All of us enjoy those glistering, golden and silver bright metal objects, coated by electroplating.  These items range from cutlery articles, household items like ironware, copperware, lamp sockets, nuts, bolts, chains, door latches, wrist watches to aircraft parts, and other automobile parts.  The list can go on unendingly.  Perhaps what most of us do not know is about the hazards posed to our environment and work force in bringing the objects in their final usable form. 

“Electroplating is process of coating a layer of one metal by electrolysis”.  It is done mainly to protect the metal surface from corrosion and to offer a pleasing decorative surface finish. 

In India there are more than 50,000 electroplating industries mostly large units will have captive plating shops whereas medium units cater to selected business groups as feeder units and small and tiny units mostly take up job plating. 

Features of small and tiny units:

Unlike the case of captive and feeder type of operations, small scale job plating involves lot of uncertainties and most of the operations are done manually.  The shape of the articles to be plated varies from small screws to big automobile parts.  Due to variations in day to day operations, standardization of practices is a bit difficult.  Effluent treatment is not done usually in these units due to space constraints as most of them come up in tiny residential areas as family owned operations.  Due to lack of proper facilities, occupational health risks are high in these units. 

Sources of Pollution:

Electroplating is done mainly in the following 3 steps:

	Pre-treatment	:	To make the surface receptive to coating by removing dust and grease by using acids, alkalis.
	Electroplating	:	Electrolytic coating of metals using salts of zinc, nickel, chromium, cadmium, gold and cyanides etc.
	After-treatment	:	To give final polish and shine to the objects, mostly chromium base solutions are used.

At each step, the process involves thorough rinsing with water and finally the articles are dried before packing.  Over a period of time the plating bath contents and the acids used in pre-treatment get contaminated and need to be disposed of for better quality plating.  However, this cycle period can be extended by following better operational practices. 

Typical waste generation sources are:

	Drag out losses	:	Drag out is the loss of bath liquids while transferring the work piece from one bath to another.  Expensive and hazardous chemicals used in the plating baths are lost in the rinse water or on the floor.
	Concentrated liquid wastes	:	Bath solutions need to be replaced when the quality deteriorates due to contamination by dissolved metals and insoluble salts.  All these concentrated spent acid baths, spent alkali baths, spent passivation dip baths, rinse waters, spent plating baths are generally dumped into drains.
	Sold waste	:	From the plating baths and pre-treatment operations some solid waste is generated in the form of sludge.
	Air pollution	:	During buffing of articles, fumes generated form the baths cause air pollution resulting in occupational health hazards for the work-force.

Environmental Impacts:

Acids and Alkalis used in the pre-treatment process are corrosive in nature and have the capacity to eat away the tissues and materials they come in contact. 

When the presence of heavy metals such as Nickel, Chromium and Zinc exceeds the toxic limits they can gradually accumulate in the body and shows their effect only a few years after exposure has begun.  Toxic properties include carcinogenicity (cancer causing), nervous disorders and mutagenecity (mutations in the genetic code). 

Pollutants from electroplating operations can find their environmental pathways into soil, air, water, food material, plant and animal tissues.  Metals tend to get absorbed easily on surfaces like soil or sediments. 

Air pollution problems are encountered due to acid mists and toxic fumes generation when cyanide wastes come in contact with acidic effluents due to unmindful dumping of wastes into the sewer lines.  Occupational health risks are inevitable for shop-floor personnel if proper precautions are not followed while operating with acids and toxic heavy metals. 

According to one survey, majority of the heavy metal pollution load to river Yamuna in Delhi is due Electroplating industries.  In a recent drive to put a stop to industrial pollution, the Supreme Court has ordered many of the small and tiny electroplating units to shift out of  Delhi.  However, clear-cut action plans for improving the situation need to be worked out while shifting, else the prevailing pollution will continue at the new site. 

Table 1 : Typical Waste Characteristics and its Impacts
Parameter	Effluent Concentration mg/I	Standards mg/I	Impacts
Ni	500-900	3.0	Toxic impact at higher concentrations
Cr+6	60-400	0.1	Irritation of skin and respiratory tract on exposure and ulceration of mucous membranes, can lead to cancer of respiratory tract.  Liver damage on long term exposure
Total Cr	9-300	2.0	-do-
Zn	100-350	5.0	Toxic to plants and human at higher concentrations
CN	70-180	0.2	Lethal to aquatic life and humans

Review of Pollution Prevention efforts

In order to understand the best practices to be followed in preventing pollution from this sector, Human Settlement Management Institute (HSMI), Delhi in collaboration with Institute for Housing and Urban Development Studies (HIS), Rotterdam, has sponsored a review study by Development Alternatives. 

