Abstract: Bellamya Quadrata was selected as the experimental organism during the sludge reduction process. Its predation ability of sludge was used to reduce  sludge. Various reaction factors were investigated, including the amounts of Bellamya Quadrata, feeding rate, feeding time and the initial MLSS (mixed liquid suspended solids). The results indicate that the sludge reduction rate increases with the increase of MLSS and addition of Bellamya Quadrata. Different survival environments contrast experiments indicate that, with enough DO (dissolved oxygen), the result of sludge reduction is satisfactory. Reduction rates of MLSS and MLVSS (mixed liquor volatile suspended solids) are 40.01% and 47.54% respectively, meeting the requirements of sludge stabilization.

Key words: feeding rate, sludge reduction, Bellamya Quadrata