EXPERIENCES WITH ZLD AND WAY FORWARD

German Water Partnership -Day 2017 German Solutions to Indian Challenges 20th Sept 2017 I. Sajid Hussain, Chief Operating Officer Tamilnadu Water Investment Company Limited. www.twic.co.in [email protected] 1

CONTENTS 

Section A : Concept of ZLD

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Section B : Brief Experience with ZLD in Textile Dyeing and tannery CETPs

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Section C: Recent advances in ZLD technologies

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Section D : Approach to ZLD

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Section E : Conclusions 2

SECTION A: CONCEPT OF ZLD

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Concept of ZLD 

ZLD – meaning zero discharge of wastewater from Industries.

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A ZLD system involves a range of advanced wastewater treatment technologies to recycle, recovery and re-use of the ‘treated’ wastewater and thereby ensure there is no discharge of wastewater to the environment.

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A typical ZLD is an hybrid system comprising of the following components: 

Pre-treatment (Primary Secondary and Tertiary treatment)

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Reverse Osmosis

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Evaporator & Crystallizer

Land application & Deep well disposal of treated effluent is not permitted (Tamilnadu).

 ZLD based on directions from SPCB. 4

Need for ZLD…1 

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MAIN MOTIVATORS- Water Scarcity, water economics, regulatory pressure. Water Scarcity Several states in India including Tamilnadu are water stressed.54% of India faces High to extremely high water stress and 54% of ground water wells are decreasing– WRI. No ground water for irrigation by 2025 in Delhi, Rajasthan and Haryana. UNESCO Report says India holds the number 1 spot for the annual Ground water extraction at 251 cu.Km as against 112 cu.km in China and USA, a distant second. Competing demands for water from agriculture and domestic use has limited industrial growth. 5

Need for ZLD…2 

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TN has taken a lead on ZLD due to absence of fully flowing Perennial River. Most rivers originate from neighboring states and water sharing is enmeshed in disputes. With ZLD the industry can be located in barren and low water potential or quality areas. Industrial Production is not affected even during drought years.

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Need for ZLD …3 Pollution issues & Regulatory pressure..1  Industrial Effluents with high salinity/TDS- polluting industries such as Pharma, Pulp& Paper, Tanneries, Textile Dyeing, Chemicals , Power Plants etc.  The TDS content is well above the statutory limit of 2100 mg/l.  Draft ZLD notification dropped by MoEF but the revised notification speaks of exhausting recycling and reuse options.  Conventional ‘Physico-chemical-biological’ treatment does not remove salinity in the treated effluent.  Discharge of saline but treated wastewater pollutes ground and surface waters. 7

Need for ZLD …4 Pollution issues & Regulatory pressure..2  189 CETPs in the country and non-compliance is a major issue. Same with STPs. Individual ETPs ?. No incentives for treatment for CETP/ STP/ETP. Recovery and reuse of water is seen to be major incentive. 

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Several landmark pollution cases and court battles -Vellore and Tirupur court cases. Most rivers in the country are polluted. ZLD is easy to monitor for compliance, any discharge from the factory 24 x7 means non-compliant. No need for lay man to complain, inspect, collect samples or test in lab and check with standards. NGT actively perusing pollution cases and prohibiting discharge to rivers. Poor experience with marine discharge and effluent channels polluting enroute and the sea, affecting coastal communities are also 8 known.

Need for ZLD …5 Water Economics 

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Indiscriminate withdrawal of ground water ‘free of cost’ in most parts of the country. Water priced low in many parts. However, cost of fresh water for Industry is rising due to scarcity, Tirupur it is Rs.78/m3, Vellore –Rs.50/m3, Pali- Rs. 100/m3. Location of industries in ‘Inland areas’ therefore marine discharge may not feasible. Cost of marine discharge increases with distance from shore and if the cost of fresh water is high (say Rs. 50/m3) then beyond 20 KM, ZLD becomes competitive. Other states such as Andhra, Telangana, Rajasthan, and Karnataka are also now enforcing ZLD in many cases. Internationally ZLD is gaining prominence – China, 9 Bangladesh, USA, Germany etc.

Barriers / Challenges in ZLD  ZLD results in generation of hazardous solid wastes creating

disposal challenges- need to think of Zero Waste Disposal (ZWD) Plants. Generate products/ by-products out of the waste.  Economic viability- cost and availability of water, regulatory pressure

are the real driving force.  High Carbon foot print- is this environmentally sustainable?  High Operating cost and financial impact on the industry and its

Regional/ National/Global competitiveness.  Technology shortcomings. 10

Benefits of ZLD 

Installing ZLD technology is beneficial for the plant’s water management; encouraging close monitoring of water usage, avoiding wastage and promotes recycling by conventional and far less expensive solutions.

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High operating costs can be justified by high recovery of water (>90-95%) and recovering of several by products from the salt.

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A more sustainable growth of the industry while meeting most stringent regulatory norms.

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Reduction in water demand from the Industry, frees up water for Agriculture and Domestic demands.

