Evaluating the Next Generation of Water Reclamation Processes

Abstract

The proper evaluation of advanced waste treatment (AWT) process alternatives for water reclamation (WR) is particularly important for those planning new or expanded facilities. Recent advances in technology, particularly with regard to the successful use of membranes in wastewater treatment applications, have provided the industry with many possible process combinations that did not exist just a few years ago.The focus of the paper will be on an evaluation that compared conventional and membrane AWT processes for the reclamation of municipal wastewater. The evaluation led to the determination that membrane bioreactor (MBR) processes are suitable for large-scale WR applications. The evaluation also led to the development of a unique process configuration using two immersed membrane reactors in series. The first reactor is a multi-zone MBR for biological treatment configured for nutrient removal and the second reactor is an immersed membrane reactor with powdered-activated carbon (PAC) addition for the removal of residual organic materials. The results of the study and the innovative solutions described in the paper may set the tone for WR in the twenty-first century.

Evaluation of Membrane Bioreactor Process Capabilities to Meet Stringent Effluent Nutrient Discharge Requirements

“…Selection of the MBR process for the new Broad Run Water Reclamation Facility (WRF) to be constructed by the Loudoun County Sanitation Authority (LCSA), Virginia, provided the opportunity to test the nutrient removal capability of the MBR process ( Fleischer et al, 2001 ). The Dulles Area Watershed Policy (DAWP) currently governs discharge requirements to Broad Run (the immediate receiving stream for the Broad Run WRF) and the entire watershed.…”

“…The treatment process selected to meet these stringent discharge standards includes influent pumping, screening (6 mm) and grit removal, primary clarification, flow equalization, fine screening (2 mm), the MBR with biological and chemical nutrient removal, activated carbon treatment (either granular or a combined powdered activated carbon/ultrafiltration (PAC/UF) process), UV disinfection, and postaeration ( Fleischer et al, 2001 ). Because of the developing nature of the MBR process, LCSA decided to conduct a pilot plant program ( CH2M HILL, 2001 ; Fleischer et al, 2002 ), which was operated between October 2000 and May 2001.…”

Evaluation of a novel membrane bioreactor system for water reuse applications in urban environments

“…The increasing interest in MBRs is fuelled not only by stricter effluent standards, but also by a steady reduction in the costs associated with membrane treatment, and improvements in membrane productivity and durability [10]. Use of MBRs for phosphorous removal has also been studied showing excellent phosphorous removal at a competitive price when compared with conventional methods [11,12]. The type of membranes used in wastewater treatment applications are micro-membranes, which have a larger nominal pore size than membranes used in drinking water treatment.…”

Water Reclamation and Reuse

“…Results of the use of an immersed UF membrane in three applications filtering secondary effluent showed excellent performance with respect to turbidity, phosphorus removal (with the addition of alum), and silt density index (Cote et al, 2001). A comparison of the costs for high-lime, multi-point alum with conventional filtration, and membrane filtration with alum addition options for a 45,400 m 3 /d (12 mgd) water reclamation facility meeting strict phosphorus limits showed that the membrane filtration options were cost competitive with conventional options (Fleischer et al, 2001). The study included the development and evaluation of a novel process with two immersed membrane filter units in series.…”