University, Chico (CSUC) student group SEEHD was established during the spring of 2005. The primary purpose of SEEHD is to collaborate with developing communities to provide appropriate and sustainable engineering solutions to address the unique needs and resources of partner communities. SEEHD began assisting the Municipality of Tela, Atlántida, Honduras in 2005 (see Exhibit 1: Site Location Map) with the design and implementation of improvements to the community’s sustainable wastewater treatment system. Since this time, it has become apparent that there is also a municipal solid waste (MSW) problem that poses an immediate threat to the environment and the health of the residents of Tela. For this reason, SEEHD has agreed to collaborate with the Municipality in order to design the closure of the existing open dump and to design a sanitary landfill where the waste generated may be disposed of in an environmentally appropriate and sustainable manner.

Ben Forte 2/18/09 10:04 AM Deleted: deposited

PROJECT DESCRIPTION The open dump receiving solid waste generated by the residents of Tela has been in operation since 1997. The open dump was originally designed as a sanitary landfill. However, due to various factors associated with cost, poor design considerations, and lack of resources available to the Municipality, the site quickly began operating as an open dump. Operating the site as an open dump exposes the public (and the approximately 50 scavengers that live in and survive off the dump) to hazardous conditions. Additionally, leachate contamination is a continual health and environmental problem at the site. For these reasons, it is vital that the Municipality close the site and obtain new property on which to develop and operate a landfill design that is more appropriate to the socioeconomic conditions in developing countries.

Ben Forte 2/18/09 10:12 AM

In order to select the best option for disposal of MSW generated, two alternative landfill designs are detailed and evaluated in this document. The first method is a semi-mechanized ‘trench method’ landfill and the second method is a fully mechanized ‘canyon/area method’ landfill; each designed to have a capacity for the MSW generated through to the year 2023.

Ben Forte 2/18/09 10:15 AM

In addition to the design and selection of a sanitary landfill, a preliminary design for the closure of the existing dump is included in this report. Proper closure of the dump is essential to ensuring the health of the residents in Tela, as it will eliminate access to the waste and that will resolve the existing problems related to municipal solid waste production. DESIGN VALUES The population of Tela in 2008 is approximately 40,000 persons. Assuming a population growth rate of 2.8%, the population will be 48,661 and 60,878 persons in 2015 and 2023, respectively. A waste generation rate of 0.6 kg/person-day yields 174,356 tons (871,781 m3 of uncompacted

I

Deleted: where

Ben Forte 2/18/09 10:12 AM Deleted: in

Ben Forte 2/18/09 10:13 AM Deleted: disposed

Ben Forte 2/18/09 10:13 AM Deleted: of

Ben Forte 2/18/09 10:14 AM Deleted: reverted Deleted: to

Ben Forte 2/18/09 10:15 AM Comment: not sure on this number, seems like it may be 20-30?

Ben Forte 2/18/09 10:18 AM Deleted: ,

Executive Summary

SEEHD

waste) over the 15 year project lifetime. COST ANALYSES LANDFILL COSTS The trench method landfill is analyzed assuming monthly use of a track loader, and the canyon/area method is analyzed for the following three options: • • •

Option 1: Track Loader; Option 2: Excavator and Dump Truck; and Option 3: Excavator, Dump Truck, and Track Tractor.

Operational cost analyses for both trench method and canyon/area method landfills are presented in Table ES-1. Table ES-1: Operational Costs for Landfill Designs Canyon Method Landfill

Units

Trench Method Landfill

Option 1

Option 2

Option 3

Equipment Cost

(USD)

240,516

797,929

864,630

1,099,176

Personnel Cost

(USD)

652,828

343,594

384,825

487,903

Component

Total Lifetime Cost (USD) =

893,344

1,141,522

1,249,455

1,587,079

Cost per Metric Ton (USD/MT) =

5.12

6.55

7.17

9.10

Cost per Metric Ton for a Contractor (USD/MT) =

10.25

13.09

14.33

18.21

II

Executive Summary

SEEHD

DUMP CLOSURE COSTS The following three options for source materials were analyzed for the dump closure: • • •

Option 1: purchasing barrier and surface soil layers from a local dealer; Option 2: excavating barrier and surface soil layers locally with rented machinery; and Option 3: purchasing the barrier layer material and excavating the soil layer material locally with rented machinery.

Various depths of cover material layers (to include a clay barrier layer and a surface soil layer) were analyzed, with total costs for each option at various depths presented in Table ES-2. Table ES-2: Total Dump Closure Project Cost for Various Options Depth

Total Cost (Material & Equipment) Option 1: Purchased

Option 2: Locally Excavated

Option 3: Locally Excavated Surface Soil, Purchased Hydraulic Barrier

Surface

Barrier

(m)

(m)

(USD)

(USD)

(USD)

0.6

388,471

253,858

353,415

0.45

331,949

222,225

296,892

0.3

275,313

190,479

240,257

0.2

237,632

169,390

202,575

0.6

348,074

222,225

321,781

0.45

291,438

190,479

265,146

0.3

234,803

158,732

208,510

0.2

197,121

137,643

170,829

0.6

0.45

0.3

0.2

0.6

307,563

190,479

290,035

0.45

250,928

158,732

233,399

0.3

194,405

127,099

176,877

0.2

156,611

105,897

139,082

0.6

280,632

169,390

268,946

0.45

223,996

137,643

212,311

0.3

167,361

105,897

155,675

0.2

129,679

84,808

117,994

Ben Forte 2/18/09 10:35 AM Deleted: is

Given the estimated costs shown in Table ES-2, it seems unlikely that the Municipality will, by itself, initiate a dump closure project without receiving external funds. This is believed to be a major reason why the current site continues to operate as an open dump after more than 10 years of operation. It is therefore recommended that the Municipality use the cost estimates presented

III

Ben Forte 2/18/09 10:36 AM Deleted: exactly

Ben Forte 2/18/09 10:36 AM Deleted: , even though it was originally designed as a mechanized landfill

Executive Summary

SEEHD

in this section as a proposal to seek funds for closure from outside funding sources. Even the lowest cost options, would be adequate and a substantial improvement over the current situation.

Ben Forte 2/18/09 10:39 AM Deleted: governmental or non-governmental organizations

Ben Forte 2/18/09 10:40 AM Deleted: although not ideal,

IV

SOLID WASTE LANDFILL DESIGN POPULATION AND WASTE GENERATION PROJECTIONS Population Projection The population of Tela in 1988 and 2001 was 22,193 and 27,990 persons, respectively (Citypopulation, 2008). Assuming an exponential growth rate, these population values are used to estimate a population growth rate, k. Population Growth Rate

Where: k P2001 P1988 t2001 t1988

= = = = =

population growth rate (decimal percent) population in 2001 (persons) population in 1988 (persons) year 2001 year 1988

According to the CIA World Fact Book, the 2008 population growth rate for Honduras is 2.024%, which is similar to the population growth rate value as calculated above. A chosen value of 2.8% will be used for design calculations in order to add a factor of safety. Although current population estimates vary, it is assumed that the current (2008) population is approximately 40,000. Projected population is displayed in Table 1 and Figure 1.

Where: Pt P2008 k t2008

= = = =

population in year t (persons) population in 2008 (persons) population growth rate (decimal %) year 2008

1

Ben Forte 2/18/09 10:41 AM Deleted: corresponds

Ben Forte 2/18/09 10:42 AM Deleted: factor

Solid Waste Landfill Design

SEEHD

Figure 1: Projected Population for Tela, Atlántida, Honduras, 2008 to 2023

Mass of Waste Generated The mass of waste generated is dependent on the number of persons contributing waste to the landfill, as well as the amount of waste generated by each person. The average waste generation per person per day in Tegucigalpa, Honduras is 0.52 kg/person-day (UNEP, 2005). This value will be used along with a factor of safety for Tela, where waste generation is assumed to be 0.6 kg/person-day.

Ben Forte 2/18/09 10:43 AM

Mass of Waste Generated

Ben Forte 2/18/09 10:44 AM

= =

Ben Forte 2/18/09 10:44 AM Deleted: factor Deleted: Tela,

Where: Gt-a W

Deleted: the

mass of waste generated in year t (metric tons) waste generation (kg/person-day)

2

Solid Waste Landfill Design

SEEHD

The mass of waste generated yearly is presented in Table 1 and Figure 2. Figure 2: Cumulative Mass of Waste Generated in Tela, 2008-2023

Volume of Waste Generated The volume of waste generated is dependent on population and the per-capita waste generation. Additionally, volume depends on the density of waste before and after compaction and decomposition. UNCOMPACTED WASTE 'Uncompacted waste’ describes waste materials that are “as is” when they arrive at the landfill. Since materials that come to landfills are usually loose, the average density of those wastes is relatively low. On average, the density of unsorted and uncompacted waste is assumed to be ρu = 200 kg/m3 (UNEP, 2005).

3

Solid Waste Landfill Design

SEEHD

Volume of Uncompacted Waste

Where: Vu-a

=

volume of uncompacted waste in year t (m3)

The volume of uncompacted waste generated yearly is presented in Table 1 and Figure 3. MECHANICALLY COMPACTED WASTE In large landfills and open dumps, heavy machinery is typically used to compact waste in order to reduce the volume required. The average density of unsorted, mechanically compacted, decomposed waste is assumed to be approximately ρmc = 450 kg/m3 (Caterpillar, 1999). Volume of Mechanically Compacted Waste

Where: Vmc-a

=

volume of mechanically compacted waste in year t (m3)

The volume of uncompacted and mechanically compacted waste generated yearly, as well as cumulative volume values (Vu-T and Vmc-T for uncompacted and mechanically compacted waste, respectively) is presented in Table 1. A graphical comparison of cumulative volumes of uncompacted and mechanically compacted waste is presented in Table 1 and Figure 3.

4

Ben Forte 2/18/09 10:47 AM Comment:

Solid Waste Landfill Design

SEEHD

Table 1: Population and Waste Generation, 2008-2023 Waste Generation Volume Uncompacted Year, t

Population, Pt (persons)

Mass, Gt-a (tons/year)

2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 TOTAL =

40,000 41,136 42,304 43,505 44,741 46,011 47,317 48,661 50,043 51,464 52,925 54,428 55,974 57,563 59,198 60,878

8,760 9,009 9,265 9,528 9,798 10,076 10,363 10,657 10,959 11,271 11,591 11,920 12,258 12,606 12,964 13,332 174,356

monthly, Vu-m (m3) 3,650 3,754 3,860 3,970 4,083 4,198 4,318 4,440 4,566 4,696 4,829 4,967 5,108 5,253 5,402 5,555 Vu-T =

5

yearly, Vu-a (m3) 43,800 45,044 46,323 47,638 48,991 50,382 51,813 53,284 54,797 56,353 57,953 59,599 61,291 63,031 64,821 66,662 871,781

Volume Mechanically Compacted monthly, Vmc-m yearly, Vmc-a (m3) (m3) 1,622 1,668 1,716 1,764 1,814 1,866 1,919 1,973 2,030 2,087 2,146 2,207 2,270 2,334 2,401 2,469 Vmc-T =

19,467 20,019 20,588 21,173 21,774 22,392 23,028 23,682 24,354 25,046 25,757 26,488 27,240 28,014 28,809 29,628 387,458

Solid Waste Landfill Design

SEEHD

Figure 3: Cumulative Volume of Generated Waste, 2008-2023

It may be observed from Figure 3 that if the waste entering the landfill are mechanically compacted (assuming no recovery), the total volume of waste to be deposited in the landfill is approximately Vmc-T = 387,500 m3. In contrast, if the wastes are deposited in the landfill without compaction, the total volume occupied is approximately Vu-T = 871,800 m3 before decomposition. It is likely that the actual volume required for the waste over the 15-year design life will be somewhere in between the compacted and uncompacted densities. Municipal Solid Waste Composition Municipal solid waste (MSW) is typically composed of a variety of materials that vary from day to day. In order to estimate composition values of the waste generated in the Municipality, data from a 1996 study of La Ceiba, Honduras is utilized, and is presented as part of Table 2.

6

Solid Waste Landfill Design

SEEHD

Table 2: Composition of MSW in La Ceiba, Honduras (1996)

Component Organics Food Waste Paper & Cardboard Textiles Plastics Wood & Leaves Rubber & Leather Inorganics Metals Glass Dirt & Ash Total

% by Weight as Generated1

Density2

Volume per 100 kg

% by Volume as Generated

Compaction Factor2

Compacted Volume per 100 kg

(%)

(kg/m3)

(m3)

(%)

(decimal %)

(m3)

% by Volume Compacted (%)

66.5 12.6 0.8 8.7 0.8 1.7

291 70 65 65 169 145

0.229 0.181 0.012 0.133 0.005 0.012

38.2 30.2 2.0 22.3 0.8 2.0

0.35 0.23 0.18 0.15 0.25 0.30

0.080 0.041 0.002 0.020 0.001 0.004

48.9 24.8 1.3 12.2 0.7 2.1

2.3 2.6 4 100.0

320 196 613

0.007 0.013 0.007 0.598

1.2 2.2 1.1 100.0

0.35 0.60 0.85

0.003 0.008 0.006 0.164

1.5 4.9 3.4 100.0

Density as Generated = 100.0 kg /(0.598 m3) = 3

Density with Compaction = 100.0 kg / (0.164 m ) = 1 2

167

kg/m3

610

3

kg/m

Source: IPES, 2006 Source: Tchobanoglous, 1993

7

 

Solid Waste Landfill Design

SEEHD

Using values that may be observed in Table 2, percent by volume of uncompacted and compacted waste generated in Tela are displayed in Figure 4 and Figure 5, respectively. Figure 4: Percent by Volume of Waste Components as Generated (Uncompacted)

Figure 5: Percent by Volume of Waste Components as Generated (Compacted)

8

Solid Waste Landfill Design

SEEHD

Resource Recovery It has been estimated that in Latin American cities, up to 2% of the population survives by scavenging (Medina, 2000). Scavengers recover materials for their own use (such as food or materials to construct a home) and to sell for recycling/reuse. Resource recovery has widespread implementation in the United States, however many of the reusable or recyclable components of municipal solid waste in Latin America have no value in developing countries. Scavengers are going to retrieve valuable items since recycling is not done in developing countries for environmental but rather economic reasons. It should be noted from observation of Figure 4 and Figure 5 that food waste, paper and cardboard, and plastics will make up a significant fraction of the waste to be deposited in the landfill. In order to reduce the amount of material deposited in the landfill, resource recovery and composting of organic waste should be considered. While scavengers currently recycle various profitable materials in the open dump, a more consistent and sanitary system should be devised for resource recovery, possibly to include a scavenger cooperative. Composting food scraps may potentially reduce the volume of municipal solid waste (MSW) by 40 to 50%, although these operations are labor-intensive and costly.

