The reduction of nitrous oxide (N₂O) emission during nitrogen removal process in municipal wastewater treatment is of great urgency. Sequencing batch biofilm reactor (SBBR) system could be a promising and efficient way to solve the problem. In order to get the high chemical oxygen demand (COD) and nitrogen removal efficiency and low nitrous oxide emission, the influence of biofilm density on SBBR was investigated. When the biofilm density changed from 15 to 30 %, the effluent COD, total nitrogen (TN) and ammonia nitrogen decreased, but the effluent TN concentration did not meet the class I-B standard of the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant in China. COD, TN, and ammonia nitrogen concentration was 42.34, 19.14 and 2.97 mg/L at 50 % biofilm density. When the density turned from 50 to 70 %, although the effluent COD, TN, and ammonia nitrogen were still decreased, N₂O emission increased from 0.45 to 0.77 %. Considering the effluent quality and N₂O emission, the optimal biofilm density in SBBR was 50 %.

Natural volcanic tuff was used for the synthesis of geopolymer and then for the removal of Zn⁺². The characteristics of the natural volcanic tuff and the synthesized geopolymer were determined by X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM). Results referred that the synthesized geopolymer had a higher efficiency uptake of 97.7 % as against 78.5 % for the natural volcanic tuff. The uptake capacity of geopolymer for Zn⁺² adsorption increased with increasing temperature in the studied range of 25–45 °C, contact time up to 30 min, pH up to 7, and initial concentration up to 160 ppm, while it decreased with an increase in geopolymer dosage. The isotherm study showed best fit on Langmuir and Radlich-Peterson models. The maximum uptake capacity obtained from Langmuir model increased from 14.7 to 17.63 mg/g as the temperature increased from 25 to 45 °C. The pseudo-second-order model showed the best fitness for the experimental data followed by intraparticle diffusion model. The adsorption process can be characterized as endothermic, homogeneous, spontaneous, irreversible, physical, and a high adhesion of the ions to the geopolymer surface. The results obtained buttressed the feasibility and applicability of producing geopolymer from natural volcanic tuff for the removal of heavy metals.

This 3-year study was aimed to understand the factors and mechanisms that cause the temporal changes in the concentration of microbiological indicators of water quality and nutrient concentration in selected sites of the Białka river catchment (southern Poland) situated in direct vicinity of the largest ski station in the region. The analysis comprised 35 sampling campaigns conducted in five sites. Water temperature, pH, and electrical conductivity were measured during sampling, laboratory analyses included determination of the selected nutrients content (NH₄, NO₃, NO₂, PO₄); and the number of mesophilic and psychrophilic bacteria, coliforms, fecal coliforms, and Escherichia coli. Based on the cluster analysis, the collected samples were grouped into three to four groups, depending on the most characteristic features. Seasonal variation was evident, showing the predominance of either anthropogenic or natural-environment factors, depending on the considered season. On the other hand, principal component analysis revealed clear effect of various forms of land use in different sites.

Tropospheric ozone (O₃) is the air pollutant of most concern to vegetation at present. Ozone impacts on stomata are still controversial, as both decreased stomatal conductance and slow stomatal responses to environmental stimuli (namely, stomatal sluggishness) have been shown. We postulated that the light environment affects stomatal sluggishness. To concurrently manipulate O₃ and light conditions and measure gas exchange at leaf level, we developed an innovative O₃ exposure system by modifying a commercially available gas exchange system. We exposed the first trifoliate leaf of the O₃-sensitive genotype S156 of snapbean (Phaseolus vulgaris) to a 1-h O₃ exposure (150 ppb) under 1000 μmol m⁻² s⁻¹ photosynthetic photon flux density, so that stomata were fully open and O₃ uptake was maximized. Then, leaves were subjected to different light intensities (200, 1000, or 1500 μmol m⁻² s⁻¹) until a steady state was reached. As a metric of sluggishness, we quantified the stomatal responses to a sharp water stress generated by cutting the petiole at steady state. The results showed that O₃ exposure induced stomatal sluggishness only under high light (stomata needed 53 % more time to half stomatal conductance relative to steady state) and did not when the plants were under lower light intensities. We conclude that O₃-induced stomatal sluggishness may occur only in fully irradiated leaves, and suggest it is a minor response when entire crowns and canopies are assessed and a major reason of the higher O₃ sensitivity of sun leaves than of shade leaves.

