SUNTEX- pH correction and decolorization of dye effluent: Laboratory level experiments have yielded encouraging results in decolourization and degradation of dye and pH correction of dye effluent using certain species of micro algae. Consultancy is being offered to field level application of this technology. Pilot plant is in operation at SUNTEX Processing Mills Pvt LTD in Gummudipoondi, Tamil Nadu, giving excellent results. Algal technology could correct the pH and prevent sludge formation. The dye bath effluent is being treated separately using micro algae. This technology is not only eco-friendly but also very economical. The complicated ETP process now being followed in various dyeing industries has been simplified. The algal biomass produced by the process is being used for composting and part of it is dried and used as a fuel. Since the process employs photosynthetic micro algae, the industry can claim carbon credits too....
PERC, Chennai has recently identified a species of algae which can effectively treat textile effluent. After successful trials at the laboratory, field level trials were conducted at SUNTEX PROCESSING MILLS, a textile dyeing industry situated in Gummudippoondy near Chennai.
Dyeing industries conventionally treat their effluent by using lot of chemicals. Highly alkaline effluent is neutralized using acid and the residual dyes are bleached using bleaching chemicals. The sludge is precipitated using a number of chemicals and the resultant sludge is dried and stored as hazardous solid waste waiting for land fill to dispose them. The liquid effluent is either discharged or sent to R/O plant for recycling. The R/O reject is again evaporated using SEPs (solar evaporation ponds). The resultant sludge is again stored as hazardous solid waste. The problems caused by effluent disposal in and around Tiruppur area are well known.
Treatment of textile effluent using algal technology (Phycoremediation):
Algal Biotechnology Unit of RKM Vivekananda College, Chennai headed by Dr V Sivasubramanian, started working on textile effluents after their successful project with SNAP ALGINATES & NATURAL PRODUCTS, Ranipet, Tamil Nadu. The first ever pycoremediation plant in the world was set up during September 2006 and has been working for the last 2 years successfully. This plant has been visited by scientists from India and abroad. The main achievements of the plant at SNAP are pH correction and sludge reduction. Following this successful demonstration of algal technology, the research scholars of algal biotechnology unit worked on effluents from STAHL India (Chemical industry producing leather processing chemicals), Ultramarine Pigments (detergent manufacturing industry) both at Ranipet, Tamilnadu and Perfetti van melle a confectionary industry near Guduvanchery, Chennai and submitted M Phil and PhD dissertations and presented research articles in conferences and published them in scientific journals.
SUNTEX PROCESSING MILLS, Gummidippoondy:
Algal biotechnology unit has set up pilot plants at SUNTEX to test the ability of algal species they have identified for treatment of textile effluent at field level. After repeated running of the plant the following results were obtained:
The micro alga selected could tolerate and grow very well in the raw effluent. Algal growth corrected the pH and removed colour, odour and sludge. Conventional treatment process employs chemicals to achieve this. Algal technology has achieved this without using any expensive and toxic chemicals. The industry saves lot of money on chemicals. Since there is significant reduction in sludge (80%, which can be improved during scaling up) the pollution problem caused is prevented. The remaining water can either be evaporated using SEPs or send to R/O plant for recycling. R/O reject can also be recycled to algal treatment plant and treated to prevent sludge formation.
Following are a few pictures depicting the pilot plant and efficiency of micro alga developed by algal biotechnology unit of R K M Vivekananda College, Chennai:-
A comparison of algal treatment with conventional treatment
Fig Legend: Tube No 1. Shows the raw effluent loaded into the treatment plant. It is darkly coloured due to dyes, highly alkaline (pH 11.4) with a high TDS (Total Dissolved Solids – 6800 mg/L)
Tube No. 2 shows effluent treated with conventional chemical treatment. The pH is around 9.6 and a TDS of 10,280 mg/L, which much higher than the raw effluent due to usage of chemicals for treatment, and sludge formation is 100%.
Tube No. 3. Shows effluent treated with algal technology. The pH is corrected to 9.5, the TDS is reduced to 5700 mg/L and there is excellent colour removal. The most significant achievement is- there is 80% reduction in sludge formation which can be improved when scaled up
The scaling up process is on now. There is also an attempt to treat the dye bath effluent separately using the algal technology. The excess algal biomass settling in the treatment tank is being dried for possible use as fuel for the boilers at SUNTEX.
Algae cake with a high calorific value from SUNTEX