KANSAS CITY, MO, May 2, 2005 -- Black & Veatch, a global engineering, consulting and construction company, has been awarded a contract to study the impacts of membrane treatment residuals, such as concentrate and membrane cleaning wastes, on wastewater and advanced wastewater treatment plant operations and processes. The research project is sponsored by the Joint Water Reuse and Desalination Task Force (JWR&DTF). In addition to the WaterReuse Foundation, which is managing the project for the task force, funding partners include the U.S. Bureau of Reclamation, California State Water Resources Control Board, Awwa Research Foundation (AwwaRF), and Water Environment Research Foundation (WERF).
Membrane processes continue to gain in popularity for potable water treatment and water reclamation applications. Microfiltration, ultrafiltration and nanofiltration effectively remove disinfectant byproduct precursors, pathogens such as Cryptosporidium, and other undesirable constituents while reverse osmosis and electrodialysis are increasingly employed to desalinate seawater and brackish water. Also growing, however, is the quantity and percentage of residual wastes from membrane filtration and cleaning that are disposed to community wastewater systems. Concern about how these concentrated contaminants affect wastewater and advanced wastewater treatment plant operations and processes is understandably rising as well.
"We realized that multiple organizations within the water industry needed to work together to identify and mitigate the impacts of membrane process residuals on treatment processes and effluent quality," said WateReuse Foundation research programs director Jeff Mosher. "Black & Veatch assembled a team with the membrane, reuse and residuals expertise necessary to provide both in-depth understanding and big-picture solutions for this complex issue."
Francis A. DiGiano, Ph.D. (University of North Carolina), and consultant Barnes Bierck, Ph.D., join Gary Hunter, of Black & Veatch, as research task leaders. The team will also rely on a small group of technical advisors representing utilities, academia, and engineering/consulting.
Membrane systems generate backwash discharges that contain raw water solids, pathogens, algae and possibly chemical residues; solids and sludge created by concentrating the solids removed from the raw water flow; and spent cleaning solutions with high levels of chlorine and other cleaning chemicals in addition to most of the raw water contaminants. Over the next 12 months, the Black & Veatch-led project team will:
-- Identify the concentrations at which constituents of concern can negatively impact wastewater treatment or treatment plant facilities;
-- Identify critical gaps n knowledge that currently limit the assessment of negative impacts of these residuals; and
-- Recommend and develop approaches for eliminating negative impacts of membrane process residuals on wastewater treatment as well as approaches for discharging residuals to wastewater systems in planning new membrane projects.
The research team has just launched a literature review and will develop a database to identify and catalogue the negative impacts of membrane residuals on wastewater treatment facilities that have currently been documented. Density impacts that result from mixing concentrate and wastewater and salt impacts to facilities, equipment and biological processes are just some of the many issues currently under investigation.
"An increase in total dissolved solids concentration entering wastewater systems can adversely affect settling, inhibit biological treatment and increase aquatic toxicity¿which in turn can limit a utility's disposal and reuse options," said Black & Veatch principal investigator Alan Rimer, Ph.D. "We are excited about this opportunity to develop recommendations that will enable utilities to improve effluent quality and keep their options open."
Following the literature review, the research team will conduct interviews with six utilities that process concentrate or other waste streams with high concentrations of total dissolved solids (TDS) at their wastewater treatment plants to gain insight into issues associated with such waste streams. The team will conduct a web-based survey of membrane facilities that discharge to wastewater systems. The resulting data, which will supplement previous work done by the Bureau of Reclamation, will assist in the development and validation of a concentration impact model. The research team will ultimately prepare a guidance manual to help utilities appropriately address issues associated with the discharge of various types of membrane residuals and high TDS waters into their treatment facilities.
Black & Veatch Corp. (www.bv.com) is a leading global engineering, consulting and construction company specializing in infrastructure development in the fields of energy, water and information. Founded in 1915, it serves clients with conceptual and preliminary engineering services, engineering design, procurement, construction, financial management, asset management, information technology, environmental, security design and consulting, and management consulting services. B&V Water, the water business of Black & Veatch, provides innovative, technology-based solutions to utilities, governments and industries worldwide. Local project managers work with a global team of water and wastewater treatment process experts to address site-specific challenges through a broad range of consulting, study, planning, design, design-build and construction management services. The employee-owned company has over 90 offices worldwide and is ranked on the Forbes "500 Largest Private Companies in the United States" listing for 2003.
The WateReuse Foundation (www.watereuse.org) is an educational, nonprofit public benefit corporation that serves as a centralized organization for the water and wastewater community to advance the science of water reuse, recycling, reclamation and desalination through research. The organization's research covers a broad spectrum of issues, including chemical contaminants, microbiological agents, treatment technologies, salinity management, public perception, economics and marketing. Its primary sources of funding are its subscribers and funding partners, which include the U.S. Bureau of Reclamation, the California State Water Resources Control Board and the Southwest Florida Water Management District. Subscribers include water and wastewater agencies and other interested organizations.
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