Development of A Decision Support System for Drinking Water Treatment Process Design (WATER-DSS)

CHUANG KUANG HONG

A project report submitted in partial fulfilment of the requirement for the award of the degree of Master of Engineering (Environmental Management)

Faculty of Civil Engineering Universiti Teknologi Malaysia

JULY, 2006

iii

To my beloved parents, Heng Siaw Ling & friends, Thank you for your support, guidance and confidence in me.

iv

ACKNOWLEDGEMENT

First of all, I would like to express a zillion thanks to my supervisor, Prof. Dr. Zaini B. Ujang. He has taught me much with examples and advice. Despite his daily hectic schedule, he has taken the trouble to guide and support me. Secondly, I would also like to express my deepest thanks to Miss Dewi, Miss Fazlin and Mr. Shukor who had shared their experience with me and guided me in my project. Furthermore, I would like to thank to Mr. Azmi, who is supervising the operation of Sayong Water Treatment Plant, Kota Tinggi, Johor. He was willing to share his experience during his work in plant. Never the less, my project will never be success without Tang Kok Mang and Khaw Boon Chai. They guided me along the building process of WATER_DSS using visual basic 6.0. I will also not forget few close friends such as Lee Xia Sheng and Low Chin Yen that has been support bring me up when I falls in the process of work. Lastly, my family and girl friend, Heng Siaw Ling has given me the biggest support in whatever way. They play the important roles not only in my project, but in my life. Again, I appreciate to all those involved directly and indirectly helping me out which I can’t state out every one of them. A special expression of gratitude is extended to everyone for their tolerance and patience in doing all the things.

v

ABSTRACT

A decision support system (DDS), named WATER-DSS has been developed to assist engineers and researchers on drinking water treatment plant. The objective of WATER-DSS was to assist designers to perform process design for drinking water treatment. WATER-DSS contains two main components: (i) knowledge-based information and (ii) programming tool. The design of drinking water treatment plant in WATER-DSS depends on the characteristic of raw water and the water quality objectives. Visual Basic 6.0 was selected to develop WATER-DSS because its capability of object oriented programming. WATER-DSS has user-friendly interfacing capability, which provides the parameters inputs, standard parameters value list, raw water treatment process information, graphical and explanations features .WATER-DSS was validated by the manual calculations and has shown the relationship between WATER-DSS output and manual calculation output is significant.

vi

ABSTRAK

Satu sistem sokongan keputusan, yang dinamakan WATER-DSS telah dibangunkan untuk membantu para jurutera and dalam proses merekabentuk system logi air. Objektif pembinaan WATER-DSS adalah untuk membantu jurutera dan penyelidik membuat keputusan dalam merekabentuk proses awal loji rawatan air. WATER-DSS mengandungi dua bahagian: (i) Pengetahuan, dan (iii) Perisian Pengaturcaraan. Rekabentuk proses awal rawatan air mentah dalam WATER-DSS adalah bergantung kepada parameter air rawatan. Visual Basic 6.0 dipilih sebagai perisian rekabentuk kerana keupayaan bahasa pengaturcaraannya. WATER-DSS mempunyai halaman yang mudah difahami dan dikenalpasti yang terdiri daripada ruang untuk memasukkan parameter air, senarai nilai standard quality air, maklumat proses air rawatan mentah, gambar beserta ulasan yang berkaitan. Keputusan yang diperolehi melalui WATER-DSS menunjukkan hubungan yang erat dengan kaedah pengiraan manual.

