Recent News:

DSWA gets strategic Arsenic wins in the Cities of Peoria, Chandler, and Mesa

On January 22, 2001, the Arsenic Rule was published in the Federal Register. The Rule updates the current maximum contaminant level (MCL) for arsenic and clarifies compliance and new source contaminant monitoring requirements for community and non-transient non-community water systems. All impacted water systems must prepare for compliance with the new 10 parts per billion MCL, meeting a compliance date of December 31, 2006. DSWA has been recently awarded contracts to design compliance solutions for several water systems in Arizona.

City of Chandler, Design of Arsenic Treatment System: Michelle De Haan, DSWA’s Senior Scientist, was selected by the City of Chandler and the Evaluation Report Team to participate on a peer review panel to review the Draft Arsenic Mitigation report. She reviewed the report, participated in panel discussions and visited several impacted sites.

Water Quality Testing at the Pilot Plant

Deer Valley Unified School District Arsenic Removal Technology Evaluation and Installation Oversight: Deer Valley Unified School District owns and operates drinking water facilities at the New River Elementary School, which is a non-transient non-community water system. Arsenic levels in the existing 130 gpm well are approximately 44 ug/L. The school district was not required to meet the 50 ug/L arsenic standard previously, but will be required to meet the new standard of 10 ug/L. This project entails upgrading the water system to meet the new standard, through selection and installation of a manufacturer supplied treatment system. The well supplies two reservoirs, one dedicated to drinking water, the other to irrigation and fire protection.

City of Peoria, Arsenic Treatment Compliance Mitigation: The City of Peoria has seven wells that require Arsenic mitigation prior to January 2006 to gain compliance with the new standard and five additional wells that are suspect for mitigation. This project entails evaluation of non-treatment arsenic reduction methods at the seven wells and continued evaluation of the five suspect wells. DSWA, in association with Malcolm Pirnie, is evaluating three non-treatment methods - variable rate pumping, well rehabilitation and blending.

City of Mesa, Preliminary Arsenic Design for 18 wells: The City of Mesa awarded this preliminary design to DSWA for eighteen wells impacted by the new arsenic standard. Beginning in December 2003, Conceptual Design for each site will be conducted comparing nontreatment and treatment solutions for compliance. Clear Creek Associates will assist DSWA with nontreatment evaluations and DSWA will evaluate potential blending options at on site. In a parallel path, the Project Team will evaluate the water quality at each site, and specific site characteristics such as land availability, sewer access, reservoir availability and neighborhood aesthetic issues. Appropriate technologies will be evaluated based on the individual site and water quality conditions. Once arsenic removal technologies have been selected for each site, generic preliminary designs will be developed for each of the 18 sites.

City of Mesa Detailed Design at Falcon #4 Well Site: After a successful pilot testing, this 3,000 gpm well site was recommended for a detailed demonstration design. The Design of the demonstration treatment plant will comprise of a brief conceptual design, preliminary design, and detailed design with plans and specifications. Challenges of this project include the potential that a sole source vendor may be required with this water, there is limited space, and the well pumps directly into the distribution system without reservoir flexibility. DSWA will also provide bid and construction phase services as well as regulatory agency coordination in support of the design.