Environmentally Sound Management of Waste Pickling Liquor

Environmentally Sound Management of Waste Pickling Liquor

By

Dr R S Mahwar, Environmental Adviser, ILZDAFormer Additional Director, Central Pollution Control Board

(Ministry of Environment, Forest & Climate Change), Govt. of India, Delhi

India Lead Zinc Development Association (ILZDA) Seminar

on

GALVANIZINGMay 5-6, 2017, Nagpur

Environmentally Sound Management of Waste Pickling Liquor

Environmentally Sound Management of Industrial Wastes in India ?

Management as per the provisions of the Hazardous and Other Wastes (Management and Transboundary Movement) Rules, 2016 (HW Rules 2016) notified by the Govt. of India on April 4, 2016

The Hazardous Wastes (Management, Handling and Transboundary Movement) Rules, 2008 (HW Rules 2008) stand repealed.

Waste Pickling Liquor Management and the HW Rules 2016

Waste Pickling Liquor: The entire liquid stream from the Pickling process including the spent acid.

Pickling Liquor/Spent Acid Classification as per the HW Rules 2016 : Hazardous Waste

• Schedule – I, Process S.No 12 : Metal surface treatment, such as etching, staining, polishing, galvanizing, cleaning, degreasing, plating, etc.

• Category 12.2: Spent acid and alkali

Definitions - Section 3(1)(*Most relevant to the Waste Pickling Liquor)

13. Environmentally Sound Management of Hazardous and Other Wastes”

Means taking all steps required to ensure that the hazardous and other wastes are managed in a manner which shall protect health and the environment against the adverse effects which may result from such waste;

14. Environmentally Sound Technologies

Mean any technology approved by the Central Government from time to time.

Definitions - Section 3(1)

31. Storage

Means storing any hazardous or other waste for a temporary period, at the end of which such waste is processed or disposed of;

35. Treatment

Means a method, technique or process, designed to modify the physical, chemical or biological characteristics or composition of any hazardous or other waste so as to reduce its potential to cause harm.

37. Utilisation

Means use of hazardous or other waste as a resource;

Grant of authorisation for Managing Hazardous and Other Wastes – Section 6(1)(c)

(i) Any person authorised under the provisions of the HW Rules 2008 prior to the date of commencement of these rules, shall not be required to make an application for authorisation till the period of expiry of such authorisation;

(Relates to the existing permitted practices of waste disposal)

(ii) any person engaged in recycling or reprocessing of the hazardous waste specified in Schedule IV and having registration under the provisions of the HW Rules 2008, shall not be required to make an application for authorisation till the period of expiry of such registration.

(Relates to the sale of Zinc Dross, Zinc Skimmings and zinc Ash)

Utilisation of hazardous and Other wastes – Section 9

(1) The utilisation of hazardous and other wastes as a resource or after pre-processing either for co-processing or for any other use, including within the premises* of the generator (if it is not part of process), shall be carried out only after obtaining authorisation from the State Pollution Control Board in respect of the wastes on the basis of standard operating procedures or guidelines provided by the Central Pollution Control Board.(* Means even a captive facility requires permission)

(2) Where standard operating procedures or guidelines are not available for specific utilisation, the approval has to be sought from Central Pollution Control Board which shall be granting approval on the basis of trial runs and thereafter, standard operating procedures or guidelines shall be prepared by Central Pollution Control Board.

Utilisation of hazardous and Other wastes – Section 9

Provided, if trial run has been conducted for particular waste with respect to particular utilisation and compliance to the environmental standards has been demonstrated, authorisation may be granted by the State Pollution Control Board with respect to the same waste and utilisation, without need of separate trial run by Central Pollution Control Board and such cases of successful trial run, Central Pollution Control Board shall intimate all the State Pollution Control Board regarding the same.

(In case the spent acid from the galvanizing industry has been in use for specific industrial applications in an environmentally sound manner, the SPCBs can use this clause to grant authorizations after conformation with CPCB)

Standard Operating Procedures or Guidelines for actual Users of Hazardous and Other Wastes – Section 10

The Ministry of Environment, Forest and Climate Change or the Central Pollution Control Board may issue guidelines or standard operating procedures (SOPs) for environmentally sound management of hazardous and other wastes from time to time.

