The objective of the study was to determine the possibility of using organic soil under willow for wastewater purification of excess nitrate and phosphates, and to estimate the applicability of redox potential for the assessment oftransformation ofnitrogen compounds in the soil under study. The study showed the suitability of organic soil and willow for wastewater purification under the conditions of the ,,Hajdów" experimental object. Also, significant relationships were shown between redox potential and nitrogen transformation occurring in soil irrigated with wastewater after 2nd stage of treatment.

The paper presents results of a study concerning ammonium and nitratc(V) fixation by soil irrigated with municipal wastcwatcrs ( 1 - 60 mm and 2 doses - 120 mm) and estimation or the possibility or using organic soil and grass-mixture for the wastewater treatment. It was found that the studied soil and the plant applied showed a very high capacity or binding ammonium ions (up to 96%), and lower in the case ofnitrates(V) (up to 71 %). It was also demonstrated that the single irrigation dose was better utilized compared to the double dose.