Onsite wastewater systems are a significant source of nutrient loading to the environment and there is a demand for technologies that remove nutrients at the source. Most desired are passive, low cost systems that can consistently remove ninety percent or greater nitrogen while having low energy input and easy operation. While numerous proprietary devices have been developed that typically employ multiple mechanical apparatus, they require active attention and provide only partial nitrogen removal. AET is developing a unique multi-chamber treatment process that provides high percent nitrogen removals, passive operation, low life cycle cost, and resilient performance. The AET process applies anaerobic biological treatment in a multi-chamber upflow solids blanket bioreactor to remove organics and recover energy, followed by selectively configured ion adsorption, aerobic and anaerobic biofilter that employ judiciously specified designer media. No operation energy is required. Nitrogen and phosphorus reductions exceeding ninety-five percent have been achieved with initially configured components, suggesting that a viable commercial system can be developed. The objective of SBIR Phase 1 is to experimentally validate two prototype designs and provide scale-up basis for Phase 2 evaluation of full scale systems. Two seventy liter multi-chamber systems will be fabricated and field tested on house sanitation water, one using whole house wastewater and the second using primary tank effluent. Monitoring will be conducted to delineate critical performance metrics, including organic conversion, suspended solids reduction and biological stability prior ion capture filtration process, speciation and retention of nitrogen and phosphorus, and the crucial role of media and water chemistry. The SBIR Phase 1 project will provide critical evaluation of system design, and identify key factor pertinent to process efficacy, long term operation, life cycle cost and commercial viability. Phase 1 results will lead directly to design of full scale Phase 2 systems. There is a high market potential for commercial application of the AET technology. Single family homes and community systems comprise greater than 25% of total U.S. wastewater flow. The AET system is projected to be life cycle cost competitive with currently available nutrient removal technologies in the single home arena. It is eminently modular and adaptable to a wide variety of recycling and reuse schemes, including blackwater treatment. The modular design is also appropriate at larger community scale and for resource recovery within centralized treatment areas. Low cost systems that recover energy and nutrients at local scale are absent in current U.S. practice.