BACKGROUND :
Most Distilleries in India have been generating huge quantities of high toxic effluents and in spite of the best efforts made so far a comprehensive treatment has not been possible. In most of the technologies, the treated effluent also yields very high BOD, COD, SS, and TDS level with black colored and odor effluent to streams, rivers & natural water.

Based on the above mentioned fact, a treatment by which it will be possible to overcome all the problems have been worked out. The concept and the treatment is based on the belief that all the BOD requirement should go down and the condensate coming out should not be polluted.

As per the practical experiments, one tonne molasses having 46 % of fermentable sugar produces 240 Liters of alcohol. In the process, it is estimated that about 10 to 15 liters of spent wash is generated per liter of alcohol produced.

A number of distilleries have gone for a primary treatment of this spent wash by setting up a biomethanation plant where even the best possible results have given a very amount of BOD reduction.

For reducing the above BOD, COD level of the effluent, SSP has suggested a technology of evaporating and drying the effluent.

GENERAL PROBLEM :
The system of evaporation and concentration of effluent from initial concentration of 4 – 5 % to about 40 – 45 % is being attempted by a number of distilleries since past few years. The problems faced in the system of concentration are

DESCRIPTION OF THE PROCESS :
The effluent with initial concentration 4 – 5 % will pass through falling film evaporators and concentrate up to 40 %. Evaporators are designed to reduce foaming and scale formation. Then the concentrate will pass through spray dryer to convert concentrate to dried powder.

The demonstration trials for above technology conducted at our R & D center and witnessed by authorities of State & Central pollution control board.

Some innovative features of the technologies are as follows.