Technical papers
Treatement approach for sugar factory effluent
The sugar factory effluent emanates mainly from washing cleaning operation thereby entraining organic load in the form of sugar juice, sugar particles, bagasse etc. in the wash waters leading to effluent generation. An in plant control in the form of controlled washing (absolutely nil washing is a theoretical phenomenon as periodic cleaning is a must for better machinery operation) can reduce the (unnecessary) hydraulic load to a great extent. Also there is a practice in the sugar factories to have open gutters and all gutters leading to the main drain, ultimately joining the effluent treatment plant. Experiments at other factories to segregate these streams (e.g. excess condensates, pump cooling etc.) and to recycle them/ subject them to partial treatment and reuse the same have yielded good results in terms of water saving and optimum hydraulic load for the effluent treatment plant which is desirable from its effective operation.Observing the characteristics, it is evident that all the effluents are highly biodegradable. After a 'Preliminary Treatment', the effluent is equalized and subjected to biological treatment. Primary anaerobic Phase imparts two advantages; One, since the phase does not involve mechanical aeration, it reduces organic matter concentration by more than 50 % efficiency, thereby making the energy requirement 50 %; and two, the most important advantage observed in case of Sugar factory effluent, i.e. the capacity to absorb shock loading compared to Aerobic mode.
The most effective Aerobic Treatment mode determined for the sugar factory effluent is 'Extended Aeration' where the F/M is kept low and MLSS concentration high by optimum sludge recirculation, Two-stage Aeration-Clarification Process is proposed followed by Tertiary Treatment in form of Filtration, making it possible to attain treated quality re-utilizable for Non process applications, and can safely be disposed on land for irrigation.