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• Anaerobic digestion in the full scale was simulated using modified ADM1xp model. • Modeled technological parameters predicted a 67% increase in methane yields. • Optimal volume was 131 m3 for the primary digester and 5000 m3 for secondary digester. • Optimal proportions of gaseous phase to digesters volume were determined. The main aim of this study was to evaluate the applicability of a mathematical model based on Anaerobic Digestion Model No. 1 (ADM1) for optimizing biogas production during a two-stage anaerobic digestion process in a full-scale biogas plant. Biogas production was analyzed in two variants. Variant I involved two decision variables: the proportion of the gaseous phase in the total volume of each digester within a preset limit of 0.05 to 0.95. Four decision variables were adopted in variant II: total digester volume during the first and second stage of anaerobic digestion, and the proportion of the gaseous phase in each digester. Digester volume was set at 10–1000 m3 for the primary digester, and at 300–5000 m3 for the secondary digester. The proportion of the gaseous phase was also set within the range of 0.05–0.95. Optimal digester volume (131 m3 for the primary digester and 5000 m3 for the secondary digester) and the optimal proportions of the gaseous phase in total digester volume (0.35 and 0.05, respectively) were generated by the modified ADM1xp model. The modeled parameters predicted a 67% increase in methane yields in a two-stage anaerobic digestion process (acidogenesis and methanogenesis). [ABSTRACT FROM AUTHOR]

Although commercially available biosurfactants are environmentally friendly and effectively remove heavy metals from soil, they are costly. Therefore, this study investigated whether inexpensive humic substances (HS) from sewage sludge compost could effectively remove copper (Cu) and cadmium (Cd) from highly contaminated sandy clay loam (S1) and clay (S2). The optimum HS concentration and pH were determined, as well process kinetics. Under optimum conditions, a single washing removed 80.7% of Cu and 69.1% of Cd from S1, and 53.2% and 36.5%, respectively, from S2. Triple washing increased removal from S1 to almost 100% for both metals, and to 83.2% of Cu and 88.9% of Cd from S2. Triple washing lowered the potential ecological risk ( E r i ) of the soils, especially the risk from Cd. HS substances show potential for treating soils highly contaminated with heavy metals, and HS from other sources should be tested with these and other contaminants. [ABSTRACT FROM AUTHOR]

Miscanthus × giganteus is a perennial rhizomatous grass which is used as a biofuel crop. Due to its high yields, low production costs, resistance to low temperatures, low soil requirements and, above all, high cellulose content, miscanthus can be a useful resource for ethanol production. The aim of this study was to determine the effect of two fertilization regimes (sewage sludge/mineral NPK) during miscanthus cultivation on the chemical composition of biomass, the content of major lignocellulosic factions and the effectiveness of miscanthus conversion to bioethanol. The results indicate that fertilization treatments influenced biomass yield and the content of major lignocellulosic fractions. Bioethanol production was higher when hydrolysis and fermentation processes were conducted separately than when saccharification and fermentation were conducted simultaneously. Ethanol production increased by 30% and 40% in response to sewage sludge and NPK (equivalent nitrogen content = 160 kg N/ha) fertilization, respectively, in comparison with unfertilized crops. [ABSTRACT FROM AUTHOR]

The potential of aerobic granules to treat BPA-rich wastewater and the morphology and species structure of the granules were investigated at influent BPA concentrations from 0 to 12 mg/L. The efficiency of BPA removal in sequencing reactors operated with 8-h cycles exceeded 97% and the BPA removal rate was highest (about 0.8 mg/(g MLVSS·h)) at 6 mg BPA/L. Ammonium removal started after BPA concentrations in the reactors dropped below 2 mg/L – after this, ammonium was fully removed in the reactor cycle at rates from 1.97 to 2.56 mg/(g MLVSS·h). Increasing BPA load diminished biomass production and extracellular polymers formation and increased granule diameters. As a result of the increased granule diameters, the core communities in the granules included not only aerobic genera such as Aquimonas and Pseudoxanthomonas , but also anoxic and anaerobic genera including Thauera and Azoarcus . Technological results and correlations between abundances of Methylobacillus sp ., Nitrosospira sp. and Sphingomonas sp. and influent BPA concentrations indicated that BPA was both co-metabolized and directly biodegraded. Metabolic intermediates of BPA degradation were not present in the effluents. This study shows that aerobic granules effectively remove BPA and it extends knowledge of how BPA affects the morphology and microbial structure of aerobic granules. [ABSTRACT FROM AUTHOR]