Preparation and characterization of a novel activated carbon obtained from vine shoots by ZnCl₂ activation and its rifampicine removal capacity were investigated in this study. The effects of activation temperature and impregnation ratio (precursor/ZnCl₂) on the activated carbon properties were investigated. The prepared activated carbon was characterized by BET surface area, surface functional group analysis by Boehm’s titration and FT-IR analysis, pHₚzc, iodine number, SEM-EDX, and particle size distribution. The results showed that the surface area, pore size, and pore volume of the activated carbon increased with the increasing temperature and impregnation ratio and reached maxima at the impregnation ratio of 40/30 at 700 °C. Under the optimal conditions, it was determined that the BET surface area, total pore volume, iodine number, and pHₚzc of the activated carbon were 1689 m²/g, 0.842 cm³/g, 1276 mg/g, and 4.8, respectively, and it has mainly acidic functional groups (total 0.2516 meq/g) on its surface. The activated carbon obtained was evaluated for rifampicine removal efficiency depending on contact time, adsorbent dosage, and initial concentration of rifampicine. Maximum adsorption capacity of rifampicine by the activated carbon (Q°) was determined according to Langmuir adsorption isotherm. The adsorption data was best fitted to the Langmuir isotherm with R ² of 0.983 and Q° was found to be 476.2 mg/g.

The objective of this research was to determine the process of atrazine transport compared to bromide and δO¹⁸ transport in sands near Denver. Three 1.5 × 2 × 1.5-m plots were installed and allowed to equilibrate for 2 years before research initiation and were instrumented with 1.5 × 2-m zero-tension pan lysimeters installed at 1.5-m depths. Additionally, each plot was instrumented with suction lysimeters, tensiometers, time domain reflectometry (TDR) moisture probes, and thermocouples (to measure soil temperature) at 15-cm depth increments. All plots were enclosed with a raised frame (of 8-cm height) to prevent surface runoff. During the 2-year period before research began, all suction and pan lysimeters were purged monthly and were sampled for fluids immediately prior to atrazine and KBr application to obtain background concentrations. Atrazine illustrated little movement until after a significant rainfall event, which peaked concentrations at depths of about 90 to 135 cm. Both Br⁻ and δO¹⁸ moved rapidly through the soil, probably owing to soil porosity and anion exclusion for Br⁻. Concentrations of atrazine exceeding 5.0 μL⁻¹ were observed with depth (90 to 150 cm) after several months. It appears that significant rainfall events were a key factor in the movement of atrazine in the sand, which allowed the chemicals to move to greater depths and thus avoid generally found biodegradation processes.

Industrial synthesis processes produce high concentration of hazardous organic pollutants into water body, which must be removed before being discharged. Advanced oxidation processes (AOPs) using heterogeneous catalysts has been widely utilized for wastewater treatment. Here, RuO₂-based catalyst was synthesized by a general impregnation method and used to oxidize phenol by peroxymonosulfate (PMS) as an oxidant in aqueous solution. The properties of this supported catalyst were characterized by SEM (scanning electron microscopy), XRD (powder X-ray diffraction), and nitrogen adsorption-desorption. The mesoporous Al₂O₃ support had large surface area and high thermal stability. It is found that ruthenium oxide-based catalyst is highly effective to activate PMS to related sulfate radicals. The effects of catalyst loading, phenol concentration, PMS concentration, reaction temperature, and reusability of the as-prepared catalyst on phenol degradation have been investigated. Overall, our findings demonstrate that in RuO₂/Al₂O₃ mesoporous catalyst, Oxone (PMS) is effectively activated, and 100% phenol degradation occurs in 60 min. To regenerate the deactivated catalyst and improve its catalytic properties, three different methods involving annealing in air, washing with water, and applying ultrasonics were used. The catalyst was recovered thoroughly by heating treatment.

