Monday, September 9, 2024
1:30 PM - 2:00 PM
Location Name
Treatment Paradigms in Water Reuse: Comparing Carbon-Based to Membrane Based Advanced Treatment
Water Resource Recovery

In Tennessee and Kentucky, the beneficial reuse of highly treated wastewater will continue to become a more promising option as utilities consider the long-term sustainability of our water systems. Drivers for this trend include pressures on existing water supplies and on more stringent discharge limitations. These beneficial end uses include landscape irrigation, industrial use, groundwater augmentation, surface water augmentation, raw water augmentation, and finished water augmentation. Treatment trains can be engineered to produce water of various qualities depending on the targeted end use, (i.e., “fit-for-use” treatment) considering factors such as effective nutrient management, pathogen control, and contaminant removal. The two most common treatment paradigms for potable reuse are carbon based advanced treatment (CBAT) and reverse osmosis based advanced treatment (RBAT). This presentation presents a comprehensive comparison between these two prominent technologies in the context of municipal water reuse applications for inland municipalities. Reverse Osmosis , which is a membrane-based technology that operates through selectively permeable high pressure membranes, is highly effective in removing dissolved salts, organic compounds, and other contaminants of concern. An RBAT reuse train may consist of low-pressure membrane filtration (MF/UF), reverse osmosis, and UV advanced oxidation. However, challenges with this train, such as energy consumption, membrane fouling, pass-through risks of certain contaminants, and high-TDS reject disposal, have led to considerations of other treatment strategies that are equally protective of public health. Carbon-based advanced treatment is built on systems that use activated carbon to adsorb and remove contaminants. These trains typically also use biologically-active filtration as an additional barrier to contaminants of concern. A CBAT treatment train may consist of ozone, biologically-active filtration, granular activated carbon and UV or UV advanced oxidation. CBAT treatment trains also have challenges related to pass-through risks and operational methodologies. This presentation will detail the advantages and limitations of CBAT in comparison to RO for water reuse applications. Comparisons will consider water quality characteristics as defined by National Primary and Secondary Drinking Water Regulations with an additional focus on microbial log reductions, organics, and contaminants of emerging concern including PFAS. Capital and operating costs, as well as other operational considerations specific to inland communities, will also be considered. The ability to protect public health for both treatment trains will be demonstrated based on HACCP principals. The objectives of this presentation are to inform our local water professionals on the considerations of these reuse treatment strategies and to identify the criteria that must be considered when evaluating the implementation of potable reuse within integrated water systems. With this information, utilities can have a better understanding of decision points for sustainable and effective advanced treatment and the role of beneficial reuse in long term planning of our water systems.