Resource detail

Title: Recycling of paint sludge
Organization:Hero Honda Motors Ltd
Source:Narang R K (Ed). 2009. Environment Best Practices: Industry Initiative. In series “Cleaner in Cheaper, Vol. 6”. New Delhi, India: The Energy and Resources Institute, 285pp.

Background: Hero Honda Motors Ltd is a joint venture between Honda Motor Co., Japan and Hero Honda Group, India, established in 1984. It is one of the finest two wheeler manufacturing company in the world.

Challenge: Painting is an essential feature of the manufacturing process in the any automobile industry. In the process, the off spray paint that doesn’t deposit on the body of the locomotive gets wasted and is collected in the form of sludge which is hazardous waste. Rules mandate the hazardous waste to be incinerated under control conditions. The residual ash generated also needs to be disposed of in secured landfills.

However the process of incineration releases harmful toxic gases, causing air pollution and threatening human health. Also, the process of landfilling is very expensive. Moreover due to increase in demand which led to increased production and subsequent increase in the waste generated was getting cumbersome to handle. Management of this waste was becoming difficult because of absence of a common treatment, storage and disposal facility in the state. Costs of incineration and disposal were also becoming prohibitive.

Initiative: In order to address the issue, the company, along with the M/s Maharani Paints India Pvt Ltd, has implemented a novel method of recovering paint (primer) from the waste paint sludge. The sludge contains paint pigment, which is one of the basic paint ingredients that can be recovered to make a paint primer. The paint primer has similar qualities as that of the virgin material..
A batch of 500 kg of paint sludge and 650 kg of additives is processed to produce 732L of anti corrosive paint primer, generating 2%-3% of residual paint sludge. The recycled primer is used in the painting process while the sludge is incinerated.

Various steps are involved in the process as given below:

♦ The paint sludge is washed for removal of all water soluble impurities and then dried in two stages.

♦ The sludge is then soaked in chemicals that soften it.

♦ It is then subjected to dispersion stirring and blending for homogenization with additives, filtration for the removal of large particles, milling and grinding to bring it in the form of paint.

♦ The final correction is made to adjust the viscosity and other parameters. The recycled primer obtained is tested for quality and packaged in steel containers.

Table. Comparison between recycled anticorrosive primer and virgin plant primer

Source: Narang R K (Ed). 2009. Environment Best Practices: Industry Initiative. In series “Cleaner in Cheaper, Vol. 6”. New Delhi, India: TERI.

Outcome/Benefits: The benefits of this move have been multifaceted. There is conservation of resources as the project recovers anti corrosive primer from the paint sludge. Lesser volume of waste is generated which is managed easily and in a much more cost effective manner than before. It has also resulted in the reduction of toxic air pollutants produced. Cost of the standard anti corrosive primer is Rs 117/L while that of the recycled anti corrosive primer is Rs 108/L. The disposal cost of the paint sludge is Rs 13.66/L of primer. Quantity of paint sludge recycled for producing 1L of primer is 0.683 kg.

Treatment and disposal cost of the plant sludge is Rs 20/kg of sludge. About 130L of anti corrosive primer is consumed per 1000 vehicles. Around Rs 2946/1000 vehicles is saved. Therefore total saving potential at full production is Rs 88,38,000 per annum @ 3 million vehicles per annum.

Commercially tested: Yes