Current Programmes > Water and wastewater treatment

3.1. ELECTROPLATING UNITS

The consultancy cell has implemented waste minimization and effluent treatment schemes in various types of electroplating units with a major emphasis on the former.  

Waste minimization - salient features:

• Counter current rinsing
• Providing adequate drip time.
• Providing drag-out recovery in static rinse water tank.
• Drag – out recovery.
• Proper plant layout
• Provision of hangers.
• Use drain boards between process baths and rinse tanks.
• Proper racking orientation.
• Multistage counter current reactive rinsing.
• Coating of hangers and fixtures with PVC.
• Segregation of wastes.

Benefits achieved: 

• Volume of wastewater reduced by 50 to 60%.
• Concentration of toxic heavy metals reduced by 25-30%.
• Saving in chemical consumption achieved :

  • Cleaning salts :      125 kgs/month
  • Chromic acid  :      50 kgs/month  
• Cost of treatment of final effluents reduced
• Pay back period : 6 – 8 months 

Effluent Treatment

Feasibility studies for setting up of CETP for Nickel Chrome electroplating units at Ludhiana.

Punjab Pollution Control Board awarded a project “Feasibility Studies for Setting up of CETP for Nickel Chrome Electroplating Units at Ludhiana” in September 2002 to the Council. The effluents from the plating industry contain highly toxic metals like chrome and nickel and the effluents need to be treated for strict compliance to environmental standards. Presently, treatment plants based on chemical precipitation methods have been put up by some of industries which results in generation of hazardous waste, besides high cost of treatment on account of chemicals.

Detailed studies revealed that the waste minimization measures in the industries need to be improved. Around 300 kg. of Nickel and 800 kg. of Chrome is being discharged daily in the effluents. The Council has perceived a set up in which ion-exchange columns are proposed to be installed for the individual units for adsorption of chromic acid. These ion-exchange columns, when saturated, would be taken to the common treatment site for recovery of chromic acid. The operation and maintenance of CETP would be entrusted to private entrepreneur on BOOT basis, who will be required to replenish the exhausted columns of each industry with a new set of columns on the lines of domestic LPG supply. The individual industry with the installation of ion-exchange columns would also get demineralised water as by-product, which will be used in the electroplating process improving the plating quality and also result in zero discharge from the chrome plating section. The project has been discussed with the industrial associations, experts at national level, leading electroplaters and Board officers and was well received by them.

Cleaner Production In Zinc Plating Units

Cleaner production in zinc plating process was demonstrated by substituting cyanide by acid based salts and passivation dip containing highly toxic hexavalent chrome by trivalent chrome.

Contact persons :
Er. M.S.Jaggi, ms_jaggi@pscst.com
 

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