Improving the efficiency of chemical treatment
of wastewater of fat-and-oil production

Summary

Wastewater of food industry enterprises is a complex physical and chemical system. Under production line conditions the high treatment efficiency of the main wastewater stream is provided with the help of chemical treatment with further solid phase separation by dissolved-air flotation method. The treatment process flow scheme used at the plant includes collection of wastewater of different composition and chemical treatment with subsequent sedimentation carried out in a batch reactor-settling tank, is characterized by the long process time and low efficiency. For the optimization of the treatment process it was suggested to replace the equipment with a comprehensive system including chemical dosing units (coagulants, flocculants), a pH-correction unit, a flocculator with static mixers and a dissolved-air flotation unit at retaining the collection and accumulation system of wastewater of different composition. The results of implementing different process flow schemes of chemical treatment of fat-and-oil production wastewater (mayonnaise section, refining section, mustard production) are presented. Chemical treatment of wastewater coming from the mayonnaise section provides for more than 97% COD and BOD5 elimination, more than 99% of fat removal and more than 98% of suspended solids removal. Chemical treatment of wastewater coming from the refining section provides for more than 65% COD and 45% BOD5 treatment efficiency, and more than 45% suspended solids removal. The treatment efficiency of wastewater coming from mustard production is more than 60% of COD and BOD5 elimination; more than 90% of suspended solids removal and more than 99% of fat removal.

Key words

reagent treatment , suspended substances , BOD5 , COD , wastewater of fat-and-oil production , fats , dissolved-air flotator