vii

CONTENT

CHAPTER

I

II

ITEMS

PAGE

TOPIC

i

AUTHENTICATION

ii

DEDICATION

iii

ACKNOWLEDGEMENT

iv

ABSTRACT

v

ABSTRAK

vi

CONTENT

vii

LIST OF TABLE

xi

LIST OF FIGURES

xii

INTRODUCTION 1.1

Research Background

1

1.2

Problem Statement

2

1.3

Objective of Study

2

1.4

Scope of Study

2

LITERATURE REVIEW 2.1

Introduction

3

2.2

Objective of Water Treatment

3

2.2.1

4

Pre-treatment

viii 2.2.1.1 Screens

4

2.2.1.2 Grit Chamber

4

Aeration

5

2.2.2.1 Type of Aerator

6

2.2.3

Pre-Chlorination

8

2.2.4

Coagulation and Flocculation

8

2.2.4.1 Coagulant

9

2.2.4.2 Type of Flocculators

10

Sedimentation

12

2.2.5.1 Type of Sedimentation tank

13

2.2.2

2.2.5

2.2.6 Filtration

2.3

13

2.2.6.1 Types of Filtration Technology

15

2.2.6.2 Membrane and RO filtration

16

2.2.7

Disinfection

17

2.2.8

Fluoridation

17

2.2.9

pH adjustment

18

Water Quality

18

2.3.1

Physical Quality

18

2.3.1.1 Colour

18

2.3.1.2 Turbidity

20

2.3.1.3 Total Dissolved Solid

20

2.3.1.4 pH

20

Chemical Quality

21

2.3.2.1 Mercury

21

2.3.2.2 Arsenic

21

2.3.2.3 Lead

21

2.3.2.4 Copper

22

2.3.2.5 Chlorine

22

2.3.2.6 Manganese

22

2.3.2.7Ammonia

22

2.3.2.8 Nitrate

23

2.3.2.9 Iron

23

2.3.2.10 Fluoride

23

2.3.2.11 Hardness

23

2.3.2

ix

2.3.3 2.4

2.3.2.12 Aluminium

24

Microbiological Quality

24

Water Parameters Removal by Water

24

Treatment Process 2.5 2.6

2.7

III

Engineering knowledge

25

2.5.1

25

Engineering Knowledge Principles

Programming Tool using Visual Basic

26

2.6.1

Behaviour present in Visual Basic

27

2.6.2

User-friendly Interface design

29

Security System by Password

29

LITERATURE REVIEW 3.1

Development of WATER-DSS

31

3.2

Forms of WATER-DSS Project in Visual Basic

32

3.2.1

Security of WATER-DSS

32

3.2.2

Welcome frame

33

3.2.3

Parameter Input Form

35

3.2.4 Water Treatment Process form

39

3.2.5

Pre-treatment Form

43

3.2.6

Aeration Form

45

3.2.7

Coagulation, Flocculation and

45

Sedimentation 3.2.8

Filtration Form

46

3.2.9

Summary Form

47

3.2.10 Thank You Form

IV

50

RESULT AND DISSCUSION 4.1

General

51

4.2

Application of WATER-DSS

51

4.3

Validation of Result

51

4.4

Discussion

52

x V

CONCLUSION 5.1

Conclusion

55

5.2

Suggestion

55

5.3

Error in Study

56

REFERENCES

58

xi

LIST OF TABLE

TABLE NUMBER TOPIC

PAGE

2.1

Design Criteria for screens

4

2.2

Grit chamber design criteria

5

2.3

Types of aerators

7

2.4

Cascade aerator typical design criteria

8

2.5

Common coagulants and doses

9

2.6

Comparison of Basic approaches to flocculation

10

2.7

Baffle channel typical design criteria

12

2.8

Types of sedimentation process

14

2.9

Typical design criteria for rectangular

15

sedimentation tank 2.10

Typical design criteria for rectangular rapid

17

sand filter 2.11

Water parameters limitation in Malaysia

19

2.12

General effectiveness of water treatment

25

processes removal 3.1

Category of water parameters

35

3.2

Simplify removal percentage by process

43

treatment and further treatment action 4.1

Comparison WATER-DSS result and Microsoft Excel result

53

xii

LIST OF FIGURES

FIGURE NUMBER TOPIC

PAGE

2.1

Aeration process

5

2.2

Cascade aerator plan layout

6

2.3

Coagulant dosing equipments

9

2.4

Baffle channels

11

2.5

Baffle channels plan layout

11

2.6

Sedimentation tank

13

2.7

Sedimentation tank layout plan

14

2.8

Four types of common filters

16

2.9

Rapid sand filtration tanks

16

3.1

WATER-DSS development structure

31

3.2

Forms in WATER-DSS

32

3.3

Password form

32

3.4

Welcome form

34

3.5

Parameter Input form

36

3.6

Water treatment process form

39

3.7

Pre-treatment form

44

3.8

Aeration form

45

3.9

Filtration form

48

3.10

Thank You form

50

51

CHAPTER 1

INTRODUCTION

1.1

Research Background The concept of DSS emerged in the 1970s, as a family of computer systems

in the field of decision theory (Gorry and Scott, 1971) showing a great potential in the field of environment management. In the last decades, numerous DSS have been developed in the field on environmental management to assist designers in making decision related to various aspects of planning, monitoring and design facilities. DSS development integrates various concepts such as spreadsheets, databases, networks, hypermedia, expert systems, visual programming, intelligent agents, neural networks, etc. (Beynon et al., 2002).

Any system supporting decision-making, including

executive information systems, executive support systems, geographic information systems and software agents, may be called a DSS (Power, 1997). DSS serves three main purposes. DSS gives us a framework to assemble our process understanding and to explore the implied system behaviours that come from that understanding. The second purpose is as a mechanism for testing data, to check for inconsistencies and errors, and fill in missing information. The third is to explore scenario options under a range of different output conditions (Silberstein, 2005). In an engineering field, DSS can assist engineer to perform complete calculation design procedures in a short time compared to manual calculation (Sairan, 2005).

2 Conventional water treatment plant include screening, grit removal, aeration, coagulation, flocculation, sedimentation, filtration, fluoridation, disinfection and conditioning. The treatment processes of raw water before it can be used for public consumption must be based on removal level of impurities to comply with various guidelines. The quality of water depends upon it physical, chemical, microbiological and radiochemical characteristic. The extent of treatment depends upon the quality of the raw water and the desired quality of treated water. The treated water constituents should meet the standard set by The Ministry of Health, Malaysia.

1.2

Problem Statement Most of the design procedures for water treatment plant have been developed

using manuals or spreadsheet calculations which are time consuming and costly. Therefore, a DSS is required to speed up the design process and reduce the design cost. In this study, a DSS called WATER-DSS will be developed to reduce the design time and cost.

1.3

Objective of Study The main objectives of this study are to: i) To develop an easier, cheaper and user-friendly DDS to assist in selecting

appropriate and essential procedures for water treatment process. ii) To validate the DSS with manual or spreadsheet calculation.

1.4

Scope of Study The scope of the study covers conventional drinking water treatment process

in Malaysia.

3

CHAPTER 2

LITERATURE REVIEW

2.1

Introduction In order to set up a useful program for water treatment plant design, a set of

technical knowledge and data needs to be gathered. Examples of technical knowledge are conventional water treatment processes, parameter removal by different treatment processes and coagulants used. Apart from that, laws, regulations and specifications also need to be considered. After that, a program is needed to design, program and assess the collected knowledge.

2.2

Objectives of Water Treatment The main objective of treating water intended for public water supplies is to

produce a supply water that is chemically and bacteriological safe for human consumption (Montgomery, 1985). In this study, conventional treatment is defined as pre-treatment,

aeration,

coagulation,

fluoridation, conditioning and disinfection.

flocculation,

sedimentation,

filtration,

4 2.2.1

Pre-treatment Pre-treatment normally is the first step after water intake from water

resources. Screens and grit chamber are commonly used in this early treatment process (Degremont, 1979).

2.2.11 Screens Bar screens are used to separate physical solids that are likely to create problems in subsequent treatment stages. This is to protect the plant against the entry of large objects likely to cause blockage in different parts of the installation. Screens are usually distinguished by three types: fine screen, medium screen and coarse screen. The design criteria of bar screen are presented in Table 2.1. Table 2.1: Design Criteria for Screens 1.

4. 5. 6.

Criteria Type of screen

Type Fine screen Medium screen Coarse screen

Cleaning purpose

-

Flow velocity Head losses

-

Description Spacing from 3 - 10 mm Spacing from 10 - 25 mm Spacing from 50 - 100 mm Provision for cleaning should be constructed in the form of access walkways located 1 m above normal water level. Average 0.6-1.0 m/s, maximum 1.2-1.4 m/s 0.05-0.15 m

(Tay, 2000)

2.2.1.2 Grit Chamber Grit chamber is to remove the gravel, sand and other mineral particles which would otherwise form deposits in channels and piping, to protect pump and other equipment against abrasion and to avoid overloading subsequent treatment stage (Prosser, 1977). The design criteria of grit chamber in Malaysia are presented in Table 2.2.

5 Table 2.2: Grit chamber design criteria 1 2 3 4 5

Design criteria Smaller particle to settle Mean horizontal velocity Maximum horizontal velocity Deposition of suspended solid Grit capacity

Description 0.2 mm 50-60% velocity of 0.2 mm dia particles 120% of mean horizontal velocity 200 mg/L 7 days of 24 hours operation/day

(Tay, 2000)

2.2.2

Aeration Aeration is the process of bringing water and air into close contact in order to

remove dissolved gases, such as carbon dioxide, and to oxidize dissolved metals such as iron. It can also be used to remove volatile organic chemicals (VOC) in the water. Aeration is often the first major process at the treatment plant. During aeration, constituents are removed or modified before they can interfere with the treatment processes (Hand et al., 1999). Example of the aeration treatment process is shown in Figure 2.1. The figure and following site plant picture is taken from Sayong Water Treatment Plant, Kota Tinggi, Johor.

