ENHANCED BIOGAS PRODUCTION FROM ANAEROBIC CO-DIGESTION OF MUNICIPAL WASTEWATER TREATMENT SLUDGE AND FAT, OIL AN GREASE (FOG) BY A MODIFIED TWO-STAGE THERMOPHILIC DIGESTER SYSTEM WITH SELECTED THERMO-CHEMICAL PRE-TREATMENT

摘要

A number of studies have shown that the municipally available organic waste fat, oil and grease (FOG) could be employed as a potential co-substrate in the co-digestion of wastewater treatment process sludges in order to increase methane production, since FOG requires less mass loading and presents a better biogas production potential than other organic wastes. Most studies that have examined FOG co-digestion performance to date have focused on the use of biochemical methane potential (BMP) tests, and little research has been conducted using bench-scale or pilot-scale continuous flow digesters. Hence, the successful implementation of this approach in Canadian municipalities has been limited. Based on the review of the current literature, anaerobic co-digestion with fat, oil and grease (FOG) in an advanced two-stage thermophilic semi-continuous digestion system combined with thermo-chemical pre-treatment could potentially yield a higher biogas production than conventional one-stage or two-stage digestions. The main objective of this research was to compare and characterize the biogas and methane productions from FOG co-digestions in two-stage semi-continuous flow co-digestion systems with thermo-chemical pre-treatment (System I) and without pre-treatment (System II).