Sewage sludge, produced in the process of wastewater treatment and managed for agriculture, poses the risk of disseminating all the pollutants contained in it. It is tested for heavy metals or parasites, but the concentration of pharmaceuticals in the sludge is not controlled. The presence of these micropollutants in sludge is proven and there is no doubt about their negative impact on the environment. The fate of these micropollutants in the soil is a new and important issue that needs to be known to finally assess the safety of the agricultural use of sewage sludge. The article will discuss issues related to the presence of pharmaceuticals in sewage sludge and their physicochemical properties. The changes that pharmaceuticals undergo have a significant impact on living organisms. This is important for the implementation of a circular economy, which fits perfectly into the agricultural use of stabilized sewage sludge. Research should be undertaken that clearly shows that there is no risk from pharmaceuticals or vice versa: they contribute to the strict definition of maximum allowable concentrations in sludge, which will become an additional criterion in the legislation on municipal sewage sludge.

An upgraded integrated fixed-film activated sludge-oxic settling anoxic (IFAS-OSA) system is a new technology for reducing nutrients and excess sludge. The results showed that the average TN removal efficiency of the IFAS-OSA system was gradually increased up to 7.5%, while the PO₄^–3-P removal efficiency increased up-to 27%, compared with that of the IFAS system. The COD removal efficiency of the IFAS-OSA system was slightly increased up-to 5.4% and TSS removal efficiency increased up to 10.5% compared with the control system. Biomass yield coefficient (Y_obs) in the IFAS and IFAS-OSA systems were 0.44 and 0.24 (gr MLSS/ gr COD). Hence, sludge production decreased by 45%. The average SVI was decreased by 48% in IFAS-OSA system compared with IFAS. This study demonstrated the better performance of the IFAS-OSA system compared to that of the IFAS system.

Municipal sewage sludge is a problematic waste that needs to be managed. Modern wastewater treatment plants (WWTPs) generate stabilized sewage sludge with good chemical and biological parameters. The Central Mining Institute (CMI, Poland) has developed a proprietary technology (patent PL233754) for production of a granulated organo-mineral fertilizer from the stabilized sewage sludge. It is a mixture of municipal WWTP-collected, dewatered sewage sludge, dolomite, lime, gypsum, ammonium carbonate, and microcrystalline cellulose. The sewage sludge contained heavy metals at levels lower than: Cr, 100 mg; Cd, 5 mg; Ni, 60 mg; Pb, 140 mg; Hg, 2 mg, and was free from live eggs of intestinal parasites of the genera Ascaria, Trichuris, and Toxacara as well as from Salmonella bacteria. Micro-field tests were conducted at WWTP in Żory (Poland) on five 5 m² fields. The effectiveness of plant growth was evaluated based on drone photos showing field coverage upon vegetation, and post-harvest determination of the plant dry mass. The analyses showed significant changes in biomass chemical composition: the N concentration was 289.6% of the control and 98.2% of commercial fertilizer, whereas the respective P content was 145.1% and 300%. The results prove that the innovative fertilizer is highly competitive with other available commercial products.

The aim of this study is to review the literature on the methods of low-rank coal enrichment by using microorganisms and their metabolites. Effective bio-beneficiation technologies for low-rank coals in the future are also suggested throughout this paper. An extensive literature review highlights...

Sewage sludge is a high-volume and low-cost waste commonly generated worldwide, so its utilization is a vital issue. The application of this waste in the manufacturing of lightweight aggregates was investigated. The process was performed using intensive mixers with volumes of 5 and 30 L, as well as the industrial 500 L mixer. Then, granulates were sintered in a tube furnace. The influence of composition and mixer size on the particle size, microstructure, mechanical performance, and stability of lightweight aggregates in different environments was analyzed. The best results were obtained for a 500 L mixer, enhancing the industrial potential of the presented process. Increasing the share of sewage sludge in the composition of aggregates enhanced their porosity and reduced the specific weight, which caused a drop in compressive strength. Nevertheless, for all analyzed materials, the mechanical performance was superior compared to many commercial products. Therefore, sewage sludge can be efficiently applied as a raw material for the manufacturing of lightweight aggregates. The presented results confirm that a proper adjustment of composition allows easy the tailoring of aggregates’ performance and cost.

The danger posed by sewage sludges, although subjected to various treatment processes, contributes to the fact that fertilizers introduced into the soil pose a sanitary and ecological threat. Minimizing the risk of using fertilizers produced from sewage sludges is possible due to legal regulations, the most important of which are the Act of 26 July 2000 on fertilizers and fertilization and numerous regulations of the Minister of Agriculture and Rural Development. Due to the fact that some parameters such as pharmaceutical substances have not been included in legal regulations, comprehensive researches on the impact of fertilizers produced from sewage sludges are justified, in particular with regard to soil, ground and water environment and also on the quality of crops. Taking into account the current legal regulations and the diverse composition of sewage sludges, full safety analysis including both biological analyses and risk assessment is necessary to perform. As part of this work, the possibilities of environmental safety assessment of fertilizer products based on stabilized municipal sewage sludges are presented. This article presents the most popular methods of sewage sludge safety analysis in the following environment: leachate, ground and surface waters, soil and plants.