Environmental science. Advances最新文献

The world's increasing dependency on fossil fuels has become a significant energy and environmental concern as they contribute 83% of the global energy supply and produce large amounts of carbon dioxide. Biohythane, a blend of biomethane (5–10%) and biohydrogen (50–60%), is emerging as a promising and environmentally friendly alternative fuel derived from organic wastes and offers a sustainable solution. The existing methods of biohythane production suffer from major limitations of being cost- and labor-intensive due to adopting bulk substrate pretreatment to enhance biohythane yield thereby limiting their industrial applications. In this study, we have developed a synthetic microbial consortium (E(C2)Tx) for anaerobic digestion by combining various organic wastes and subjecting them to heat pre-treatment and acclimatization to enrich biohydrogen producers and methanogens, respectively. Raw cow dung was anaerobically digested as the substrate with E(C2)Tx and this resulted in the production of biohythane with 3% biohydrogen and 36% biomethane. The consortia designing strategy avoided any bulk substrate pretreatment and only included the pretreatment of the inoculum which is used in four times less volume than the substrate. A 16S rRNA gene based metagenomic analysis revealed that the CD samples treated with E(C2)Tx were enriched in cellulolytic and hydrogen-producing Firmicutes, along with methylotrophic and hydrogenotrophic methanogens. The developed technology offers promising commercial benefits by requiring less energy for biohythane production. In addition, it offers environmental advantages by providing an efficient CD waste management alternative and reducing climatic impact by lowering greenhouse gas emissions associated with fossil fuel burning. Using a waste complementarity approach for consortia designing aligns with the principles of circular economy and presents a sustainable, scalable energy solution. The developed method can support the growing energy market by increasing biohythane yield and lowering its production cost.

Ammonia recovery from food waste (including its liquid digestate) is highly emphasized in wastewater treatment and management. Among various membrane-based separation technologies, bipolar membrane electrodialysis (BMED) without anion exchange membranes (AEMs) is an attractive candidate for selective ammonia separation with reduced scaling problems. In this study, a bench-scale BMED stack was built using 5 pairs of cation exchange membranes (CEMs) and bipolar membranes (BPMs). A simulated food liquid digestate was treated using a lab-scale BMED stack to examine the ammonia separation with 3 different intermembrane distances (0.82, 1.64, and 2.46 mm). The highest electric current and ammonia separation were obtained for the intermembrane distance of 1.64 mm, while the BMED stack with 3 spacer gaskets (2.46 mm) still showed comparable separation performance without significant decreases in electric current or ammonia recovery. The residual Ca²⁺ and Mg²⁺ in the cleaning-in-place (CIP) solutions indicated that there were no noticeable scaling problems during the BMED operation. Finally, the pH polarization between the base and feed cells was found to minimize the ammonia back-diffusion even with the highly accumulated ammonia concentration (>11 000 mg_N L⁻¹) in the base cell. With the relatively low energy requirement (1.24–6.78 kW h kg_N⁻¹), BMED lacking AEMs with wide intermembrane distances was confirmed to be a sustainable candidate for ammonia recovery from wastewater with high levels of ammonia.

Antibiotic resistance poses an escalating threat to global health, with environmental reservoirs being pivotal areas of concern, as well as opportunities for potential mitigation. Stormwater systems are an important type of environmental reservoir in the urban water cycle with a dearth of research related to impacts on antibiotic resistance. In particular, there has been limited research exploring the impact of diverse antibiotic resistance genes (ARGs) carried by stormwater from various land uses on surface water, nor has there been an examination of the role played by green stormwater infrastructure (GSI) in mitigating this impact. Therefore, this study sought to elucidate the variability of ARGs across diverse land uses and evaluate the efficacy of GSI in mitigating ARG dissemination. Five distinct stormwater samples—representing mixed, residential, urban, and GSI-treated effluents—were taken to assess variations in ARG resistomes based on land use types. The ARGs in stormwater collected from different land uses were found to be similar in composition and represent a similar level of diversity. A GSI system with a rock swale and bioretention cell connected in series, was also sampled to see how GSI impacted ARGs, and this GSI system did substantially alter the diversity of ARGs. Moreover, the bioretention cell was found to reduce ARG concentrations by 30%. This research also sought to assess the impact of all five stormwater samples on the resistome of surface water via lab-scale microcosm experiments. The urban and residential stormwater significantly (p < 0.05) altered the resistome of surface water, while the mixed-land use sample did not. This finding underscored stormwater's pivotal role in introducing distinct ARG resistome compositions into downstream waters, heightening the chances for development of antibiotic resistant bacteria. The effluent stormwater from the GSI system, however, had less of an impact on the resistome of surface water in the microcosm experiments in comparison to the influent (untreated) stormwater. In managing stormwater runoff through GSI systems, this study's findings highlight the potential of GSI designs and practices to limit the dissemination of diverse and abundant ARGs, safeguard public health, and contribute to sustainable stormwater management by minimizing the impact on downstream surface waters.

