Bacteria for Colour Removal from Textile Wastewater

Today India is the 6^th largest exporter of textiles and apparel in the world. The textile industry contributes a whopping 12% of the total revenue earned through exports by India. Unfortunately, the textile industry is also tagged as one of the leading polluting industries in the country. It is said that for every kilo of textile products manufactured, 100 litres of textile effluent is generated.

Textile wastewater has high pH, concentrated suspended solids, chlorides, nitrates, metals like manganese, sodium, lead, copper, chromium, iron, and high BOD and COD levels. A major issue with textile effluent is the presence of refractory dyes and toxic organic chemicals. Some of the toxic compounds are even known carcinogens.

Dye decolourization and degradation of toxic organic compounds is a critical goal of textile wastewater treatment. While there is a slew of technologies available to reduce colour in textile wastewater, most of them fall beyond the practical and financial reach of small and micro-scale units in India.

Bacterial degradation of dyes and organics remains to be the most effective solution at hand. Although both aerobic and anaerobic bacteria from Evolon Biotech can degrade dyes, we have found the best results with a combination of both. The best route will be to first carry out anaerobic digestion of wastewater with Evobac ANB, followed by degradation by aerobic bacteria Evobac. The combination of these two biocultures was found to work best for biological colour removal from textile wastewater.

This method of using Evobac ANB bacteria followed by Evobac bacteria works best for degrading chromophore components of azo type, and the anthraquinone type dyes. First, the Azo dye linkage ( the nitrogen double bond) is broken in the anaerobic process by Evobac ANB. This is followed by aerobic degradation by Evobac where the bacteria break the aromatic amines leading to the complete colour removal from the effluent.

Here we can see a successful colour reduction by one of the textile units in Chennai, India, using Evobac ANB and Evobac.