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Abstract:The work presents examination results of the common determination of PAHs and PCBs in industrial sludge and supernatants. Sewage sludge was taken from the wastewater treatment plant, and supernatants were obtained by their centrifuging. The prepared samples of sewage sludge and supernatants were subjected to extraction with applying the mixture of organic solvents. Cyclohexane and dichloromethane were used for constant samples, and methanol, cyclohexane and dichloromethane -for liquid. Extracts, after separation from samples of sewage sludge and supernatants, were cleared on the silica gel in vacuum conditions and concentrated in the stream of nitrogen. In such prepared extracts there was conducted the qualitative-quantitative analysis of 16 PAHs using the GC-MS system. Next, the samples were evaporated and poured with water and methanol until the clear solution was obtained. Extracts were cleared on octadecyl C18 columns, and then concentrated in the nitrogen stream. In these extracts PCBs was also determined with the application of the gas chromatograph with mass spectrometer. The range of concentrations 16 PAHs in sewage sludge equalled 10-16 mg/kg d.w. . Summary average concentration 16 PAHs in supernatants was reached 17 μg/L. Average recovery of PAHs introduced to sewage sludge in the form of reference mixture was 78% (with consideration of naphthalene). In the case of supernatants, the average value of recovery reached 60%. Average PCBs concentration in supernatants equalled 10 ng/L. For sewage sludge the sum of marked PCBs was an average 1.23 μg/kg d.w. . In the case of particular PCBs the percentage recovery of the reference mixture for supernatants was 86%, while for sewage sludge it was 55%.

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The progress of civilization brings with it the development of advanced technologies and increased demand for electric and electronic equipment. That directly influences the increase of produced e-waste, called Waste of Electrical and Electronic Equipment (WEEE). Due to the fact that deficit and critical metals are running out throughout the World, and due to increased demand for those metals, their alternative source and recovery methods have to be found. As an alternative biotechnological methods can be used. The advantage of biological methods over chemical processes is its selectivity in regard to different metal groups, simplicity of technological process, economic effectivity (lower energy expenditure) and lack of negative impact on environment. The aim of this work was to compare the effectiveness of biological and chemical leaching of copper (Cu), nickel (Ni) and zinc (Zn) from circuit boards (PCBs).The experiment was conducted in variants which included factors such as temperature (24°C and 37°C) and speed of mixing. In case of all metals higher effectiveness was achieved in variants conducted in the temperature of 24°C and faster mixing than in temperature of 37°C and slower mixing. In case of cooper and zinc better results of metal removal were achieved in bioleaching variant. In case of nickel faster result of metal removal were achieved in chemical leaching, but at the end of the experiment the effectivity of chemical leaching and biological leaching was similar. The maximum efficiency of cooper, nickel and zinc release was adequately 100%, 90%, 65%.