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No loss in production even during drought years. 11

Section B- Brief experience with ZLD in Textile Tannery CETPs and Pulp & Paper

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Textile Dyeing CETPs in Tirupur  

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18 CETPs established based on ZLD. Most CETPs are based in treated brine reuse technology and Sodium Sulfate salt crystallization and reuse. Design Capacities range from 1.5 MLD to 12 MLD. Currently operating at 30 -90% capacity (average 50%). 95-98% recovery of water and 80% recovery of salt. Operating costs at Rs. 200-250 Rs/m3. Expected to go down to Rs. 180/m3 with further project modifications. Net operating cost after salt and water recovery at ~ Rs. 100-150 per m3. Financial Impact: 5 to 6% on production cost. Rs. 4 to Rs. 5 per Kg of dyed fabric. Independent O&M agency for all CETPs, PMA agency is 13 operator in most cases.

Tirupur Dyeing ZLD CETP Project Concept Well water / River water for Top up

*90-95% 110-120%

Textile Dyeing Units

Recovered water for reuse

Treated Brine for resue (Mixed salt )

Raw effluent

Chemical sludge (Lime sludge) for Brick Manufacturing /Co-Processing in Cement Industry ZLD CETP

Bio sludge for manufacturing briquettes after blending with Agro waste and usage as fuel in

Recovered sodium sulphate salt for top-up / sale 14

Process Schematic for a typical ZLD based Textile CETP

Biomass Recirculation

Raw effluent from member dyeing units Storage and Homogenization tank

Reverse Osmosis

Biological Oxidation Tank

MVR

Secondar y Clarifier

Chlorine contact Tank

Back wash/CIP to SHT

Quartz Filter

Excess sludge

Resin Regenerate Liquor

Reactor Clarifier

Sludge Thicken er

Filter Press

MEE

Adiabatic Chiller

Solar Evaporation Pan

Pusher Centrifuge

Waste salt for disposal

ML Bio sludge cake for disposal

Ultrafiltration system Decolourant Resin Filter

Recovered water for reuse (RO Permeate & Evaporator condensate)

Recovered Glauber’s salt (Na2SO4.10 H2O) for reuse

Brine Treatment system

Major quantity Sludge Thicken er

Legend

Softener Filter

Filter Press

Lime Sludge to Cement Industries

Brine for reuse at member units 100-150gpl

Raw effluent line Reject line Pretreatment Units Tertiary Treatment units Reject Management system Resin regenerate treatment system

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Tirupur Textile Effluent Management Project, Tirupur.. 3

Pretreatment

Untreated & Treated Effluent

Biological Treatment

Reverse Osmosis

R.O reject – before treatment

Lab trails using RO brine 16

R.O reject – after treatment

O & M of Tirupur Textile CETP at Tirupur

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2. Tannery CETPs in Vellore 

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12 CETPs established, 10 based on ZLD,1 partial ZLD and 1 very small CETP (500 m3- SF-F) based on irrigation on trial basis. Most CETPs are based Evaporator crystallization and storage of waste salt. Design Capacities range from 0.5 MLD to 4.5 MLD. Currently operating at 30 -75% capacity. Operating costs at Rs. 460 to 480 per m3. Net operating cost after water recovery at ~ Rs. 390-410 per m3.

Membrane Bioreactor (MBR) Vaniyambadi

Financial Impact:  

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8 to 10% on production cost. Rs. 5 to Rs. 6 per sq.ft of finished leather. Rs. 15-18 per pair of shoes. RO plant at Ambur

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3. Technical

and Commercial Feasibility for Development, Financing, Implementation and Operation of Zero Liquid Discharge Effluent Project for Pulp & Paper Major

Aeration Tank

Nano Filtration

Ultra Filtration

Reverse Osmosis

>95% recovery of water. Recovery of Sodium Sulphate and Sodium Choride Salts. 19

SECTION C: RECENT ADVANCES IN ZLD TECHNOLOGY

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RECENT ADVANCES IN ZLD TECHNOLOGIES 

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Electro-oxidation for colour & recalcitrant COD removal as alternative to Decolourant Resin Filters or chemical precipitation. High Pressure RO (both SWRO and HPPTRO) upto 200 bar feed pressures to reduce volume of rejects for thermal evaporation. Need for Captive Power with cogen Membrane Distillation as alternative to MEE. Possibility of use of hot water (solar) instead of steam. Thereby reducing carbon foot print. Forward Osmosis for brine management at very concentrations at reduced energy requirements. TWIC has developed a near Zero Waste Salt Technology. O&M costs will substantially reduce with these technologies and is expected to go down further in the near future. 21

Project Concept with Captive Power with cogenJajmau Tannery CETP, Kanpur

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Web based on-line monitoring system

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Project Concept with Solar thermal Heating with Membrane Distillation- Sree Bhavani, Textile CETP, Erode

