The sewage sludge originating from wastewater treatment plants (WWTP) serving rural areas is suggested for agricultural or natural usage. However, sewage sludge is beforehand subjected to the several pre-treatments, which involve stabilization, hygienisation and pre-composting. These methods mainly decrease the amount of organic substances and the presence of microorganisms, but hardly affect the concentrations of heavy metals. The advantages of using sludges as fertilizer for improving and sustaining soil fertility and crop production are numerous. The addition of sewage sludge to soils could affect the potential availability of heavy metals. Trace elements are distributed in the soil in various forms: solid phases, free ions in soil solution, soluble organicmineral complexes, or adsorbed on colloidal particles. The most undesirable heavy metals in sewage sludge that are toxic for the living organisms include: cadmium, chromium, nickel, lead and mercury. In the study, the concentrations of trace elements (Pb, Cd, Cr, Hg, Ni, Zn, Al, As, Se, B, Ba, Br, Ca, Cu, Fe, Mn, Na, Ga, Li, Mo, Sr, Mg, K, Ru, Tl, V, U) were tested in the sewage sludge obtained from a WWTP serving rural areas (PE< 9 000). In each case, the tested sewage sludge was meeting the criteria of stabilization and was used for agriculture and land reclamation purpose. All the samples were collected in 2016 and subjected to microwave mineralization in a closed system in aqua regia. The total amounts of macro and microelements were determined with a spectrophotometer Coupled Plasma emission ICP-OES. It was found that the total concentrations of trace metals in all of sewage sludges are the same as the Polish regulation limit of pollutants for sludge to be used in agriculture. European legislation is less restrictive and permits higher contents of heavy metals in sludge used for agriculture than Asia. The trace elements (cadmium: 1.16 mg·kg . The two of the tested heavy metals (beryllium, bismuth) were under the detection limit, while gallium, molybdenum, thallium, vanadium and silver were detected in the concentrations lower than 0.005 mg·kg -1 /d.m. According to the obtained results, in all the tested samples, the total amount of trace elements, did not exceed the limit values in sewage sludge for their use in agriculture and land reclamation.

Abstract. The article presents, with an example of four cities of various size, a phenomenon of a drop in water consumption by the city population in Poland. The paper draws on 1995-2012 official statistics. A significant decrease in household water consumption was observed, which refers to both the total water volume used by households as well as the average daily water consumption per resident. The article also determines the most essential factors affecting the amount of water consumed, out of which the price of water appears to be of the most significant one.

Abstract. The currently heavy metal pollution in rainwater is a huge problem, especially in industrial areas. Sediment from devices for stormwater runoff treatment, especially those located in city centers, industrial districts and within the area of highways is characterized by a high content of heavy metals and is found to be most contaminated. A significant fraction of these harmful chemicals are deposited on the surface of highways and urban roads and eventually transported into local waterbodies by stormwater runoff that is the primary source of water quality impairments in urban areas. This review analyzes and interprets the collected results of tests for the content of heavy metals in sediments from the urban drainage to determine the actual threat they pose to the environment. As a result of the combustion of liquid fuels, significant amounts of nickel, vanadium, cadmium and zinc get into the aquatic environment. Due to the amount of sediments accumulated in the rainwater drainage system, periodic pollution monitoring should be carried out leading to the determination of the method of management and utilization of sludge. The use of separators contributes to the reduction of the presence of heavy metals in the aquatic environment.