Hydrolytic pretreatment of oily wastewater by immobilized lipase.
The purpose of this study was to evaluate the hydrolysis of wastewater with high oil and grease (O&G) concentration from a pet food industry using immobilized lipase (IL) as a pretreatment step for anaerobic treatment through batch and continuous-flow experiments. The intrinsic Michaelis constant (K(m)) and maximum reaction rate (V(max)) were estimated experimentally and the K(m) value of IL (22.5g O&G/L) was six-folds higher than that of the free lipase (FL) (3.6gO&G/L), whereas V(max) of both FL (31.3mM/gmin) and IL (33.1mM/gmin) were similar. Preliminary batch anaerobic respirometric experiments showed that chemical oxygen demand (COD) and O&G reduction were 49 and 45% without pretreatment and 65 and 64% with IL pretreatment respectively, while the maximum growth rate (micromax) for pretreated wastewater (0.17d(-1)) was 3.4-folds higher than that of raw wastewater (0.05d(-1)) with similar Monod half-saturation constants (K(s) approximately 2.7gCOD/L). The continuous-flow experimental study showed the feasibility of employing the hybrid packed bed reactor (PBR)-upflow anaerobic sludge blanket (UASB) system for the treatment of high-strength oily wastewater, as reflected by its ability to operate at an oil loading rate (LR) of 4.9kgO&G/m(3)d (to the PBR) without any problems for a period of 100days. During pseudo-steady-state conditions, the hybrid UASB produced relatively higher biogas compared to the control UASB, The effluent COD and O&G concentrations of hybrid system were 100mg/L lower than that of the control UASB reactor and no foam production was observed in the hybrid UASB compared to the control UASB reactor.
Jeganathan
Jeganaesan
J
Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ont. N6A 5B9, Canada.
Nakhla
George
G
Bassi
Amarjeet
A
D000693:Anaerobiosis; D002175:Candida / Q000201:enzymology; D004800:Enzymes, Immobilized; D019649:Food Industry; D006868:Hydrolysis; D007700:Kinetics; D008049:Lipase / Q000737:chemistry*; D009821:Oils / Q000032:analysis / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*
D004800:Enzymes, Immobilized; D009821:Oils; D014874:Water Pollutants, Chemical; D008049:Lipase