Standards and Regulations for discharge of liquid effluents and Gaseous Emissions related to chlor alkali industry Shri Paritosh Kumar,AD & Shri Dinabandhu Gouda, SEE CENTRAL POLLUTION CONTROL BOARD DELHI –

Facts of Caustic Soda Industry 1.95% of world chlorine production is by this industry 2.The caustic soda industry has attracted particular attention of pollution control authorities world over. 3.The concern is due to the release of mercury into the environment from industrial unit using mercury cell process (a polluting process) for the manufacture of caustic soda. 4.Caustic soda is mainly produced by two electrolytic processes – Mercury Cell and Membrane Cell Technology. 5.Stoichiometrically 1.46 MT salt (100% NaCl) and 0.45 MT water is converted to produce 1 MT of caustic soda, 0.89 MT of Chlorine and 25 kg of Hydrogen.

Caustic Soda Demand in India(%)

5.Chlorine is largely used in the synthesis of chlorinated organic compounds. Vinyl chloride monomer (VCM) for the synthesis of polyvinyl chloride (PVC) still remains the driver of chlor-alkali production in the world. 6.Chlorine is used in 98% of the water treatment plants in the world.

Operational Status of Caustic Soda Plant in India No. of Caustic Soda Plants in Operation :  Mercury + Membrane Cell Plants:03 (i)Atul Ltd, Gujarat (ii)Hindustan Paper Corporation, Cacher, Assam (iii)Hindustan Paper Corporation, Nagaon, Assam  Mercury Cell Plants closed:02 (i)Hindustan Heavy Chemical Ltd, West Bengal (ii)Solaris Chemtech, Karnataka  Membrane Cell Plants (Exclusively):32 Total : 37 plants ProcessInstalled Capacity (Lakh MTA) Production in (Lakh MTA ) Total

Trend of Technology Shift in Chlor-Alkali Sector

Energy Consumption in 5 th Generation Membrane cell The energy consumption in a Membrane cell is of the order of 2,000–2,200 kilowatt-hours per metric tonne of caustic. Electrode gap plays an important role in cell voltage, as the electrode gap reduces there will be an reduction in electrolyte internal resistance which lowers the cell voltage. This gap cannot be reduced to zero because of the following reasons. Risk of friction between membrane and electrodes Special cathode coating required Corrosion attack of fine mesh by chlorine gas penetration and stagnation Complex and expensive manufacturing

Wastewater is generated from Cell house, Brine purification section, chlorine Hhydrogen handling section HCl manufacturing unit. Brine sludges are one of the largest waste streams of the chlor-alkali industry. EFFLUENT TREATMENT SYSTEM ADOPTED IN CAUSTIC SODA INDUSTRIES IN INDIA Combination of Treatment Procedures Adopted by Caustic Soda Plants:  Sodium sulphide treatment  Activated carbon bed filtration  Sand filtration   Ion exchange resin columns

SOLID WASTE DISPOSAL  Brine sludge generation range: 0.03 to 0.05 t/t of NaOH  Hg conc. in brine sludge: mg/kg Observations:  Need for vacuum dewatering system/washing of brine mud.  Need for proper storage of brine mud to avoid entry of rainwater and its spillage.  Need for proper collection and containment of brine mud.  Need for periodic monitoring around the storage/disposal areas for any spillage/percolation of mercury bearing waste.

Brine Sludge Area Before Earth Capping

Brine Sludge Area After Earth Capping

12  All the industries has been complied 12 action points out of 13 action points suggested by CREP.  Mercury emission to environment has been decreased to 0.64 gram/Ton against CREP recommendation 2 gram/ton.  Mercury consumption has been reduced to gram/ton against CREP recommendation 50 gram/ton.  All the mercury cell plant has been planned to switch over membrane cell technology by 2012 much ahead of EU target of CREP : Chlor-Alkali Industry CREP : Chlor-Alkali Industry

ENVIRONMENTAL REGULATIONS Wastewater Discharge Standards Parameter Concentration not to exceed  Total concentration of : 0.01 mg/l mercury in final effluent · Mercury bearing wastewater : 10 Kl/ton of NaOH production generation (Flow) · pH : 5.5 to 9.0 ProcessPollutantsEmission limits (mg/Nm 3 ) Mercury processMercury (H 2 gas holder)0.2 All processChlorine (Hypo tower)15 All processHydrochloric vapor/mist (Hydrochloric acid plant) 35 Air Emission Standards

SubstancePermissible limits for Mercury & Chlorine Work zone conc. in mg/m 3 (8 hrs. time- weighted avg.) Mercury Chlorine HCl mist Permissible Limit for Mercury/Chlorine in Work Environment as per the Factories Acts, 1948

Hazardous Waste Generation from Chlor-alkali Industry as per HW(M,H,T)Rules, 2008  Processes (Schedule-I) oCat:16.1: Mercury bearing sludge oCat:16.2:Residue sludge and filter cakes oCat:16.3:Brine sludge containing Mercury  SPCB to issue authorisation for collection, storage, treatment & disposal of HW.