Figure 2.1

Aeration process

6 2.2.2.1 Type of Aerator Normally there are four basic types of aerators as below, more detail of aerators are presented in Table 2.3 (Crittenden et al., 2005). Different types of aerator serve different type of needs and loading rate. i) Droplet or thin-film air-water contactors ii) Diffusion or bubble aerators iii) Aspirator-type aerators iv) Mechanical aerators In Malaysia, almost all water treatment plant apply the droplet or thin-film air-water contactors which consists of 87% cascade aerators, other 7% and 4% made up from multiple tray and spray aerator respectively (The Malaysia Water Association, 2005). Figure 2.2 shows the cascade aerator layout while cascade aerator design criteria are provided in Table 2.4 (Mariappan, 2005).

Figure 2.2

Cascade aerator plan layout

Aspirator-type aerators Mechanical aerators

Diffusion or bubble aerators

Droplet or thinfilm air-water contactors

Type of Aerators

Hydraulic aspirator Mechanical aspirator Mechanical aerator

Dispersed air

Diffuser

Multiple tray

Cascade

Spray tower

Contacting device Spray aerator

Water to be treated trickles by gravity through trays containing media to produce thin-film flow. Typical media used include coarse stone or coke Fine bubbles are supplied through porous diffusers submerged in the water to be treated. Compressed air is supplied through a stationary sparser orifice-type dispersion apparatus located directly below a submerged high speed turbine A gas stream is educed into the liquid stream with a venture-type device A hollow-blade impeller rotates at a speed sufficient to aspirate and discharge a gas stream into the water Surface aerators and aeration pumps are primary types of mechanical aerators

Water to be treated is sprayed through nozzles to form disperse droplets; typically a fountain configuration Water to be treated is sprayed downward through nozzles to form disperse droplets in a tower configuration; typically countercurrent flow. Water to be treated flows over the side of sequential pans, creating a waterfall effect to promote droplettype aeration.

Process description

Table 2.3: Types of aerators

Compressed ozone, CO2, Cl2 Compressed air or ozone Mechanical agitation of water into surrounding air

Aeration primarily by natural convection Natural or forced-draft aeration Compressed air or ozone Compressed air or ozone

Method gas transfer Natural aeration through convection Forced-draft aeration

-

-

-

-

0.007-0.014 m/s 0.1-1 L air/L water

-

-

Loading factor Surface area of 0.1-0.3 m2.s/L

(Crittenden et al., 2005)

O2 absorptio, VOC removal when 1.0 m 300 mm Backwash 600-1000 mm 0.55-0.95 1.5-1.7 5% 2.55-2.65

(Tay, 2000)

2.2.7

Disinfection Disinfection is normally the last step in purifying drinking water. Water is

disinfected to destroy any pathogens which passed through the filters (Haas, 1999). Chlorine is the one of the most common disinfection chemical that being used. As in Malaysia, most of the plants surveyed used chlorine as their disinfection agent (The Malaysia Water Association, 2005).

2.2.8

Fluoridation Fluoridation is the process where fluoride is added to water for the purpose of

preventing tooth decay. Fluoride is an essential component for normal mineralization of bones and formation of dental enamel (Bell and Ludwig, 1970). Fluoride is usually added after the disinfection process. 82% of sodium silicofluoride and 18% of sodium fluoride is used in Malaysia in fluoridation process (The Malaysia Water Association, 2005).

18 2.1.9

pH adjustment If the water is acidic, lime or soda ash is added to raise the pH. 85% of

Malaysia plant using lime and 15% using soda ash process (The Malaysia Water Association, 2005). Lime is the more common of the two additives because it is cheaper, but it also adds to the resulting water hardness. Making the water slightly alkaline ensures that coagulation and flocculation processes work effectively and also helps to minimise the risk of lead being dissolved from lead pipes and lead solder in pipe fittings.

2.3

Water Quality The quality of water depends upon its physical, chemical, microbiological

and radiochemical characteristic. Obtaining a desired quality of drinking water often requires treatment. The extent of treatment depends upon the quality of the raw water and the desired quality of treated water (Tay, 2000). The overall accepted values for quality of treated water are presented in Table 2.11.

2.3.1

Physical Quality The principal physical characteristics of water are colour, turbidity, taste,

odour, pH, suspended and dissolved solids (Letterman et al., 1999).

2.3.1.1 Colour Water should be as colourless as possible. Presence of water indicated the presence of complex organic compounds, colloidal forms of iron and manganese, or highly coloured industrial wastes. The standard for colour in drinking water is less than 15 TCU (Tay, 2000). Colour in water can usually be reduced to within the recommended limit by conventional treatment if the raw water does not contain more

19 Table 2.11: Water parameters limitation in Malaysia Category/group Microbiology

Group I Physical

Group II Inorganic

Group III

Thihalo-methane

Group IV

Group V Radioactivity

Parameter Total Coliform E.coli Faecal Streptococci Viruses Protozoa Helminths Turbidity Colour pH Chlorine Monochloramine Total dissolve solids Chloride Ammonia Nitrate Iron Fluoride Hardness Aluminium Manganese Mercury Cadmium Arsenic Cyanide Lead Chromium Copper Zinc Sodium Sulphate Chloroform Bromoform Dibromochlorome Selenium Silver Magnesium Nickel Aldrin DDT Heptachlor Alachlor Chlorofuran Cyanazine Propanil Benzena Gross Į Gross ȕ

Max accepted value Absent in 100 ml sample Absent in 100 ml sample Absent in 100 ml sample Absent in 100 ml sample Absent in 100 ml sample Absent in 100 ml sample 5 NTU 15 TCU 6.5-9.0 1.0 mg/L 3 mg/L 1000 mg/L 250 mg/L 0.5 mg/L 10 mg/L 0.3 mg/L 0.6-0.9 500 mg/L 0.2 mg/L 0.1 mg/L 0.001 mg/L 0.003 mg/L 0.01 mg/L 0.07 mg/L 0.05 mg/L 0.05 mg/L 1.0 mg/L 3 mg/L 200 mg/L 250 mg/L 0.2 mg/L 0.1 mg/L 0.1 mg/L 0.01 mg/L 0.05 mg/L 150 mg/L 0.02 mg/L 0.00003 mg/L 0.002 mg/L 0.00003 mg/L 0.02 mg/L 0.007 mg/L 0.0006 mg/L 0.02 mg/L 0.01 mg/L 0.1 Bq/L 1.0 Bq/L

(Ministry of Health Malaysia, 1983)

20 than 75 TCU. For higher levels, activated/powdered carbon or ozonation may be required in addition to the conventional treatment.

