A brush of hair

Can help treat oily wastewater

Published: Sunday 15 August 2004

-- (Credit: EMKAY)a team of Indian engineers have chanced upon an unusual property of the human hair -- it can separate oil from water. Their preliminary studies reveal that removal rates of free-floating oil by healthy hair is almost 100 per cent, while they can scavenge about 95 per cent of oil found in the emulsified form (partially dispersed with water).

The problem of separating oil from water is widely faced by many enterprises, especially the petroleum industry, effluent treatment plants and sewage treatment plants. Conventionally, sedimentation is used for separating free oil from water. Separation of oil in small plants can also be done manually, but the continuous removal requires expensive processes. Furthermore, emulsified oil can be separated only with the help of chemical clarification.

"Our process is ecofriendly and does not require any chemicals," concur Z V P Murthy and colleagues from Vadodara-based Dharmsinh Desai Institute of Technology in a paper published in the Indian Journal of Chemical Technology (Vol 11, No 2, March 2004). According to Murthy, who is now with the chemical engineering department of Sardar Vallabhbhai National Institute of Technology, Surat, their experiments showed that hair has the property of selectively adsorbing oil. But Murthy is quick to add that more work is needed to ascertain the efficiency of the technique in real life situations, as the laboratory conditions are quite different. The quality of hair will also impact the process to a large extent.

Industrial waste contains nearly 70 per cent floating oil, 25 per cent emulsified oil and five per cent soluble oil. Separation of oil from water is necessary due to a variety of reasons. Oil slick on surface of water can prevent oxygen transfer from atmosphere to water, and the resultant very low dissolved oxygen levels reduce efficiency of microbes and chemicals treating wastewater. Besides, oils and waxes may solidify at low temperatures and cause clogging in pipes and sewer lines. The technique can also prove helpful to clean up oil slicks, which are responsible for the death of birds, with the oil penetrating their feathers and affecting their insulation and buoyancy.

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