Ben Forte 2/18/09 10:55 AM Comment: Recyclable materials are sold to recyclers locally and then transported to the US facilities. This is of course a significant amount of energy for recycling purposes, but still occurs as it does provide an income.

Ben Forte 2/18/09 10:57 AM Comment: Can we/should we provide a cost analysis for a composting progam?

Special and Hazardous Waste Certain MSW including chemicals, hospital waste, tires, batteries and large appliances are considered to be special or hazardous waste. These components, are presented in Table 3 along with descriptions of the hazard/problem and appropriate management strategies.

Ben Forte 2/18/09 11:02 AM Deleted: as

Ben Forte 2/18/09 11:02 AM Deleted: well as

Ben Forte 2/18/09 11:02 AM Deleted: descriptions

Ben Forte 2/18/09 11:02 AM Deleted: are presented as Table 3

9

Solid Waste Landfill Design

SEEHD

Table 3: Special and Hazardous Waste Management MSW Component Hazard/Problem Description Tires If buried, tires will eventually rise up to the surface of the landfill. They also may hold water or leachate that is hazardous and is a breeding ground for insect vectors such as mosquitoes.

Medical Waste

Hazard to landfill workers, scavengers, animals, chance of cross-contamination.

Batteries

Batteries, especially large car batteries, may leak hazardous chemicals.

Chemicals

Chemicals may leak and harm workers, scavengers, and animals and may react with other chemicals in the dump, possibly causing an even more toxic byproduct.

Large Appliances

Appliances take up large amounts of room in landfills and do not allow for adequate compaction

Management Strategy The landfill should have a separate area for tires where they may be stacked or used for slope stabilization at some location in the landfill. Whatever remedy is chosen, care should be taken so that stagnant water will not sit in the tires. Medical waste will be separated in to a separate designated trench and covered monthly. This trench will preferably be located in an area that will never have regular traffic and is a low point in the local geography. Batteries, especially spent automobile batteries, should be separated and taken to a facility (if available) or put in a separate designated trench. Chemicals should be placed in a separate trench away from the rest of the waste. Mixing of chemicals should be avoided as much as possible. This trench will preferably be located in an area that will never have regular traffic and is a low point in the local geography. Large appliances should not be placed in landfills, but should be recycled or placed in a separate area.

Ben Forte 2/18/09 11:07 AM Deleted: In t

Ben Forte 2/18/09 11:07 AM Deleted: ,

Ben Forte 2/18/09 11:08 AM

TRENCH METHOD LANDFILL DESIGN

Deleted: , depending on the

Ben Forte 2/18/09 11:08 AM

A semi-mechanized trench landfill is the first of two landfill methods that is being considered for Tela in this report. The trench method consists of a series of properly sized trenches in parallel that are excavated as required by the design. Waste is deposited in the trench, when the trench is full (which will occur approximately once-per-month for a properly designed trench), the

10

Deleted: process

Ben Forte 2/18/09 11:09 AM Deleted: es

Ben Forte 2/18/09 11:08 AM Deleted: and

Solid Waste Landfill Design

SEEHD

excavated material is used as cover. Immediate availability of cover without the need for fulltime heavy equipment to compact, excavate and haul cover is a major advantage of the trench method. An illustrative trench method plot plan is presented as Exhibit 2, and an image of the semi-mechanized trench landfill in Villanueva, Honduras is presented in Photo 1 and Photo 2. In a trench method landfill, waste that is not classified as special or hazardous is to be disposed of into a series of trenches where the waste will be allowed to settle naturally and decompose anaerobically. This process is known as auto-compaction-decomposition.

Ben Forte 2/18/09 11:10 AM Deleted: deposited

Ben Forte 2/18/09 11:11 AM Deleted: for at least 6 months during which time anaerobic decomposition will naturally occur

11

Solid Waste Landfill Design

SEEHD

Photo 1 & Photo 2: The municipal landfill in Villanueva, Honduras, which has been in operation for 10 years, is an excellent example of the sustainability of the semi-mechanized trench method.

12

Solid Waste Landfill Design

SEEHD

Waste Auto-Compaction and Decomposition Using known solid and water composition ratios of various organic components of MSW (including food waste, newspaper, cardboard, office paper, and yard waste), and autodecomposition reduction in volume, the reduced volume may be estimated. It is estimated that the volume of waste buried in the trenches will reduce by 33% over time. A table of volumes for the auto-compacted-decomposed waste generated yearly is presented in Table 4.

Ben Forte 2/18/09 11:13 AM Deleted: contents

Ben Forte 2/18/09 11:12 AM Deleted: of

Table 4: Volume of Auto-Compacted-Decomposed Waste, 2008-2023 Annual Volume Auto-CompactedYear, t Decomposed Waste, Vacd-a (m3) 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 TOTAL =

29,346 30,179 31,036 31,918 32,824 33,756 34,714 35,700 36,714 37,756 38,829 39,931 41,065 42,231 43,430 44,663 584,093

Daily Cell Design

Ben Forte 2/18/09 11:19 AM

A criticle factor in the design of any type of landfill is the amount of cover material required. This is the main reason for the use of a trench type landfill in developing countries since, in a trench, the exposed surface area is minimized, decreasing the amount of cover and mechanization required. A diagram of the exposed area of the daily cell is presented as Figure 6.

13

Deleted: One of the most important

Ben Forte 2/18/09 11:19 AM Deleted: s

Ben Forte 2/18/09 11:24 AM Comment: Maybe add the fact that large area/canyon methods have a better cover to waste ratio, but at a certain level of waste generation, the cover to waste ratio increases to exceed the practicalitly of this method. Trench methods would be ideal for smaller communities, etc.

Solid Waste Landfill Design

SEEHD

Figure 6: Exposed Area and Dimensions of Daily Cell for Trench Method

For the optimal daily cell, several things must be considered. These include the depth of the trench to be excavated, the width of the trench, the length of the trench, and the exposed surface area that will require cover in order to minimize leachate production and exposure to vectors. Calculations for daily cell dimensions are as follows (with results presented in Table 5): Length of Daily Cell

Where: ld Vd p a

= = = =

length of daily cell (m) volume of MSW deposited in trench daily (m3) depth of trench (m) width of trench (m)

Area of Top Exposed Surface of Daily Cell

14

Solid Waste Landfill Design

Where: As-d

=

SEEHD

area of top exposed surface of daily cell (m2)

Area of Front Exposed Surface of Daily Cell

Where: Af

=

area of front exposed surface of daily cell (m2)

Total Exposed Area of Daily Cell

Where: AST-d

=

total exposed area of daily cell (m2)

Various possible dimensions of the daily cell in 2008 and 2023 (assuming auto-compacteddecomposed volume) are displayed in Table 5.

15

Solid Waste Landfill Design

SEEHD

Table 5: Summary of Daily Cell Dimensions, 2008 and 2023 Daily volume, Vacd-d

Depth, p

Width, a

Length, ld

Area of top exposed surface of daily cell, As-d

Area of front exposed surface of daily cell, Af

Total exposed area of daily cell, AST-d

(m3/day)

(m)

(m)

(m)

m2

m2

m2

80

5

2

8.0

16.1

10.0

26.1

80

5

3

5.4

16.1

15.0

31.1

80

5

4

4.0

16.1

20.0

36.1

80

5

5

3.2

16.1

25.0

41.1

80

4.5

2

8.9

17.9

9.0

26.9

80

4.5

3

6.0

17.9

13.5

31.4

80

4.5

4

4.5

17.9

18.0

35.9

80

4.5

5

3.6

17.9

22.5

40.4

80

4

2

10.1

20.1

8.0

28.1

80

4

3

6.7

20.1

12.0

32.1

80

4

4

5.0

20.1

16.0

36.1

80

4

5

4.0

20.1

20.0

40.1

122

5

2

12.2

24.5

10.0

34.5

122

5

3

8.2

24.5

15.0

39.5

122

5

4

6.1

24.5

20.0

44.5

122

5

5

4.9

24.5

25.0

49.5

122

4.5

2

13.6

27.2

9.0

36.2

122

4.5

3

9.1

27.2

13.5

40.7

122

4.5

4

6.8

27.2

18.0

45.2

122

4.5

5

5.4

27.2

22.5

49.7

122

4

2

15.3

30.6

8.0

38.6

122

4

3

10.2

30.6

12.0

42.6

122

4

4

7.6

30.6

16.0

46.6

122

4

5

6.1

30.6

20.0

50.6

Year 2008

Year 2023

16

Solid Waste Landfill Design

SEEHD

The exposed area of the daily cell as a function of the trench width and depth (for a daily cell volume of 122 m3) are presented in Figure 7 and Figure 8. Figure 7: Exposed Area of Daily Cell as a Function of Trench Width

Figure 8: Exposed Area of Daily Cell as a Function of Trench Depth

17

Solid Waste Landfill Design

SEEHD

Although the minimum cover required for both 2008 and 2023 occurs with a daily cell depth of p = 5 m and width a = 2 m (as shown in Figure 7 and Figure 8), this will require a very long monthly trench. Therefore, more feasible daily cell dimensions require depth of p = 4.5 m, a width of a = 4 m, and a length, ld, that will vary with the amount of waste generation. Figure 9 shows the relationship between the top area of the daily cell, As-d, to the depth of the trench, p. Figure 9: Top Surface Area (m2 ) of Daily Cell as a Function of Trench Depth

Trench Landfill Design A generic diagram of a total trench system design is presented as Figure 10.

18

Solid Waste Landfill Design

SEEHD

Figure 10: Total Trench System Design Diagram

TRENCH DESIGN CALCULATIONS It is recommended that a trench is designed to have a capacity for approximately one month of MSW (Oakley, 2005). This will allow the excavator to be used for a few days per month to cover the trench and to dig the next trench where waste will be deposited. The appropriate distance between trenches, b, is determined by the soil composition and land area available. It is important to minimize distance between trenches in order to reduce land usage, thus the distance between trenches shall be b = 2 m based on soil composition. Selected trench calculations are carried out as follows (with results presented in Table 6): Monthly Length of Trench

Where: lm Vu- m

= =

monthly length of trench (m) monthly volume of MSW deposited in trench (m3)

Length of Trench Required per Year

19

Ben Forte 2/19/09 10:55 AM Comment: It would be nice to do some actual soil tests.

Solid Waste Landfill Design

SEEHD

Where: la

=

yearly length of trench required (m)

Cumulative Trench Volume over Design Life

Where: Va-T

cumulative volume over design life (m3)

=

Yearly Ground Surface Area of Trench

Where: −

=

trench area required per year (m2)

Cumulative Ground Surface Area of Trench Over Design Life

Where: ATST-t =

cumulative area over design life (m2)

Cumulative Number of Trenches Required

Where: nT

=

cumulative number of trenches required

20

Solid Waste Landfill Design

SEEHD

Cumulative Total Area Required for Trench System

Where: n b

= =

number of trenches required per year distance between trenches (m)

It should be observed in Table 5 that the length of trench required for a monthly capacity, lm, will increase from 200 m in 2008 to 304 m in 2023. Furthermore, although the minimum daily cell capacity is used for calculations, the amount of decomposition and auto-compaction that will occur over time should leave capacity for the increased MSW volume generated due to local population growth.

Ben Forte 2/18/09 11:26 AM Deleted: may

Ben Forte 2/18/09 11:27 AM Deleted: It should be noted that

COVER DESIGN CALCULATIONS The depth of applied cover should be at least E = 0.3 m thick, assuming that approximately half of the cover will subside into the waste (Bolton, 1995). This should leave a minimum of 0.15 m of cover separating the waste and finished grade. Annual and cumulative volumes of material to be excavated and used as cover, as well as cover to waste ratio calculations are carried out as follows (with results presented in Table 6):

Ben Forte 2/19/09 10:57 AM

Volume of Cover Material Required Yearly

Ben Forte 2/19/09 10:59 AM



=



Where: Vc-a AST-a

= =

Vc-T

=

Ben Forte 2/19/09 10:58 AM Deleted: will Deleted: s

( )

volume of cover material required per year (m3) total exposed surface are of daily cell per year (m2)

Cumulative Volume of Cover Material Required

Where:

Deleted: fall

cumulative volume of cover required (m3)

21

Solid Waste Landfill Design

SEEHD

Volume of Excess Cover Material per Year

Where: VSE-T

=

cumulative volume of excess cover material accumulated (m3)

Ratio of Cover to Waste

Where: Vu-m Vc-a

= =

volume of uncompacted waste generated in a given month (m3) volume of cover required per year (m3)

FILLING PLAN The filling plan for the trench method landfill that shows the order of trench filling, is presented in Exhibit 2, and images of waste being unloaded by gravity into trenches are presented in Photo 3 and Photo 4.

