Modern biogas generation method based on ultrasonic and anaerobic fermentation of municipal wastewater biological sludge

Abstract

Classical biogas generation during the municipal wastewater treatment flow is based on anaerobically fermentation of biological sludge.The efficiency of organic matter conversion into higher biogas volume depends on organic load (COD/BOD) of active biological sludge, especially in soluble form. Soluble COD amount can be rise by non-conventional pretreatment methods as ultrasonic application. Ultrasonic pretreatment of biological sludge increases the amount of biogas from anaerobic digestion phase comparing with traditional process. This paper shows the influence of ultrasonic field on biological sludge fermentation. Ultrasonic treatment step was performed in a field, in a medium size wastewater treatment plant, at industrial pilot scale level using biological sludge, before anaerobic fermentation phase. Laboratory fermentation tests have proved that ultrasonic pretreatment lead to biogas higher production with 84%.