Oxidative decomposition of excess waste sludge was attempted by using Fenton's reagent, which is the combination of hydrogen peroxide and iron salt. Effect of various factors on digestibility of cells was examined. The digestibility was significantly affected by pH. Maximum digestibility was observed at pH 2.5 and it increased with increasing pH in alkaline solution. Also, it increased with increasing temperature and hydrogen peroxide concentration. In the absence of Fe²⁺, digestibility increased with addition of hydrogen peroxide compared with that without hydrogen peroxide, and it increased with Fe²⁺ concentration. Increase of sludge concentration lowered the digestibility, probably due to hydrogen peroxide decomposing enzymes.

View full abstract