2020•Applied Ecology and Environmental ResearchOpen access
EARLY WARNING OF INSTABILITY DURING MESOPHILIC ANAEROBIC DIGESTION OF CHICKEN MANURE
L. Chen, Tianlong Zheng, Qichen Cao, Yingjie Zhou, X. Liu, Dong Li
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Abstract
Anaerobic digestion (AD) of chicken manure (CM) is easily inhibited by excessive ammonia. To determine early warning indicators of this process, mesophilic AD of CM was conducted by organic loading rate (OLR) from 1.0 to 7.0 g volatile solids (VS)/(L.d). Process parameters were monitored every day. At the maximum stable OLR of 5.0 g VS/(L.d), the volumetric methane production rate reached the maximum value of 1.13 L/(L.d), and the yield of methane was 178 ml/g VS. Meanwhile, the total and free ammonia nitrogen increases to 3900 and 300 mg/L (the maximum value), respectively. Bicarbonate alkalinity (BA) and volatile fatty acid (WA) values were 12200 similar to 47400 mg/L and 1000 similar to 2200 mg/L, respectively. This process was severely inhibited by high ammonia concentration when the OLR reached 6-7 g VS/(L.d). According to our study, the most useful early warning indicators are CH4/CO2, VFA/BA, and individual VFAs for AD of CM.