2.3.1.2 Turbidity Turbidity may be due to organic or inorganic impurities suspended in water. In Malaysian waters, silt, clay and finely divided organic matter are the predominant suspended solids. It is an indication of the clarity of water. The maximum turbidity level allowed in drinking water is 5 NTU (Tay, 2000). Turbidity in raw water can be reduced to accepted levels by appropriate coagulation, flocculation, sedimentation and filtration.

2.3.1.3 Total Dissolved Solid Total dissolved solid (TDS) is a quantitative measurement of the dissolved salts in a water. For given water the dissolved solids concentration can be directly related to the conductivity. The maximum accepted TDS in water treatment plant is 1000 mg/L (Tay, 2000).

2.3.1.4 pH The pH value is a measurement of the acidity or alkalinity of water. It is one of the most important parameter in water chemistry since many of the processes involved in water treatment are pH-dependent. The recommended value of pH of treated water is between 6.5 and 9.0. All treated water should be “conditioned” and adjust before it is sent into the distribution system.

21 2.3.2

Chemical Quality This is the most difficult group to deal with since conventional treatment

techniques generally are not effective. Therefore, first consideration should be given to alternative sources and blending of sources. Fortunately they are not usually present in concentrations anywhere near the maximum permissible levels. They are generally found only when industrial contamination is present.

2.3.2.1 Mercury Mercury is a toxic element and has no beneficial physiological function in man. In drinking water it is predominantly in the inorganic form, which is poorly absorbed. The concentration of 0.002 mg/L is the maximum allowable value (Letterman et al., 1999).

2.3.2.2 Arsenic The maximum allowable concentration in drinking water for arsenic is set at 0.05 mg/L (Tay, 2000). It can be found in surface waters from areas where there are certain type of metalliferous ore.

2.3.2.3 Lead Lead is a cumulative body poison and the hazards of exposure to lead have been well documented. It is rare to find natural waters with a lead concentration more than 0.02 mg/L (Tay, 2000). The maximum allowable value is 0.05 mg/L of lead.

22 2.3.2.4 Copper Copper in drinking water can be derived from rock weathering, however the principal sources are the corrosion of brass and copper piping and the addition of copper salts when treating water supplies for algae control. Standard of 1.0 mg/L copper concentration applies to water leaving the plant (Letterman et al., 1999).

2.3.2.5 Chlorine Chlorine is the most commonly used agent for the disinfection of water supplies. Chlorine is a strong oxidizing agent capable of reacting with many impurities in water including ammonia, proteins, amino acids, iron, and manganese. A maximum chlorine content of 1.0 mg/L has been recommended in treated water treatment plant (Tay, 2000).

2.3.2.6 Manganese Manganese resembles iron in its chemical behaviour and occurs in natural waters, but normally in lower concentration then iron. Manganese can be a troublesome element even when a present in small quantities. Manganese has a common value 0.1 to 1 mg/L (Crittenden et al., 2005). It can be deposit out of the distribution systems in the presence of oxygen.

2.3.2.7 Ammonia Ammonia is one of the forms of nitrogen found in water. It is usually found in most natural waters. They originate from various sources, some of which are completely harmless, for example decomposing vegetation. Up to 0.5 mg/L are accepted in treated water (Tay, 2000). Ammonia is effectively removed by chlorination.

23 2.3.2.8 Nitrate The nitrate is the final stage of oxidation nitrogen compounds and is related to organic matter present in the water. Waters containing high nitrate concentrations are potentially harmful. Upper limit of 10 mg/L of nitrate has been set for treated water (Letterman et al., 1999).

2.3.2.9 Iron Iron is found in most raw waters where it can impart a bitter taste when present in large amounts, making the water unpalatable. Iron standard value is 0.3 mg/L in treated water (Crittenden et al., 2005). Currently treatment process involved aeration follow by adequate coagulation, flocculation, sedimentation, filtration and pH control.

2.3.2.10 Fluoride Fluoride content of surface waters in Malaysia is usually low. Fluoride is added to provide substantial protection against dental caries. However, too high fluoride concentration in drinking water will lead to adverse health effects varying from mottling of teeth to crippling fluorosis (Crittenden et al., 2005). A maximum fluoride content of 0.9 mg/L has been recommended in treated water treatment plant.

2.3.2.11 Hardness Water hardness is a measure of polyvalent cation contents, predominant of calcium and magnesium, but also include strontium, barium etc, in term of CaCO3 equivalent in mg/L (Letterman et al., 1999). The conventional treatment hardness of up to 500 mg/L is permitted.

24 2.3.2.12 Aluminium The most usual source of aluminium in drinking water comes from corrosion of aluminium utensils, tanks or pipes or from incorrect dosing of aluminium sulphate as coagulant at the treatment works. Ideally water going into supply should contain less than 0.2 mg/L (Tay, 2000).

2.3.3

Microbiological Quality Microbiological quality of drinking water is the greatest importance and must

never be compromised. The microbe is believed exist when there is pollution. Urgent measures must be taken out to find out the source. No faecal coliform should present in 100 mL treated water (Tay, 2000).

2.4

Water Parameters Removal by Water Treatment Process Several parameters in water that impact drinking water and treatment process

that may be used to remove them are reported in Table 2.12 (Crittenden et al., 2005). The performance of these treatment processes for a given constituent is presented subjectively in terms of removal efficiencies reported in various studies. The information presented in Table 2.12 can be used as a general guideline when a particular parameter must be removed. However, parameters that comprise background water matrices can vary widely with respect to their number and concentration and can impact treatment process performance.

25 Table 2.12

General effectiveness of water treatment processes removal

Type

Parameters

Inorganic

Arsenic (+3) Barium Chromium (+3) Copper Fluoride Hardness Iron Lead Manganese Mercury Nitrate Perchlorate Radium Uranium VOCs SOCs Colour TTHMs MTBE NDMA

Organic

Aeration P P P P P P F-G P F-G P P P P P G-E P-F P G-E G-E P

Coagulation, Sedimentation, Filtration G-E G-E G-E G F-G P F-E E F-E F-G P NA P-F G-E P P-G P-G P P NA

Note: P-poor (0-20% removal), F-fair (20-60% removal), G-good (60-90% removal), E-excellent (90-100% removal) (Crittenden et al., 2005)

2.5

Engineering knowledge The process of building knowledge-based systems is called knowledge

engineering (KE). It has a great deal in common with software engineering, and is related to many computer science domains such as artificial intelligence, databases, data mining, expert systems, decision support systems and geographic information systems. (Negnevitsky, 2004).

