A Survey of Water Consumption and Product Output from Ten Sago Factories in India

Most of the tapioca processing units in India separate starch from slurry by employing the gravity settling method. Sedimentation in settling tanks allows the contact of starch with water. This process leads to fermentation in which alcohols and organic acids are for med and polluting the environment. Wastewater from tapioca processing factories contain high chemical oxygen demand (1 1,077-19,083 mg t^-1), low pH (4.33-5.60) an d causes pollution. The effluent from tapioca industries is acidic and organic in nature, contributing biological oxygen demand in the range of 1500 to 2000 g m^-3 , Inorgani c constituents like phospha te, sulphate, chloride, and several metals are also found in trace quantities. This paper explains the water consumption, product output and effluent generation in tapioca processing industries. The average water requirement was 4.512 m^3 to process1000 kg of cassava tubers. When the tubers are used for starch manufacture, a product yield of 16. 7% starch, 1.6% dirty starch and 7.0% thippi were obtained, and 18.6% sago, 1.8% dirty starch, 19.1% peel and 3.9% thippi were obtained when the tubers are used for sago manufacture. About 95% of the consumed water is leaving the factory as effluent.