Experimental Study On Food Waste Wastewater By Biological Treatment

Food waste degreasing wastewater contained rich protein, carbohydrates and smallamount of grease. For the characteristics of high organic concentration, high nitrogen andphosphorus content，two biotechnology processes which include the UASB-SBR andIC-ALR was used to treat food waste degreasing wastewater and compare them.Experimental results show that up-flow anaerobic sludge blanket reactor which hadgranular sludge treat it well. During the stable operation period, when the influent CODconcentration stabilized at15g/L, COD removal rate remains at about90%. Food wastewastewater was treaed by internal circulation reactor which mixed the digested sludge andgranular sludge. The rapidly increasing load to5Kg/(m3.d)and stabilizing for several daysin the start-up period can improve the activity of the sludge and accelerate sludgegranulation. The maximum volume load of food waste wastewater which IC treated is25.2Kg/(m3.d).The9.0mmol/L VFA of effluent does not adversely affected the stableoperation of the IC. SBR and ALR reactor was used to treat the effluent of UASB and ICrespectively. When organics and ammonia concentration of influent of SBR reached1500mg/L and385mg/L，the COD and NH4+-N removal rate reaches70%and88.6%.Freeammonia of30~~80mg/L will significant inhibit the activity of Metabolism of nitrifyingbacteria of SBR. The effluent of IC reactor was treated by ALR reactor. When COD andNH4+-N concentrations reached1850mg/L and420mg/L，it can removal75percent of theorganic matter and91percent of ammonia. The NH4+-N and COD concentration ofeffluent of SBR and ALR can achieve B grade requirements of CJ343-2010. Bycomparing the analysis of results，it was found that IC-ALR process was better thanUASB-SBR process in efficiency and investment, so it deserves wide application.