Anaerobic Codigestion of Poultry Manure and Sewage Sludge under Solid-Phase Configuration

摘要

Anaerobic digestion (AD) is an efficient technology for valorizing biomass. However, when considering livestock farm operation, the dilution of the biomass to be treated in a conventional anaerobic digester may not be a suitable alternative. Solid phase percolating system may circumvent this problem. These types of digestion systems require low volume of water, thus needing a smaller reactor. In this line, AD of poultry manure (PM) and primary sludge (PS) was studied in a percolating reactor with high-solid content. The process was carried out in laboratory-scale plant at mesophilic conditions. The addition of PS as cosubstrate in a 10.1 ratio of volatile solids (VS) improved biogas yield as well as VS removal. Two-fold higher biogas production was observed with the addition of cosubstrate along with an increase from 46 to 64% in the removal of VS. The initial acidification of the percolate could be perfectly balanced by the high alkalinity of the system. Methane yield obtained from the codigestion experiment was 56.5 l CH_4/kg VS while the digestion of PM resulted in a value of 24.6. The ammonium concentration values measured in the percolate did not reach inhibitory levels in spite of the high nitrogen content present in PM.