The article presents research on the possibility of using troublesome waste such as: sewage sludge, mineral fraction of municipal waste <10 mm, stabilizer after mechanical-biological processing (MBP), carbon waste, glass -as a flux in the production of new light ceramic materials. Clay was used as the basis of the material. In order to determine the possibility of using individual materials to produce a ceramic material, the oxide composition of individual components was examined using the XRF method. XRF analysis showed the presence of quartz and aluminosilicates in the materials, which makes it possible to use these wastes to produce new materials. Then the waste was ground in a ball mill and mixed in different proportions by adding water and three different materials were obtained. Material A: clay, sewage sludge, waste water, glass. Material B: clay, mineral fraction of waste <10 mm, flotation waste, glass. Material C: clay, stabilizer after mechanical-biological processing, post-mining waste, glass. The materials were subjected to strength and absorbability tests. The most stable was Material B. The highest variability of properties was observed in Material A. On the other hand, a high heterogeneity was observed in Material C. The bulk density for all materials was 658kg/m 3 on average.

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As a waste neutralization facility, the landfill is a kind of bioreactor producing landfill gas or (LFG) -biogas, which should be captured and neutralised for environmental reasons. One of the ways of its utilisation is the combined production of heat and electrical energy in combined heat and power (CHP) cogeneration systems. For that purpose, the assessment of the energy efficiency of a cogeneration unit was undertaken in this work on the basis of the unit performance over the last 5 years. The analysis of the CHP system energy performance demonstrated that the ratios range at the lower limits for units up to 0.5 MW. The lower efficiency of fuel chemical conversion in the CHP plant (0.70) stems from the failure to use the rated thermal and electrical power fully (74.2%), which is caused by the insufficient stream of biogas collected from the landfill (161.46 m 3 •h -1 ). The analysis of the generated energy usage, particularly in terms of heat, has shown a surplus which is not used and therefore is a loss. The proposed solutions in this area should optimize the use of heat generated from the renewable source, i.e. landfill biogas.

Waste from street cleaning is usually of a fine fraction below 10 mm and varies greatly in both quantity and composition. It may be composed of chlorides, especially for that resulting during winter due to the use of street de-icing agents. Chlorides can cause the salinization of surface water and groundwater, and the salinization of soils, which in turn lead to the deterioration of water purity and a decrease in biodiversity of aquatic organisms, changes in microbiological structure, and increases in toxicity of metals. Therefore, it is very important to determine the level of salinity in stored waste and its impact on the environment. The present study was conducted in a city of about 55,000 inhabitants. The highest chloride concentrations were observed after winter in waste from street and sidewalk cleaning around the sewer gullies, amounting to 1468 mg/dm3. The lowest chloride concentration in this waste occurred in summer and amounted to 35 mg/dm3. The multi-criteria analysis indicated that the most beneficial form of street cleaning and, thus, of reductions in chloride concentration in the waste from street cleaning, would be sweeping and daily washing. The objective of this research was to determine the amount of chlorides in sweepings on an annual basis in order to determine the potential risks associated with their impact on select aspects of the environment and to evaluate the frequency of necessary cleaning for city streets, considering the effects. The methodology used was a multi-criteria evaluation, which as a decision analysis, allowed us to determine the frequency of cleaning and washing of streets, in such a way that an ecological effect is achieved with simultaneous economic efficiency.

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