A team of scientists from CSIR-Indian Institute of Chemical Technology (CSIR-IICT) have designed a unique Effluent Treatment Plant (ETP) for industrial aroma chemicals, based on a high rejection hyperfiltration membrane technology, it was announced on Friday.
Chief scientist S. Sridhar and principal investigator-senior scientist S. Chandra Sekhar from the Membrane Separations Laboratory designed the plant for the U.K. Aromatics Pvt. Ltd., Boisar, Maharashtra.
The effluent is a condensate coming from a multiple-effect evaporator (MEE) containing considerable content of total dissolved solids (TDS), turbidity, and colour besides high chemical oxygen demand (COD) levels due to the presence of significant concentrations of aroma chemicals such as esters, flavours, and perfumes with smaller concentrations of toluene and cyclohexane solvents used in azeotropic distillation for isolation of the esters.
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The membrane is specifically developed at CSIR-IICT from ‘hydrophilised polyamide’ which is more hydrophilic or dissolves in water, chemically inert, with a thicker selective skin layer as compared to commercial membranes.
Dr. Sridhar stated that the pilot plant has an operational flexibility across a permeate capacity of 1,000 – 2,000 lit/hr and removes TDS from an initial value of 1,500 to 2,500 ppm in the effluent feed to less than 100 ppm in the permeate water. A TDS rejection of more than 95% with an average COD removal of 75% is achieved at a permeate water recovery of 80%, he explained.
The pre-treatment assembly comprises coagulation, bag filtration, deep bed sand and activated carbon column, micron cartridge filter, antiscalant dosing, and pH correction. The 20% reject stream is recycled to the multiple-effect evaporator for the next operational cycle to ensure zero liquid discharge (ZLD) as per PCB regulations.
₹12 lakh expenditure
The capital expenditure for installing the plant is ₹12 lakh, and the operating expenses is approximately 10 to 12 paise per litre of effluent treated. About 200 MT of effluent has been treated till date at the company, said a press release.
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