 Liquid effluent: 0.1 gm/t of Cl 2 (~ 0.09 gm/t NaOH)  Emission from cell room: 1.7 gm/t of Cl 2 (~ 1.55 gm/t NaOH)  Products: 0.1 gm/t of Cl 2 (~ 0.09 gm/t NaOH)  Total Hg release: 2.0 gm/t of Cl 2 (~ 1.82 gm/t NaOH) USEPA  Liquid effluent: 0.23 gm/t of Cl 2 (~ 0.21 gm/t NaOH) – max. for one day : 0.1 gm/t of Cl 2 (~ 0.09 gm/t NaOH) – max. avg. for 30 days  Sludge: 17 mg/kg  Leachate for solid waste: 0.2 mg/l INTERNATIONAL REGULATIONS (Standards for Hg bearing streams) StreamLimit for mercury EUROCHLOR

International Regulations Contd. …. StreamLimit for mercury SWEDEN  Liquid effluent : 0.1 gm/t of Cl 2 (~ 0.09 gm/t NaOH)  Ventilation air from cell room : 1.0 gm/t of Cl 2 (~ gm/t NaOH)  H 2 gas : 0.5 gm/t of Cl 2 (~ 0.45 gm/t NaOH) WHO  Conc. in Cell Room: 0.05 mg/m 3 China Wastewater: 0.01 mg/l Air: mg/m 3

JAPAN Two types of requirements for effluent control in Japan:  Regulations or standards issued by the environmental agencies; and  Guidelines issued by the Ministry of Interior, Trade and Industry (MITI). Standards for industrial discharges of mercury:  WW discharge standards for mercury :5.0 ppb (0.005 mg/l)  Standards for water quality :0.5 ppb ( mg/l) Guidelines issued by MITI to all Chlor alkali plants:  All process water contaminated with mercury must receive full recycling.  Mercury cell must be phased out (5 yrs. from recycling date).

Realising problem associated with mercury based caustic soda plant, Govt. of India : i.Issued notification under EPA 1986 for liquid effluent and gaseous emission standards for controlling mercury from stationary sources; and ii.Recommended commissioning of new plants and expansion of Hg cell based plants not to be allowed with effect from 1986 and adopt the cleaner production process (i.e. membrane cell process). The production of caustic soda by Hg cell plant since then gradually declined.

Name of IndustryProduction capacity Date of Inspect ion Complying/ Non complying Remarks Rayalaseema Alkaliies and Allied Chemicals, Kurnool, Andhra Pradesh Caustic soda TPD Partially complying –PM- 126 > 115 mg/Nm3 HCl-7.5<35 Cl2-9.5<15.0 Letter to APPCB to direct industry to take necessary action SIEL chemical complex,Patiala, Punjab Caustic soda TPD complying Hindustan Heavy Chemicals Ltd, West Bengal Caustic soda-42 TPD Not complying. Mercury released to environment is 5 gm/ton >2 gm/ton CPCB issued direction u/s 18 (1) b to WBPCB and Closure notice issued by WBPCB

Name of Industry Productio n capacity Date of Inspection Complying/ Non complying Remarks Aditya Birla Chemical Ltd, Renukoot,UP Caustic soda TPD complying Travancor Cochin Chemicals,Cochin, Kerala Caustic soda TPD Non complying Cl2- 124>15 mg/Nm3 HCl-339 >35 mg/Nm3 CPCB issued direction u/s 18 (1) b to Kerala Board RIL,Dahej,Gujarat Caustic soda-450 TPD Complying- Shriram Chemical and Fertiliser,Kota, Rajasthan Caustic soda-325 TPD complying-

Name of Industry Producti on capacity Date of Inspection Complying/ Non complying Remarks Grasim Industries Ltd,Nagda, MP Caustic soda TPD Partially complying Letter to the unit to install continuous monitoring system Gujarat Alkali and Chemical Ltd, Vadodara, Gujarat Caustic soda TPD Non complying Chloride mg/l>600 mg/l and incinerator is operating without APCD CPCB issued direction u/s 18 (1) b to Gujarat PCB and GPCB issued direction u/s 31 A and 33 A Lords Chlor Alkali, Alwar,Rajasthan Caustic soda- 30 TPD Complying-

Name of Industry Producti on capacity Date of Inspec tion Complying/ Non complying Remarks Tamilnadu Petroproducts,Manali, Chennai,Tamil Nadu Caustic soda TPD Non complying Ph-11.4>9.0 SS-302>30 mg/l Oil and Grease 121 >10 mg/l Cl2-41>15 mg/Nm3 Direction u/s 5 issued to the unit by CPCB DCW,Thoothkudi, Tamil Nadu Caustic Soda- 280 TPD Non complying Ph-2.4<5.5 Hg-0.02>0.01 mg/l CPCB issued direction u/s 18 (1) b to Tamilnadu PCB and TNPCB issued direction u/s and 33 A

Name of Industry Product ion capacity Date of Inspection Complying / Non complying Remarks Durgapur Chemicals Ltd, Durgapur, West Bengal Caustic soda- 100 TPD complying- Aitya Birla Chemicals Ltd, Palamau, Jharkhand Caustic soda TPD complyingLetter to the unit to connect CPCB server Jayshree chemicals Ltd, Ganjam, Odisha Caustic soda TPD complying Status of Caustic soda Plant

All the Caustic Soda Plant should : Not by-pass any control system. Maintain operational parameter during start-up & shut down, like Redox meter in Hypo tower. Maintain desired strength of caustic concentration in HT. Use of good quality salt Provide continuous Cl 2 and HCl monitoring system at all strategic location, stacks, work-zone areas and its recording on strip chart in control room.

Issue of Brine Sludge generated from Membrane cell plants in the light of Hazardous Waste(M,H,T) Rules,2008 Review of effluent and emission standards Applicability of continuous effluent and emission monitoring system

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