2.6.1

Engineering Knowledge Principles Since the mid-1980s, knowledge engineers have developed a number of

principles, methods and tools that have considerably improved the process of

26 knowledge acquisition (Russell, and Norvig, 2003). Some of the key principles are summarized as follows: i) Knowledge engineers acknowledge that there are different types of knowledge, and that the right approach and technique should be used for the knowledge required. ii) Knowledge engineers acknowledge that there are different types of experts and expertise, such that methods should be chosen appropriately. iii) Knowledge engineers recognize that there are different ways of representing knowledge, which can aid the acquisition, validation and re-use of knowledge. iv) Knowledge engineers recognize that there are different ways of using knowledge, so that the acquisition process can be guided by the project aims. v) Knowledge engineers use structured methods to increase the efficiency of the acquisition process.

2.7

Programming Tool using Visual Basic Visual Basic (VB) is an event-driven programming language and associated

development environment prototyped by Alan Cooper as Project Ruby, then bought and vastly improved upon by Microsoft. Visual Basic was designed to be easy to learn and use. The language not only allows programmers to easily create simple graphical user interface applications, but also has the flexibility to develop fairly complex applications as well. Programming in VB is a combination of visually arranging components or controls on a form, specifying attributes and actions of those components, and writing additional lines of code for more functionality. Since default attributes and actions are defined for the components, a simple program can be created without the programmer having to write many lines of code. Performance problems were experienced by earlier versions, but with faster computers and native code compilation this has become less of an issue (Corburn, 1999). Although programs can be compiled into native code executables from version 5 onwards, they still require the presence of runtime libraries of approximately 2 MB in size. This runtime is included by default in Windows 2000

27 and later, but for earlier versions of Windows it must be distributed together with the executable. Forms are created using drag and drop techniques. A tools palette is used to place controls (e.g., text boxes, buttons, etc.) on the form (window). Controls have attributes and event handlers associated with them. Default values are provided when the control is created, but may be changed by the programmer. Many attribute values can be modified during run time based on user actions or changes in the environment, providing a dynamic application. For example, code can be inserted into the form resize event handler to reposition a control so that it remains centred on the form, expands to fill up the form, etc. By inserting code into the event handler for a key press in a text box, the program can automatically translate the case of the text being entered, or even prevent certain characters from being inserted (Coburn, 1999).. A Visual Basic application can consist of one or more windows, or a single window that contains Multiple Document Interface (MDI) child windows, as provided by the operating system. Dialog boxes with less functionality (e.g., no maximize/minimize control) can be used to provide pop-up capabilities. Controls provide the basic functionality of the application, while programmers can insert additional logic within the appropriate event handlers (Mckeown 2004). For example, a drop-down combination box will automatically display its list and allow the user to select any element. An event handler is called when an item is selected, which can then execute additional code created by the programmer to perform some action based on which element was selected, such as populating a related list.

2.7.1

Behaviour Present in Visual Basic Visual Basic has the following special traits:

i) Boolean constant True has numeric value -1. In most other languages, True is mapped to numeric value 1. This is because the Boolean data type is stored in the same way as a 16 bit signed integer. In this construct -1 evaluates to 16 binary 1s (the

28 Boolean value True), and 0 as 16 0s (the Boolean value False). This is apparent when performing a Not operation on a 16 bit signed integer value 0 which will return the integer value -1. This inherent functionality becomes especially useful when performing logical operations on the individual bits of an integer such as And, Or, and Not (Coburn, 1999). ii) Logical and bitwise operators are unified. This is unlike all the C-derived languages (such as Java or Perl), which have separate logical and bitwise operators. iii) Variable array base. Arrays are declared by specifying the upper and lower bounds in a way similar to Pascal. It is also possible to use the Option Base statement to set the default lower bound. Use of the Option Base statement can lead to confusion when reading Visual Basic code and is best avoided by always explicitly specifying the lower bound of the array. This lower bound is not limited to 0 or 1, because it can also be set by declaration. In this way, both the lower and upper bounds are programmable. In more subscript-limited languages, the lower bound of the array is not variable. iv) Ability to run the application without performing a full compile or making an executable, allowing for edit-and-continue changes. v) Relatively strong integration with the Windows operating system. vi) Banker's rounding as the default behaviour when converting real numbers to integers. vii) Integers are automatically promoted to real in expressions involving the normal division operator (/) so that division of an odd integer by an even integer produces the intuitively correct result. There is a specific integer divide operator (\) which does truncate.

29 2.7.2

User-friendly Interface design Here are a few recommendations and examples for Microsoft Access

developers who want to make user-friendly interface Access database interfaces (Mckeown 2004): i) Colours - Choose screen colours with good contrast. If the first thing a person notices when viewing the screen are the colours then you have gone too far in colorizing your screen. The user should first notice the field labels followed by the data MS Access developers. Bold black letters on grey background is preferred for the boilerplate and black letters on white background is preferred for data. Use colours to highlight important fields or data in your form designs. Consider making required fields standout from other fields. ii) Fonts - The fewer the fonts the better. Fonts without serifs tend to be easier to read. Avoid using several different font sizes - stick to one or two. Don't use a lot of italics, and underlines. iii) Layout - When you have many fields to display on a form try to group them. For instance you can group Name, Address, etc. together on the form and separate this information from other supporting information in the data record. Don't forget to set the tab order on your form correctly. iv) Buttons - Avoid creating your own navigation and function buttons whenever these buttons are already available in a standard Microsoft Access form. Examples of some standard buttons/functions are Next Record, New Record, Sort, etc.

2.8

Security System by Password Security is an important concept in information an system that is aimed to

protecting them from unauthorized entry (Chua, 1997). The user is usually given passwords to enter the program. Passwords vary in the degree of public awareness, security protection and frequency of change. The most public, and therefore least

30 secure, password might be one that is given to members of a group, a committee or some other organization for instance, "public_library", "internet" or "AAA_finance" are all examples of easily remembered passwords. In controlling access to anything, trade-offs are made between security and convenience. If a resource is protected by a password, then security is increased with a consequent loss of convenience for users. The amount of security and inconvenience inherent in a particular password system or policy are affected by several factors addressed below. However, there is generally no one universal best way to set a proper balance between security and convenience for all cases (Mckeown, 2004).

