Effects of modified chitosan on dewatering performance of sludge

The effects of some flocculants such as polyaluminium chloride, chitosan and the other 3 carboxymethyl chitosan(N-carboxymethyl chitosan, N,O-carboxymethyl chitosan and O-carboxymethyl chitosan) on the dewatering performance of sludge were studied. The results of the test show that: when used as a flocculant, the dewatering effect of carboxymethyl chitosan on sludge is obviously better than that of other ordinary flocculants because its floccules has higher intensity and is harder to break up. Toward the said 3 types of carboxymethyl chitosan, N-carboxymethyl chitosan has the best dewatering effects on sludge and the lowest sludge specific resistance, compared with the situation without flocculant, the moisture content decreases from 99.1% to 73%, the volume of sludge is decreased by a factor of 30, and the heat value increases 40 times.