The Effects of Physicochemical Properties of Sludge on Dewaterability Under Chemical Conditioning with Amphoteric Polymer

This study investigated the effects of chemical conditioning with amphoteric terpolymer poly (acrylamide-'acryloyloxyethyl trimethyl ammonium chloride -2-acrylamido-2-methyl-propane sulfonate) (PADA) on sludge dewaterability. Particle size, fractal dimension, surface charge, extracellular polymeric substances (EPS) and trivalent metal ions (Al³⁺ and Fe³⁺) of sludge were monitored and Pearson statistical analysis was used to understand the correlation of dewaterability and physicochemical properties of sludge. The results revealed that: (1) Sludge dewaterability was significantly enhanced by amphoteric polymer PADA. (2) Particle, fractal dimension and surface charge of sludge were associated with anionic degrees and molecular weights of polymer. (3) PADA had apparent effects on removal of EPS and enrichment of metal ions in sludge system. (4) Content of water and specific resistance to filtration had statistically strong correlations with the values of particle size, fractal dimension and EPS, but had weak correlations with values of surface charge and metal ions.