Effect of the enzymatic hydrolysis pretreatment of lipids-rich wastewater on the anaerobic biodigestion

A low-cost commercially available lipase preparation from animal source was used to perform enzymatic hydrolysis pretreatment of lipid-rich wastewater from dairy industries. The hydrolysis was carried for different incubation time (4–24 h) and the pretreatment efficiency was verified by running comparative biodegradability tests (crude and treated effluents). All pretreated assays showed higher reaction rate in relation to crude wastewater assay, which was confirmed by the increased levels of biogas production and higher organic matter (COD) and color removal. The pretreatment was optimized for 12 h hydrolysis time, enabling high-biogas formation (445 ± 29 mL) and organic matter removal (78.2%). Promising results in relation to the biogas formation (354 ± 34 mL) were also found when hydrolysis and biodegradation steps were carried out simultaneously. The use of enzymatic treatment seemed to be a very promising alternative for treating wastewaters having high-fat contents, such as those from the dairy industry.