Seasonal changes of iron and manganese concentrations in sewage effluent from sediment well-traps in the city of Cracow

Sediments that appear in sewage system constructions were determined on the basis of examination of samples from sewage catch pits of main streets of Cracow. Sampling was carried out in four seasons. Concentration of Fe and Mn was estimated, taking into account granulation and phase composition of sewage sediments. Changeable influence of physico-chemical indicators of aquatic environment: pH, Eh and PEW were also considered. Seasonal differentiation of Fe and Mn concentration in sewage sediments results from variable environment pollution by industry, transport and municipal economy. Corrosion of sewage infrastructure cannot be neglected either. Qualitative phase composition of bottom sediments of sewage systems have indicated a degree of environmental pollution as well as conditions of infrastructure of Cracow Conurbation pipe-away sewage system.