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AWWA WQTC69444
- Damage Control: Managing the Residuals Generated during Arsenic Treatment
- Conference Proceeding by American Water Works Association, 11/01/2008
- Publisher: AWWA
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The recently reduced U.S. Environmental Protection Agency (USEPA) maximum contaminant level (MCL) for arsenic indrinking water has forced facilities to either implement new or modify existing arsenicremoval technologies to meet the 10 µg/L MCL. The favored USEPA-identified treatmentoption is adsorption onto solid media. These treatment processes generate arsenic-bearingsolid residuals (ABSR) that must be tested and potentially treated prior to disposal. Agrowing body of research has demonstrated that these residuals may pose anunacceptable risk if disposed untreated in non-hazardous landfills. This risk motivatedthe development of an innovative stabilization method, polymeric encapsulation.This method out-performs the only reported alternative encapsulationtechnique, cement stabilization, with respect to both residual loading capacity (greaterthan 3-fold increase) and leach resistance. Another method for reducing the risk of ABSRdisposal is to reduce the amount of ABSR generated, which can be achieved throughthe use of regenerable media. However, regeneration produces an arsenic-laden brinethat must then be treated prior to disposal. This research investigated the use of the lesscommon, non-iron-based adsorption media for the treatment regenerate brine wastestreams. Four media types (lanthanum hydroxide, ferric/lanthanum hydroxide, zirconiumdioxide, and titanium oxide composition) were identified as potential treatment optionsbased on their ability to retain relatively high arsenic capacities relative to traditionaliron-based media. Includes 2 references, tables, figures.