Arsenic Water Technology Partnership Final Technical Report

Abstract

Congress created the Arsenic Water Technology Partnership (AWTP) in 2002 to develop and provide solutions for the cost-effective removal of arsenic from drinking water. The AWTP was funded by four congressional appropriations (FY03-FY06) to evaluate and develop new technologies that could significantly reduce compliance costs associated with the new 0.010 mg/L maximum contaminant level (MCL) for arsenic in drinking water. Initially focused on arsenic research, in FY06 the AWTP was expanded to include desalination research upon recognition that the research challenges were similar. The funding for the research and subsequent transfer of technology was made available by Congress through the Department of Energy (DOE). The AWTP was a collaborative effort between DOE’s Sandia National Laboratories (Sandia), Water Research Foundation (WaterRF, formerly Awwa Research Foundation) and WERC: A Consortium for Environmental Education and Technology Development based at New Mexico State University (WERC). Key features of the AWTP included technology development, technology implementation/testing and technology transfer. Each of the partners evaluated and oversaw development of new arsenic and desalination treatment technologies, and the technology transfer program ensured that successful technologies were transferred to the water supply community. Through the use of an arsenic treatment cost model, training sessions and a web site, information on arsenic removal and desalination technologies was transferred to stakeholders. KEY ACCOMPLISHMENTS The AWTP partnership funded research on, and deployment and testing of, innovative arsenic and desalination removal technologies; education for small and large water system operators; and development of a comprehensive web-based tool for arsenic treatment technology selection using site-specific data. As water becomes scarcer, and potable water supplies become increasingly vulnerable to contamination, the development of affordable water treatment systems is critical. Choosing the best available treatment system can be difficult. The AWTP has developed and evaluated improved arsenic and desalination treatment systems and provided that information to water utilities and stakeholders. Key technology advancements achieved by the partnership include: ARSENIC Development and full-scale implementation (San Antonio, NM) of an in-situ treatment process that is producing drinking water without the generation of any residuals that require disposal. The way is now paved for in-situ treatment to be used throughout the U.S. Detailed information on how to evaluate and prevent unintended consequences of bringing an arsenic treatment technology online prior to implementation, including: -potential for increased distribution system corrosion -potential for treatment systems to release arsenic into drinking water due to unintended pH variation Methods and options on the most appropriate ways to classify, stabilize and dispose of potentially hazardous arsenic-containing water treatment residuals A much improved understanding of water quality characteristics that impact specific treatment technologies allowing for site-specific selection of a best-available-technology Demonstrated at pilot scale that use of ultra-light filter media in a coagulation–filtration process can significantly reduce required backwash water volume and achieve 99 percent feedwater recovery while effectively removing arsenic Development of a polymeric ligand exchanger that selectively and effectively removes the oxidized form of arsenic under typical groundwater conditions, which is best utilized for treating water with high sulfate and relatively low alkalinity Development of iron–granular activated carbon (GAC) and titanium–GAC composite adsorbents for arsenic removal, which can simultaneously remove contaminants that adsorb onto activated carbon, e.g., neutral organic chemicals, radionuclides, and taste-and-odor compounds DESALINATION Development of a comprehensive and detailed set of guidelines for utilities wanting to evaluate and bring a desalination treatment process online Improved understanding of membrane fouling in seawater desalination, and evaluation of a pretreatment method to minimize fouling Improved understanding of mechanisms underlying VSEP, a membrane-based inland brackish desalination process that may enhance recovery by up to 25% Demonstrated a hybrid reverse osmosis-forward osmosis process which can enhance seawater desalination through dilution with treated wastewater