BIOLOGICAL LIQUEFACTION AND ANAEROBIC TREATMENT OF FLESHING GENERATED FROM TANNERIES

Fleshing is one of the major solid wastes generated from tanneries. In tanneries after liming fleshing operation is carried out. While processing 1000Kg of hide, 100–150Kg of fleshing is generated. At present in India fleshing is stored in unlined pits. This has lead to leachate problems. To solve this problem a study was undertaken to recover energy by treating anaerobically in Upflow Anaerobic Sludge Blanket (UASB) with liquefied fleshing mixed with tannery wastewater. Fleshing with moisture content of about 80–90% and Volatile Solids (VS) concentration of 0.4–0.8g/g of dry solids was liquefied and the liquefied fleshing and tannery wastewater was mixed in the ratio of 1:2 and this was fed into UASB reactor. Feed was fed intermittently using timer controlled peristaltic pumps. The biogas produced in the reactor was passed through the soda lime pellets column, which absorbs H2S and CO2. The methane gas was measured using wet flow gas meter. The paper illustrates the performance of UASB lab scale reactor treating liquefied fleshing with tannery wastewater at an average Hydraulic Retention Time (HRT) of 1.25 days. During the study period maximum methane production was observed with loading rate of 15 Kg/m3.day. It was noted that Chemical Oxygen Demand (COD) removal efficiency was not affected with increase in load upto 15 Kg/m3.day. Around 65 75% of COD (T) removed was observed. 0.35 – 0.5m3 of methane was produced / Kg of COD removed was observed in this study. This work shows that biologically liquefied fleshing with tannery wastewater can be treated well in UASB reactor with maximum production of methane and simultaneously the problem of disposal of fleshing is solved in and around tanneries.