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Treatment performance of seven full-scale innovative onsite wastewater treatment systems installed as remedial systems was evaluated for a one-year period. The systems installed consisted of three textile filters, one followed by a raised bottomless sand filter; one drip irrigation system with a flushable disk filter; one single pass sand filter; one modular peat biofilter followed by a UV light disinfection unit; and one fixed activated sludge treatment system followed by a UV light disinfection unit. Treatment performance of these systems was monitored monthly for BOD5, TSS, fecal coliform, and TN. All sand, peat, and textile packed bed filters operating in a recirculating or single pass mode produced mean BOD5 and TSS effluent that was typically between 1 and 8 mg/l. The fixed activated sludge treatment system effluent BOD5 and TSS concentrations averaged 15 and 9 mg/l, respectively. TN reductions averaged 16 to 18% for the single pass sand filter and modular peat biofilter and approximately 34 to 38% for the textile filters. Mean TN concentrations in the fixed activated sludge treatment system and the one textile filter operating in a mixed effluent mode were 20 and 9 mg/l, respectively. The single pass sand filter achieved the highest level of fecal coliform reduction (3.6 logs), followed closely by the peat filter (3.4 logs) and then the textile filters (3 logs). Ultraviolet light disinfection units produced a high quality effluent with a mean between 0 and 278 fecal coliform counts/100ml. Blower motor modification experiments to lower operating cost of the fixed activated sludge treatment system resulted in a general reduction in treatment performance of all wastewater contaminants studied. Required operation and maintenance needs are outlined for the systems studied.