Pretreatment of food waste by ultrasonication for sugar production

Abstract

Biofuel and methane are clean and renewable energy sources. They can be produced from food waste via fermentation but the bioconversion efficiency is low. To increase the efficiency, pretreatment of food waste is needed. There are many pretreatment methods, such as heat treatment, microwave treatment and chemical treatment. The pretreatment methods studied in this report were ultrasonication and combination of ultrasonication with chemicals. Different pretreatment conditions were investigated, such as chemical concentration, total solid concentration of food waste and ultrasonication power input density. Among the studied conditions, the most suitable conditions were determined as 10 % food waste solid content loading, 1250 W/L input power density and 1.5 % chemical loading to improve SCOD production. Ultrasonication and ultrasonication with chemical as pretreatment methods were efficient to improve the biodegradability of food waste by anaerobic digestion. The methane gas production per volatile solid loading increased 41%, 55.7% and 97.8% by using ultrasonication, ultrasonication with HCl, ultrasonication with NaOH, respectively when compared with unpretreated food waste. This finding suggests that ultrasonication with NaOH is the