22

Solid Waste Landfill Design

SEEHD

Table 6: Design Calculations for Trenches and Cover Material Cubic meters waste per month, Vu-m

Cubic meters waste per year, Vu-a

Cumulative volume MSW, Vu-T

Depth of Trench, p

Width of Trench, a

Length of Monthly Trench, lm

Cumulative Number of 100 m Trenches required, nT

Distance Between Trenches, b

Cumulative Ground Surface Area of Trench and Distance Between Trenches, ATST-T

Depth of Applied Cover, E

Volume of Cover Required Yearly, Vc-a

Cumulative Volume of Cover Required, Vc-T

Excess Cover Material Yearly, VSE-a

Cumulative Excess Cover Material Per Year (BCM), VSE-T(B)

Cumulative Excess Cover Material Per Year (LCM), VSE-T(L)

(m3)

(m3)

(m3)

(m3)

(m)

(m)

(m)

(#/year)

(m)

(ha)

(m)

(m3/yr)

(m3)

(m3/yr)

(m3)

(m3)

-

2008

120

3,600

43,200

43,200

4.5

4

200

24

2

1.4

0.3

2,880

2,880

40,320

40,320

52,416

0.067

2009

123

3,702

44,427

87,627

4.5

4

206

47

2

2.4

0.3

2,962

5,842

41,465

81,785

106,320

0.067

2010

127

3,807

45,688

133,315

4.5

4

212

70

2

3.4

0.3

3,046

8,888

42,642

124,427

161,755

0.067

2011

131

3,915

46,986

180,300

4.5

4

218

92

2

4.5

0.3

3,132

12,020

43,853

168,280

218,765

0.067

2012

134

4,027

48,320

228,620

4.5

4

224

114

2

5.6

0.3

3,221

15,241

45,098

213,379

277,393

0.067

2013

138

4,141

49,692

278,312

4.5

4

230

134

2

6.7

0.3

3,313

18,554

46,379

259,758

337,685

0.067

2014

142

4,259

51,103

329,415

4.5

4

237

155

2

7.8

0.3

3,407

21,961

47,696

307,454

399,690

0.067

2015

146

4,379

52,554

381,969

4.5

4

243

174

2

9.0

0.3

3,504

25,465

49,050

356,504

463,456

0.067

2016

150

4,504

54,046

436,015

4.5

4

250

194

2

10.2

0.3

3,603

29,068

50,443

406,947

529,032

0.067

2017

154

4,632

55,581

491,596

4.5

4

257

212

2

11.5

0.3

3,705

32,773

51,876

458,823

596,470

0.067

2018

159

4,763

57,159

548,755

4.5

4

265

230

2

12.8

0.3

3,811

36,584

53,349

512,172

665,823

0.067

2019

163

4,899

58,782

607,538

4.5

4

272

248

2

14.1

0.3

3,919

40,503

54,863

567,035

737,146

0.067

2020

168

5,038

60,451

667,989

4.5

4

280

265

2

15.5

0.3

4,030

44,533

56,421

623,456

810,493

0.067

2021

173

5,181

62,168

730,157

4.5

4

288

282

2

16.9

0.3

4,145

48,677

58,023

681,480

885,924

0.067

2022

178

5,328

63,933

794,090

4.5

4

296

298

2

18.3

0.3

4,262

52,939

59,671

741,151

963,496

0.067

2023

183

5,479

65,749

859,839

4.5

4

304

314

2

19.8

0.3

4,383

57,323

61,365

802,516

1,043,271

0.067

Year, t

Daily volume waste uncompacted, Vu-d

Ratio of monthly cover material required to monthly volume a-c-d MSW, Relation of Vc-a/Vu-a

Assumptions: Production per capita = 0.6 kg/person-day, p = 4.5 m, a = 4 m, lm = 100 m, b = 2 m, E = 0.3 m

23

Solid Waste Landfill Design

SEEHD

Photo 3 & Photo 4: Wastes are unloaded by gravity into the trenches, which are designed to minimize total exposed surface area to avoid problems with vectors and leachate production.

24

Solid Waste Landfill Design

SEEHD

Equipment Selection One of the main advantages of a trench method landfill is the relatively small frequency of heavy machinery required. However, in order to control vectors and leachate production, it is neccesary to cover exposed solid waste as often as is feasible. A trench method landfill may be successfully operated using a properly selected excavator, with relatively low frequency of need. Due to the prevalence of Caterpillar brand heavy machinery, specifications for this design are taken from the Caterpillar Performance Handbook, 32nd Edition (2001). However, it should be noted that any excavator with the required specifications may be used.

Ben Forte 2/19/09 11:01 AM Deleted:

The effectiveness of an excavator may largely be thought of as a function of the flywheel power, bucket capacity, boom and arm lengths, and cycle time. Another extremely important consideration in equipment selection is availibility, especially in developing countries. In order to minimize land area use, the optimal trench depth was found to be 4.5 m. Therefore, an excavator with a boom and arm with this depth capability must be selected. A machine with appropriate power capabilities for moving large quantities of soil must be selected based on local conditions. One model that is appropriate for the situation being examined is the Caterpillar (CAT) Excavator Model 320C or equivalent; it typically has a 1.5 m3 bucket size and 138 hp flywheel power. This, or another model with the similar capabilites, is recommended for use in this trench method design.

Ben Forte 2/19/09 11:05 AM Deleted: is available in Honduras

TRENCH EXCAVATION CALCULATIONS The excavator cycle time is dependent on machine size, bucket size, operator experience, cycle time, and site conditions. Difficult excavating conditions or a deep trench both increase cycle time. The location where cover material will be stored is also a consideration, since this may greatly lengthen the cycle time (CAT, 2001). The following factors are assumed in cycle time estimates: • • • •

no obstruction in right of way; above average job conditions; an operator of average ability; and 60° to 90° swing angle.

At the proposed landfill site, there will not be obstructions in the right of way. Average job conditions will be assumed, although, some periods of the year may be extremely rainy, making work more difficult, and there will likely be various unforseen conditions. For these reasons, the slow range of cycle times with hard clay conditions are selected for design calculations, resulting in a 30 second assumed cycle time (2 cycles per minute) (CAT, 2001). Assuming a bucket size of 1.5 m3 for the Caterpillar Model 320C, and the 30 second cycle timewith 75% job efficiency, the actual hourly production is calculated as 180 m3/hr of “loose” material. The expansion from bank to loose volume may be estimated using the Caterpillar chart excerpt presented in Table 7. Assuming wet clay and adding a 5% safety factor (resulting in an

Ben Forte 2/19/09 11:06 AM Deleted: .

Ben Forte 2/19/09 11:06 AM Deleted:

Ben Forte 2/19/09 11:08 AM Deleted: ,

Ben Forte 2/19/09 11:08 AM Deleted: A

Ben Forte 2/19/09 11:08 AM Deleted: Hourly

Ben Forte 2/19/09 11:08 AM Deleted: Production

Ben Forte 2/19/09 11:08 AM Deleted: loose

25

Solid Waste Landfill Design

SEEHD

expansion factor of 30), the actual hourly production is found to be 126 m3/hr of “bank” material.

Ben Forte 2/19/09 11:09 AM Deleted: bank

Table 7: Expansion Factors for Clay Weight of Material Clay

Natural Bed Dry Wet

Loose (kg/m3) 1,660 1,480 1,660

Bank (kg/m3) 2,020 1,840 2,080

Expansion (%) 22 24 25

Source: CAT, 2001

In 2008, approximately 120 m3 MSW will be generated per day, which equates to 3,600 m3 MSW per month. In 2023, approximately 183 m3 of MSW will be generated daily, which equates to 5,479 m3 MSW per month. Thus, time required for trench excavation in 2008 is 29 hours per month and time required in 2023 is approximately 44 hours per month. It is concluded that an excavator would be needed for approximately 4 days per month in 2008 and 6 days per month in 2023. The excavator will also be required to cover a small medical waste trench on a monthly basis, although the time this will take is assumed to be negligable since the monthly cell will be extremely small. It should be noted that the values in Table 6 are minimum surface area values. It is advised that when the final landfill site is selected, the total area should be about 20% greater, or 24 ha, to provide area for an access road (that should be designed as displayed in Figure 11), special waste, and other on-site requirements. This will also ensure that if waste generation was underestimated, there will be extra capacity to accommodate the higher demand. Figure 11: Total Trench System Design Diagram

Ben Forte 2/19/09 11:17 AM Comment: We should get some numbers on medical waste production, and how is it going to be separated?

Ben Forte 2/19/09 11:18 AM Deleted: leave

Ben Forte 2/19/09 11:20 AM Comment: Provide more detailed drawing, ie; cutfill slope, drainage depth, road base depths.

Note: All dimensions are in meters Source: UNEP, 2005

Leachate Production

26

Solid Waste Landfill Design

SEEHD

Leachate production is the primary environmental and health concern from landfills in developing communities. To control leachate production, the amount of water that penetrates the landfill must be minimized. The simplest way to minimize leachate is to slope the cover material over each finished trench to shed water and prevent penetration into the disposed waste. Because there will be an abundance of excess cover material on-site (see Table 6), slopes in excess of 7% shall be constructed on all filled MSW trenches. The soil in Tela may be classified as loamy with unknown concentrations of sand, silt, and clay. In order to add safety factors to calculations, a minimum runoff coefficient for sandy soil at > 7% slope, CE, will be used. Additionally, a moisture content capacity of Ccc = 375 mm H2O/m bgs for clayey loam will be used. Average values for precipitation and evaporation from Cuenca Cangrejal are also utilized in calculations. Leachate production in 2008 is calculated as shown below, and monthly results are displayed in Table 8. Amount of Water to Penetrate Surface of Landfill

Where: q P CE Ccc Eq

= = = = =

amount of water to penetrate surface of landfill (mm/month) average monthly precipitation (mm/month) runoff coefficient moisture capacity of cover and waste (mm/month) average monthly evaporation (mm/month)

Table 8: Trench Method Leachate Production, 2008 (Promedio Mensual (Anos 1986-96) de Temperatura, Precipitacion y Evaporacion, Cuenca Cangrejal, Estacion El Cural, Latitud 15° 44’ 13”, Longitud 18° 51’ 15”) Month Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec TOTALS = 1

Precipitation, P1 (mm)

Evaporation, EL1 (mm)

P-E (mm)

CE

Ccc (mm/month)

q (mm/month)

281.0 210.4 247.6 95.5 45.3 103.0 119.6 181.8 217.7 458.3 442.8 351.2 2,754.2

87.4 104.5 133.1 156.7 160.7 149.6 155.3 146.9 120.3 99.1 83.0 81.5 1,478.1

193.6 105.9 114.5 -61.2 -115.4 -46.6 -35.7 34.9 97.4 359.2 359.8 269.7

0.15 0.15 0.15 ----0.15 0.15 0.15 0.15 0.15

375.0 375.0 375.0 ----375.0 375.0 375.0 375.0 375.0

-223.6 -300.7 -297.6 -----367.4 -310.3 -84.5 -81.6 -158.0

Source: Departamento de Servicios Hidrologicos y Climatologicos, Secretaria de Recursos Naturales y Ambiente, Gobierno de Honduras.

27

Ben Forte 2/19/09 11:20 AM Deleted: countries such as Honduras

Ben Forte 2/19/09 11:21 AM Deleted: In order to

Ben Forte 2/19/09 11:24 AM Deleted: completed

Solid Waste Landfill Design

SEEHD

It may be observed from Table 8 that when trenches are covered and sloped there will not be any leachate produced using a trench method landfill, given the various assumptions (that include multiple safety factors). Although no leachate production is expected, slopes in excess of 7% shall be constructed on all completed trenches. Leachate will be produced, however, when trenches being filled are uncovered during the rainy season. A typical solution for leachate production control intrenches is to install a french-drain system in the bottom of the trenches in order to drain the leachate by gravity into an; evaporation pond, stabilization pond, or subsurface leachate disposal system. As shown in Table 8, yearly precipitation, P, is greater than the yearly evaporation, Eq, and therefore an evaporation pond would be suitable for a landfill in Tela.

Ben Forte 2/19/09 11:28 AM Comment: A small amount of leachate is produced through decomposition, no? Even with the cover material, water will still penetrate, and over time, when the waste settles naturally, there will most likely be ponding.

Ben Forte 2/19/09 11:28 AM Deleted: remediation

Ben Forte 2/19/09 11:32 AM Deleted: for

Trench Method Landfill Cost Analysis

Ben Forte 2/19/09 11:29 AM Deleted: open

Ben Forte 2/19/09 11:29 AM

REQUIRED PERSONNEL

Deleted: being filled

The personnel needs at the landfill include; one operator, and two laborers who each shall work six days per week for eight hours per day. An engineer will also be required four days per month to ensure that the site is being operated correctly, and an excavator operator when the excavator is used to dig the trenches. The engineer’s work may include, but is not limited to, visiting the landfill, taking and evaluating samples of waste, and making recommendations to the operator to help the landfill run more efficiently. The operator will be in charge of following the landfill layout, and overseeing the overall site use such as; construction of daily cells, trenches, waste disposal, and placement of cover. This operator must be trained on how to effectively manage a trench method landfill operation. It is also important that this operator understands why all measures are in place, so the likelihood of successful landfill management will be increased. The laborer may be in charge of day-to-day routines such as; directing traffic and dumping, and ensuring separation of special waste such as medical waste, tires, and large appliances. According to Cámara Hondureña de la Industria de la Construccion Lista de Precios de Mano de Obra por Jornada en San Pedro Sula (1996), skilled workers such as carpenters, bricklayers, and demolitionists earn approximately 250 Honduran Lempiras/day (~US $14/day), which is assumed for the operator. Market price laborer wages are 100 Honduran Lempiras/day (~US $5.25/day). Therefore it is assumed that the skilled operator earns approximately US $15/day and the laborer makes US $5.25/day. An engineer is reported to make the equivalent of US $42/day.

Ben Forte 2/19/09 11:30 AM Deleted: construction

Ben Forte 2/19/09 11:30 AM Deleted: of channels that lead to a leachate

Ben Forte 2/19/09 11:31 AM Deleted: a

Ben Forte 2/19/09 11:34 AM Deleted: a

Ben Forte 2/19/09 11:34 AM Deleted: not work

Ben Forte 2/19/09 11:37 AM Comment: Hours of operator needed?

