Response of Different Types of Biosolids to Simultaneous Dewatering and Pathogens Inactivation by Electrokinetic System

Only electrokinetic system and its effect on the inactivation of pathogenic organisms in biosolids were investigated. Bench scale experiments were conducted in a series of electrokinetic (EK) reactors. Ten EK reactors were set up with different types of sewage sludge: primary, secondary (attached growth culture), secondary (activated sludge), and anaerobically digested sludge, coming from Auteuil Wastewater Treatment Plant, (Quebec), or R.O. Pickard Environmental Centre, Ottawa (Ontario), respectively. The characterization of the sludge was performed followed by electrokinetic (EK) tests and data analysis. A conditioning liquids was also added to some reactors. Potential gradients of less than 5V/cm were applied to the reactors. Biosolids in some reactors also contained biocides. Blower system was integrated into the EK system for four reactors. After EK treatment (from 1 to 9 days) biosolids were analyzed. Total solids, fecal coliform colonies counts, Clostridium perfringens, reovirus, and Salmonella spp. were indicator organisms spiked in the study. The highest total solids content (98.5% TS) was achieved in reactor with combined primary and secondary sludge with lower voltage gradient and in the presence of the conditioner under the blower system. The highest, 11log, reduction of Salmonella spp. was achieved in the reactor with anaerobically digested sludge under a low electrical gradient. Clostridium perfringens and fecal coliforms were below detection level in all reactors. Higher than 6-log reduction of reovirus was also observed in all tested EK reactors. The developed EK process can be applied to different types of sludge in order to upgrade it to Class A biosolids due to simultaneous dewatering and disinfection.