Summary:

Majority of on-site wastewater treatment plants discharge effluents to the soil by infiltration systems. The aim of the study was to compare choosen methods of determinantion of soil permeability for its use as a receiver for domestic wastewater. Filtration coefficiens were determined in on-site percolation test, laboratory test (de Wit aparatus) and calculation method (base on grain size analysis). Soils from seven different potential locations of on-site wastewater treatment systems were tested. Soils were characterised as sandy loams and loamy sands. The highest values of filtration coefficients were obtained from percolation tests and the lowest from the calculation method. Calculated hydraulic loads in all cases are lower than values of LTAR (Long-Term Acceptance Rate). The possible reason is that used equation was developed for simple septic systems and includes clogging of soil by solids from pre-treated wastewater. In case of biologically treated wastewater distributed in tested fine-grained soils, infiltration surface determined base on the percolation test, will ensure safe disposal of wastewater for long time of operation of on-site wastewater treatment system.