State Water Resources Research Institute Program (WRRI)

Details for Project ID 2016NC208G, 2016

The role of environmental buffers in potable water reuse

Institute: North Carolina
USGS Grant Number: G16AP00194
Start Date: 2016-09-01 End Date: 2018-08-31
Total Federal Funds: $109,123 Total Non-Federal Funds: $109,123

Principal Investigators: Olya Keen, Mariya Munir, Michael Meyers

Abstract: With a large percentage of US population residing in arid areas, indirect potable water reuse is becoming a wide-spread practice. Among the pioneering states are California and Colorado, where drinking water treatment plants acknowledge the contribution of treated wastewater effluent to their source water and purposefully include this source in their water supply planning. On the other hand, many areas that have no necessity to include reuse water in the potable supplies still practice the unacknowledged, or so called “de facto” potable water reuse when a drinking water treatment plant is located downstream of a wastewater treatment plant. Due to general public opposition to direct potable reuse, an environmental buffer (river, aquifer or reservoir) is frequently in place to mitigate the “toilet-to-tap” perception. The goal of this study is to evaluate the effectiveness of the environmental buffers for water quality improvement. Samples will be collected from potable water reuse systems (acknowledged or de facto) that utilize a variety of environmental buffers: wetlands, groundwater recharge, riverbank filtration, river and reservoir/lake. Multiple contaminant classes will be analyzed (salts, metals, pharmaceuticals, antibiotic resistance genes, pesticides/herbicides, nutrients, microorganisms, suspended solids and organic carbon) to determine whether the environmental buffers reduce or increase the contaminant load at the drinking water treatment facility. It is anticipated that while some of the contaminants may get attenuated in the environment (nutrients), some may get reintroduced (pesticides and herbicides, suspended solids, microorganisms), potentially resulting in a higher cost of treatment with an environmental buffer than without it. Additionally, environmental buffers allow contact between trace antibiotics in wastewater effluent and microorganisms – a phenomenon linked to development of antibacterial resistance in the environment. Environmental buffer may also allow some attenuation of emerging contaminants, and different pathways will be evaluated: photolysis, adsorption and biodegradation. A best management practice recommendation will be proposed as a result of this research that would include the pros and cons of environmental buffers, the effectiveness of different types of buffers for attenuation of various contaminant classes, and estimated difference in the water reuse treatment cost with and without different types of environmental buffers.