Evaluating Treatment Approaches for Sustainable Reuse of Greywater, Wastewater, and Stormwater

Thompson, Kyle Andrew

Graduate Thesis Or Dissertation

Evaluating Treatment Approaches for Sustainable Reuse of Greywater, Wastewater, and Stormwater Public Deposited

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Citeable URL: https://scholar.colorado.edu/concern/graduate_thesis_or_dissertations/6969z1010

Abstract

Water is becoming increasingly scarce; approximately 2 billion people currently live in annual water scarcity, and 3 to 4 billion people are expected to live in water scarcity by 2050 due to population growth alone. Therefore, there is need to determine suitable alternative drinking water sources. Alternative sources present different advantages in terms of supply, initial contamination, and variability. Different technologies may be most effective or sustainable for treating these alternative source waters depending on scale and application (e.g., toilet flushing, irrigation, or potable reuse). Previous reuse research has focused on biological treatment of greywater, passive treatment of stormwater, and reverse osmosis or advanced oxidation for wastewater effluent. The objectives of this dissertation were to (i) study the effectiveness of conventional drinking water treatment (CDWT) for potable reuse of alternative source waters and blends, (ii) compare the environmental sustainability of novel sorbents for micropollutant removal from wastewater effluent, (iii) develop an improved synthetic bathroom greywater that closes matches the characteristics and treatability of real bathroom greywater, and (iv) compare activated carbon and biochar for dissolved organic carbon (DOC) removal from raw and pretreated greywater. Bench-scale experiments simulating CDWT achieved high turbidity removal in alternative source waters. Average maximum TOC removal with CDWT was 19%, 27% and 37% for greywater, wastewater effluent, and stormwater, respectively. However, no wastewater effluents and only one stormwater met drinking water regulations for disinfection byproduct formation control. Environmental sustainability was assessed using life cycle methodology. For micropollutant removal from wastewater effluent, wood-based biochar was more sustainable than activated carbon in most environmental impact categories. Higher adsorption capacity was associated with greater environmental benefits. A new synthetic bathroom greywater (SynGrey) was developed that closely matches the median characteristics of forty-nine real bathroom greywaters, and matched the treatability of real bathroom greywater in chlorination, biodegradation, and sorption. Five biochars were screened for greywater treatment, and activated carbon removed more DOC than the best biochar from raw, coagulated, aerated, and rainwater-blended greywater. This research will contribute to the selection and design of effective, sustainable treatment systems for potable and nonpotable reuse of alternative source waters.

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