Sewage farm belongs to one of the oldest technologies used for wastewater treatment. Many years of sewage farm exploitation causes an important change in the chemical composition of the soil profile. The most hazardous is decomposition of sulphides of heavy metals in soil.
Discontinuance of sewage farm exploitation leads to change in aerobic conditions. Organic soil aeration leads to mobilization of biochemical oxidation of organic master, ammonia nitrogen and sulphides. This can result In rapie aci-dification of the soil environment. This paper presents original results of studies carried out in the laboratory on the effects of dynamic changes in organic soil pH planted with rushes, taken from sewage farm in Wrocław It has been show that in extreme cases soil pH could be lowered after a few months after cessation of se-wage farm of up to 3,5 pH