Krzysztof Czerwionka

Recovering nitrogen from wastewater is vital for a circular economy, yet conventional air stripping is limited by aerodynamic backpressure and CO₂-induced pH drops. This study evaluates a novel pilot-scale engineering approach for municipal reject water, integrating chemical phosphorus precipitation with a fundamentally redesigned ammonia stripping column. Upstream calcium hydroxide dosing achieved >99.9% phosphorus recovery and spontaneously alkalized the effluent (pH > 12.1), eliminating supplementary caustic addition. The downstream stripping column utilized negative-pressure (vacuum) operation and high-pressure liquid atomization to maximize mass transfer while preventing flooding and alkalinity neutralization. Comprehensive on-site testing established a clear mathematical relationship between aerodynamics and efficiency. Results demonstrate that high-efficiency recovery requires gas-to-liquid (G/L) ratios exceeding 70:1, a threshold uniquely unlocked by this negative-pressure design. Under optimal conditions, the continuous-flow system achieved 87.6% ammonia removal. A low-resistance acid scrubber captured ~100% of the volatilized ammonia (exhaust 0–1 ppm), producing a concentrated ammonium sulfate bio-fertilizer. This integrated technology provides a scalable, applied engineering blueprint for advancing sustainable Water Resource Recovery Facilities.

Nitrogen pollution poses significant environmental challenges, contributing to eutrophication, soil acidification, and greenhouse gas emissions. This study explores advanced methods for nitrogen removal and recovery from municipal and industrial wastewater, with a focus on biological, chemical, and physical processes. Key processes, such as nitrification–denitrification and emerging technologies like shortcut nitrogen pathways, were analyzed for their efficiency, cost-effectiveness, and environmental benefits. This review highlights the integration of innovative techniques, including membrane systems and ammonia stripping, with traditional approaches to enhance nitrogen management. Emphasis is placed on optimizing operational conditions, such as pH, temperature, and carbon-to-nitrogen ratios, to achieve high removal rates while minimizing energy consumption and environmental impact. These findings underline the critical role of interdisciplinary strategies in addressing the challenges of nitrogen pollution and promoting sustainable wastewater management.

This review paper explores Circular Economy (CE) initiatives and Green Public Procurement (GPP) practices in Poland, focusing on practical implementation and regulatory frameworks. The concept of CE is explored in depth, focusing on its potential to mitigate climate change and resource depletion...

In this paper, the possibility to obtain an alternative source of energy from methane fermentation, catalysed by biomass, has been discussed in detail. As a main substrate, the distillation residue from the distillery industry was taken in the case of mono-fermentation and its co-fermentation with sewage sludge. The results showed that higher biogas and methane production can be obtained in a mono-fermentation process. Fermentation lasted for 23 days, and during this time, 333.14 and 249.64 L/kg VS of the total biogas for mono- and co-fermentation was subsequently obtained, which gives around 63% and 50% of methane in both types of the process, respectively. Additionally, to interpret the experimental data obtained and to predict the trend of the accumulation curves, a simple Gompertz model has been applied. The application of the Gompertz model has enabled us to estimate some important parameters with a strict physical meaning, namely, the maximum production value of the biogas and its components, the production rate of a given gas, as well as the incubation phase time. Finally, an approximate analysis of the potential volume of biogas production was also carried out, based on the mass of distillation residue produced annually in Poland.

The aim of the presented research was the assessment of phosphorus speciation impact on the precipitation of phosphorus in reject water using Ca(OH)₂. To achieve this, phosphorus speciation (organic and inorganic phosphorus in suspension and in dissolved form) in reject water that is produced during sludge dewatering, after methane digestion in wastewater treatment plants (WWTPs), was determined. This study covered the materials from four WWTPs with different compositions of feedstock for anaerobic digestion (AnD). In one, the AnD process of primary and secondary sludge was carried out without co-substrate, while in three others, co-substrate (waste from the agri-food industry and external waste-activated sludge and fats from industrial plants) was examined. The investigation was conducted in batch reactors using doses of Ca(OH)₂ ranging from 2500 to 5500 mg Ca/dm³. The percentage of phosphorus forms determined in the raw reject water was similar, with the dominant form being soluble reactive phosphorus (SPR) (percentage from 87 to 96%). The small differences observed were dependent on the composition of the AnD feedstock. The results showed that, in all analysed wastewater, very high (exceeding 99.9%) phosphate phosphorus removal efficiencies were obtained using Ca(OH)₂ for short reaction times (t = 1 h). The efficiency of phosphate removal depended on pH but not on the forms of phosphorus in the analysed reject water.

