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Abstract
This report is intended to answer the following question: What is the fate of nitrogenous and phosphoric compounds in microbial inoculator generators and phosphorus adsorption devices in an onsite treatment application? In anticipation of a long-term investigation, a short-term [four months] pilot study was undertaken to validate the study's research design and to collect preliminary results to answer the research question. A pilot study was conducted at Brookfield Wastewater Treatment Facility [WWTF] in Brookfield, Wisconsin. The pilot study featured a small wastewater treatment system consisting of one septic tank, two microbial inoculator generators [MIGs], one tank with a pump for recycle flow, and one phosphorus adsorption device. The study was conducted at the Brookfield facility because of the easy access to sufficient amounts of wastewater. During the pilot study, it was discovered that an unusual syphon developed in the system, associated with the configuration of the system. A syphon occurs when a pipe becomes pressurized, forcing liquids to flow when a pump is not in operation. In this study, the syphon operation had a dramatic effect on the fate of nitrogenous compounds in the final effluent. Sampling began June 17, 2022, then the syphon was discovered August 25, 2022, and the final sample was collected October 20, 2022. This syphon is unlikely to occur in a normal installation of the equipment, so the nitrification and denitrification results for this pilot study are separated by results that include the data following date of the appearance of the syphon and those that do not. However, the fate of phosphoric compounds was unaffected by the syphon, so all available phosphorus data were used for results. The results of this pilot study suggest that the use of MIG and phosphorus-removal technology for private onsite wastewater treatment systems [POWTSs] shows promise in the removal of nitrogen and phosphorus nutrients. Leveraging the lessons learned from this pilot study, a long-term and comprehensive study is recommended.