Standards and Regulations for discharge of liquid effluents and Gaseous Emissions related to chlor

alkali industry       

 

Shri Paritosh Kumar ,AD & Shri Dinabandhu Gouda, SEECENTRAL POLLUTION CONTROL BOARD

DELHI – 110 032

 

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 plantsProcess Installed Capacity

(Lakh MTA)Productionin 2012-13(Lakh MTA )

Total 27.94 21.61

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 INCAUSTIC SODA INDUSTRIES IN INDIA

Combination of Treatment Procedures Adopted by Caustic Soda Plants:

     Sodium sulphide treatmentActivated 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 : 25-235 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 14.91 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 2020.

CREP : Chlor-Alkali IndustryCREP : Chlor-Alkali Industry

ENVIRONMENTAL REGULATIONS

Wastewater Discharge Standards  Parameter Concentration not to exceed

   Total concentration of : 0.01 mg/lmercury in final effluent

 ·    Mercury bearing wastewater : 10 Kl/ton of NaOH productiongeneration (Flow)

 ·   pH : 5.5 to 9.0

Process Pollutants Emission limits (mg/Nm3)

Mercury process Mercury (H2 gas holder) 0.2

All process Chlorine (Hypo tower) 15

All process Hydrochloric vapor/mist (Hydrochloric acid plant)

35

Air Emission Standards

Substance Permissible limits for Mercury & Chlorine

Work zone conc. in mg/m3 (8 hrs. time-weighted avg.)

• Mercury

• Chlorine

• HCl mist

0.05

3.00

7.00

Permissible Limit for Mercury/Chlorine in Work Environmentas per the Factories Acts, 1948

Hazardous Waste Generation from Chlor-alkali Industry

as per HW(M ,H,T)Rules , 2008 Processes (Schedule-I)

o Cat:16.1: Mercury bearing sludge

o Cat:16.2:Residue sludge and filter cakes

o Cat:16.3:Brine sludge containing Mercury

  SPCB to issue authorisation for collection, storage, treatment & disposal of HW.

 

Liquid effluent : 0.1 gm/t of Cl2 (~ 0.09 gm/t NaOH)

    Emission from cell room : 1.7 gm/t of Cl2 (~ 1.55 gm/t NaOH)

    Products : 0.1 gm/t of Cl2 (~ 0.09 gm/t NaOH)

    Total Hg release : 2.0 gm/t of Cl2 (~ 1.82 gm/t NaOH)  USEPA

  Liquid effluent : 0.23 gm/t of Cl2 (~ 0.21 gm/t NaOH) –

max. for one day: 0.1 gm/t of Cl2 (~ 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)

   Stream Limit for mercury

  EUROCHLOR

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 (0.0005 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 Industry

Production capacity

Date of Inspection

Complying/Non complying

Remarks

Rayalaseema Alkaliies and Allied Chemicals, Kurnool,Andhra Pradesh

Caustic soda -520 TPD

24.11.2009

Partially complying –PM-126 > 115 mg/Nm3HCl-7.5<35Cl2-9.5<15.0

Letter to APPCB to direct industry to take necessary action

SIEL chemical complex ,Patiala,Punjab

Caustic soda -250 TPD

25.06.2013

complying

Hindustan Heavy Chemicals Ltd, West Bengal

Caustic soda-42 TPD

19.11.2009

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

Production capacity

Date of Inspection

Complying/Non complying

Remarks

Aditya Birla Chemical Ltd, Renukoot ,UP

Caustic soda - 220 TPD

21.04.2010 complying

Travancor Cochin Chemicals ,Cochin,Kerala

Caustic soda -175 TPD

21.09.2009 Non complyingCl2- 124>15 mg/Nm3HCl-339 >35 mg/Nm3

CPCB issued direction u/s 18 (1) b to Kerala Board

RIL ,Dahej,Gujarat

Caustic soda-450 TPD

17.11.2009 Complying -

Shriram Chemical and Fertiliser ,Kota,Rajasthan

Caustic soda-325 TPD

17.09.2012 complying -

Name of Industry

Production capacity

Date of Inspection

Complying/Non complying

Remarks

Grasim Industries Ltd,Nagda, MP

Caustic soda - 750 TPD

22.02.2012

Partially complying

Letter to the unit to install continuous monitoring system

Gujarat Alkali and Chemical Ltd, Vadodara,Gujarat

Caustic soda -500 TPD

18.02.2011

Non complyingChloride -1873 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

17.12.2010

Complying -

Name of Industry

Production capacity

Date of Inspection

Complying/Non complying

Remarks

Tamilnadu Petroproducts,Manali, Chennai,Tamil Nadu

Caustic soda - 225 TPD

16.12.2013

Non complyingPh-11.4>9.0SS-302>30 mg/lOil and Grease 121 >10 mg/lCl2-41>15 mg/Nm3

Direction u/s 5 issued to the unit by CPCB

DCW ,Thoothkudi,Tamil Nadu

Caustic Soda-280 TPD

22.04.2008

Non complyingPh-2.4<5.5Hg-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 Industry10.04.2013

Production capacity

Date of Inspection

Complying/Non complying

Remarks

Durgapur Chemicals Ltd, Durgapur,West Bengal

Caustic soda-100 TPD

18.01.2011 complying -

Aitya Birla Chemicals Ltd, Palamau, Jharkhand

Caustic soda - 550 TPD

25.09.2013 complying Letter to the unit to connect CPCB server

Jayshree chemicals Ltd, Ganjam,Odisha

Caustic soda - 150 TPD

10.04.2013 complying

Status of Caustic soda PlantStatus 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 Cl2 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

THANK YOU