5LIAO B Q, ALLEN D G, DROPPO I G, et al. Surface properties of sludge and their role in bioflocculation and settleability[ J]. Wat Res,2001,35(2) :339 - 350.
6DIETER H, ERHARD H. Particle size analysis and sedimentation properties of activated sludge flocs [ J ]. Wat Sci Tech, 1997,36(4) : 167 - 175.