CPCB has published the documents

Standard Operating Procedures and Checklist of Minimal Requisite Facilities for utilization of hazardous wastes <http://www.cpcb.nic.in/SoPs_for_utilisation_of_HW_July2016.pdf>

Processing of the proposals<http://www.cpcb.nic.in/SOP_Rule_9_Dec_2016.pdf>

SOPs Prepared by CPCB for Use of the Spent Acid Generated from Different Industrial Activities

Utilization of Spent H2SO4 generated form Pickling of MS Rods/Sheets for manufacturing Ferrous Sulphate. (Use of Ferrous Sulphate in water purification not permitted) .

Utilization of Spent HCl generated form steel rolling mills for producing Ferric Chloride. (Use of Ferric Chloride in water purification and agricultural applications not permitted)

Utilization of Spent Acid (H2SO4 & HNO3 mixture) containing Molybdenum generated from filament industries for producing Molybdenum Trioxide by heating process.

Management of Waste Pickling Liquor (WPL) in Galvanizing Industry – Possible Options

The Waste Pickling Liquor Management- Primarily the problem of managing the spent pickling acid.

Possible Options

• Acid Purification/recovery and reuse on site

• Acid Purification/Recovery at a common facility

• Management/Disposal of WPL on site

• Utilization of the spent acid by other industries

Viability of the Spent Acid Purification/Recovery and Reuse on Site

Easy and cheap availability of the virgin Hydrochloric Acid (Strength about 33%) in India.

Virgin Hydrochloric Acid is a by-product of Caustic Soda Industry.

Application virgin HCl in galvanizing industry -already a reuse.

Viability of the Spent Acid Purification/Recovery and Reuse on Site (contd.)

Spent acid Purification/Recovery of virgin acid on site requires:

• Proper segregation of the pickling bath discharges from other liquid waste streams to prevent the impurities getting into the acid

• Purchase of Virgin acid is still required though in reduced quantities.

• Savings due to reduction in the disposal costs and reduced virgin acid purchases are not expected to be more than the overall costs involved in meeting the demand through purchase of the virgin acid.

Viability of the Spent Acid Purification/Recovery and Reuse on Site (Contd.)

• Distillation of the spent acid (just 5% w/w):

Energy intensive

High O/M costs including the O/M of the ECS/APCS.

The residue Iron Oxide is unfit for the other applications as it contains high concentration of heavy metals.

Viability of the Acid Purification/Recovery at a Common Facility

Involvement of all issues stated in respect of the on site purification/recovery of the spent acid.

Hazards/risks involved in the collection of the spent acid from the individual industries and its transportation to the common facility and supply of the recovered acid back to the industries ?

Quality of the spent acid/recovered acid ? Disposal of the Iron Oxide Containing high levels of heavy Metals ? Landing cost of the recovered acid compared to the fresh acid ? The Establishment of a common facility –Requires Environmental

Clearance as per the EIA notification 2006 (Common facilities for the treatment of waste liquid streams are encouraged only for the industries located in clusters/specific industrial areas)

Management/Disposal of the Waste Pickling Liquor on Site

Preparation of a protocol by each industry for the Environmentally Sound Management of the Waste Pickling Liquor (WPL) at its own level.

Fixing the Objectives

• Treatment of the WPL ?

• Sale/Giving of the Spent Pickling Acid (SPA) to other industries and treatment of rest of waste water in ETP ?

Treatment of the Waste Pickling Liquor

Step -1:

Ensure following of the BMPs in regard to minimization of the generation of waste water

Best Management Practices & Environmental Regulations for Galvanizing Industry in India <https://www.slideshare.net/rsmahwar1/best-management-practices-environmental-regulations-for-galvanizing-industry-in-india>

Step -2: (Optional..?)

Add a pre-calculated quantity of iron oxide to the spent pickling acid before the latter becomes part of the WPL.

Treatment of the Waste Pickling Liquor Step-3:

• Treat the WPL with lime in a way that the mixture has a pH of 9 along with aeration to enable conversion of Ferrous into ferric and precipitation as Ferric Hydroxide.