Phosphogypsum (PG) is an industrial waste composed mainly by sulfate, turning it a suitable sulfate source for sulfate-reducing bacteria (SRB). In the present work, the capability of two SRB communities, one enriched from Portuguese PG (culture PG) and the other from sludge from a wastewater treatment plant (culture WWT-1), to use sulfate from PG was compared. In addition, the impact of this sulfate-rich waste in the microbial community was assessed. The highest efficiency in terms of sulfate reduction was observed with culture WWT-1. The bacterial composition of this culture was not significantly affected when sodium sulfate from the nutrient medium was replaced by PG as a sulfate source. Next generation sequencing (NGS) showed that this community was phylogenetically diverse, composed by bacteria affiliated to Clostridium, Arcobacter, and Sulfurospirillum genera and by SRB belonging to Desulfovibrio, Desulfomicrobium, and Desulfobulbus genera. In contrast, the bacterial structure of the community enriched from PG was modified when sodium sulfate was replaced by PG as the sulfate source. This culture, which showed the poorest performance in the use of sulfate from PG, was mainly composed by SRB related to Desulfosporosinus genus. The present work provides new information regarding the phylogenetic characterization of anaerobic bacterial communities with the ability to use PG as sulfate donor, thus, contributing to improve the knowledge of microorganisms suitable to be used in PG bioremediation. Additionally, this paper demonstrates that an alternative to lactate and low-cost carbon source (wine wastes) can be used efficiently for that purpose.

Research was carried out on the granulometric, mineral composition and fractional distribution of some elements in surface sediments of the Zeya River basin (Far East, Russia). The order of sediments’ pollution by heavy metals due to man-caused impact on the Zeya River’s ecosystem was determined. The compound forms of heavy metals in sediments were studied. It presented the most of the Fe, Ni, Cr, Mn, Co, Cu and Zn accumulated in bottom fraction; Pb and Cd—also in Fe and Mn hydroxides and bottom fractions. On average, 56% Pb, 83% Cd, 27–37% Cu, Co and Zn (of total amount) are held in geochemical moving forms.

Embryonic and early postembryonic development of the cuttlefish Sepia officinalis (a cephalopod mollusk) occurs in coastal waters, an environment subject to considerable pressure from xenobiotic pollutants such as pharmaceutical residues. Given the role of serotonin in brain development and its interaction with neurodevelopmental functions, this study focused on fluoxetine (FLX), a selective serotonin reuptake inhibitor (SSRI, antidepressant). The goal was to determine the effects of subchronic waterborne FLX exposure (1 and 10 μg L⁻¹) during the last 15 days of embryonic development on neurochemical, neurodevelopmental, behavioral, and immunological endpoints at hatching. Our results showed for the first time that organic contaminants, such as FLX, could pass through the eggshell during embryonic development, leading to a substantial accumulation of this molecule in hatchlings. We also found that FLX embryonic exposure (1 and 10 μg L⁻¹) (1) modulated dopaminergic but not serotonergic neurotransmission, (2) decreased cell proliferation in key brain structures for cognitive and visual processing, (3) did not induce a conspicuous change in camouflage quality, and (4) decreased lysozyme activity. In the long term, these alterations observed during a critical period of development may impair complex behaviors of the juvenile cuttlefish and thus lead to a decrease in their survival. Finally, we suggest a different mode of action by FLX between vertebrate and non-vertebrate species and raise questions regarding the vulnerability of early life stages of cuttlefish to the pharmaceutical contamination found in coastal waters.