The research focuses on ammonia and phosphate removal from wastewater by using a novel metal and microwave-treated clinoptilolite. For increasing adsorption capacity, the samples were calcinated or microwave irradiated in the solutions of Fe(III), Cu (II), or Ca(II) chlorides. BET-specific surface area measurement revealed that the calcination led to a decrease from 18.254 to 11.658 m²/g. The adsorption results were fitted to theoretical models. The PO₄³⁻ adsorption in all samples as well as NH₄⁺ adsorption in natural and Fe- and Ca-modified samples is best described using the Langmuir–Freundlich model, but in calcinated and Cu-modified clinoptilolite the NH₄⁺ sorption is better characterized by the Freundlich model. The PO₄³⁻ adsorption in natural and all modified samples is best described using the Langmuir–Freundlich model. Fe-modified and calcinated clinoptilolite showed the highest NH₄⁺ adsorption capacity of 4.375 and 2.879 mg/g. Ca-modified samples demonstrated the lowest adsorption capacity of 0.875 mg NH₄⁺/g. The metal-modified samples exhibit a significantly higher phosphate sorption capacity (from 800.62 for Cu-sample to 813.14 mg/g for the Fe-modified sample) than natural (280.86 mg/g) or calcinated samples (713.568 mg/g). Experimental studies in dynamic conditions revealed high NH₄⁺ and sufficient PO₄³⁻ ions captured on modified clinoptilolite. This study provides a feasible approach for the synchronous removal of the main eutrophication agents for implementation in additional (tertiary) wastewater treatment facilities.

After biological wastewater treatment, ammonium nitrogen (NH₄-N), nitrate nitrogen (NO₃-N), and phosphate phosphorus (PO₄-P) remain in the effluent, which is discharged into natural water bodies. For further removal of these wastewater compounds, three selected materials were used as filter media: quartz sand used in drinking water treatment plants, Purolite A502PS resin, and natural zeolite. After placing all selected materials in the first filtration column (height of each layer-30 cm), the concentration of NH₄-N in the wastewater was reduced by 5 times (from 8.22 to 1.5 mg/L), the concentration of NO₃-N by 6 times (from 2.46 to 0.44 mg/L), and the concentration of PO₄-P by 3 times (from 1.56 to 0.45 mg/L). The second column was without a Purolite A502PS layer, so the concentration of NO₃-N in the filtrate from the second column was not reduced. The filtration columns were operated for about 2 months, and the filtration was stopped due to clogging with suspended solids (TSS) with an average concentration of 53.2 mg/L. The preliminary removal of TSS from wastewater before filtration through sorbents is recommended. The tested materials effectively treat wastewater of nitrogen (average efficiency 80–83%) or phosphorus (average efficiency 65–67%) and do not pollute the wastewater with environmentally hazardous substances, so they can be used in the development of tertiary wastewater treatment filters.

The conventional wastewater treatment methods only remove up to 80% of total nitrogen (N) or phosphorus (P) from wastewater, so additional facilities are needed. This article describes a newly created other wastewater treatment unit (NCU) that increases the effectiveness of P and N removal of the small-scale biological wastewater treatment plant. This work aims to evaluate the capacity of simultaneous elimination from wastewater nitrogen (NH₄-N, NO₃-N) and phosphorus (PO₄-P) by adsorption. NCU was filled with the sorbent material zeolite (clinoptilolite) and OCS (Fe, Mn, Ca oxides coated sand). After treatment in the main plant, wastewater flows through the NCU without using electric power. A compact system consisting of a main treatment plant and the NCU worked for 4 months, as the harmonized European Standard EN 12566-7 recommended. The NCU unit reduced PO₄-P, NH₄-N, and NO₃-N concentrations in the effluent (74–98%, 52–99%, and 50–98%, respectively). In general, the small-scale system treated wastewater did not contain more than 1 mg/L phosphorus concentration and not more than 10 mg/L nitrogen concentration. This study demonstrates that treatment in NCU is an ecological and environmentally friendly method suitable for decentralized wastewater treatment.

This scientific study investigated the adsorption capabilities of biochar samples derived from municipal sewage sludge pellets. Sewage sludge was pyrolyzed at various temperatures (400, 500, and 600 °C), and the biochar’s properties, including specific surface area, pore volume, and pore size distribution, were assessed. The results indicate that the sewage sludge biochar samples are mesoporous materials with significant potential for good adsorption performance. Despite showing a decrease in specific surface area compared to that achieved with pyrolysis at 400 °C, samples pyrolyzed at 600 °C demonstrated an increase in mesopore surface area, enhancing their adsorption potential. Two filtration experiments, conducted at a flow rate of 8 mL/min, revealed that the column containing sewage sludge pyrolyzed at 600 °C retained phosphorus the most effectively during the first and second experiments (with retention efficiencies of 87% and 78%, respectively). The study concludes that municipal sewage sludge biochar could be a promising material for the removal of phosphorus from wastewater and represents a viable solution for sustainable environmental development.