A hybrid anaerobic solid–liquid system for food waste digestion

A hybrid anaerobic solid – liquid (HASL) system was developed to enhance food waste bioconversion in comparison with the conventional two-phase anaerobic digester. The advantages of the HASL system were the higher efficiency of methane production and smaller volume of effluent from the system. The biogas, which was generated from the methanogenic phase, had an average methane content of 71–72%. Total removal of volatile solids consisted of 78–80%. The HASL system can be operated in both batch and semi-continuous modes with satisfactory performance. The addition of a submerged biofilter for ammonia removal to the HASL system further enhanced the performance of anaerobic digestion. Methane production in the enhanced HASL system was increased by 26% in comparison with the HASL system without submerged filter. This paper describes the development of the enhanced HASL system for anaerobic treatment of food waste.