Enhancing End-User Water Quality through the Characterization of Reclaimed Wastewater and Modifications to Existing Treatment Practices
AuthorHelander, Weston M.
AdvisorMarchand, Eric A
Civil and Environmental Engineering
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Up to half of all freshwater demand in certain regions of the United States is used for the irrigation of lawns and gardens, prompting the need for water reclamation and recycling in dry, arid cities. In order for reclaimed water to be successful, it must meet certain water quality criteria to satisfy the needs of end users. In recent years, reclaimed water from the South Truckee Meadows Water Reclamation Facility (STMWRF) has experienced challenges in meeting the quality criteria of its customers. The aim of this study was to monitor water quality in the Huffaker Hills Reservoir and determine the feasible options for the improvement of reclaimed water quality from STMWRF. Treatment efficiencies in STMWRF's oxidation ditch and filtration media system were measured to assess the effects of cyclical aeration and chemical coagulation on effluent water quality, respectively. Additionally, weekly water quality analyses were performed to determine the seasonal changes associated with algae growth in various locations in the storage reservoir and reclaimed water distribution system. High nutrient concentrations in the reservoir allowed for significant algal activity, with the greatest activity occurring from June to September. Cyclical aeration in the plant's oxidation ditch was found to have a severe impact on nutrient loading to the storage reservoir. Ammonia and phosphorus loadings to the reservoir could be reduced by as much as 78% and 40%, respectively, if the oxidation ditch were aerated continuously. Pilot-scale filtration tests were run using ferric chloride and aluminum sulfate (alum) as coagulants at various doses run in triplicate. Variation in removal of alum and ferric chloride at each dose narrowed as concentration increased, though it was difficult to accurately predict future removal efficiencies due to changes in influent water characteristics such as pH and turbidity.