Potential of rapid anaerobic fermentation on animal slurry for biogas production and storage of biogas slurry

Abstract

A study was designed aiming at the degradation of organic matter in liquid phase of pig manure, the inactivation of pathogenic microorganisms and biogas production at different storage temperatures. A low cost rapid anaerobic fermentation, and biogas sewage storage system was constructed. After the four-day anaerobic fermentation, three treatments were set up: the average temperature of spring and autumn (16.1ºC), summer (25ºC), and winter (0.6ºC) in Yantai City was used as storage temperature for 90 days, respectively. The results showed that the biogas potential of anaerobic fermentation and biogas sewage storage at 16.1ºC and 25ºC was higher than that stored at 0.6ºC. During the experiment, total solids (TS) and organic matter contents in fecal sewage were decreased with time, and the value was determined at 25ºC. Total phosphorus and potassium contents in biogas sewage did not change significantly over time, but the total nitrogen content decreased. The content of the 5 day biological oxygen demand (BOD5), the chemical oxygen demand (CODCr) and suspended solid concentration (SS) in fecal sewage showed a downward trend over time. The egg mortality of Ascaris lumbricoides increased in different degrees under the three storage conditions. The number of E. coli in biogas sewage stored at 0.6ºC and 16.1ºC showed a downward trend, and the number of E. coli in biogas sewage stored at 25ºC was significantly higher than at 0.6ºC and 16.1ºC. The comprehensive analysis showed that at temperature 25ºC, the an-aerobically produced fecal sewage after fermentation had best potential for biogas production.