Ben Forte 2/19/09 11:37 AM Deleted: smoothly

Ben Forte 2/19/09 11:39 AM Deleted: as far as

Ben Forte 2/19/09 11:40 AM Comment: What about the pickers and recycling?

Ben Forte 2/19/09 11:40 AM Deleted: have a working knowledge of

Ben Forte 2/19/09 11:41 AM Deleted: that

EQUIPMENT

Ben Forte 2/19/09 11:41 AM Deleted: proper

Rental of a 210 hp Caterpillar excavator is approximately 1,114 Honduran Lempiras/hour, or US $59 per hour (Cámara, 1996). It will be assumed that the cost of the 128 hp Caterpillar Model 320C will be similar. Therefore, the cost of equipment rental in 2008 may be estimated as US $1,593 per month and the cost in 2023 may be estimated as US $2,478 per month. Therefore an average monthly rental cost of US $2,000 will be assumed for 2008-2023. Additional equipment shall be needed, however, these items have not been adjusted into cost 28

Ben Forte 2/19/09 11:44 AM Deleted: /hr

Ben Forte 2/19/09 11:45 AM Deleted: Although

Ben Forte 2/19/09 11:45 AM Deleted: figured

Solid Waste Landfill Design

SEEHD

estimates. This items includesafety equipment for landfill workers such as; steel-toed work boots, heavy gloves, and masks. It would also be useful to have a small sanitation building so workers may wash and use the restroom. Additionally, when the dump is operating in rainy weather, it will be neccesary to have water-proof rain gear such as; a jacket, pants, and boots for workers who will be working in rainy conditions.

Ben Forte 2/19/09 11:45 AM Deleted: ,

Ben Forte 2/19/09 11:46 AM Deleted: may be needed

Ben Forte 2/19/09 11:47 AM Deleted: where

OPERATIONAL COSTS OF TRENCH METHOD LANDFILL

Ben Forte 2/19/09 11:47 AM Deleted: could

Operational costs for a trench method landfill over the project lifetime with compound interest is presented as Table 9.

Ben Forte 2/19/09 11:48 AM Deleted: standing out

Ben Forte 2/19/09 11:48 AM

Table 9: Operational Costs of a Trench Method Landfill

Deleted: for extended periods of time

Daily Cost

Daily Cost

Purchase

Monthly Cost

Yearly Cost

(Lps/Day)4

(USD/day)

Frequency

(USD/month)

(USD/year)

Engineer

800

42.11

4 days/month

168

2,021

Skilled Worker

250

13.16

24 days/month

316

3,789

Two Laborers

200

10.53

24 days/month

253

3,032

--

--

once/month

2,000

24,000

TOTAL =

2,737

32,842

Labor

1

Equipment Excavator

2

3

i =

0.067

n=

15

Approximate Yearly Cost in 2008 =

32,842

Approximate Yearly Cost in 2015 =

51,711

Approximate Yearly Cost in 2023 =

86,875

Total (15 year) cost w/ compound interest =

893,344

Total cost per MT (174,356 MTs total) = 1

5.12

Cámara Hondureña de la Industria de la Construcción Lista de Precios de Mano de Obra por Jornada en San Pedro Sula

2

2000 is assumed average rental cost at US$59/hour over 15 years (from US $797 per month in 2008 to US $1,239 per month in 2023) 3 Source: CIA World Factbook, 2008 4 Honduran Lempiras abbreviated as Lps

Post-Lifetime Trench Landfill General Closure Plan Prior to reaching the landfill capacity (presumably in 2023), site closure precautions must be taken. All hazardous material such as chemicals and medical waste must be carefully buried, preferably in a location that will not receive regular traffic. Some of the special waste, such as appliances and other large discards can be recycled. Other waste such as tires and batteries require special consideration. These materials might be relocated to a larger landfill elsewhere in Honduras. If this is not possible, then burial in a separate area of the existing landfill should be

29

Ben Forte 2/19/09 11:49 AM Deleted: When

Ben Forte 2/19/09 11:49 AM Deleted: is reached

Ben Forte 2/19/09 11:53 AM Comment: Tires can be used in various

Solid Waste Landfill Design

SEEHD

considered. The landfill should be closed off from access for at least one year to allow for natural decomposition and compaction. This will reduce the chance that anyone will be injured. Additionally, this will protect the cover layer that may be damaged if it is disturbed, thereby increasing the risk of leachate production. One of the advantages of a trench method landfill is the possible uses after closure. Assuming the landfill is operated properly, the excess cover material may eventually be applied to level the landfill area, and the site may be used as an athletic field. This area should not be developed in the near future, as the large mass of a building on decomposing waste may cause structural problems, and there are environmental and health concerns associated with living in a close proximity of the landfill waste. Landfill gas (LFG) production is an important health concern related to the decompostition of MSW. A solution to effectively extract hazardous gasses, particulary methane, is exempliefied in the waste trenches serving Villanueva, Honduras. Villaneuva installed an inexpensive methane chimney system (as discussed in the Dump Closure section of this report) to vent the LFG, this system is presented in Photo 5 and Photo 6. A completed trench that is filled with waste and covered with the material from the trench excavation is shown in Photo 7.

Ben Forte 2/19/09 11:59 AM Deleted: possible

Ben Forte 2/19/09 11:58 AM Deleted: T

Ben Forte 2/19/09 11:58 AM Deleted: at the

Ben Forte 2/19/09 11:58 AM Deleted: landfill

Ben Forte 2/19/09 12:00 PM Deleted: with

Ben Forte 2/19/09 12:01 PM Deleted: are

Ben Forte 2/19/09 12:01 PM Deleted: ,

Ben Forte 2/19/09 12:01 PM Deleted: and a

Ben Forte 2/19/09 12:02 PM Deleted: original material from the

Ben Forte 2/19/09 12:03 PM Deleted: at the landfill

30

Solid Waste Landfill Design

SEEHD

Chimney For Methane

Photo 5 & Photo 6: In the trench method used in Villanueva, trenches are of sufficient size to last up to one month. Chimneys are installed at selected intervals within each trench for methane control. 31

Solid Waste Landfill Design

SEEHD

Chimney for Methane

Photo 7: A completed trench filled with wastes and covered with the original material from the excavation. Note the excess material that can be used for other purposes. The cost of operation of this landfill in Villanueva was approximately US $4 per metric ton in 2006. It is the only municipally operated landfill in Honduras that has been successful. CANYON/AREA METHOD LANDFILL DESIGN A mechanized canyon/area landfill is the second landfill method that is considered for Tela in this report. In a canyon method landfill, compacted daily cells are built into designed ‘lifts,’ that are abutted against a canyon wall that cover material may be excavated from. The current open dump site, as presented in Exhibit 1, is analyzed as the site for a canyon method landfill to illustrate the problems with this method and why this design failed. A topographic map of the site prior to the open dump is presented as Exhibit 3. Daily Cell Design As with the trench method landfill, one of the essential design parameters for the canyon method landfill is proper dimensioning of a daily cell in order to minimize required cover material. The optimum daily cell dimensions for the canyon method are calculated by determining a fixed waste volume for a given year and assuming daily cell side slopes of 3/1 (this is slope ratio is optimal for compaction). By varying values for daily cell depth and width and observing the resulting ratio of cover-to-waste, an optimal daily cell dimension for the given year may be chosen. A diagram of a typical daily cell for the canyon method is presented as Figure 12.

32

Ben Forte 2/19/09 12:44 PM Deleted: cover

Ben Forte 2/19/09 12:45 PM Deleted: that

Solid Waste Landfill Design

SEEHD

Figure 12: Exposed Area and Dimensions of Daily Cell for the Canyon Method

In order to minimize the cover material required, the following calculations were performed using various width and heights of daily cells to find optimal cell dimensions for 2008, 2015, and 2023. Volume of Daily Cell

Where Vd-c Gd ρmc

= = =

volume of daily cell (m3) daily production of MSW (kg/day) density of mechanically compacted waste (kg/m3)

The width of the daily cell, ad (an assumption), should be the minimum possible width that will still permit trucks to unload in front of the daily cell. Additionally, the daily cell height, hd, should be assumed. Advance of the Daily Cell 

Area of parallelepiped = Where Vd-c ad ld hd

= = = =

volume of daily cell (m3) width of daily cell (m) advance of daily cell (m) height of daily cell (m)

33

Solid Waste Landfill Design

SEEHD

Top Exposed Surface Area

Where AST-d

=

total exposed surface area of daily cell (m2)

Surface Area of Sloped Side

Where Al-d lp

= =

surface area of sloped side of daily cell (m2) width of the sloped side of the daily cell (m)

Front Exposed Surface Area

Total Exposed Surface Area of Daily Cell

Where As-d Al-d Af-d

= = =

top exposed surface area of daily cell (m2) surface area of sloped side of daily cell (m2) area of front exposed surface of daily cell (m2)

Corresponding graphs of the total daily exposed surface area as a function of daily cell height for 2008, 2015, and 2023 are presented as Figure 13 through Figure 15.

34

Solid Waste Landfill Design

SEEHD

Figure 13: Cell Dimension Relationships, 2008

Figure 14: Cell Dimension Relationships, 2015

35

Solid Waste Landfill Design

SEEHD

Figure 15: Cell Dimension Relationships, 2023

36

Solid Waste Landfill Design

SEEHD

It may be observed from Figure 13 through Figure 15 that the exposed surface for each year is minimized when the daily cell height is approximately 2 m. Results of cell dimensions with the minimum cover to waste ratio using a daily cell height of 2 m in 2008, 2015, and 2023 are presented in Table 10. It can be seen that the ratio of waste to cover for the optimum cells is much larger than what is assumed for mechanized landfills.

2.0

5.0

5.3

2015

64.9

2.0

5.0

2023

81.2

2.0

5.0

(m2)

(m2)

(m2)

(m3)

3

6.3

26.7

31.6

33.7

92.0

27.6

0.52

6.5

3

6.3

32.4

31.6

41.0

105.1

31.5

0.49

8.1

3

6.3

40.6

31.6

51.3

123.6

37.1

0.46

Ratio of waste to cover, Vc-d/Vd-c

(m2)

Face, lp

(m)

Slope of side of daily cell

Volume of cover required per day, Vc-d E=0.3

53.3

Total exposed surface area of daily cell, AST-d

2008

Sloped side of daily cell surface area, Al-d

(m)

Front surface area of daily cell, Af-d

Depth of daily cell, ld

(m)

Top surface area of daily cell, As-d

Width of daily cell, ad

(m)

Depth of daily cell along 3/1

Height of daily cell, hd

(m3/day)

Year

Volume of waste generated per day, Vmc-d

Table 10: Optimal Daily Cell Dimension Calculations, 2008, 2015 and 2023

Reviewing Table 10, the optimal height and width of the daily cell are 2 m and 5 m, respectively. The optimal depth of the daily cell changes over the design life of the landfill, from 5.3 m in 2008 to 8.1 meters in 2023.

Ben Forte 2/19/09 12:51 PM Deleted: It may be observed from

Ben Forte 2/19/09 12:51 PM Deleted: that

Ben Forte 2/19/09 12:55 PM

Canyon Landfill Design

Comment: Is it important to note here that the waste and cover should be compacted at 6-12” lifts (.15-.3 m)?

LANDFILL CAPACITY AND USEFUL LIFE Landfill Volumetric Capacity Determining the volume of the site that may be used for waste disposal is critical to determining the useful life of the site. AutoCAD software was used to calculate the landfill volume for the site, using the topographic map presented as Exhibit 3. Design contours with an optimal 3:1 slope are presented as Exhibit 4, and a final surface plot plan for the canyon method is presented as Exhibit 5. Using the area of each planned 2 m lift height, an approximate area (calculated by averaging the areas of the top and bottom of each lift) and volumetric capacity (calculated by multiplying the average lift area by the 2 m height of each lift) may be calculated for the site. Results are displayed in Table 11.

37

Ben Forte 2/19/09 12:54 PM Deleted: /

Ben Forte 2/19/09 12:53 PM Deleted:

Solid Waste Landfill Design

SEEHD

Table 11: Canyon Method Site Capacity Analysis Lift No. 1 2 3 4 5 6 7 8 9 10 11 12 13

Elevation

Area

Average Lift Area

Volume of Lift (2 m depth)

(m amsl)

(m2)

(m2)

(m3)

785

1,569

1,969

3,937

3,096

6,192

3,980

7,959

5,786

11,572

5,858

11,715

5,776

11,551

136

271

731

1,461

976

1,951

1,159

2,318

1,174

2,347

214

428

31,640

63,280

16

227

18

1,342

18

1,301

20

2,636

20

2,636

22

3,556

22

3,556

24

4,403

24

5,731

26

5,841

26

5,939

28

5,776

28

5,754

30

5,797

14

64

16

207

16

580

18

881

18

881

20

1,070

20

1,070

22

1,248

22

1,134

24

1,213

14

55

16

373 Total =

Source: Bryant, 2008

It may be observed from Table 11 that the total volumetric capacity of the site is approximately 63,280 m3. This corresponds to a useful life of approximately 3 years, without accounting for the volume of the waste already disposed of in the open dump and the volume of the cover material that would be used in landfill operations. This analysis shows the site has severe limitations and should never have been originally selected as the landfill site.

Ben Forte 2/19/09 12:57 PM Deleted: deposited

Ben Forte 2/19/09 12:57 PM Deleted: on the site

Ben Forte 2/19/09 12:59 PM

COVER DESIGN CALCULATIONS

Deleted: Therefore, the current open dump site is not appropriate for a properly designed landfill.