Innovative low-temperature disintegration (process temperature 55 °C and oxygen concentration 0.2 mg/dm³) can be an economically rational technology to intensifying energy production from renewable sources. The proposed process can achieve a degree of disintegration—under optimal conditions—of about 50%, which is excellent when compared with other methods of feed pre-treatment. The low-temperature disintegration of distillation residue and waste-activated sludge before the co-fermentation process increased biogas production by 30% and methane production by 65% (over a 26 d duration). The obtained results confirm that the low-temperature disintegration method can be effectively used to pre-prepare this type of feed. At the same time, it was discovered that the Gompertz model can be used to mathematically describe the biogas accumulation curves in the methane co-fermentation processes of the tested feeds (the correlation coefficients were higher than 0.98).

Implementation of anaerobic digestion of primary sludge in modern wastewater treatment plants (WWTPs) limits the availability of organic carbon for denitrification in conventional nitrification-denitrification (N/DN) systems. In order to ensure efficient denitrification, dosage of the external carbon source is commonly undertaken. However, application of commercial products, such us ethanol or acetate, greatly increases operational costs. As such, inexpensive and efficient alternative carbon sources are strongly desirable. In this study, the use of the fusel oil, a by-product from the distillery industry, was validated in terms of the denitrification process enhancement and impact on the activated sludge bacterial community structure. The experiment was conducted at a full scale biological nutrient removal facility (210,000 PE), in the set of the two technological lines: the experimental line (where fusel oil was introduced at 45 cm³/m³ dose) and the reference line (without an external carbon source addition). During the experimental period of 98 days, conventional nitrate utilization rate (NUR) measurements were carried out on a regular basis in order to assess the biomass adaptation to the fusel oil addition and denitrification process enhancement. While the NURs remained at a stable level in the reference line (1.4 ± 0.1 mg NO₃-N/g VSS·h) throughout the entire duration of the experiment, the addition of fusel oil gradually enhanced the denitrification process rate up to 2.7 mg NO₃-N/g VSS·h. Moreover, fusel oil contributed to the mitigation of the variability of NO₃-N concentrations in the effluent from the anoxic zone. The bacterial community structure, characterized by 16S rRNA PCR—DGGE and the clone libraries of the genes involved in the denitrification process (nirS and nirK), was comparable between the reference and the experimental line during the entire experimental period. In both analyzed lines, the most frequent occurrence of denitrifiers belonging to the genera Acidovorax, Alcaligenes, Azoarcus, Paracoccus and Thauera was noticed. Our results proved that fusel oil would a valuable substrate for denitrification. The addition of fusel oil enhances the process rate and does not reflect a severe selection pressure on the bacterial community at applicable doses. Practical application of fusel oil generates opportunities for the WWTPs to meet effluent standards and reduce operational costs, as well as optimizing waste management for the distillery industry.

Energy self-sufficiency is a current trend in wastewater treatment plants. This effect can be achieved by increasing the production of electricity from biogas and by reducing energy consumption for technological processes. One idea, in line with the circular economy concept, is the use of waste rich in organic matter as co-substrates for the fermentation process. The aim of this study was to determine the effect of waste co-fermentation on biogas production and nitrogen concentration in the reject water. A co-fermentation process with flotate or flotate and vegetables increased biogas production compared to primary sludge by 162 and 180%, respectively. During the tests, there was no inhibition of the fermentation process. Hydrolysis of organic compounds contained in flotate and vegetables resulted in a significant increase in ammonium nitrogen (by 80–100%) and dissolved organic nitrogen concentration (by 170–180%). The biogas and methane production rate as well as the ammonium and total nitrogen release rate were calculated. An energy balance was made, which took into account the variable amount of electric energy production depending on the efficiency of the cogeneration systems and energy consumption for supplying oxygen necessary to remove nitrogen contained in the reject water. A positive energy balance was obtained for all analyses.