Treatability and kinetics studies of mesophilic aerobic biodegradation of high oil and grease pet food wastewater.
In this work, batch activated sludge studies were investigated for the treatment of raw pet food wastewater characterized by oil and grease concentrations of 50,000-66,000 mg/L, COD and BOD concentrations of 100,000 and 80,000 mg/L, respectively, as well as effluent from an existing anaerobic digester treating the aforementioned wastewater. A pre-treatment process, dissolved air flotation (DAF) achieved 97-99% reduction in O&G to about 400-800 mg/L, which is still atypically high for AS. The batch studies were conducted using a 4-L bioreactor at room temperature (21 degrees C) under different conditions. The experimental results showed for the DAF pretreated effluent, 92% COD removal efficiency can be achieved by using conventional activated sludge system at a 5 days contact time and applied initial soluble COD to biomass ratio of 1.17 mg COD/mg VSS. Similarly for the digester effluent at average oil and grease concentrations of 13,500 mg/L, activated sludge affected 63.7-76.2% soluble COD removal at 5 days. The results also showed that all kinetic data best conformed to the zero order biodegradation model with a low biomass specific maximum substrate utilization rate of 0.168 mg COD/mg VSS day reflecting the slow biodegradability of the wastewater even after 99% removal of oil and grease.
Liu
Victor Lei
VL
Department of Chemical and Biochemical Engineering, The University of Western Ontario, London, Ont., Canada N6A 5B9.
Nakhla
G
G
Bassi
A
A
D000332:Aerobiosis; D000818:Animals; D000829:Animals, Domestic; D001673:Biodegradation, Environmental; D018533:Biomass; D019149:Bioreactors; D005525:Food-Processing Industry / Q000379:methods*; D007219:Industrial Oils / Q000032:analysis*; D007220:Industrial Waste / Q000517:prevention & control*; D007700:Kinetics; D012722:Sewage / Q000737:chemistry*; D014876:Water Pollution / Q000517:prevention & control*
D007220:Industrial Waste; D012722:Sewage