Fundamental and applied studies on anaerobic biotechnology for the treatment of high strength cheese processing waste

The average biochemical methane potential (BMP, g CH₄-chemical oxygen demand (COD)/g COD) and specific methanogenic activity (SMA, g CH4-COD/g TVSS-day) values of cheese processing waste were 0.88–0.93 and 0.06–0.08 for pig wastewater sludge, and 0.42–0.44 and 0.05 for municipal wastewater sludge. Nutrient supplements only affected BMP and SMA values when pig wastewater sludge was used. The sludge type had significant effects on the values of BMP and SMA with pig wastewater sludge being more effective than municipal wastewater sludge. This waste was not found to be toxic to both starter sludges. The inhibition concentrations (mg/L) of sodium and potassium were 1,110 and 6,228 and 1,628 and 7,990 for municipal wastewater sludge and pig wastewater sludge, respectively. The inhibition was more pronounced when municipal wastewater sludge was used as a starter.; Four bacteria species (C. cadveris, C. perfringes, C. bifermentans , and E. lentum) were isolated from an anaerobic sludge. E. lentum was the only nonsaccharoclastic-proteolytic that could degrade whey protein and produce hydrogen. The theoretical biochemical hydrogen potential (BHP, g-H₂-COD/g-COD) value of the artificial cheese processing waste was 0.79, whereas the experimental values of BHP were 0.050 and 0.045 with and without bioaugmentation, respectively. The experimental values of specific hydrogenogenic activity (SHA, g-H₂-COD/g-TVSS-hour) were 0.11 and 0.07 with and without bioaugmentation, respectively. Bioaugmentation significantly increased the BHP and SHA but did not affect the H₂ content in the biogas. The results obtained from the completely mixed anaerobic batch reactor (CMABR) study indicated that bioaugmentation had significantly affected the reductions in protein and COD, and the production of volatile fatty acids (VFAs), but did not affect the reduction in lactose. Increasing the volume of the bacterial culture could increase their conversion rates. Most lactose and protein were converted to VFAs during the first 72 hours.; The results obtained from the anaerobic sequencing batch reactor (ASBR)-upflow anaerobic sludge blanket (UASB) system with bioaugmentation studies indicated that the ASBR-UASB overall removal efficiencies for lactose, protein, and COD were 100, 94, and 90%, respectively. This system could be used to directly treat high strength cheese processing waste.