31

CHAPTER 3

METHODOLOGY

3.1

Development of WATER-DSS The DDS in this study is known as WATER-DSS. The development of

WATER-DSS

applies

methods

of

conventional

computing

practices

and

programming techniques. WATER-DSS was built by integrating the conceptual design of drinking water treatment through conventional method into a computer program, which has capability as a DDS. The structure design of WATER-DSS is shown in Figure 3.1. Student Visual Basic 6.0

Lecturer

Master Student

Regulator End User Contractor Engineer

WATERDSS

Lecturer Knowledge & Expertise

PhD Student

Consultant

Articles

Authority Manuals

Figure 3.1

WATER-DSS development structure

32 3.2

Forms of WATER-DSS Project in Visual Basic WATER-DSS program is planned to provide the security system, welcoming

frame, parameter input, water treatment process, summary sheet and appreciation frame. These forms are created in Visual Basic 6.0, as shown in Figure 3.2.

Figure 3.2

3.2.1

Forms in WATER-DSS

Security of WATER-DSS One of the most widely used systems for providing protection for an

information system is to require a password that is known only to an authorized user. User can assess WATER-DSS if they enter the correct password. If fail to do so, the program will be terminated. A security Password form is created as Figure 3.3.

Title Label Textbox Command1 Timer1 Background

Figure 3.3

Password form

33 Double click on command1, key in the below code.

Private Sub Command1_Click() If Text1 = "FKA" Then Timer1.Enabled = False Form0.Hide Form00.Show Else MsgBox ("Sorry, invalid password."), , "password" End If End Sub Password of WATER-DSS is temporary set to “FKA”. To login WATER-DSS, “FKA” has to be entered in the textbox in Figure 3.3. If user insert wrong password, message box indicating “Sorry, invalid password.” will appear. To enhance the security system, 20 seconds limitation is set for user to enter the correct password. The code of timer1 is as below:

Private Sub Timer1_Timer() MsgBox ("sorry, your time is up."), , "Bye bye.." End End Sub

3.2.2

Welcome frame

If correct password (“FKA”) is entered, a welcome screen is shown in Figure 3.4. Double click on Command1 and insert the following code:

Private Sub command1_Click() Form00.Hide Form01.Show End Sub

34

Textbox

Command1

Command2

Image

Figure 3.4

Welcome form

After enter the code, the form00 (Password form) will be closed and form01 (Parameter Input form) will be opened. Double click on Command2 and insert the following code:

Private Sub command2_Click() Form00.Hide Form10.Show End Sub After enter the code, the form00 (Password form) will be closed and form01 (Thank You form) will be opened. To make sure the textbox is not changeable, textbox properties are edited and changed to: Name

: Text1

Text

: Welcome to WATER-DSS 2006

Font

: Time New Romans, Bold, 16

Tabstop

: False

Locked

: True

Backcolour

: &H00FFFFC0&

35 To set this form is not show in early program, double click on form background and insert the following code: Private Sub Form_Load() Form00.Hide End Sub Images are input from the picture taken in the Sayong Water Treatment Plant, Johor.

3.2.3

Parameter Input Form

Parameter Input form is considered one of the most important form where user can input all the collected data from field or site to do further checking. In the form, textbox for parameter input is provided. Standard parameter value based on the Malaysia National Water Quality Standards is also shown. Picturebox is prepared to recognise the parameter values and present related treatment information if the values exceed the range of requirement standard. The design interface of this form is illustrated in Figure 3.5. In WATER-DSS, the parameters are basically divided into four sections which are shown in Table 3.1 Table 3.1: Category of water parameters 1 2

Section Physical Inorganic

3 4

Metal Microbiological

Parameter Turbidity, colour, pH and chlorine. Total Dissolve Solids (TDS), manganese, ammonia, nitrate, iron, fluoride, hardness and aluminium. Mercury, arsenics, lead and copper. Faecal coliform.

36

Command1

Command2

Command3

Frame1

Frame2

Picturebox Picture1, 2…

Frame3

Label (Standard)

Frame4

Textbox Text1, 2…

Figure 3.5

Parameter Input form

i) Double click on Command1 and insert the following code (this code also enables the calculation to run if user not inserts all the input parameters):

Private Sub Command1_Click() Picture1.Cls If Text1 vbnouncestring Then If Text1 5 Then Picture1.BackColor = &HC0C0FF Picture1.Print strtitle$ End If Picture2.Cls

37 If Text2 vbnouncestring Then If Text2 15 Then Picture2.BackColor = &HC0C0FF Picture2.Print strtitle$ End If Picture3.Cls If Text3 vbnouncestring Then If Text3 >= 6.5 And Text3 = 6.5 And Text3 9 Then strtitle$ = "pH adjustment-Lime" If Text3 < 6.5 Or Text3 > 9 Then Picture3.BackColor = &HC0C0FF Picture3.Print strtitle$ End If Etc…… End Sub ii) Double click on Command2 and insert the following code:

Private Sub Command2_Click() Form01.Hide Form02.Show End Sub iii) Double click on Command3 and insert the following code:

Private Sub Command3_Click() Form10.Show

38 End Sub iv) The picturebox properties are edited and changed to: Name

: Picture1, Picture2, Picture3 ….

Text

: (None)

Font

: Time New Romans, Italic, 12

Tabstop

: False

Locked

: True

Backcolour

: &H00FFFFC0&

v) Double click on form textbox and insert the following code:

Private Sub Text1_Change() Form04.Text1 = Text1 Form09.Text1 = Text1 End Sub Private Sub Text2_Change() Form04.Text2 = Text2 Form09.Text2 = Text2 End Sub Private Sub Text3_Change() Form04.Text3 = Text3 Form09.Text3 = Text3 End Sub After these codes are entered, any data that input into these textbox will be automatically transfer to textbox in form04 (Aeration form) and form09 (Summary form).

39 3.2.4

Water Treatment Process form This is the form where overall of conventional water treatment process is

presented. From here, user can select any process that he needs to get more information. The design interface of the form is illustrated in Figure 3.6. Additional information about pre-chlorination, coagulant, pH adjustment, fluoridation and disinfection is supplied.

Command1

Command2

Command3

Command8 Command9

Command4

Command10

Command5

Command6

Command11

Command7

Command12 Command13 Command14

Figure 3.6

Water treatment process form

Command1, Command2, Command3, Command4, Command5, Command6 and Command7 are created to link user to Pre-treatment form, Aeration form, Coagulation form, Flocculation form, Sedimentation form, Filtration form and Summary form respectively. Below are codes that need to be entered after double clicking on those commands.

