Ming Chang, Shungui Zhou, Qihong Sun, Tiexiang Li and Jinren Ni
State Key laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
The recovery of Bacillus thuringiensis (Bt) based biopesticides from fermented sludge broth via cross-flow microfiltration (CFMF) was evaluated. Three types of microfiltration membranes, WX-model cellulose, cellulose acetate, and polyethersulfone, were tested for their permeate flux and restoration capacity. The cellulose acetate membrane with a pore size of 0.8 μm was selected for further process optimization and modeling of CFMF. Under optimal conditions, the permeate flux could be greater than 20 l/m2/h if the retentate contained was less than 100 g/l. The spore and crystal proteins recoveries were found to be 99 and 95%, respectively. The standard hydraulic resistance-in-series model was used to determine the parameters of CFMF of Bt fermented sludge. The results demonstrated that CFMF was effective for Bt based biopesticide recovery from fermented sludge.