Browne, J., Allen E., Murphy, J.D.

Fourth International Symposium on Energy from Biomass and Waste, Venice 2012

Improving hydrolysis in multiphase digestion of food waste

2012

November

Published

1

()

This paper explores the first phase (hydrolysis and acidogenisis) of a two phase anaerobic digestion system digesting source separated food waste. The paper suggests that hydrolysis is primarily affected by the rate of leachate recirculation and pH. Two dilution rates were investigated: 1 and 6 dilutions per day. The increase in dilution rate improved removal of volatile solids from 48% to 73% with a 24 day solid retention time (SRT). The performance of the Leach Bed Reactor (LBR) was investigated with and without connection to an upflow anaerobic sludge blanket (UASB). It was noted that the pH of the leachate without connection to the UASB stayed within the range of 4 to 5 while with connection the pH raised to the range of 6 to 8. The volatile solid destruction rate increased to 87% with the higher dilution rate at a SRT of 24 days. Separate experiments showed that retention times in excess of 28 days at the high flow rate did not improve volatile solids destruction.