Parameters Affecting Conditioning Enhancement of Biosolids by Electron Beam Treatment

Abstract

High-energy radiation has been investigated as an alternative method for sludge conditioning. Since the efficiency of sludge disinfection and toxic organic chemical destruction due to irradiation is well documented, this study concentrated on theoretical and experimental aspects of sludge dewatering enhancement (conditioning) due to irradiation. The primary parameters used for evaluation of conditioning were specific resistance of filtration, bound water current, and zeta potential of sludge. Experimental results showed that the scavenging power of sludge systems was higher at larger absorbed radiation doses. When the scavenging power exceeded 109 (s−1), the scavenger (KCNS), could completely eliminate the effect of conditioning of liquid sludge by radiation-absorbed doses up to 2,000 krads. It was observed that bound water content was reduced by irradiation processes, and sludge zeta potential became more positive with increased doses. The experimental results also showed that larger absorbed radiation doses yielded better treatment results, but generally with a lower efficiency within the tested dose range. These findings confirm that irradiation can reduce sludge bound-water content and enhance agglomeration by altering sludge particle surface charges.