Evaluation Methodology Framework for Processes to Reduce Waste Activated Sludge

Abstract

Water Environment Research Foundation's 05-CTS-3 Evaluation of Processes to Reduce Activated Solids Generation and Disposal aims to establish a comprehensive evaluation methodology for waste activated solids (WAS) reduction processes based on the in-depth consideration of a select number of technologies considered to be representative of the many options currently available in the marketplace. These technologies cover both those intended to reduce the generation of wastewater treatment residuals from the liquid process, as well as those designed to pre-condition solids in order to make it more susceptible to subsequent stabilization processes such as anaerobic digestion.In conjunction with the previous papers -"Current State of the Practice of the Sludge Reduction Technologies" (Sandino et al, 2008) and "Underlying Mechanistic Principles and Proposed Modeling Approach for Waste Activated Sludge Reduction Technologies" (Whitlock et al, 2009) -this paper is the third in a series and is intended to present an evaluation methodology framework for solids reduction technologies. In addition, this paper provides an update of the performance data collected from full-scale facilities. Laboratory analyses conducted at Virginia Polytechnic Institute from samples collected from these same facilities are included as well.The evaluation methodology framework contains a suite of tools, including Sludge Testing Protocol, Process Modeling, Life-Cycle Cost Module, and Multi-Criteria Analysis. This paper discusses the mechanisms behind the technologies, presents performance data, and discusses the operational considerations influencing the observed performance (e.g. wastewater characteristics, activated solids operational practice, solids reduction technology design basis and operation).