(119a) Effective Application of Established Treatment Technologies for Metals, Metalloids, and Oxyanions

The underlying theories and fundamentals of application of treatment technologies for control of metals, metalloids and oxyanions are well established.  However, the complexity of the wastewater matrix to be treated can introduce unanticipated responses to the applications of such technologies, including when discharge limits are unusually restrictive due for example to water quality-based effluent limitations, or in scale-up from treatability investigations to full-scale application.  This Presentation will provide an overview of such theories and applications, and address pollutant speciation, wastewater matrix, and treatment technology aspects which can enhance or interfere with the effectiveness of treatability performance.  Such aspects include target pollutant oxidation state and speciation, interfering (or enhancing) interactive species, wastewaters containing multiple (potentially non-compatible) target species, and other issues.  Effective pretreatment can be requisite to the efficient application of the appropriate treatment technology.  Pretreatment options may include extraction or chemical modification of complexing or other interfering species, electrochemical pre-oxidation or reduction of a target speci, and management of adsorptive surface area and electrical charge in applications of inherent primary, or applied secondary co-precipitation.  Improved awareness and understanding of such issues support cost- and performance-effective application of treatment technology.