Valorization of agro-food waste by converting it into a renewable resource plays a crucial role in a bio-based circular economy. Therefore, this study was designed to evaluate the suitability of distillery stillage (DS), which comes from alcohol production from cereals, for producing value-added products that can be used synergistically. The main objective was to investigate the usefulness of two substances for the recovery of phenolic acids, which have antioxidant activity, from the liquid fraction of DS: namely, tetrahydrofurfuryl alcohol (THFA) as a solvent and biochar as an adsorbent, both produced from the solid fraction of cereal processing waste. The effect of THFA concentration (80 and 100%) on phenolic acid yield in ultrasound-assisted extraction was studied. The solubilization predictions of phenolic compounds by the Hansen solubility parameters were in accordance with the experimental results: the yield of phenolic acids in the extracts was highest (3.76 μg g−1 dry mass) with 80% THFA. Among the extracted phenolic acids, hydroxycinnamic acids predominated over hydroxybenzoic acids, which may affect the bioactive properties of the extracts and their future applications for industrial purposes. Phenolic acids from the extracts were adsorbed on 17–170 g biochar L−1 and desorbed into water at 40–60 °C. The phenolic acid recovery was highest (∼92%) when the biochar dose was 85 g L−1 and when desorption was performed at 50 °C. After adsorption/desorption, ∼95% of the antioxidant activity of the phenolic acids in the extracts was maintained. As biochar has a smaller specific surface area than commercial powdered activated carbon (PAC), the biochar dose should be about 5 times higher than an equivalent PAC dose for adsorption efficiency above 90%. [Display omitted] • Tetrahydrofurfuryl alcohol (THFA) and biochar produced from cereal processing waste. • THFA and biochar effective in recovering phenolic acids from distillery stillage. • Highest phenolic acid recovery with 80% THFA, 85 g biochar L−1 and 50 °C. • Predomination of hydroxycinnamic acids in phenolic acids recovered. • Higher dose of biochar than of commercial adsorbent for the same adsorption effect. [ABSTRACT FROM AUTHOR]

This article presents the results of a 3-year field study into the yield and energy efficiency of maize, sweet sorghum, giant miscanthus, Amur silver grass, Virginia fanpetals and alfalfa with timothy grass grown in a farm in north-eastern Poland. The species with the highest DMY (dry matter yield) were the giant miscanthus (25.3 Mg ha −1 y −1 ) and maize (22.7 Mg ha −1 y −1 ). The production of 1 Mg of giant miscanthus DMY was least energy-intensive (0.74 GJ). In the remaining species, the energy inputs required to produce 1 Mg of DMY ranged from 1.12 to 1.40 GJ (maize, Amur silver grass, sweet sorghum) to 2.66 GJ (Virginia fanpetals). Giant miscanthus and maize were characterized by the highest energy outputs of 468 and 404 GJ ha −1 y −1 , respectively. The biomass of the remaining crops accumulated 31–68% less energy. In the climate of north-eastern Poland, the most energy-efficient crop was giant miscanthus (25.0), followed by maize (15.8), Amur silver grass (14.7) and sweet sorghum (12.5), whereas the lowest values of the energy efficiency ratio were noted in alfalfa with timothy grass (10.0) and Virginia fanpetals (7.0). [ABSTRACT FROM AUTHOR]

The potential for bisphenol A (BPA) removal by mixed consortia of immobilized microorganisms with high nitrification activity was investigated with BPA concentrations in the influent from 2.5 to 10.0 mg/L. The presence of BPA limited ammonium oxidation; nitrification efficiency decreased from 91.2 ± 1.3% in the control series to 47.4 ± 9.4% when BPA concentration in wastewater was the highest. The efficiency of BPA removal rose from 87.1 ± 5.5% to 92.9 ± 2.9% with increased BPA concentration in the influent. Measurement of oxygen uptake rates by biomass exposed to BPA showed that BPA was mainly removed by heterotrophic bacteria. A strong negative correlation between the BPA removal efficiency and nitrification efficiency indicated the limited contribution of ammonia-oxidizing bacteria (AOB) to BPA biodegradation. Exposure of biomass to BPA changed the quantity and diversity of AOB in the biomass as shown by real-time PCR and denaturing gradient gel electrophoresis. [ABSTRACT FROM AUTHOR]

• Bisphenol A (BPA) in wastewater affects microbial activity in aerobic granules. • Direct BPA biodegradation predominated in granules at 2 to 12 mg BPA/L. • Upregulation of amoA expression indicated BPA co-metabolism at 12 mg BPA/L. • Low BPA concentration increased activity of biomass and pollutant removal rates. • bisdA gene coding for ferredoxin is a reliable marker of BPA-degrader activity. Wastewater is the major source of bisphenol A (BPA) in the environment, however, the results regarding main mechanisms of BPA biodegradation in wastewater treatment systems are divergent. The effect of BPA concentration in wastewater (0, 2, 6, 12 mg BPA/L) on respirometric activity and expression of selected genes in aerobic granules was examined. A real-time protocol for analysis of direct BPA-degrader activity targeting gene coding for ferredoxin was developed. At 2 mg BPA/L, respirometric activity of granules was the highest, which favored the fastest pollutant removal, and BPA-degraders were active at the beginning of the reactor cycle and no by-products of BPA degradation were detected. At 6 and 12 mg BPA/L, the activity of BPA-degraders was much higher, peaking after feeding and again when a BPA metabolite (3-(benzyloxy)benzoic acid) appeared in the reactor. The upregulation of gene coding for ammonia monooxygenase indicated that co-metabolism occurred mostly at 12 mg BPA/L. [ABSTRACT FROM AUTHOR]