Private Sub command1_Click() Form02.Hide Form03.Show End Sub

40 Private Sub command2_Click() Form02.Hide Form04.Show End Sub Private Sub Command3_Click() Form02.Hide Form05.Show End Sub Private Sub Command4_Click() Form02.Hide Form06.Show End Sub Private Sub Command5_Click() Form02.Hide Form07.Show End Sub Private Sub Command6_Click() Form02.Hide Form08.Show End Sub For providing additional information, double click on command8, command 9, command10, command11, command12, comman13, and insert the following code:

Private Sub Comman8_Click() MsgBox ("Remove ammonia; 1 mg/L ammonia required 10 mg/L Chlorine."), , "Pre-clorination" End Sub Private Sub Command9_Click() MsgBox ("Add fluoride to reduce dental decay"), , "fluoridation"

41 End Sub Private Sub Command10_Click() MsgBox ("pH increase, encourage coagulation process"), , "Coagulation-lime" End Sub Private Sub Command11_Click() MsgBox ("Remove iron and manganese."), , "Coagulation-alum" End Sub Private Sub Command12_Click() MsgBox ("Increase pH up to drinking standard"), , "pH adjustment" End Sub Private Sub Command13_Click() MsgBox ("Disinfection, remove any potencial bacteria"), , "Chlorination" End Sub Command7 is the command buttons where user can straight forward go to the summary form without going trough all detail process. After clicking this button, the data need to transfer from Parameter Input form (Form01) into the Summary form (Form09). At the same time, the analysed parameter value is straight presented in the Summary form. The calculation is based on the percentage removal which is given in Table 3.2. The output values that exceed or not in the range compare standard value will automatic change to red colour. IF the parameter remains good quality from input until output, the remark of “No specific treatment required” is shown. If parameter can be treatment by the treatment process, the remark of “Can be treated by treatment” is shown. Further action if needed is presented in Table 3.1. To this, this code need to key in after double click on the Command7 button:

Private Sub Command7_Click() Form02.Hide

42 Form09.Show If Form01.Text1 vbnouncestring Then Form09.Text1 = Form01.Text1 Form09.Text18 = Form01.Text1 * 0.1 Form09.Picture1.Cls If Form09.Text1 5 And Form09.Text18 5 Then strtitle$ = "Not suitable for water intake" If Form09.Text18 5 Then Form09.Picture1.BackColor = &HC0C0FF If Form09.Text18 5 Then Form09.Text18.BackColor = &HC0C0FF Form09.Picture1.Print strtitle$ End If If Form01.Text2 vbnouncestring Then Form09.Text2 = Form01.Text2 Form09.Text19 = Form01.Text2 * 0.9 * 0.55 Form09.Picture2.Cls If Form09.Text2 15 And Form09.Text19 15 Then strtitle$ = "Not suitable for water intake" If Form09.Text19 15 Then Form09.Picture2.BackColor =

43 &HC0C0FF If Form09.Text19 15 Then Form09.Text19.BackColor = &HC0C0FF Form09.Picture2.Print strtitle$ End If Etc……………. End Sub Table 3.2: Simplify removal percentage by process treatment and further treatment action 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Parameter Turbidity Colour pH Chlorine TDS Manganese Ammonia Nitrate Iron Fluoride Hardness Aluminium Mercury Arsenic Lead Copper Total coliform

Aeration 10% 40% 10% 55% 10% 10% 40% 10% 10% 10% -

CFSF 90% 45% 65% 90% 10% 85% -

Fail meet standard after treat Not suitable for water intake Not suitable for water intake check lime dosing Check chlorine dosing Not suitable for water intake Add more coagulant Add more chlorine Not suitable for water intake Add more coagulant Stop Fluoride dosing, waiting dilution Not suitable for water intake Check dosing alum Not suitable for water intake Not suitable for water intake Not suitable for water intake Not suitable for water intake Not suitable for water intake

Note: CFSF – Combination coagulation, flocculation, sedimentation, filtration.

3.2.5

Pre-treatment Form Pre-treatment is a water treatment process to remove large objects such as

logs, sticks, fish, and plants. This is to prevent damage and avoid silting in treatment plant. In this form, information about coarse screens and pre-sedimentation is given.

44 Pre-sedimentation form interface is shown in Figure 3.7. Calculation of removal parameters is not included in this form.

Coarse screen

Description Design criteria

Presedimentation

Additional information

Command2

Command1 Command3

Figure 3.7

Pre-treatment form

To avoid this form shown at early, the code need to enter is (This code is used to all other forms except the Password form):

Private Sub Form_Load() Form03.Hide End Sub The Next command button is to bring user to the next form; Back command button is to bring user back to Water Treatment Process form. In order to do so, the following code need to key into the command button:

Private Sub command1_Click() Form03.Hide Form02.Show End Sub Private Sub Command2_Click()

45 Form03.Hide Form04.Show End Sub

3.2.6

Aeration Form Aeration is a process of bringing water and air into close contact in order to

remove dissolved gases and to oxidise dissolved metal that assist in removal iron and manganese. In this Aeration form, the interface is design as shown in Figure 3.8. Output of parameters after this aeration treatment is calculated and presented in the output textbox. Removal parameter percentage can refer in Table 3.2. If the output calculated not reach the standard value, the textbox will change to red colour

Output Text18, 19… Input Text1, 2... Description

Design criteria

Additional Information

Command1

Figure 3.8

Standard

Aeration form

46 In this form, to calculate the output of the input parameter value, command1 as the run button need to be entered the following code:

Private Sub Command1_Click() If Text1 vbnouncestring Then Text18 = Text1 If Text18 > 5 Then Text18.BackColor = &HC0C0FF If Text18 15 Then Text19.BackColor = &HC0C0FF If Text19 9 Then Text20.BackColor = &HC0C0FF If Text20 >= 6.5 And Text20 5 Then Text18.BackColor = &HC0C0FF If Text18 15 Then Text19.BackColor = &HC0C0FF If Text19 9 Then Text20.BackColor = &HC0C0FF If Text20 >= 6.5 And Text20 = 6.5 And Text3 = 6.5 And Text20 9 Then strtitle$ = "check lime dosing" If Text20 >= 6.5 And Text20 9 Then Picture3.BackColor = &HC0C0FF Picture3.Print strtitle$

50 End If Etc……… End Sub

3.2.9

Thank You Form After finish using the WATER-DSS, an interface that appreciate user is

created. WATER-DSS is ended by click on the command button “Quit” shown in Figure 3.9, and a Thank You form should pop out before the WATER-DSS is completely end. Thank You form is shown in Figure 3.10.

Cancel

Command1

Figure 3.10

Thank You form

Command1 is used to terminate this WATER-DSS program and the code is:

Private Sub command1_Click() End End Sub If user changes mind to continue using this program, he/she can simply click on the cancel button shown in Figure 3.10.