There are two possible sources of cover material for the canyon method design; material excavated from the sloped canyon walls as filling occurs, and material excavated elsewhere on the site. A cover material plan is presented as Exhibit 6. Site section diagrams generated from 38

Ben Forte 2/19/09 12:59 PM Deleted: had

Ben Forte 2/19/09 1:00 PM Deleted: :

Solid Waste Landfill Design

SEEHD

topographic maps aid in determination of the feasibility of each option and are presented as Exhibit 7. At the existing open dump site, there is cover material available from the canyon slope, although by the time the 4th lift is in place the slope becomes too steep to excavate adequate cover material; thus, it will have to be obtained from elsewhere on the site. Table 12 shows the cover material analysis. It should be noted that the cover material shortfall of nearly 9,000 m3 could possibly be satisfied from material excavated elsewhere on this site. Table 12: Cover Material Availability and Requirement Analysis Lift No. 24 20 16 14

Serving Lifts

Area 2

(m )

11,12, 13, 14 2,479 3, 4, 9, 10 2,237 1, 2 2,254 5, 6, 7, 8 1,052 Available Cover Material = Required Cover Material = Shortfall of Cover =

Volume, (m3) 7,438 8,947 4,508 2,104 22,997 31,636 8,639

Source: Bryant, 2008

FILLING PLAN The filling plan for the canyon method landfill displays the sequence that each lift should be constructed. The lifts should be filled in an increasing numerical order, as presented in the section view diagram of Exhibit 7. Plot plans of the existing and final surfaces at the site are presented as Exhibit 8. Equipment Selection Daily use of heavy machinery is required for a canyon method landfill. The equipment is used to spread and compact waste, and to excavate, spread, and compact cover material. Proper equipment selection is integral to a well-functioning landfill. Analysis of equipment travel distances and the quantities of materials to be handled are used to evaluate the best equipment or combination of equipment for a canyon method landfill for Tela. It should be noted that waste generation values for 2008 are used for calculations in this section. TRAVEL DISTANCES AND MATERIAL QUANTITIES Using the topographic map and lift plans presented in Exhibit 3 through Exhibit 5, the average distance between the excavation source and the daily cell is determined to be approximately 50 m. The quantity of waste to be spread and compacted daily is 122 m3, and the quantity of cover to be moved and compacted daily is 61 m3.

39

Ben Forte 2/19/09 1:01 PM Deleted: A plot plan of the existing and final surfaces at the site are

Solid Waste Landfill Design

SEEHD

EQUIPMENT OPTIONS In order to evaluate the best equipment option for the site, the following three options are evaluated: • • •

Option 1: track loader; Option 2: excavator and dump truck; and Option 3: excavator, dump truck, and track tractor.

The cost analysis for Option 1 is performed using a 7.5 year equipment ownership period since the track loader will most likely need to be replaced during the landfill lifetime, as it will receive a lot of wear as the only machine used. For Option 2 and Option 3 it is assumed that the equipment will last through the 15 year landfill lifetime since there will be less wear on each piece of equipment. In addition, cycle times are estimated for all equipment for each option in order to calculate daily equipment usage requirements. For the purposes of calculations in this section, it will be assumed that a track loader and track tractor operate at an average speed of 5 km/hr, and an excavator operates at an average speed of 2 km/hr (CAT, 2001). An example of a fully mechanized canyon method landfill in La Ceiba, Honduras that is operated by a private contractor is shown in Photo 8 and Photo 9. A track tractor, an excavator, and a dump truck were initially used at this landfill.

40

Ben Forte 2/19/09 1:06 PM Comment: Bull-dozer, or is track tractor what CAT calls this equipment?

Ben Forte 2/19/09 1:05 PM Comment: Are there other reasons backing the lifetime estimations?

Ben Forte 2/19/09 1:07 PM Comment: Bulldozer?

Ben Forte 2/19/09 1:07 PM Comment: Bulldozer?

Solid Waste Landfill Design

SEEHD

Photo 8 & Photo 9: The fully mechanized canyon method has been utilized in La Ceiba, Honduras. This site is operated by a private contractor and initially used three pieces of equipment: a track tractor, an excavator, and a dump truck. In 2005 the operating cost to

Ben Forte 2/19/09 1:07 PM Comment: Bulldozer?

41

Solid Waste Landfill Design

SEEHD

the city was approximately US $15 per metric ton. Option 1 A Track Loader is a versatile piece of equipment, consisting of a tracked chassis with a bucket for digging and loading material. In a landfill with a track loader as the sole piece of machinery, the bucket would be used to excavate cover material, to move around waste and cover material, and the tracks would be used for compaction of waste and cover material. Estimated daily usage requirements for the track loader in Option 1 are presented as Table 13. Table 13: Option 1 Daily Usage Requirements Maneuver Description

Time for Maneuver (min)

Track Loader

1

Round trip time for cover excavation and delivery to daily cell Excavation time

2

73 20

Spread and compact waste3 Spread and compact cover

20

3

13

Subtotal operating time Subtotal operating time with 30% safety factor Total Time Required (hours) =

126 176 3

1

5 km/hour machine speed, 100 m round trip distance, 61 m3 of cover required daily, 2 m2 bucket size 2

Includes 20 seconds for loading, maneuvering, and dumping for each cover excavation and delivery trip. 3

5 m wide daily cell, 0.8 m wide tracks, 1 pass for each 1/2 m compacted waste (4 daily)

It may be observed in Table 13 that a track loader would be required for approximately 3 hours daily, which includes a 30% safety factor. Although any track loader with similar specifications may be used, a cost analysis for a new Caterpillar 939C track loader is presented as Table 14.

42

Solid Waste Landfill Design

SEEHD

Table 14: Option 1 Hourly Owning and Operating Cost Estimate Machine Designation Estimated Ownership Period

Units

Equipment

--

CAT 939C

years

7.5

hours/year

936

hours

7,020

Delivered Price, to the customer

USD

135,000

Less Residual Value at Replacement

USD

10,000

Net Value to be recovered through work

USD

125,000

Cost per Hour:

USD/hour

17.81

Interest per Hour2

USD/hour

5.48

Insurance Costs3

USD/hour

0.82

Total Hourly Owning Cost

USD/hour

24.10

Fuel4

USD/hour

16.25

Planned Maintenance

USD/hour

2

Undercarriage5

USD/hour

6.29

Repair Cost

USD/hour

5

Special Wear Items

USD/hour

1

Operator's hourly wage6

USD/hour

2.19

Total Operating Costs

USD/hour

32.73

Estimated Yearly Usage1 Estimated Total Usage1 Owning Costs

Operating Costs

Total Hourly Owning and Operating Cost (USD/hour) = Lifetime Owning and Operating Cost (USD) = 1

56.83 797,929

Track loader to be used 6 days per week for 5 hours per day throughout year.

2

Interest rate = 6.7% (CIA World Factbook, 2008). Calculated as follows: [((ownership period+1)/(2*ownership period))*(Delivered Price*Interest rate)]/(estimated yearly usage)

Ben Forte 2/19/09 1:09 PM Comment: Monthly/yearly would be nice too?

3

Rate estimate = 1.0%. Calculated as follows: [((ownership period+1)/(2*ownership period))*(Delivered Price*rate estimate)]/(estimated yearly usage) 4

Fuel cost: US $1.25 per hour. CAT 939C fuel usage: 13L per hour

5

Calculated as (Impact + Abrasiveness + Z factor)*Basic Factor = (0.3 + 0.4 + 1.0)*3.7 = hourly undercarriage cost. Source: Caterpillar 6

Skilled Worker Wages = 250 Lps./day = US $2.19/hour. Source: Cámara Hondureña de la Industria de la Construcción Lista de Precios de Mano de Obra por Jornada en San Pedro Sula

As observed in Table 14, the total hourly owning and operating cost for Option 1 is US $56.83/hour, and the lifetime owning and operating cost for Option 1 is US $797,929. It should be noted that the primary disadvantage of using a track loader as the only piece of equipment is the wear on the tracks. The heavy and consistant use will require increased maintenance and eventually replacement. Track maintenance and repair is extremely expensive and may be difficult due to the distance of Honduras from equipment manufacturers.

Ben Forte 2/19/09 1:09 PM Deleted: It may be

Ben Forte 2/19/09 1:09 PM Deleted: that

Ben Forte 2/19/09 1:10 PM Deleted: , which

Ben Forte 2/19/09 1:10 PM Deleted: break and require

43

Solid Waste Landfill Design

SEEHD

Option 2 In a landfill with an excavator and a dump truck, the excavator would be used to obtain cover material, the dump truck would transfer the cover material, and the excavator bucket would be used to move around and compact waste and cover material. Estimated daily usage requirements for the excavator and dump truck in Option 2 are presented as Table 15. Table 15: Option 2 Daily Usage Requirements Time for Maneuver

Maneuver Description

(min)

Excavator1 Travel time Excavation time

3 20

Spread and compact waste2

10

Spread and compact cover2

14

Subtotal operating time Subtotal operating time with 30% safety factor Total Time Required (hours) =

47 62 2

Dump Truck3 Travel time Loading time Dumping Time Subtotal operating time Subtotal operating time with 30% safety factor Total Time Required (hours) =

2 41 20 63 82 2

1

2 km/hour excavator speed, 100 m total distance daily, 61 m3 of cover required daily, 1.5 m3 bucket size, 30 second excavator cycle time. 2 5 m wide daily cell, 5.3 m deep daily cell, 1.5 m wide bucket, 1 pass for each 1/2 m compacted waste (4 daily) 3 15 km/hour dump truck speed, 100 m round trip distance, 10m3 bucket capacity.

As may be observed in Table 15, the excavator and dump truck would each be required for approximately 2 hours daily, which includes a 30% safety factor. Although any excavator or dump truck with similar specifications may be used, a cost analysis for a new Volvo EC210 Excavator and a new Ford 650 Dump Truck is presented in Table 16.

44

Solid Waste Landfill Design

SEEHD

Table 16: Option 2 Hourly Owning and Operating Cost Estimate Units Machine Designation

--

Estimated Ownership Period

years

Equipment Volvo EC210 15

Ford 650 Dump Truck 15

Estimated Yearly Usage1

hours/year

624

624

Estimated Total Usage1

hours/year

9,360

9,360

Owning Costs Delivered Price, to the customer

USD

192,000

90,000

Less Residual Value at Replacement Net Value to be recovered through work Cost per Hour:

USD USD USD/hour

20,000 172,000 18.38

5,000 85,000 9.08

Interest per Hour2

USD/hour

10.99

5.15

Insurance Costs3

USD/hour

1.64

0.77

Total Hourly Owning Cost

USD/hour

31.01

15.00

Fuel4

USD/hour

18.75

10.00

Planned Maintenance

USD/hour

3

1

Tires: Replacement Cost/life in hours

USD/hour

--

0.50

Undercarriage5

USD/hour

2.10

0.00

Repair Cost

USD/hour

5

1

Special Wear Items

USD/hour

1.00

0.50

Operator's hourly wage6

USD/hour

2.19

1.32

Total Operating Costs

USD/hour

32.04

14.32

63.05

29.32

Operating Costs

Subtotal Hourly Owning and Operating Cost (USD/hour)= Total Hourly Owning and Operating Cost (USD/hour)= Lifetime Owning and Operating Cost (USD) =

92.38 864,630

1

Excavator to be used 6 days per week for 2 hours per day throughout year, Dump truck to be used for 6 days per week for 2 hours per day throughout year. 2 Interest rate = 6.7% (CIA World Factbook, 2008). Calculated as follows: [((ownership period+1)/(2*ownership period))*(Delivered Price*Interest rate)]/(estimated yearly usage) 3

Rate estimate = 1.0%. Calculated as follows: [((ownership period+1)/(2*ownership period))*(Delivered Price*rate estimate)]/(estimated yearly usage) 4

Fuel cost: US $1.25 per hour. Volvo EC210 fuel usage: 13L per hour, Ford 650 fuel usage: 8 L/hour.

5

Calculated as (Impact + Abrasiveness + Z factor)*Basic Factor = 3*(0.2+0.2+0.3) = hourly undercarriage cost. Excavator Operator Wage = 250 Lps./day = US $2.19/hour. Dump Truck Driver Wage = 150 Lps./day = US $1.32/hour Source: Cámara Hondureña de la Industria de la Construcción Lista de Precios de Mano de Obra por Jornada en San Pedro Sula 6

It may be observed in Table 16 that the total hourly owning and operating cost for Option 2 is US $92.38/hour, and the lifetime owning and operating cost for Option 2 is US $864,630. It should be noted that landfill operation with two pieces of equipment (an excavator and a dump truck) is beneficial since wear on the undercarriage of the excavator is minimal, as it will only need to be moved from the cover material excavation site to the daily cell location. Additionally, the dump truck may be used for other applications during the hours of the day when it is not 45

Ben Forte 2/19/09 1:14 PM Comment: Break up this sentence

Solid Waste Landfill Design

SEEHD

required at the landfill. Option 3 In a landfill with an excavator, a dump truck, and a bull dozer, the excavator is used to obtain cover material, the dump truck is used to transfer the cover material, and the track tractor is used to spread and compact waste and cover material. Estimated daily usage requirements for the excavator and dump truck in Option 3 are presented as Table 17.

Ben Forte 2/19/09 1:15 PM Deleted: track tractor

Table 17: Option 3 Daily Usage Requirements Time for Maneuver

Maneuver Description

(min)

Excavator1 Excavation time Subtotal operating time Subtotal operating time with 30% safety factor Total Time Required (hours) =

20 20 26 1

Dump Truck2 Travel time Loading time Dumping Time Subtotal operating time Subtotal operating time with 30% safety factor Total Time Required (hours) =

2 41 20 63 82 2

Track Tractor3 Spread and compact waste Spread and compact cover Subtotal operating time Subtotal operating time with 30% safety factor Total Time Required (hours) =

20 13 33 42 1

1

2 km/hour excavator speed, 100 m total distance daily, 61 m3 of cover required daily, 1.5 m3 bucket size, 30 second excavator cycle time. 2

15 km/hour dump truck speed, 100 m round trip distance.

