Paint Sludge recycling Turning Paint Sludges into Valueable Products

Author / Editor: AS VISHNOI / Dominik Stephan

Lets face a simple fact: Paint sludge is a hazardous waste that poses serious risk for both health and environment – yet they often an not be avoided in the process industry. Now, after four years of research, Indian experts were to convert paint sludge into industrial primers, that conform to every specification of the user industry...

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Semi finished parts are being spray painted in a factory.
Semi finished parts are being spray painted in a factory.
(Picture: depositphotos.com / Corepics VOF)

You just say ‘paint sludge’ and anybody running the paint-shop for an industry or is concerned directly or indirectly to any industrial paint shop will feel disturbed and concerned. It is not because they do not understand what is ‘paint sludge’, but because they know what a big problem it is.

In fact, industrial ‘paint sludge’ is a waste, which cannot be prevented from getting generated, because when any product or component is finished by spray painting with liquid solvent based paint, 20 to 60 per cent paint goes as off-spray waste and gets collected outside the paint-shop in a sludge pit with the help of regularly flowing water stream through the paint booth, either in front of the painter as a water screen or under the floor grating of the paint booth.

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Paint Sludge: A Hazardous, Yet Unavoidable Waste

This collected off-sprayed paint churned and mixed with water along with some detackifying chemicals, known as booth additives, is known as ‘paint sludge’. This semi-solid lumpy material is classified as a hazardous waste – because if it is thrown freely anywhere on the ground it deteriorates the fertility of soil badly, and by way of leachates generated by it – the ground water gets polluted. It is not only

harmful for the agricultural land, but also it destroys the flora and fauna of the area wherever it is thrown or disposed off.

To provide respite to the generators of the ‘paint sludge’ against the stringent environmental law, which does not permit exit of the paint sludge’ out of the four walls of the industrial unit where it is generated, Maharani Paints took the challenge to develop a process by which industrial ‘paint sludge’ could be recycled back to a product – which is highly useful, and can be consumed without any hassle by the industry.

Recycling Paint Sludge – A Bumpy Road

Our technology today recycles the ‘paint sludge’ to industrial primers conforming to different parties’ specifications. Establishing the technology The challenge was full of bumps and hurdles and the biggest obstacle was the preoccupied mental blocks against using a recycled product for finishing a new product. Maharani Paints kept on struggling and convincing the people of different industrial houses and after untiring long efforts of more or less two years, they had a breakthrough....

First Punjab Tractors and then Hero Honda Motors came forward to go for recycling of their ‘paint sludge,’ and Maharani Paints worked on their ‘paint sludge’ in their R&D Lab., and developed the primers for tractor parts of Swaraj and motorcycle parts for Hero Honda’s motors bikes.

As on date, they are recycling ‘paint sludge’ and supplying the ‘recycled industrial primers,’ conforming to the specifications of the consumers, to Hero Motor Corp. (formerly known as Hero Honda), Tata Motors (Pune, Jamshedpur and Pant Nagar), Mahindra & Mahindra (Mumbai) and some of their ancillaries.

Paint Sludge Treatment in India – Burning Instead of recycling?

As far as ‘paint sludge’ generation is concerned – every year India alone generates about 65,000 K.Ltrs. of industrial ‘paint sludge,’ out of which about 40,000 K.Ltrs. is generated by the organised sector that can be collected for recycling.

Unfortunately, the Govt. of India has allowed to incinerate and co-incinerate the ‘paint sludge’ by industrial incinerators and in cement kilns respectively. Therefore, it is difficult to get the ‘paint sludge’ from the industry, because everybody wants to follow an easier route without any consideration that whether it is in the interest of the nation or not.

An Eco–Friendly Process

Incineration and co-incineration – both are non- eco-friendly processes, and are having some or the other pollutant generation either by way of emission or as residual wastes. This technology is completely environmental friendly....

The technology, which Maharani Paints uses, has been supported by the Ministry of Environment & Forests in collaboration with National Productivity Council, by sponsoring a project. The company has also received some other awards for this process, to name a few: ‘Innovation for India Awards 2008’ from Marico Innovation Foundation, ‘Corp-Excel Awards (National MSME Excellence Awards) 2008’ by Corp Bank, ‘Innovation of the Year Award,’ by Faridabad Chamber of Commerce & Industries, ‘Innovation Award on Green Technology’ by Manufacturers Association, Faridabad and ‘Parivartan 2011 Award’ from Carbon Outlook.

Future Expectations and Steps – Paint Sludge Incineration Soon Thing of the Past?

Maharani Paints is hopeful that incineration and co-incineration will be banned generators will come forward to get their ‘paint sludge’ recycled. The company is now conducting R&D on the alternative usage of ‘paint sludge’ to accommodate the bigger volumes of ‘paint sludge’ being generated by the passenger car industry – who practically use no solvent base primers, for finishing their product.

For them, Maharani Paints have developed a process of blending the ‘paint sludge’ with the road construction bitumen that will improve the water resistance of the bituminised road, and hence will increase the life of the bituminous road and will keep them free from potholes. Recycling the ‘paint sludge’ is also an economically viable proposal as it saves the cost of incinerating for the industries disposing it off by incineration.

They will also save the cost of disposal for the remnant ash, which is also a hazardous waste and needs to be disposed off at TSDF site.

* Author AS Vishnoi is the GM - Technical at Maharani Paints.

* Author Sunil Lal is an independent Management Consultant.

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