Prolonging the time of manure by water soaking can alleviate the inhibition of lime disinfection wastewater in a batch anaerobic digestion of swine manure

Abstract

The African swine fever poses significant challenges for swine farms using lime-based disinfectants, leading to pronounced inhibition of anaerobic digestion systems due to the influx of lime disinfection wastewater. This study focuses on treating swine manure containing lime through water soaking (2d, 4d, 6d, 8d) before biogas digestion. An 8-day water soaking period significantly reduces Ca2+ and PO43--P concentrations by 20.36 % and 56.79 %, respectively. Batch tests show enhanced performance, with T1, T2, T3, and T4 witnessing increases in biogas production of 25.73 %, 114.36 %, 119.59 %, and 181.83 %, and Ca2+ sedimentation rates escalating by 6.59 %, 13.47 %, 28.94 %, and 35.64 %, respectively, compared to the control group (CK). In continuous tests, the pre-treated sample C1 maintains Ca2+ at 4.1 g/L, leading to a 104.86 % increase in biogas production compared to the control group. The study advocates extending water soaking durations as a strategy to mitigate lime disinfectant inhibition in swine manure anaerobic digestion systems, highlighting its potential for enhancing acidification, hydrolysis, and ultimately, the efficiency of biogas production.