3

5 m wide daily cell, 0.8 m wide tracks, 1 pass for each 1/2 m compacted waste (4 daily)

As observed in Table 17, the excavator and bull dozer would each be required for approximately 1 hour daily, and the dump truck would be required for 2 hours daily (each including a 30% safety factor). Although any excavator, dump truck, or track tractor with similar specifications may be used, a cost analysis for a new Volvo EC210 Excavator and a Ford 650 Dump Truck is presented in Table 16. A cost analysis for a new Volvo EC210 Excavator, a new Ford 650 Dump Truck, and a new Caterpillar D5K LGP is presented in Table 18. In practice, any excavator or dump truck with similar specifications may be used.

46

Ben Forte 2/19/09 1:15 PM Deleted: may be

Ben Forte 2/19/09 1:15 PM Deleted: track tractor

Solid Waste Landfill Design

SEEHD

Table 18: Option 3 Hourly Owning and Operating Cost Estimate Units Machine Designation Estimated Ownership Period

-years

Equipment Volvo EC210 15

Ford 650 Dump Truck 15

CAT D5K LGP 15

Estimated Yearly Usage1

hours/year

312

624

312

Estimated Total Usage1

hours/year

4,680

9,360

4,680

Delivered Price, to the customer

USD

192,000

90,000

142,000

Less Residual Value at Replacement

USD

30,000

5,000

25,000

Net Value to be recovered through work

USD

162,000

85,000

117,000

Cost per Hour:

USD/hour

34.62

9.08

25.00

Interest per Hour2

USD/hour

21.99

5.15

16.26

Insurance Costs3

USD/hour

3.28

0.77

2.43

Total Hourly Owning Cost

USD/hour

59.89

15.00

43.69

Fuel4

USD/hour

18.75

10.00

25.00

Planned Maintenance

USD/hour

3

1

2

Tires: Replacement Cost/life in hours

USD/hour

--

0.50

--

Undercarriage5

USD/hour

2.10

0.00

6.29

Repair Cost (per hour)

USD/hour

5

1

5

Special Wear Items: Cost/life

USD/hour

1.00

0.50

1.00

Operator's hourly wage6

USD/hour

2.19

1.32

1.32

Total Operating Costs

USD/hour

32.04

14.32

40.61

91.93

29.32

84.30

Owning Costs

Operating Costs

Subtotal Hourly Owning and Operating Cost (USD/hour)= Total Hourly Owning and Operating Cost (USD/hour)= Lifetime Owning and Operating Cost (USD) =

205.55 1,099,176

1

Excavator to be used 6 days per week for 3 hours per day throughout year, Dump truck to be used for 6 days per week for 6 hours per day throughout year. Track Tractor to be used 6 days per week for 3 hours per day throughout year. 2

Interest rate = 6.7% (CIA World Factbook, 2008). Calculated as follows: [((ownership period+1)/(2*ownership period))*(Delivered Price*Interest rate)]/(estimated yearly usage) 3 Rate estimate = 1.0%. Calculated as follows: [((ownership period+1)/(2*ownership period))*(Delivered Price*rate estimate)]/(estimated yearly usage) 4 Fuel cost: US $1.25 per hour. Volvo EC210 fuel usage: 13L per hour, Ford 650 fuel usage: 8 L/hour, CAT D5K LGP fuel usage: 20 L/hour L/hour. 5

Calculated as (Impact + Abrasiveness + Z factor)*Basic Factor = (0.3 + 0.4 + 1.0)*3.7 = hourly undercarriage cost. Source: Caterpillar

6

Excavator Operator Wage = 250 Lps./day = US $2.19/hour. Dump Truck Driver Wage = 150 Lps./day = US $1.32/hour Source: Cámara Hondureña de la Industria de la Construcción Lista de Precios de Mano de Obra por Jornada en San Pedro Sula

It may be observed in Table 18 that the total hourly owning and operating cost for Option 3 is US $205.55/hour, and the lifetime owning and operating cost for Option 2 is US $1,099,176. It is important to note that for landfill operation using multiple types of heavy equipment (an excavator, a dump truck, and a bull dozer) is beneficial since wear on the undercarriage of the excavator and track tractor would be minimized.

47

Ben Forte 2/19/09 1:16 PM Deleted: track tractor

Solid Waste Landfill Design

SEEHD

Images of the La Ceiba landfill are presented in Photo 10 and Photo 11. La Ceiba is having problems repairing the tracks on the bull dozer, and has resorted to using an excavator for the; excavation of cover, compaction of wastes, and application of cover. This problem has occurred at various other waste disposal sites in the region which are also operated by municipalities such as; La Paz, Puerto Cortés, and Roatán.

Ben Forte 2/19/09 1:17 PM Deleted: had

Ben Forte 2/19/09 1:17 PM Deleted: track tractor

Ben Forte 2/19/09 1:17 PM Deleted: , as

Ben Forte 2/19/09 1:17 PM Deleted: happened

Ben Forte 2/19/09 1:18 PM Deleted: to

48

Solid Waste Landfill Design

SEEHD

Ben Forte 2/19/09 1:19 PM

Photo 10 & Photo 11: In 2007 the contractor at La Ceiba had problems repairing the tracks on the bull dozer, and resorted to using an excavator for excavation of cover, compaction of wastes, and application of cover. An excavator may be the most costeffective option for operating a mechanized landfill, depending on the size of the municipality and waste generated. The situation in La Ceiba also illustrates the problems with heavy equipment use in landfills. Had this facility been operated by the municipality rather than a private contractor, it likely would have failed and converted to an open

Deleted: track tractor

Ben Forte 2/19/09 1:19 PM Deleted: as well

Ben Forte 2/19/09 1:20 PM Deleted: This

Ben Forte 2/19/09 1:20 PM Deleted: ;

Ben Forte 2/19/09 1:20 PM Deleted: had

49

Solid Waste Landfill Design

SEEHD

dump, as has happened to various municipalities such as La Paz, Puerto Cortés, and Roatán. Leachate Production As with the trench method landfill leachate production calculations, a minimum runoff coefficient for sandy soil at 0 and 3/1 (33.3%) slopes, CE, will be used. Additionally, a moisture content capacity of Ccc = 375 mm H2O/m bgs for clayey loam will be used. Average values for precipitation and evaporation from Cuenca Cangrejal are also utilized in calculations. Leachate production in 2008 is calculated as shown below, and monthly results are displayed in Table 19. Table 19: Canyon/Area Method Leachate Production, 2008 (Promedio Mensual (Anos 1986-96) de Temperatura, Precipitacion y Evaporacion, Cuenca Cangrejal, Estacion El Cural, Latitud 15° 44’ 13”, Longitud 18° 51’ 15”) Month Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec 1

Precipitation, P1

Evaporation, E L1

P-E

(mm)

(mm)

(mm)

0 Slope

3:1 Slope

(mm/month)

0 Slope

3:1 Slope

281.0 210.4 247.6 95.5 45.3 103.0 119.6 181.8 217.7 458.3 442.8 351.2

87.4 104.5 133.1 156.7 160.7 149.6 155.3 146.9 120.3 99.1 83.0 81.5

193.6 105.9 114.5 -61.2 -115.4 -46.6 -35.7 34.9 97.4 359.2 359.8 269.7

0.05 0.05 0.05 ----0.05 0.05 0.05 0.05 0.05

0.15 0.15 0.15 ----0.15 0.15 0.15 0.15 0.15

375.0 375.0 375.0 ----375.0 375.0 375.0 375.0 375.0

-195.5 -279.6 -272.9 -----349.2 -288.5 -38.7 -37.3 -122.9

-223.6 -300.7 -297.6

CE

Ccc

q (mm/month)

-367.4 -310.3 -84.5 -81.6 -158.0

Source: Departamento de Servicios Hidrologicos y Climatologicos, Secretaria de Recursos Naturales y Ambiente, Gobierno de Honduras.

It may be observed from Table 19 that when daily cover is used and graded correctly, there should not be any leachate produced using a canyon method landfill due to run-off, given the various assumptions (that include multiple safety factors). Canyon Method Landfill Cost Analysis REQUIRED PERSONNEL According to Cámara Hondureña de la Industria de la Construcción Lista de Precios de Mano de Obra por Jornada en San Pedro Sula, skilled workers such as carpenters, bricklayers, and demolitionists earn approximately 250 Honduran Lempiras/day (~US $14/day), which is assumed for the skilled operators. Market price laborer wages are 100 Honduran Lempiras/day (~US $5.25/day). Therefore it is assumed that the skilled operators earn approximately US $14/day and the laborers make US $5.25/day. An engineer makes the equivalent of at US 50

Ben Forte 2/19/09 1:22 PM Deleted: will

Solid Waste Landfill Design

SEEHD

$42/day.

51

Solid Waste Landfill Design

SEEHD

Option 1 The personnel needs for Option 1 include two skilled operators and two laborers, six days per week for eight hours per day. An engineer will also be required four days per month to ensure that the site is being operated correctly. The skilled operators will be in charge of following the landfill layout, and overseeing the overall site, as well as operating the track loader. The laborers should be in charge of day-to-day routines such as; directing traffic and dumping, and ensuring separation of special waste. The special waste concerns are; medical waste, tires, and large appliances. The operators shall also run the gate house for the site.

Ben Forte 2/19/09 1:23 PM Deleted: such as

Ben Forte 2/19/09 1:24 PM

Option 2

Deleted: , as well as operating a

The personnel needs for Option 2 include two skilled operators and three laborers, six days per week for eight hours per day, and an engineer four days per month. The responsibilites are the same as for Option 1, although the skilled operator will operate the excavator instead of the track loader. The additional laborer for Option 2 will be in charge of operating the dump truck. Option 3 The personnel needs for Option 3 include three skilled operators and three laborers, six days per week for eight hours per day, and an engineer four days per month. The responsibilites are the same as for Option 2, although the extra skilled operator will operate the bull dozer. Personnel costs for each canyon method landfill option over the project lifetime with compound interest is presented as Table 20.

52

Ben Forte 2/19/09 1:25 PM Deleted: track tractor

Solid Waste Landfill Design

SEEHD

Table 20: Canyon Method Landfill Options Lifetime Personnel Costs Daily Cost

Daily Cost

Purchase

Monthly Cost

Yearly Cost

(Lps/Day)

(USD/day)

Frequency

(USD/month)

(USD/year)

Engineer

800

42.11

4 days/month

168

2,021

Each Skilled Operator2

250

13.16

24 days/month

316

3,789

Each Laborer3

100

5.26

24 days/month

126

1,516

Option 1 Total =

1,053

12,632

Option 2 Total3 =

1,179

14,147

Option 3 Total4 =

1,179

Labor

1

2

17,937 i5 =

0.067

n=

15

Option 1 Total (15 year) cost w/ compound interest = Option 1 Total cost per MT (174,356 MTs total) = Option 2 Total (15 year) cost w/ compound interest = Option 2 Total cost per MT (174,356 MTs total) = Option 3 Total (15 year) cost w/ compound interest = Option 3 Total cost per MT (174,356 MTs total) = 1

Cámara Hondureña de la Industria de la Construcción Lista de Precios de Mano de Obra por Jornada en San Pedro Sula

2

Option 1 requires one engineer, two skilled operators, and two laborers.

3

Option 2 requires one engineer, two skilled operators, and three laborers.

4

Option 4 requires one engineer, three skilled operators, and three laborers.

5

Source: CIA World Factbook, 2008

OPERATIONAL COSTS OF CANYON METHOD LANDFILL Total costs for each canyon method landfill option are presented in Table 21. Table 21: Operational Costs of Canyon Method Landfill Canyon Method Landfill Component

Units

Option 1

Option 2

Option 3

Equipment Cost

(USD)

797,929

864,630

1,099,176

Personnel Cost

(USD)

343,594

384,825

487,903

1,141,522

1,249,455

1,587,079

6.55

7.17

9.10

Total Lifetime Cost (USD) = Cost per Metric Ton (USD/MT) =

53

343,594 1.97 384,825 2.21 487,903 2.80

Solid Waste Landfill Design

SEEHD

OPERATIONAL COSTS OF A CONTRACTOR The cost analyses in this document were performed under the assumption that the equipment was purchased by the Municipality and operated by employees of the Municipality. Another option that should be considered is to contractlandfill operations to a private company that has experience with landfill operation. In general, contractor costs per ton may be estimated as double the non-contracted cost per ton. Total costs for contracting out landfill operations for the trench method and each canyon method option are presented in Table 22.

Deleted: individual

Ben Forte 2/19/09 1:26 PM Deleted: city

Ben Forte 2/19/09 1:26 PM Deleted: ing out

Table 22: Cost of Contracting Landfill Operations

Cost per Metric Ton for a Contractor (USD/MT) =

Ben Forte 2/19/09 1:26 PM

Canyon Method Landfill

Trench Method Landfill

Option 1

Option 2

Option 3

10.25

13.09

14.33

18.21

HEALTH RISKS & OCCUPATIONAL PLAN FOR SCAVENGERS In developing countries, it is common for many scavengers to live in open dumps or in scavenger communities around dumps. Approximately 50 scavengers reside in the current open dump serving Tela. Even if the dump is closed and a sanitary landfill is opened, it is likely scavengers will attempt to sell items found in the proposed sanitary landfill that have resale value. Scavengers are usually thought of as a nuisance, although they play an important role in the salvage process and may extend the life of a landfill. Some studies have found that scavengers have significantly reduced life spans and high infant mortality relative to the general population. The prevalence of parasitic and enteric diseases is also high. Diseases such as; typhoid, fever, choleral, dysentery, tuberculosis, anthrax, polio, pneumonia, and malaria (among others) have been identified in scavengers (Medina, 2000). Scavengers in open dumps encounter a plethora of seen and unseen occupational hazards. Among the more obvious are direct hazards associated with waste such as toxic chemicals, hospital refuse, used sanitary supplies contaminated with human excrement, and batteries. Open dumps attract animals that add more hazards to the dump including excrement and contamination. Dumps typically become breeding areas for mosquitos, rodents, vultures and other vectors that transmit numerous communicable diseases. Moreover, leachate is produced when water penetrates the waste, which further contaminates; the site groundwater and downstream surface water. This leachate may be more toxic than the original chemicals that are disposed of in the landfill because it facilitates contact among various chemicals that may result in chemical reactions. Since the scavengers are eating food found in the dump, there is a significant chance that it also will be contaminated with leachate or anything else it may have come in contact with in the open wastes. Scavengers currently working and possibly residing in the open dump are shown in Photo 12 and Photo 13.

