Over 150 water professionals met for two days in Sacramento, California, on February 5-6, 2013 to hear the latest on inorganic contaminants in drinking water. The conference was hosted by the California-Nevada Section of the American Waterworks Association (CA-NV AWWA).
“We’re thrilled to host this international exchange of knowledge and information,” said Dr. Timothy Worley, executive director of CA-NV AWWA. “Some of the best research on water quality is happening here in California.”
Experts on hand to address important issues
Presenters included a fertile mix of water utilities, consultants and academia. The stage was set with a keynote by AWWA’s Alan Roberson, who predicted that many regulations are “on the move,” and that lower levels of contaminant detection will likely cause problems for smaller water systems, which was a theme that was repeated throughout the two days. Roberson reminded participants that EPA rule-making is a function of three drivers: Potential health effects, occurrence and the (sole) judgment of the EPA administrator.
“When we’re targeting smaller and smaller risks,” said Roberson, “the small groundwater systems are the ones that will be most impacted by inorganic contaminant regulations.”
In general, the program reflected Roberson’s conclusion that disinfectant byproducts removal and arsenic non-compliance are hot topics in the regulatory arena. EPA is also under pressure to regulate nitrosamines and other contaminants of concern, including chlorate and strontium. Lisa Ragain at Aqua Vitae closed the morning session with a heads up on the need to advance water system communication practices in regard to organics.
In addition to arsenic, perchlorate (of particular concern in both California and Nevada) and chromium was a strong presence on the program. Russell Bartlett at California Department of Public Health discussed “life stage effects” in risk assessment for standards development (infants and toddlers being most at risk with iodine uptake by the thyroid). California issued a draft public Health Goal in December 2012 of 1 ppb, but Bartlett said that a new perchlorate MCL has yet to be initiated, with Cr(VI) being the current priority.
In the afternoon session, James Leserman at Castaic Lake Water Agency reported unintended consequences of treatment initiated after wells were shut down for perchlorate contamination as well as the utility’s long-term management plan for safeguarding system water quality, including water imports.
Kip Duchon from the Centers for Disease Control and Prevention (CDC) gave a presentation on fluoride's effects and suggested that a revised standard of 0.7 for drinking water looks like “just a matter of time” with CDC recommendations now working “up the rope” in the Department of Health and Human Services. The current national regulation of fluoride is complicated because the EPA has both a primary MCL (4 ppm) for potential adverse health effects and a secondary MCL (2 ppb) for aesthetic effects (tooth discoloration).
Tuesday’s afternoon sessions were broken out into two separate tracks. The first track addressed exclusively with inorganic nitrogen. Presentations included: Implications of raw ammonia on water quality (Phil Brandhuber, HDR Inc.); biological ammonia removal (Nicholas R. Dugan, EPA); a report on using chlorite to control nitrification in a demonstration project in Irvine, California (Xueying Wu, Hazen and Sawyer); another session on nitrate removal via ion exchange (Richard Dennis, Severn Trent Services); selective electrodialysis as a new treatment in nitrate removal (Craig Gorman, Jacobs Engineering); and successful biological denitrification in a pilot project in the City of Glendale, California (Issam Najm, Water Quality Treatment Solutions).
On the second track, Sarah Clark of HDR Inc. presented guidance for manganese control in drinking water; Jantinus Bruins, UNESCO-IHE, presented on the use of MOCS and MOCA for shortening ripening time of filter media for manganese removal and Chance Lauderdale of Carollo Engineers described an approach to managing manganese using biofilters.
Water utility concerns about costs associated with disposal of treatment waste streams (spent media, backwash water and brine) were addressed in another Carollo Engineers presentation by Erin Mackey describing its proprietary system of using tailor fixed bed biological treatment (BIOTTA) for contaminant removal without brine disposal. It was a general conclusion that although the efficacy of biological treatment has been repeatedly demonstrated, one issue in its widespread adoption will likely be the level of operator certification required. Cindy Bertsch of Waterworks Engineers closed the day with a case study on its approach to managing a challenging groundwater source with ammonia, methane, TOC/DOC, manganese, iron and color.
Wednesday morning’s arsenic presentations included AWWA research on the impact of household income on arsenic compliance (Roberson), which showed a correlation, but not as significant as had been projected, and a detailed presentation by EPA’s Thomas Sorg on capital and operating costs of small arsenic removal adsorptive media systems, reporting equipment costs at 67 percent, engineering at 15 percent and installation and startup at 18 percent. The complete report is available on EPA’s website.
Richard Brown of EE&T Inc. reported on treatment issues related to minimization and treatment of arsenic residuals, and Masakazu Kanematsu at UC Davis presented a study comparing chromate and arsenate adsorption onto a goethite-based adsorbent in the presence of co-existing ions.
Also on Wednesday morning, Mac Gifford of Arizona State University reported on the simultaneous removal of hexavalent chromium and arsenic using commercially available sorbents. Kathita Chittaladakorn of Virginia Tech presented on the effect on water chemistry of Cr(VI) release in stainless steel plumbing and Andrew Eaton from Eurofins Eaton Analytic raised questions about evaluating hexavalent and total chromium in "Data and occurrence – are we sure of our measurements?”
The Water Resource Foundation hosted a Cr(VI) workshop the day before the symposium, featuring results from a number of collaborative research projects and examining issues related to chromium compliance, including potential cost effects. Presentations are available on the foundation’s collaborative website, http://collab.waterrf.org.
Issues regarding infrastructure were raised in a number of presentations — recommendations concerning onsite hypochlorate as a source of chlorate, percholarate and bromate (Aleksey Pisarenko, Trussell Technologies Inc.); long-term evaluation of partial lead service line replacements and influence of real world connections on lead release (Justin St. Clair, Virginia Tech); accumulation, binding and release of inorganic contaminants by corrosion scales formed in drinking water, with recommendations for removal (Gregory Korshin, University of Washington); implications and mitigation of inorganic contaminant accumulation (Andrew Hill, Confluence Engineering Group); and rapid destructive corrosion of a stainless steel air stripper by chloramines (Jerry Lowry of Lowry Engineering). John Consolvo presented on Philadelphia’s investigation of Iodine-131 in its drinking water, and William Rhodes at Virginia Tech University reported on the effects of green building design on water quality.
The symposium was chaired by Philadelphia Water Department's John Consolvo. For a summary of Roberson's presentation on inorganic contaminants regulation — where we are and where we're headed — see the Spring 2013 issue of Source magazine.
The California-Nevada Section of the American Waterworks Association represents water industry professionals in these two key western states. Members include water and wastewater utilities, engineering and consulting firms and members of the regulatory and academic communities involved with water and water issues. Source magazine is the Section's flagship publication published quarterly and available online at the Section's website, Ca-nv-awwa.org. CA-NV AWWA sponsored the Inorganic Contaminants Symposium, which featured presenters from the U.S. and a number of foreign countries.