The article examines the characteristics of sewage sludge and its impact on the environment. The description of technical installations, sludge sites in the city's sewage treatment systems, which are sources of unfavorable sanitary and epidemiological condition of the studied territory,...

Four series of experiments were carried out to study the possibility of replacing clay and an iron-containing component with tefritobasalt and lead slag as part of the initial charge for Portland cement. The experiments were carried out at atmospheric pressure and a temperature of 1350 °C. It was shown that the replacement of clay and an iron-containing component with tefritobasalt and lead slag as part of the initial charge in the cement industry will lead to a decrease in temperature by 100 °C in the technological scheme of production and a reduction in energy consumption, since the theoretical specific consumption of raw materials is 1.481 t/t of clinker, which is approximately 70 kg lower than in traditional mixtures. The content of non-traditional components in total was 24.69%. In addition, tefritobasalts improved clinker formation processes, contributed to a decrease in the firing temperature, and intensified the clinker firing process. A small amount of lead slag (5.06%) introduced into the mixture changed the structure of the clinker and improved the process of mineral formation while also improving roasting and reducing the anthropogenic impact on the environment through the disposal of man-made waste. The strength of the experimental composite cements was tested after 7 and 28 days on small samples measuring 2 × 2 × 2 cm. The physicomechanical characteristics and structure of composite cements were studied.

This study investigated the photocatalytic degradation of hydrocarbon pollutants in petroleum refinery wastewater (PRWW) using graphene oxide (GO)-based metal oxide composites as photocatalysts. GO was synthesized from waste plant biomass using modified Hummer’s method. Composites of various metal oxides and GO were prepared by loading different weight percentages of TiO₂, Fe₂O₃, and ZnO through the wet impregnation method. The composition and morphology of the photocatalysts were evaluated by FTIR, XRD, SEM, TGA, and EDX analysis. Batch mode catalytic oxidation experiments were conducted on PRWW with an initial chemical oxygen demand (COD) of 986 mg/L, at pH 8.5, temperature 25–30 °C, reaction time 50 min, and catalyst dose of 0.02 g per 20 mL of sample. It was observed that maximum COD removals of 96% and 100% were achieved by photocatalysts ZG11 (ZnO/GO 1:1) and TZG111 (TiO₂/ZnO/GO 1:1:1), respectively. GC–MS analysis showed that hydrocarbon compounds were absent in the treated PRWW sample; only traces of oxygenated hydrocarbons were found. This method can be applied to large-scale industrial wastewater treatment. This study offers an effective approach to improve the removal rate of high COD from PRWW and makes a practical contribution to wastewater treatment technology.