54

Ben Forte 2/19/09 1:28 PM Deleted: ly operating

Ben Forte 2/19/09 1:29 PM Deleted: that a number of the

Ben Forte 2/19/09 1:30 PM Deleted: a

Ben Forte 2/19/09 1:30 PM Deleted: may

Ben Forte 2/19/09 1:31 PM Deleted: ,

Ben Forte 2/19/09 1:31 PM Deleted: may

Ben Forte 2/19/09 1:31 PM Deleted: was

Ben Forte 2/19/09 1:31 PM Deleted: , and d

Ben Forte 2/19/09 1:33 PM Deleted: dump

Ben Forte 2/19/09 1:33 PM Deleted: , as well as

Solid Waste Landfill Design

SEEHD

Photo 12 & Photo 13: There are approximately 50 scavengers who work in the dump, including many women and children, who face serious public health risks. Any proposed solutions need to address their needs.

55

Solid Waste Landfill Design

SEEHD

Other health risks for scavengers include those associated with the continual open burning that occurs at many unregulated dump sites. Tires and any other waste may continually burn, releasing smoke and toxins that are inhaled by scavengers. Additionally, when landfill waste piles up, an anoxic environment develops in the landfill subsurface, and anaerobic decomposition of organics occurs that release landfill gasses such as methane. If the methane is not vented, it causes a potential for an explosion at the site. Another hazard of improperly managed waste in an open dump is the possibility of ‘avalanches’ of waste that may hurt or kill humans residing at the dump.

Ben Forte 2/19/09 1:35 PM Deleted: may

Ben Forte 2/19/09 1:36 PM

According to Medina, “scavenging tends to persist despite efforts to eradicate it. Therefore, a more humane and socially desirable response would be to helping scavengers to achieve a better existence. Supporting scavengers to organize themselves, to obtain higher incomes, and to improve their working and living conditions can also make economic and environmental sense.” In order to reduce the exploitation of scavengers by middlemen or waste dealers that sell recyclables collected by scavengers in large quantities to industry, a cooperative is one way to empower scavengers. Since the industry usually buys cleaned, baled, and crushed recycling, it is probably neccesary that scavengers have some sort of assistance in organizing.

Deleted: s

More immediate efforts, however, should have priority over the process of establishing a cooperative. These efforts should be to improve the substandard living conditions that scavengers live and work in. Health related risks are dependent on the materials placed in the dump, therefore, it is nearly impossible to predict all of the hazards that may be encountered by scavengers.Nevertheless, there are a number of improvements that may be made in order to improve the living and health conditions for scavengers, independent of the dump conditions. Some improvements that may be part of an occupational safety and health plan for scavengers are presented as Table 23.

Deleted: s

Table 23: Occupational Health and Safety Plan Matrix Improvement Benefit Restroom Facilities Washing Facilities

Concrete Foundations for Living Structures Equipment

Separation of special

Reduction of human excrement contamination in the dump, thereby reducing contact of scavengers. (Including showers, sinks, soap, etc.) Allows scavengers to maintain an increased level of personal hygiene and reduces danger of contact between scavengers in homes, etc. Small concrete pads for scavengers to construct homes on would improve sanitary conditions inside living structures by eliminating contact with waste that homes are currently constructed on. Rubber boots, gloves, face masks, and first aid equipment should be made available for scavengers in order to reduce direct contact with waste and to block smoke from burning waste. While it is unlikely that no burning will occur in an

56

Ben Forte 2/19/09 1:36 PM Deleted: dump

Ben Forte 2/19/09 1:39 PM Deleted: of the best

Ben Forte 2/19/09 1:39 PM Ben Forte 2/19/09 1:40 PM Deleted: than

Ben Forte 2/19/09 1:40 PM Deleted: may be made

Ben Forte 2/19/09 1:42 PM Deleted: While

Ben Forte 2/19/09 1:42 PM Deleted: in a dump since

Ben Forte 2/19/09 1:41 PM Deleted: risks are so dependent on the materials placed in the dump, However

Ben Forte 2/19/09 1:43 PM Deleted: no matter

Solid Waste Landfill Design

waste

SEEHD

open dump, it would be useful to attempt to set tires in a separate location that will not be burned.

Typically the landfill area should be kept free of cattle, livestock, wild birds, or any other animals. No people without special permission (that may include scavengers) should be allowed inside a dump or landfill without careful supervision. LANDFILL DESIGN RECOMMENDATIONS Site Selection Various criteria should be taken into account when selecting an appropriate site for a landfill. Although not limited to the following, these include: • • • • • • • • • • • •

distance from population center (should be no more than 30 minutes); access (should be a “good” road to the site); neighboring populations (should be far enough to avoid odors); special restrictions (airports, flooding, seismic, archaeological); area sufficient to support design period (15 years); topography (for the trench method it should be flat with minimal natural water runoff); soil condition; wind; natural runoff (minimal diversion required); hydrogeology (ground water); availability of cover material; and site closure considerations.

The current open dump site is not appropriate for either a trench or canyon method landfill, as it has the volumetric capacity for less than three years worth of waste generated. Therefore, a larger site without waste that inhibits access to cover material should be chosen for the selected landfill. More investigation and coordination with the Municipality must be performed before an actual site is selected for the proposed landfill. Comparison of Trench and Canyon Method Landfills The three primary considerations when selecting the appropriate landfill design are land requirements, environmental impacts, and cost. LAND REQUIREMENTS In general, more land is required for a trench method landfill than a canyon method landfill if optimal sites are selected for each. However, the actual land area requirements of the canyon

57

Solid Waste Landfill Design

SEEHD

method may be deceptive since it relies on the useable volume of a site. Additionally, a relatively level site is required for the trench method, whereas varied terrain is required for the canyon method. ENVIRONMENTAL IMPACT Environmental impacts resulting from landfill operations include leachate and greenhouse gas production, as well as any impacts resulting from hazardous waste (such as chemicals) deposited in the landfill. Leachate Production Leachate production is minimal for properly operated trench and canyon method landfills under the assumptions discussed in each section. If wastes are left uncovered during the rainy season, large quantities of leachate could be produced. Greenhouse Gas Production Greenhouse gas (GHG) production is not emphasized in this report since there are more immediate health and environmental concerns for the residents of Tela. It is estimated that GHG production from waste decomposition is similar for the trench and canyon methods, although much more GHG will be produced in a canyon method operation as a byproduct of equipment operation. OPERATIONAL COSTS PER TON OF WASTE The cost per ton of waste disposed is the most significant difference between the two methods, and is the principal consideration for selection of a landfill method. As calculated in earlier sections of this report, the cost of a trench method landfill is US $5.12/MT, and the cost of a canyon method landfill ranges from US $6.55-9.10/MT. Hiring a contractor would approximately double the cost of landfill operation, which would cost US $10.24/MT for a trench method landfill, and would cost between US $13.10-18.20/MT, depending on which option is selected. FEASIBILITY Although a canyon method landfill may be successful if operated correctly, it is often not practical in small communities. Maintaining the equipment required and properly operating a canyon method landfill is costly and complicated.It is largely due to this reason that the open dump serving Tela (that was originally designed as a landfill) is currently the major problem. The likelihood of proper operation of a canyon method landfill for an extended period of time is much less than for a trench method landfill; therefore, a trench method landfill is strongly recommended for Tela. The municipality of Villanueva has successfully operated its landfill using the trench method for 10 years. Images of old, broken down equipment at the Tela open dump are presented as Photo 14 and Photo 15.

58

Ben Forte 2/19/09 1:46 PM Deleted: in a developing country such as Honduras

Ben Forte 2/19/09 1:46 PM Deleted: , and

Ben Forte 2/19/09 1:46 PM Deleted: the

Ben Forte 2/19/09 1:47 PM Deleted: a

Solid Waste Landfill Design

SEEHD

59

Solid Waste Landfill Design

SEEHD

Photo 14 & Photo 15: Old, broken down equipment are one of the principal reasons the municipality could never operate the site as a mechanized landfill. Without significant capital and personnel inputs, it is unlikely that Tela is capable of operating a fully mechanized landfill.

60

DUMP CLOSURE DESIGN Most of the waste generated in Tela is currently disposed in an open dump, which, unless closed, has the potential to become a major environmental and public health hazard for the entire municipality. A closure design for the dump is detailed in the following section.

GOALS OF DUMP CLOSURE A proper design for closure of a dump ensures that the waste will be covered with a minimum thickness of soil, known as the final cover (or cap). In Solid Waste Landfills in Middle and Lower-income Countries: A Technical Guide (1999), it is specified that a properly designed final cover should: • Control infiltration of rainfall into the waste; • Control erosion of its surface (by wind and water runoff); • Provide durable surface drainage systems over the landfill; • Control the migration of gas and leachate generated within the landfilled wastes; • Support the planned after-use of the site; and • Maintain all the above while the landfilled wastes continue to decompose and settle. In addition to these factors, a cap is necessary to protect scavengers and local residents from disease resulting from vectors that may be in contact with the MSW in the dump. A pre-dump site topographic map from 1996 is presented as Exhibit 9, and images of hazardous medical waste at the dump are presented as Photo 16 and Photo 17.

61

Dump Closure Design

SEEHD

Photo 16 & Photo 17: Medical wastes that are disposed with municipal wastes pose a serious hazard to scavengers and municipal employees who work in the dump.

62

Dump Closure Design

SEEHD

POPULATION AND WASTE GENERATION ESTIMATES The open dump has been in operation since 1997. In order to estimate per capita waste generation during the lifetime of the dump, population estimates must be made from 1997 through 2007, using the assumed population of 40,000 in 2008 and the 0.6 kg/person-day waste generation rate, as well as a -2.8% decay rate (from a 2.8% growth rate used in the Landfill Design section of this document). Additionally, the density value for loose waste (200 kg/m3) and the 33% volume reduction for auto-compacted-decomposed waste (also from the Landfill Design sections of this report) are used. Results for population and waste generation calculations may be found in Table 24. Table 24: Population and Waste Generated by Mass and Volume, 1997-2008 Year

1 2

Population1

Mass Yearly

Yearly Uncompacted Volume

Yearly Auto-CompactedDecomposed Volume

(persons)

(kg/year)

(m3/year)

(m3/year)

29,397 30,231 31,090 31,973 32,880 33,814 34,774 35,762 36,777 37,822 38,896 40,000 413,4152

6,437,858 6,620,666 6,808,664 7,002,001 7,200,827 7,405,300 7,615,578 7,831,828 8,054,218 8,282,923 8,518,122 8,760,000 90,537,984

32,189 33,103 34,043 35,010 36,004 37,026 38,078 39,159 40,271 41,415 42,591 43,800 452,690

12,876 13,241 13,617 14,004 14,402 14,811 15,231 15,664 16,108 16,566 17,036 17,520 181,076

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 TOTAL =

Population decay rate k = -0.028. Used for per-capita waste generation calculations.

CURRENT CONDITIONS AT THE TELA OPEN DUMP Site Characteristics SURFACE AREA A site layout map in AutoCAD format was used to estimate the surface area at the current open dump as 21,500 m2.

63

Dump Closure Design

SEEHD

VOLUME OF WASTE ON SITE Current and pre-dump site topographic maps in AutoCAD format were used to estimate the current volume of waste in the open dump as 66,116 m3. LANDFILL CAPACITY In order to investigate the feasibility of converting the current open dump to a canyon-method sanitary landfill, pre-dump site topographic maps in AutoCAD format were used to estimate the total site volumetric capacity, that is 63,271 m3 without any waste (using 3/1 slopes and proper canyon method landfill design). Therefore, even if the site had not been used as an open dump since 1997, there would still only be enough capacity at the site for approximately 3 years of waste generated in Tela. Overall views of the open dump are presented as Photo 18 and Photo 19.

64

Dump Closure Design

SEEHD

Photo 18 & Photo 19: The open dump in Tela was originally designed as a fully mechanized landfill, but has been operated as an open dump since it began operation over 10 years ago. The area of the dump is about 2 hectares, and the depth of wastes between 5 to 6 meters. The estimated volume of deposited and decomposed wastes is 63,000 cubic meters. PER-CAPITA WASTE GENERATION CALCULATION AND COMPARISON The waste in the open dump is assumed to be well compacted and decomposed, since much of it has been in the dump for an extended time. Therefore, a density of 500 kg/m3 is assumed, and a waste generation rate may be calculated as follows:

65

Dump Closure Design

SEEHD

34,451

This value is similar to the estimate of waste generation used for the landfill design of 0.6 kg/person-day. Some waste may also be dumped outside the landfill, and burning of waste is known to occur. These practices may explain the discrepancy between the waste generation values. A current (2008) site topographic map is presented as Exhibit 10, with corresponding section views in Exhibit 11 and Exhibit 12. CLOSURE DESIGN AND CONSTRUCTION

Ben Forte 2/19/09 1:51 PM Deleted: Waste

Ben Forte 2/19/09 1:51 PM Deleted: ,

Ben Forte 2/19/09 1:51 PM Deleted: which

Final Cap The final cap design for the open dump will be simple as compared to a final cap that would be constructed in industrialized countries such as the United States; however it should still be sufficient to ensure that the goals of a cap system (as previously mentioned) are satisfied. FINAL CAP DESIGN Figure 16: Basic Design of a Final Cap System

Ben Forte 2/19/09 1:52 PM Comment: Provide depths of the various layers?

