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Constructed Wetlands for Treatment of Organic and Engineered Nanomaterial Contaminants of Emerging Concerns (WaterRF Report 4334)
Citation:
Westerhoff, P., F. Sharif, R. Halden, P. Herckes, AND R. Krajmalnik-Brown. Constructed Wetlands for Treatment of Organic and Engineered Nanomaterial Contaminants of Emerging Concerns (WaterRF Report 4334). Water Research Foundation, Denver, CO, 2014.
Impact/Purpose:
Sources including upstream wastewater discharges are currently and will be increasingly in the future discharging contaminants of emerging concern (CECs), such as organic chemicals and engineered nanomaterials (ENMs), into surface waters that serve as drinking water supplies. Following the concept that multiple barriers can serve as pathogen protection in finished water (which includes watershed controls), we believe engineered wetlands may play a role in reducing CECs in drinking water intakes. The current criteria design approaches for constructed wetlands include hydraulic loading rates, wetland depth, carbon loading rates from wetland plants, and amount of planted versus open wetland area. While constructed wetland design has been opti¬mized for denitrification and/or establishment of ecological habitat, few design guidelines exist for removing CECs in these engineered systems. Thus, this study is aimed at identifying factors influencing removal of organic and nano-material CECs in constructed wetlands, with the goal of establishing design criteria suitable for CEC removal in wetlands located between CEC sources and raw potable water supplies.
Description:
The goal of this project was to determine hydraulic and carbon loading rates for constructed wetlands required for achieving different levels of organic and nanomaterial contaminants of emerging concern (CECs) removal in constructed wetlands. Specific research objectives included the following: 1. Determine dominant removal mechanisms (abiotic, biotic) for different classes of emerging pollutants. 2. Develop design relationships based on laboratory experiments and computational models. 3. Assess validity of design relationships based on targeted sampling at full-scale constructed wetlands. 4. Assess changes in other key water quality parameters (organics and nitrates) across constructed wetlands that may impact water supplies. 5. Develop recommendations for utilities on the potential benefits from constructed wet¬lands for treating surface waters.