• Ferrous Hydroxide is very sticky and difficult to handle. The appearance of greenish blue colour in the lime dosing tank indicates precipitation of ferrous hydroxide.

Step-4:

Filter the mixture into filter press to get the cake and filtrate.

Treatment of the Waste Pickling Liquor Step- 5: • Disposal of the Filter cake The cake falls in the category 35.3 – “Chemical sludge from

waste water treatment ” as per Schedule-I of the HW Rules 2016

Send the cake to TSDF or to the cement plants as per the conditions of the authorization

Get the Toxicity Characteristic Leaching Procedure (TCLP) or Soluble Threshold Limit Concentration (STLC) tests done for the cake as per Schedule –II of the HW Rules 2016.

In case the waste passes the TCLP and STLC tests apply to MoEFCC seeking exemption of the wastes from being classified as Hazardous.

Initiation of the action for seeking exemption from MoEFCC is better if taken at the Association level.

Treatment of the Waste Pickling Liquor Step- 6 :

• Disposal of the Filtrate

Filtrate Contains very High TDS

Direct discharge into marine coastal areas in case of no limit of TDS prescribed in the consent.

Solar/forced evaporation or RO treatment in the premises.

The treatment for TDS at the industry level is not expected to be viable except for solar evaporation which also needs a large open to sky area and also much less effective in the rainy season.

A common RO or MEE facility for TDS is more viable and effective

Treatment of the Waste Pickling Liquor

Transportation of the filterate to CETP.

The treatment of high TDS at a common facility is much better as the treated waste water with only high TDS does not involve hazards in its transportation.

Step-7:

• Disposal of the Evaporation residue (Evaporation in Industry)

Get the TCLP and STLC tests done for the residue.

Dispose as non hazardous waste in case it passes the tests

Dispose as per the authorization in case it does not pass the tests.

Utilization of the Spent Pickling Acid (SPA) in other Industries

Step -1: • Obtain data on the average quality of the spent HCl generated

from the steel rolling mills and keep that as a reference for maintaining the quality of the Spent HCl generated in Galvanizing.

The quality of the spent HCl generation from the Galvanizing industry is expected to be inferior compared to steel rolling mills.

SOP for Utilization of Spent HCl generated form steel rolling mills for producing Ferric Chloride already published by CPCB . Use of Ferric Chloride in water purification and agricultural applications not permitted.

Utilization of the Spent Pickling Acid in other Industries

Step-2:

• Make arrangements for the separate collection of the spent pickling HCl in way that the other liquid streams are not allowed to mix with it.

Step-3:

• Identify the broad range of the industrial applications of the spent HCl generated from the Galvanizing industry.

Action needs discussions at the Association level, survey and input of experts.

Utilization of the Spent Pickling Acid (SPA) in other Industries

Step-4:

• Make an application under Rule 9 of the HW Rules 2016 to CPCB for obtaining the permission.

This will involve conducting of the trial runs by the user industries as per the SOPs/Protocol of CPCB.

• CPCB’s permission expected only if the findings of the trial runs confirm environmentally safe use of the Spent HCl.

Step-5:

• Obtain Authorization from the SPCB to sale the Spent HCl for the uses specified in the permission of CPCB.

Conclusions and Recommendations

The Environmentally Sound Management of Hazardous Wastes in India is governed by the methods, technologies and Standard Operating Procedures notified under the HW Rules 2016.

The cheap and easy availability of the virgin Hydrochloric Acid in India does not leave much scope for considering recovery of the spent acid from the Waste Pickling Liquor and reuse at site.

The disposal of the WPL in the industry’s own premises appears to be most viable and environmentally sound option.

Conclusions and Recommendations (contd.)

The problems of TDS in the treated waste water could be better managed at a common facility.

There is scope for utilization of the Spent Hydrochloric Acid in other industrial applications which should be identified and permissions obtained from CPCB.

The segregation of the Spent Hydrochloric Acid at source and use in other industrial applications will also eliminate the problem of TDS in the treated waste waters from galvanizing industries.