Source: UNEP, 2005

A basic final cap system has a hydraulic barrier layer and a surface (soil) layer (see Figure 16), although it is best to also include a foundation layer, that is a bottom layer of compacted soil that 66

Dump Closure Design

SEEHD

is placed directly on the top lift of the waste to serve as a buffer between the final cover and the waste it is designed to support. The hydraulic layer is the most important component of a final cap, although without the surface layer, the hydraulic layer may easily be destroyed, especially with the amount of precipitation in Tela. The main function of the hydraulic barrier is to prevent infiltration of water into the waste, thereby preventing the formation of leachate. A surface layer of top soil should be placed over the hydraulic barrier layer. After the surface soil layer has been applied and lightly compacted, a vegetative layer, consisting of rapidly growing native plant species should be planted in order to prevent surface erosion and to stabilize the slopes of the cap (UNEP, 2005). The foundation layer may be constructed of native soil, and should be thick enough to provide a solid base upon which the clay barrier layer may be constructed. It is recommended that the depth of the foundation layer be 15-30 cm. According   to   UNEP   (2005),   in   industrialized   countries,  hydraulic  barriers  are  made  of  fine-­‐grained  soil  that  is  carefully  compacted,  and   may   be   mixed   with   other   materials   such   as   bentonite   clay   and   fly   ash   in   order   to   reach   the   desired   permeability.   However,   due   to   the   economic   situation   and   availability   of   materials,   clay   is   most   likely   the   best   material   available   for   use   as   the   hydraulic   barrier.   The ideal thickness of the clay barrier is 60 cm, although a minimum depth of 30 cm may be sufficient, depending on the hydraulic permeability of the layer. The surface (soil) layer should be thick enough to support the planned vegetation without fatal disturbance of the clay barrier layer by roots, and may be constructed of native soil in order to reduce cost. The thickness of the surface layer may range from 30-60 cm. 60 cm is preferable (UNEP, 2005). Although these are the recommended layers and respective depths, the feasibility of constructing all of these layers (due to the economic situation in developing countries) is low. FINAL CAP COST ANALYSIS The cost of cover material will be a limiting factor for the open dump final cap construction, so the following three cover material scenarios are considered for cost analyses: • • •

Option 1: purchasing barrier and surface soil layers from a local dealer; Option 2: excavating barrier and surface soil layers locally with rented machinery; and Option 3: purchasing the barrier layer material and excavating the soil layer material locally with rented machinery.

Advantages and disadvantages of each option are displayed in Table 25.

67

Ben Forte 2/19/09 1:55 PM Comment: It is recommended to select soil that has a permeation rate of 7% slope (CE = 0.2) is used. Since the moisture content capacity will vary between n layers, a more generic equation (as compared to the Landfill Design Sections), is used for dump closure calculations, as follows (with result presented in Table 30): Amount of Water to Penetrate Surface of Landfill

Where: q P CE Eq

= = = =

amount of water to penetrate surface of landfill (mm/month) average monthly precipitation (mm/month) runoff coefficient average monthly evaporation (mm/month)

Volume of Leachate Produced

Where: Qm AE

= =

amount of leachate produced (m3/month) surface area of waste (m2)

78

Dump Closure Design

SEEHD

TOTAL = 1

0.05 0.05 0.05 ----0.05 0.05 0.05 0.05 0.05

0.2 0.2 0.2

0.2 0.2 0.2 0.2 0.2

179.6 95.4 102.1 ----25.8 86.5 336.3 337.7 252.1

31.2 62.4 83.6 ----110.5 76.8 7.4 0.0 11.3

(m2) 21,500 21,500 21,500 ----21,500 21,500 21,500 21,500 21,500

(m3/month) (m3/month) (m3/month) 1,930 1,025 1,098 ----277 930 3,615 3,630 2,711

335 671 898 ----1,188 825 80 0 121

Total Leachate Produced Yearly (m3) =

2,754.2 1,478.1

Source: Departamento de Servicios Hidrologicos y Climatologicos, Secretaria de Recursos Naturales y Ambiente, Gobierno de Honduras.

79

Total Leachate Produced

Quantity of Leachate Produced, 3/1 Slope

193.6 105.9 114.5 -61.2 -115.4 -46.6 -35.7 34.9 97.4 359.2 359.8 269.7

(mm/month) (mm/month)

Quantity of Leachate Produced, Flat Surface

87.4 104.5 133.1 156.7 160.7 149.6 155.3 146.9 120.3 99.1 83.0 81.5

Area of Site

281.0 210.4 247.6 95.5 45.3 103.0 119.6 181.8 217.7 458.3 442.8 351.2

q, 3/1 Slope

(mm)

q , Flat Surface

(mm)

Runoff Coefficient, 3/1 slope

Precipitation Evaporation

(mm)

Runoff Coefficient, Flat Surface

Evaporation

Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec

Precipitation

Month

Table 30: Monthly Leachate Production (Sloped and Flat Surfaces) (Promedio Mensual (Anos 1986-96) de Temperatura, Precipitacion y Evaporacion, Cuenca Cangrejal, Estacion El Cural, Latitud 15° 44’ 13”, Longitud 18° 51’ 15”)

2,266 1,696 1,996 ----1,466 1,755 3,695 3,630 2,832 15,706

Dump Closure Design

SEEHD

It may be observed in Table 30 that approximately 15,706 m3 of leachate will be produced yearly if a final cap system is not constructed. This gives an approximation of the volume of leachate that is currently being produced and discharged to the environment from the open dump.

Ben Forte 2/19/09 2:02 PM Deleted: in

LEACHATE MANAGEMENT By constructing a final cap (with a clay barrier layer) on the waste, penetration of water into the waste (and subsequent leachate production) will be minimized, which will protect groundwater and surface water, and the health of local residents. In order to minimize leachate production, surface water that would normally penetrate the landfill during rainfall should be diverted when possible. It is recommended that any surface water runoff that will compromise the integrity of the cap system should be diverted using properly placed drainage channels.

Ben Forte 2/19/09 2:03 PM Deleted: as much

Ben Forte 2/19/09 2:03 PM Deleted: as possible

Post-closure monitoring of on-site and off-site leachate production and migration should be performed so that appropriate diversion channels may be constructed. However, it is unlikely that monitoring will be performed, so care should be taken to ensure that the cap is not damaged since the cap is the most economical method of managing leachate production. Gas Production and Remediation POST-CLOSURE METHANE GAS PRODUCTION As organic wastes (mainly food and paper) in the capped landfill decompose in the anaerobic environment, methane gas will be produced. Because much of the waste in the open dump is well decomposed, calculations of future methane production are performed assuming half of the waste has not currently undergone decomposition. An estimate of methane production is presented as Table 31. Table 31: Closed Dump Gas Production Volume of Waste

Mass of Waste To Degrade Food Paper Waste1 Waste2 Total

CH4 Production by Mass Food Paper Waste1 Waste2

CH4 Production by Volume Total Total Volume MTCE3

Total

To Degrade

m3

m3

MT

MT

MT

MT

MT

m3

MTCE

66,166

33,083

18,196

12,100

2,293

2,250

487

1,368,809

7,839,172

1

Food waste is 66.5% of total waste, 70 % H2O, 90% volatile solids, 82% biodegradable fraction, and 0.36 kg CH4 is produced per MT MSW Paper waste is 12.6% of total waste, 90 % H2O, 90% volatile solids, 82% biodegradable fraction, and 0.32 kg CH4 is produced per MT MSW 3 Global warming potential for methane is 5.727. 2

METHANE MANAGEMENT The methane produced in the anaerobic landfill subsurface will migrate through the path of least resistance, until it escapes through, or is trapped under the landfill cap. In order to avoid methane

80

Ben Forte 2/19/09 2:05 PM Deleted: organic waste (mainly food and paper) in the capped landfill decomposes

Dump Closure Design

SEEHD

buildup, which may disturb the cap or cause an explosion, a series of paths for the methane to escape from the landfill subsurface are required to prevent methane buildup. A series of pipes or gravel trenches are usually constructed on the ground surface before waste is deposited at a landfill in industrialized nations. The trenches lead to gas vents that allow methane to escape from the subsurface. Since the Tela site is already an open dump, and there is not enough money to construct such a system, the most feasible method of managing landfill gas is to construct passive gas vents (or chimneys) throughout the capped area. This will provide a preferential escape route for the gas produced in the landfill subsurface. An economical and efficient method to construct a methane extraction vent is to use rocks held in place by wire fencing, similar to a french-drain design. An excavator should be used to dig pits to the bottom depth of disposed waste at each vent location. Laborers should create a column using the fence material, which will subsequently be filled with rock before the waste is re-compacted around the newly constructed vent. The vent should be raised to a minimum elevation of 1 m above the finished grade of the final cap, and a sloped cover should be constructed over the top of the vent in order to minimize the amount of rainwater penetrating the landfill through the vent. The placement of the rock vents depends on the capped dump surface area, depth of compacted waste and the estimated methane production. For the dump site there should be approximately ten vents spaced 50 m apart. Proposed gas vent locations are presented in Exhibit 14.

Ben Forte 2/19/09 2:07 PM Deleted: The best

Ben Forte 2/19/09 2:07 PM Deleted: material

Ben Forte 2/19/09 2:07 PM Deleted: initially

Ben Forte 2/19/09 2:08 PM Deleted: the

Ben Forte 2/19/09 2:09 PM Deleted: , and l

Ben Forte 2/19/09 2:09 PM Deleted: cylinder

Ben Forte 2/19/09 2:10 PM

Post-Closure Activities and Recommendations

Deleted: at least

Ben Forte 2/19/09 2:11 PM

SAFETY PRECAUTIONS

Comment: Is there a drawing showing detailed construction design?

The closed dump site should be closed off to access for a minimum of ten years (although twenty or thirty years would be preferable), in order to allow for; settling and decomposition of the waste, and to protect the cap which may be easily destroyed by foot or vehicle traffic. Additionally, this will protect humans and animals from the unstable surface, combustible gases produced in the landfill subsurface, and any other hazardous waste or chemicals that may be components of the waste. A recommended option to prevent access to the closed dump site would be to construct a fence around the perimeter of the closed dump and hire a security guard.

Ben Forte 2/19/09 2:11 PM

MONITORING Routine post-closure activities for a landfill in an industrialized nation would involve groundwater, surface water, and gas vent monitoring. In a location such as Tela, this type of monitoring is not logistically or economically feasible. Therefore, the landfill should be regularly inspected to ensure that the final cap is in good condition, and if there are any voids or large cracks they should be filled with native soil. SITE USES

81

Deleted: ,

Ben Forte 2/19/09 2:12 PM Deleted: The best

Dump Closure Design

SEEHD

The closed landfill may eventually be used as pasture or an athletic field. The land should not be used for farming land (to grow food crops) because it is likely that the cover will not be deep enough to prevent roots from penetrating the waste, or plows could ruin the cap. No development should occur on the site because of the subsurface gas production, possibility of concrete corrosion, low load-bearing capacity, and uneven settlement associated with the construction and utilization of structures erected on a completed fill.

DUMP CLOSURE DESIGN RECOMMENDATIONS Given the estimated costs shown in Table 29, it is unlikely that the Municipality will by itself initiate a dump closure project without receiving external funds. This is exactly why the current site continues to operate as an open dump after more than 10 years of operation, even though it was originally designed as a mechanized landfill. It is therefore recommended that the Municipality use the cost estimates presented in this section as a proposal to seek funds for closure from governmental or non-governmental organizations. Even the lowest cost options, although not ideal, would be adequate and a substantial improvement over the current situation.

82

REFERENCES Bolton,  N.  The  Handbook  of  Landfill  Operations,  Blue  Ridge  Services,  Inc.,  Atascadero,   California,  1995.   Bryant, Benjamin L. Select AutoCAD Figures and Site Analysis. 2008 Cámara Hondureña de la Industria de la Construcción. Lista de Precios de Alquiler de Equipo en San Pedro Sula. June, 2006. Caterpillar, Inc. Caterpillar Performance Handbook: Edition 32. Peoria, Illinois, U.S.A. October 2001. Caterpillar, Inc. 939C Hystat Track-Type Loader. December, 2008. Central Intelligence Agency (CIA). The World Factbook. October, 2008. City Population, August 2008, http://www.citypopulation.de/Honduras.html Departamento de Servicios Hidrologicos y Climatologicos, Secretaria de Recursos Naturales y Ambiente, Gobierno de Honduras. Promedio Mensual (Anos 1986-96) de Temperatura, Precipitacion y Evaporacion, Cuenca Cangrejal, Estacion El Cural, Latitud 15° 44’ 13”, Longitud 18° 51’ 15”. Environmental Protection Agency. Emission Facts: Average Carbon Dioxide Emissions Resulting from Gasoline and Diesel Fuel. October 2008. Environmental Protection Agency. Municipal Solid Waste in the United States: 2005 Facts and Figures. Office of Solid Waste, October, 2006. Instituto de Promoción de la Economía Social (IPES). Gestión Ambiental de los Residuos Sólidos Urbanos en La Ceiba. Fondo Hondureño de Inversión Social (FHIS), June 1996. Medina, Martin. Scavenger cooperatives in Asia and Latin America. Resources, conservation, and recycling v. 31, pp. 51-69, 2000. Oakley, Stewart M. Manual de Diseño y Operación de Rellenos Sanatarios en Honduras. USAID, 2005. Tchobanoglous, G., Theisen, H., and Vigil, S. Integrated Solid Waste Management, 2nd Edition. McGraw-Hill, Inc., New York, 1993.

83

REFERENCES (CONTINUED) Volvo, Rushbrook, Philip, and Pugh, Michael. Solid waste landfills in middle and lower income countries : a technical guide to planning, design, and operation. The International Bank for Reconstruction and Development, The World Bank. 1999. United Nations Environment Programme. Solid Waste Management. Volumes 1 and 2. 2005.

84

EXHIBITS

Suggest Documents