Hot Water @ 84OC

Well water / River water for Top up

Recovered water for top up

Solar Thermal Heating System

*90-95% 110-120%

Recovered water for reuse

Textile Dyeing Units

Chemical sludge for brick manufacturing or co-processing in cement industry ZLD CETP

Treated Brine for resue (Sodium chloride ) Raw effluent

* Net recovery after internal consumption in cooling tower and for solar thermal system

Biolsudge for making briquettes and blending with agro-waste as boiler fuel Recovered Sodium Sulphate for top-up or sale /

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Low Carbon footprint of ZLD-ZWS technology as compared with Conventional treatment & discharge plants and existing ZLD technologies

Resource (Water & Salt) Recovery

100%

CO2 Emission (tons/ annum), 17000

CO2 Emission (tons/ annum), 39000

95%

95%

CO2 Emission (tons/ 45000 annum), 13500 40000 95% 100% 35000

80%

30000 70%

70%

60%

20000

40%

15000 10000

20% 0%

25000

0%

5000

0%

Conventional Treatment for discharge to River/ Sea (Primary + Secondary Teatment Only + grid power)

0 Existing ZLD (MEE + Bolier+ grid power)

Water Recovery

Existing ZLD technology ZLD-ZWS Technology (MEE+ CPP cogen) (Membrane Distillation + Solar Thermal + grid power)

Salt Recovery

CO2 Emission (tons/ annum)

Note: For Southern Grid power, weighted average emission factor has been taken as 1 MWH = 0.81 Ton of CO2 as per CEA report for FY 2013 -14

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CO2 emission in tons/ annum

CO2 Emission (tons/ annum), 32000

120%

SECTION D: APPROACH TO ZLD

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Approach to ZLD.. 1 •

Technology 

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Need for extensive piloting before implementation to demonstrated Technocommercial feasibility. One Size does not fit all:Need to remember “not all Textile dyeing effluent are same” or “not all Tannery effluent are same” or “not all paper industries are same” or “not all ZLD are same”. Since almost no EPC company provides ‘in-house’ all components of ZLD, there is an extensive need for integrating the complete process components to avoid problems. Therefore the Consultant should assure process performance guarantees.

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Not just water balance but material balance for several critical parameters (not just TDS) a must for correct process design.

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Internal recirculation:Quality and quantity of backwash/ regeneration/ CIP /cleaning on the entire treatment process to be carefully accounted for in process design.

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System design should be based on high ‘Reliability Index’. High Process Flexibility to be built in for various components to handle variations in effluent quality/ individual component performance. Design should be based on multiple process streams including standby and downtime. 27

Approach to ZLD…2 

Must focus on reduction of brine concentrate to reduce the need for evaporation and crystallization.

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Higher recovery in R.O possible subject to osmotic pressure limitations, but with elimination of Hardness, silica, foulants. High Pressure R.O systems available and are cost effective such as DTRO (90 – 160 bar).

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Think “Zero Waste Discharge” to achieve Zero Liquid Discharge”. Focus on salt recovery and reuse, salt separation and reduced sludge generation.

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Approach to ZLD…3

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O&M 

Need for independent (for CETPs) and Professional O&M.

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Most CETPs /ETPs are poorly managed and there is complete lack of certified ETP operator courses and dearth of well trained manpower.

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Expenditure on O&M is an issue.

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EPC contractors fail to deliver on performance.

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The consultant/ designer can be held responsible for process performance through O&M. 29

NEED FOR POLICY FRAMEWORK…1 

There is a need for a comprehensive policy and standards for ZLD.

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Need for a higher grant towards capex as most such polluting industries fall under the Tiny and SME category.

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Issues with Regional/ National competitiveness due higher operating expenses due to ZLD.

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Polluting industries such as Tannery and Textiles are essentially based on “Job Work”. Therefore there is an issue with transfer of higher costs to the “buyer”.

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The ultimate customer may be able to bear the additional 30 cost due to ZLD. E.g. Rs. 20 on a pair of shoes.

NEED FOR POLICY FRAMEWORK…2

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A Environmental cess on the finished product out of a cluster can be used to reimburse ZLD costs of a CETP/ IETP. or an additional duty drawback on exports can be some policy decisions. A green labelling scheme can be initiated, which could be leveraged for better export prices for the goods, thereby offsetting the higher input costs. 

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e.g. Gold rating given to a ZLD Tannery CETPs in TN by LWG, UK, leading to a higher market price.

However, all these are only suggestions and needs to be finalized in consultation with all the stakeholders.

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Section E: Conclusions 

ZLD is a Technological Challenge, and the focus must be on Zero Waste Disposal (ZWD).

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Extensive research and piloting necessary for every single case for Technology selection and financial viability.

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Brine Concentration, Evaporation and Crystallization and disposal still a major issue. Focus must be on recovery and reuse of salts.

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Water Scarcity, Water economics and regulatory pressure are the main drivers of ZLD and will determine financial viability. 32

Tirupur Videohttps://www.youtube.com/watch?v=42jbPRb7xvg

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