| Abstract | Anaerobic digestion of manures induces deodorization and conserves nitrogen. Livestock producers could transform their long-term (250-300 day) manure storages into psychorphilic anaerobic digesters, thus greatly reducing the investment, operational and technical cost associated with the treatment. But, sufficient inoculation is required and the feeding regime differs from that of a fixed volume digester, as the fed manure volume to digester content ratio is ever decreasing over time and the retention time is as long as the storage period. The project was designed to establish, in the laboratory, the inoculation conditions and feeding regime leading to the efficient establishment and operation of anaerobic digestion in conventional storages. In the laboratory using biochemical methane potential test (BMP), methane production was monitored from swine manure inoculated with one of the three inocula (cattle manure-B; municipal wastewater anaerobic sludge-R, and; food processing wastewater anaerobic sludge-C) at four ratios (0, 10, 30 and 50%). Also, six prototype digesters were used to simulate VSS digestion in conventional storages, under two feeding regimes (once every week and every two weeks) and using three inocula. With the BMP and for all three inocula, a ratio of 10% provided the fastest initiation and the highest methane production. Both R and C initiated methane production as of the 1st day because of their active bacterial population, while B, obtained from a faculatative system, required 24 days. After 100 days, all three inocula had produced the same amount of methane, for the same inoculation ratio. In the prototype digesters, both R and C inocula produced methane as of the first day, while the B inoculum produced methane after day 45 and 78 days, for the 1/week and 1/2week feeding regime, respectively. For both feeding regimes and after 148 days, all three inocula produced the same cumulative amount of methane. Thus, 10% B can initiate anaerobic conditions in swine manure during storage, as long as the storage period exceeds 140 days and a 45 day initiation period at a temperature is 35°C. |
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