A number of sources currently are and increasingly will be discharge organic chemicals and engineered nanomaterials into surface waters that serve as drinking water supplies. Water and wastewater systems have long since realized the benefits to public health and ecosystems gained from multiple barrier management approaches. Constructed wetlands are increasingly being built to provide multiple benefits ranging from habitat rehabilitation to purification of water as part of a multiple barrier management approach. For example, constructed wetlands in California remove a range of endocrine disrupting compounds (EDCs) and pharmaceuticals or personal care products (PPCPs) discharged by several wastewater treatment plants (WWTPs) and stormwater discharges. These compounds are removed as a result of several synergistic processes (biotransformation, sorption and photolysis). Simultaneously there is concern over new classes of pollutant, including engineered nanomaterials, which will be present in WWTP effluent and stormwater discharges. There is a need to understand basic design criteria for constructed wetlands that allow them to simultaneously remove a range of these emerging pollutants. Constructed wetlands may be placed near outfalls (wastewater, stormwater, agriculture runoff, animal feed lots, etc) or in-stream to address seasonally variable low-flow conditions where emerging contaminants may be present at elevated levels. The goal of this project is to determine hydraulic and carbon loading rates for constructed wetlands required to achieve different levels of EDC/PPCP and engineered nanomaterial (ENM) removal in constructed wetlands as a function of hydraulic loading rates. In addition, we will determine dominant removal mechanisms (abiotic, biotic) for the different classes of emerging pollutants. Laboratory experiments will be used to develop design relationships, and then targeted sampling at full-scale constructed wetlands will be made to help validate the design relationships. In addition to assessing removal of emerging pollutants, we will also assess other water quality changes that may impact downstream water utilities (e.g., organic matter, nitrate). Recommendations to utilities on the potential benefits from constructed wetlands for treating surface waters will be developed.
|Effective start/end date||8/16/10 → 1/19/14|
- EPA: Region 9: $250,000.00