Comparative study of sludge dewatering and thickening characteristics for biological phosphorus removal process and conventional activated sludge process sludges

TR Number



Journal Title

Journal ISSN

Volume Title


Virginia Polytechnic Institute and State University


Due to the unpredictable nature of sludges, it is imperative to test a sludge from every new process in order to design the sludge handling equipment properly. In this study, sludge from the Virginia Initiative Plant, a pilot scale unit employing the UCT biological nitrogen and phosphorus removal process, operating at Lambert's Point Primary Treatment Plant in Norfolk, Virginia, was tested against sludge from a conventional activated sludge process. A bench scale waste activated sludge unit was employed for the purpose. Tests were conducted to compare batch thickening, vacuum dewatering and centrifugal dewatering characteristics of both sludges. The results obtained indicated both sludges to be highly comparable in all the areas of testing. The results obtained have also been explained in terms of AVI, a measure of sludge floc water content, a fundamental sludge property. Due to the similar nature of the sludges, previously established design criteria can be used for designing the sludge handling equipment for BPR sludges.