Characterization of synthetic and activated sludge and conditioning with cationic polyelectrolytes

This study investigates the effect of cationic polyelectrolytes on the final properties of synthetic and activated sludge. Synthetic sludge was prepared according to established procedures. Activated sludge was produced in a labscale, continuous-flow reactor which was fed with live activated sludge from a waste-water treatment plant. Capillary suction time (CST) was used to evaluate the sludge dewatering behaviour. The results from experiments indicated that the cationic polyelectrolytes had a critical effect on sludge dewatering, and made an improvement in the final properties of sludge. The two types of sludge have very similar dewatering characteristics after cationic polymer conditioning. The development of synthetic sludge is suggested also to be a possible surrogate for studying the final properties of activated sludge.

mainly consumed in the neutralization of biopolymers and the flocculation of colloids, and to a lesser extent in rebuilding floc fragments and improving existing flocs, which is especially evident with high degrees of stirring. This, however, depends strongly on sludge characteristics. The addition of calcium can also decrease polymer demand for the conditioning. Therefore, the C The effects of calcium and cationic polyelectrolytes on the resulting final properties of sludge, such as settling and dewatering and sludge conditioning have been measured and characterized for both synthetic and activated sludge. The calcium ion content in wastewater can have a major impact on the settling and dewatering characteristics of both synthetic and activated sludge.