The study reveals that very little effort was made in the past by the National Productivity Council and the Ministry of Environment as demonstration exercises to prove the point that prevention of pollution is both economically and environmentally beneficial.  In one of the studies conducted by the National Productivity Council (NPC) Nickel-Chrome Unit it was found that the unit was losing 55% of Nickel and 71% of Chromium, the input chemicals, at various stages of plating operations. 

Pollution prevent techniques demonstrated in this unit have resulted in substantial economic returns, besides reducing about 40% of pollution load to environment through avoidance of loss of valuable resources in the process.  Some of these prevention options include: 

a)	Use of fume suppressants in chrome plating bath to reduce air emissions and toxic vapours;
b)	Conversion of rinse water tanks into dragout collection tanks for recovery of dragout losses;
c)	Controlled addition of plating bath chemicals to minimise unnecessary wastage of resources;
d)	Better Jerking and hanging of plated objects to minimise losses in rinse water;
e)	Provision of drain boards between plating and rinse water tanks to reduce losses on to the floor;
f)	Coating of fixtures and holders of objects with PVC to avoid unnecessary plating of object holders.
g)	Use of demineralised water and maintenance of required bath conditions through regular monitoring to extend the bath life,
h)	Continuous filtration of bath contents to extend bath life;
i)	Energy conservation through proper electrical fittings.

With a nominal investment of Rs. 5,000/-, the entrepreneur was able to save about Rs. 2,16,000/- per annum.  By following some of the options, a Delhi based Nickel-Chrome Unit which does job plating for electrical irons was able to save about Rs. 87,000/- per annum with nominal investments.  However, these pollution prevention initiatives seem to be limited to units where demonstration exercises were conducted and no widespread adaptation is taking place.  

Reasons for non – adoption of pollution prevention practices

a)No regulatory incentives : In spite of the attractive economic returns, in the absence of regulatory incentives for pollution prevention, large scale adaptation of these practices is not taking place.  Though not highly substantive, the electroplaters are happy with whatever profit margins they are able to make.  Besides this, the cost of resources is not priced high enough to make resource recovery more attractive.

a)	Quality Changes	:	Many of the entrepreneurs are resisting process changes due to the apprehensions about quality of plating.
b)	Workforce related problems	:	Apart from the reasons mentioned above, most of the best practices require involvement and cooperation from shop-floor personnel.  The manager has a constant fear of losing the workforce, if he has to put too many demands on the work force.
c)	Technology Availability	:	Moreover, simple and affordable devices for bath condition maintenance for effective rinsing and for recovery of chemicals are not available for this sector.
d)	Information Sharing	:	Lack of effective information dissemination and sharing among the small scale entrepreneur is another reason.
e)	Unable to meet regulatory standards	:	Since pollution prevention practices cater to only 40-60% pollution load reduction,from the point of regulatory compliance, it is an unattractive proposition for the entrepreneur.

 

Issues still to be addressed

Efforts to prevent pollution in India so far has a heavy emphasis on source reduction through operational improvements. However, issues such as use of alternative less hazardous chemicals (eg. Cyanide free operations), waste segregation and recovery through common facilities, pre-treatment of effluents followed by final treatment in a common treatment facility, safe disposal of remaining sludge etc. have not been adequately dealt with by the pollution prevention promoters.  No efforts were made so far to utilise the pollution prevention practices in meeting the regulatory standards in an incremental way.

Keeping in view the increasing growth rate of the small scale electroplating units and in view of the pending shifting of old units to new sites, a holistic approach to promote minimisation of pollution from this sector needs to be adopted.  The review study has identified national levels strategies to be adopted for prevention of pollution and has specified training modules that need to be developed for promoting prevention based environmental management.

Recommended Strategy

In order to achieve acceptability to cleaner production practices by large number of units in the electroplating sector, the following strategy could be considered.

a)	Demonstration of financially feasible cleaner production practices that need to be followed both at individual unit level and cluster level to achieve regulatory compliance.
b)	Exploration of the market potential for prevention based technologies and technical consultancy services and provision of those services on commercial basis.
c)	Training and information dissemination to workforce and entrepreneurs respectively on pollution prevention aspects.
d)	Policy interventions to encourage pollution prevention practices.
e)	Dissemination of technical packages on pollution prevention to various technical NGOs, consultants, academic institutions to cater to large scale adoption.

Mounting pressure from local people and shop floor personnel for their right to clean surroundings and health working conditions could bring the change at a  faster rate.  But that will happen only if the citizens and workforce are informed of their rights and responsibilities.

Electroplating industry is a classical demonstration case of pollution preventions really paying – making a tremendous difference to the bottom line.  When will the entrepreneurs realise this ?

By P. Ratna Prasad and K. Vijay Lakshmi. 

The authors work in the Environment Systems Branch of Development Alternatives

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