Industry manufacturing refined edible oil with a capacity of 18000 tones/annum generated wastewaters and solid wastes (viz. spent earth, chemical and biological sludges). The wastewater streams were mainly from vat house after soap splitting, floor washing, cooling tower, boiler and filter press. The chemical composition of the wastewater from cooling tower and boiler sections and solid wastes indicated that these wastes could be recycled and reused in the process after preliminary treatment. The combined wastewater from other streams was being treated in the existing effluent treatment plant (ETP) and the treated effluent was not conforming to the limits prescribed for discharge into inland surface water as stipulated by Central Pollution Control Board, Government of India. After adoption of some of the suggested measures, the treatment efficiency of the existing ETP improved and treated effluent conformed to the prescribed limits for discharge into inland surface water. The recycle, recovery and reuse of the wastes were adopted in the industry in order to achieve zero discharge for economical and ecological gains.
Water is an essential raw material for almost any human activity. Until recently, water was viewed as a nearly free raw material and recipient of water streams in many countries. It is increasingly noticed that clean water supply will become more and more difficult. 97.5% of the global water is salt-water. 70% of the remaining 2.5% fresh-water is frozen in the polar area. Most of the residual 30% is inaccessible in atmospheric humidity and deep-water. Just 0.007% of all the water on earth is present in rivers, lakes and in useful groundwater reservoirs. From the estimated 12.5 x1012 m3 water, that humanity can directly use, today more than 50% are used already.