The main objective of this study was to evaluate the usefulness of nonwoven filters with a constant wastewater table as part of individual wastewater treatment plant in the context of achieving effluent concentrations of pollutants permissible by the Regulation of the Minister of the Environment of 18 November 2014. During the study two eightlayer filters (7.2 mm thickness) and one four-layer filter (3.6 mm thickness) were used. In the inflowing and outflowing wastewater COD, BOD5, total suspended solids and total phosphorus were determined. Average concentrations of pollution indicators in wastewater inflowing to the filters were: COD – 377.1 mg O2 · dm^–3, BZT5 – 149.4 mg O2 · dm^–3, total suspended solids – 166.8 mg · dm^–3. The highest treatment efficiency for most of the pollution indicators were obtained for the filters having the maximum thickness and the observed differences in average removal effectiveness between the various thicknesses of the filter layer were confirmed statistically. In author’s opinion the filters in the technical conditions should comply with the Regulation of the Minister of Environment of 18 November 2014. The studies have shown that the nonwoven filter with in conditions of stable wastewater table can be a useful technology as the second stage of the individual (on-site) wastewater treatment plant (for sludge fouling), especially in the conditions of discharge of treated wastewater into surface waters.

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