INFLUENCE OF SLUDGE INOCULATION VOLUME ON METHANOGENESIS OF RESIDUE FROM ANAEROBIC FERMENTATIVE HYDROGEN PRODUCTION USING COMBINED SLUDGE AND FOOD WASTE UNDER MEDIUM TEMPERATURE CONDITION

Methane production from residue of anaerobic fermentative hydrogen production using combined sludge and food waste is a promising method to further exploit the potential resource of the residue of hydrogen production. This study explored the influence of inoculation volume on the methane production from the residue of anaerobic hydrogen fermentation using combined sludge and food waste under medium temperature condition, analyzed its gas and methane production performance and the changes of the substrate in the anaerobic system before and after fermentation, aimed to seek the optimum inoculation volume and the corresponding changes of the substrate in the anaerobic system, including saccharide, protein, TVFA, pH and ammonia. The results showed that, under medium temperature conditions, neither high nor low inoculation volume was conducive to methane production performance improvement. The optimum inoculation volume was 30%, then we got the fastest growth rate of methane concentration during the anaerobic fermentation, and the largest accumulative methane yield was 171.1 mL/gDS. The changes of substrate concentration in the anaerobic system proved that organic substrates were consumed greatly during fermentation, and the degradation yield of total saccharide was 39.01% and the total protein was 28.09%. It was also found that degradation rate of soluble saccharide was greater than insoluble saccharide, and the former mainly contributed to the saccharide degradation; while the degradation of insoluble and soluble amount of protein was equivalent. After the fermentation was finished, the pH in the system rose.