Contact of concrete with aggressive factors, technological structures, reduces their durability through microstructural changes. This work presents the results of research on determining the influence of post grit chamber sewage and sewage from the active sludge chamber in three different environments, i.e., acidic, neutral, and alkaline, on the structure and compressive strength of concrete. Compressive strength tests were carried out after 11.5 months of concrete cubes being submerged in the solutions and compared. To complete the studies, the photos of the microstructure were done. This made it possible to accentuate the relationship between the microstructure and performance characteristics of concrete. The time of storing the cubes in both acidic environments (sewage from post grit chamber and active sludge chamber) has a negative influence on their compressive strength. The compressive strength of cubes decreases along with the time. Compressive strength of cubes increases with increasing pH of the environment.

Composting enables the recycling of significant amounts of biodegradable waste, while ensuring its disposal. The addition of fly ash increases the concentration of fertilizing substances in the compost. Compost is a source of many nutrients for plants. The addition of fly ash might also cause a slower release of these nutrients into an aqueous solution, meeting the fertilization needs of plants over a longer period of time. Tests were carried out using sewage sludge (WWTP Piaseczno, 163,500 P.E.), straw as a structure-forming material and fly ash (WWTP Krakow, 780,000 P.E.). The compost obtained in the research was analyzed in terms of environmental conditions specified in legal regulations. The most favorable compost mass density (520 kg/L) and the amount of air supplied to the process (5.0 L/(h∙kg d.m.)) were determined. The addition of fly ash to the compost mass did not significantly affect the temperature distribution obtained in the process. The increase in fly ash content increased the pH of the compost mass and was associated with higher nitrogen losses. It was found that the factor which may limit the possibility of using fly ash as a compost substrate is the presence of higher concentrations of heavy metals, especially chromium. It was determined that the maximum addition of fly ash to the compost mass was 154 kg d.m._ash/(ton d.m._straw+sludge).

The article presents an analysis of the results of research on the composition of fly ash from the thermal processing of sewage sludge [SSA] collected from three incineration plants located in Warsaw, Cracow and Łódź. It determines the leaching values of selected heavy metals from the tested fly ash and ordinary class concrete C20/25 with partial replacement - up to 20% of cement with fly ash. The laboratory tests performed showed that they have a comparable granulometric composition. In contrast, the physico-chemical properties of the tested fly ashes differ from ashes from coal combustion traditionally used in concrete technology. SSA is characterized by an average lower content of silicon, iron, and aluminium oxides with a much higher content of phosphorus oxides. Leaching tests indicate low mobility of heavy metals, meeting Polish regulations regarding the possibility of using SSA in construction for specific applications. At the same time, they do not pose a significant threat to human health or the environment. Construction waste containing SSA may be disposed of in inert waste landfills.

The process of aerobic stabilization of sludge is a process used in small or medium sewage treatment plants (up to 15 000 ENI). Owing to its energy intensity resulting from the need for intensive sedimentation and longterm process, many researches are being conducted on its intensification. One such method is disintegration. The purpose of disintegration is to increase the susceptibility of sewage sludge to aerobic decomposition by breaking up sediment flocs into fine particles along with the breakdown of cell membranes and then allowing biodegradation. The paper presents results of research of aerobic stabilized sludge, which is a mixture of non-disintegrated and microwave disintegrated sludge in different volume proportions. It was shown that sludge stabilized more quickly during the first days of the process. The minimum reduction of organic solids required at 38% for stabilized sludge occure earlier in mixed sludge tests than in non-disintegrated sludge.

Treatment of bath greywater using cartridge filters as a way to reduce water consumption in households. Nearly one third of the high quality water in households is used for flushing toilets. Water resources in Poland are relatively poor. Therefore the use of water of inferior quality parameters to flush the toilet bowls is satisfactory. It is possible to use for this purpose the greywater from the washing of the body (the bath water) after treating it to the level which doesn’t threatens human life or health. The paper presents preliminary results of research on potential use of cartridge filter to treat greywater from the washing of the body (from bath) in order to re-use water in households. It was found not significant effect of increasing the quality of bath greywater treatment using polypropylene and carbon cartridge filters.