51

CHAPTER 4

RESULT & DISSCUSION

4.1

General Throughout the study, a decision support tool for design and process selection

of drinking water treatment plant using conventional method has been developed. It has been given name of WATER-DSS.

4.2

Application of WATER-DSS The WATER-DSS is a tool that assists decision making on the process of

drinking water treatment plant using conventional treatment methods. The process consists of pre-treatment, coagulation, flocculation, sedimentation, filtration and disinfection. The processes are selected based on the requirement to treat the raw water, chemically, physically and microbiologically. Each parameters of water has it own treatment procedure but often it can combine.

4.3

Validation Of Result To validate WATER_DSS, three sets of data have been entered into the

Parameter Form and run. At the same time, manual calculations are made using

52 Microsoft Excel spreadsheet which refers Table 3.2. The output of WATER-DSS is then verified using Microsoft Excel. The validation of WATER-DSS is presented in Table 4.1.

4.4

Discussion WATER-DSS has been successfully developed. Using WATER-DSS, user

can design the water treatment process as well as maintain the plant operation. This application is simple through input parameter water quality that collected from the side into WATER-DSS Parameter Input form. The result of parameters is analysed and essential water treatment process is presented. The final result after treatment using conventional method can be checked in the Summary form. In Summary form, further treatment or action is suggested according to the output of treatment process. If user desires to get more details information about the treatment processes, he/she can enter the related treatment forms. In the detail treatment form, user can gain information such as description of process, typical design criteria of treatment plant, alternative suggestions of the practice and the removal of the parameters by treatment. The entire form are interrelated and connected, user can freely enter any form they wish to obtain the needed information. WATER-DSS has been set only to allow the authorise user. This is to enhance the security and privacy system. Virtually everyday news about hacker breaking into a computer system for “fun” or with criminal intent can be observed (Mckeown, 2004). If user fails to entry the correct passwords into the Password form, they are denied to login WATER-DSS. WATER-DSS has been developed as a user-friendly program. The form, background, font, colour, title, textbox, picture, link are all design, arrange and set to attractively, accordingly and systematically. User can easily run and access WATERDSS as they wish.

Turbidity Colour pH Chlorine TDS Manganese Ammonia Nitrate Iron Fluoride Hardness Aluminium Mercury Arsenic Lead Copper Total coliform

Parameter 12.375 12.375 6.8 6.8 0.2 0.2 120 120 0 0 0.01 0.01 0.081 0.081 0.0135 0.0135 0.09 0.09 99 99 0.2 0.2 0 0 0 0 0.018 0.018 0 0 0 0 1

30 50 6 2 1500 0.3 0.5 7 0.25 0.2 450 0.2 0.01 0.03 0.04 0.4 0

3 50 6 2 1500 0.063 0.05 5.67 0.017 0.18 405 0.2 0.006 0.06 0.036 0.36 0

3 50 6 2 1500 0.063 0.05 5.67 0.017 0.18 405 0.2 0.006 0.06 0.036 0.36 0

SET 2 Corr. Input W-D M-E

1

Corr. 60 80 8 1.5 900 0.3 0.5 8 0.5 0.5 550 0.4 0.03 0.03 0.06 0.9 2

Input 6 39.6 8 1.5 900 0.063 0.07 6.48 0.034 0.45 495 0.4 0.018 0.027 0.054 0.81 2

6 39.6 8 1.5 900 0.063 0.07 6.48 0.034 0.45 495 0.4 0.018 0.027 0.054 0.81 2

SET 3 W-D M-E

Corr.: Correlation obtain using Microsoft Excel (1 = significant direct relation, 0 = not significant relation)

M-E: Microsoft Excel result

6.8 0.2 120 0 0.1 0.1 0.2 0.1 110 0.2 0 0 0.02 0 0

25

SET 1 Input W-D M-E 2 2 20

Comparison WATER-DSS result and Microsoft Excel result

Note: W-D: WATER-DSS result

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Table 4.1

1

Corr.

51

51 WATER-DSS is also validated using Microsoft Excel. The comparison in Table 4.1 prove the relationship between the WATER-DSS output and manual calculation output is significant.

55

CHAPTER V

CONCLUSION

5.1

Conclusion The conclusions of this study are as follows: i) A DSS called WATER-DSS was successfully designed and developed

according to the planned output. ii) Validation of WATER-DSS was conducted using comparison output between WATER-DSS and Microsoft Excel and it show significant relationship.

5.2

Suggestion To enhance WATER-DSS for future quality and value, some suggestion has

made: i) Technical knowledge - There is more information need to be added into WATERDSS in the future development. Calculation forms such as coagulant dosing, output of jar test, tank estimation, efficiency of treatment, cost analysis need to be provided. All parameters exist in standard need to be offered to enable user to gain all the needed data. More real water treatment plant data need to be collected especially the

56 removal percentage of parameters to verify the WATER-DSS program. Information of alternative treatment process need to be included such as spray aerator, mechanical flocculators, inclined parallel plate settler sedimentation tanks, slow sand filters and etc. More pictures such as design layout plan of aerator, flocculator and filtration tank can be added. ii) Human Power - An expert in computer programmer is needed to assist in the WATER-DSS development. With the computer knowledge of him/her, the WATERDSS can present more useful data, information in a user-friendly form. iii) Computer system – WATER-DSS can provide storage of database information in order to allow user to save, load and trace back their previous data and information. Print function should be enabled to allow user to print any form that they require. Password setting modify to changeable to let user change passwords periodically. A form that store all the information on the site such as location, name of river, date, temperature can be created to differential the study area. Flow of parameter is suggested to be presented in graph so that the value changes throughout the treatment process by process are clearly illustrated.

5.3

Error in Study Throughout the study and development of WATER-DSS, some errors or

inaccuracies have been identified. Due to time constrain, the error was notable to be corrected. i) Knowledge-base information - The removal of parameters in WATER-DSS is obtained from the Water Treatment Principle and Design textbook. The removal percentage is a typical value which may different from one treatment plant to another treatment plant. Further checking and validation need to be carried out to ensure the quality and reliability of WATER-DSS. A categorization mistake has been made in Parameter Input form. For example, arsenic is origin from metal class. The parameters classification should be follow the Malaysia National Water Quality Standard (2004). Parameter such as pH, chlorine, aluminium is not changed during

57 the WATER-DSS. More research and study need to be made to ensure the accurate output of the entire parameters can be obtained. ii) Computer program - The “print” command not yet being enabled. In future not only this command button should be modified, command such as “save”, “load” and “clear input” must be added.

58

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