Membranes can be effective in treating effluents from dyes production

The dyestuffs industry that has an acute problem with tackling wastes generated in manufacturing processes can benefit significantly by using membrane solutions at several stages including for dye desalting, concentration and purification of the finished products. Integration of membrane processes with downstream zero liquid discharge (ZLD) systems helps in effluent treatment, with saving of energy cost and recovery of 95-98% of the water used.

This was the central message delivered by Mr. Ajay Popat, President, Ion Exchange (India) Ltd., while speaking at the 68th AGM & Awards Function of the Dyestuffs Manufacturers Association of India (DMAI) in Mumbai on July 6, 2018.

A membrane is a thin layer of semi-permeable material that separates substances when a driving force is applied across it. Water treatment processes employ several types of membranes including micro-filtration (MF), ultrafiltration (UF), reverse osmosis (RO), and nanofiltration (NF) membranes. MF membranes have the largest pore size and typically reject large particles and various microorganisms. They can be applied to separate reactive, sulphur, direct and acid dyes, besides application for food colours and pigment concentration. Ion Exchange is a leading supplier of membranes in India, for several applications, and offers a complete system, which is pre-engineered, pre-designed or customised for a specific application.

According to Mr. Popat, membrane filtration results in ≥95% desalting, ≤0.1% dye loss and increased dye concentration from 5% to 30%. “The benefits are product quality, increased yield and dryer throughput/capacity,” he added.

Ion Exchange, he added, has the largest number of working references, amongst vendors in India, to treat effluents, for recovery of valuable by-products, water and achieve ZLD. “These solutions are economically priced with very attractive payback on regular investment,” he added.