As an alternative to the anthraquinone process that can be used directly on site without storage and transport, electrochemical peroxide synthesis is a promising technology to produce reagents for water remediation via Advanced Oxidation Processes (AOP). The focus of research here is on anodic peroxide production, since cathodic synthesis is already at a high degree of maturity. Different materials and electrolytes have been reported for the anode reactions so far. It has also been shown that some electrolytes such as carbonate-based ones lead to the formation of secondary peroxides such as percarbonates which are well-suited as oxidants for AOP. Herein, these materials and electrolytes are evaluated under different conditions with particular focus on the actual oxidation power of the formed product mixtures.

Fog is a common atmospheric event in northern India. Frequently, dense and prolonged fog envelops the entire Indo-Gangetic Plain (IGP), especially in the winter season. During winter, conducive atmospheric conditions also facilitate the accumulation of airborne particulates near the earth surface, significantly reducing atmospheric visibility in the presence of water vapour and gases. Besides, fog formation can also change the characteristics of the biological component of the air (bioaerosols). The Anderson six-stage bioaerosol cascade impactor was therefore used to collect bioaerosols during winter-specific foggy and non-foggy days to assess how fog formation affects the loading and characteristic of bioaerosols. It has been found that the concentration of bioaerosols increases during foggy days (2223 ± 553 CFU m⁻³) compared to non-foggy days (days including both before and after fog; 1478 ± 490 CFU m⁻³). Nearly, a 50% rise in the total culturable microbe concentration was noted during foggy days as compared to non-foggy days in an urban habitat over the central IGP. Approximately 46% and 55% increase in bacterial and fungal bioaerosol concentration, respectively, was found to be associated with foggy days. The size of bioaerosols also varied with the change in atmospheric conditions. During foggy days, bacterial and fungal concentration increased in the coarse size fraction (4.7–7.0 μm) compared to fine (0.65–7.0 μm) particles. The presence of bacteria such as Bacillus; Enterobacter; Cocci and fungi such as Aspergillus, Cladosporium and Penicillium were found during foggy days. The measured concentration of bioaerosols did not exhibit strong association with meteorological variables and other atmospheric co-pollutants. Health risk assessment of the exposure to bioaerosols revealed strong possibility to cause adverse human health effects in the exposed population.

In recent years, the issues pertaining to the micro-/nano-plastics (MNP) pollution in urban water have escalated due to their detrimental environmental consequences, which not only disrupt aquatic habitats and harm marine life but also serve as vectors for toxic pollutants, potentially entering the food chain and posing risks to human health. Although conventional techniques such as filtration, sedimentation, and electrocoagulation have been extensively utilized for MNP removal, ongoing concerns persist regarding their effectiveness, sustainability, and cost implications. Hence, it is imperative to critically assess the performance of conventional techniques in addressing MNP-induced pollution and to shed light on the potential of some emerging technologies as promising next-generation solutions. However, the dearth of standardized approaches and the scarcity of comprehensive data contribute to the disturbing extent of uncertainties in utilizing such techniques to address MNP pollution. Therefore, the current review theoretically emphasizes on innovative use of biochar, electrospun fibers, and aerogels as sustainable adsorbents for managing MNP pollution. Further, it offers a systematic overview elucidating the foundational understanding pertaining to the sources, fate, and transport dynamics of microplastics within the environment. Apart from this, the article explores the integration of such adsorbents into existing water treatment systems and examines the associated challenges and future perspectives in real-world applications. Thus, the contextual review provides valuable insights into designing next-generation technologies aimed at controlling MNP pollution in water systems which not only enhances the understanding of the fate and transport mechanisms of emerging MNP pollutants treatment of water to make it portable but also assists material designers in evaluating and refining existing methodologies and thereby promoting a multi-faceted and synergistic approach to combat the complex issue of MNP pollution.

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Valuing the ecosystem services provided by nature is essential for estuarine habitat conservation and restoration. Recreational fisheries rely on fish stocks that are dependent on productivity derived from the plants that comprise estuarine habitats, however the value of these habitats to recreational fishing is rarely considered. Here, we consider expenditure on recreational fishing activities as an indicator of coastal wetland habitat value, by synthesising data on routinely collected recreational effort, catch, and expenditure from telephone surveys alongside trophic subsidy models within a simple framework. The approach is demonstrated for the Clarence River and the Hunter River estuaries (New South Wales, Australia). Expenditure on recreational fishing activities was apportioned to mangrove and saltmarsh habitats via the ‘trophic subsidy’ (or nutrition) originating from primary producers in these habitats that fuels the biomass of important recreational species. The values estimated exceeded that of similarly apportioned commercial fisheries revenue, with the biggest difference observed for saltmarsh in the Clarence River (∼$17 million AUD per annum [recreational expenditure] compared to ∼$8 million AUD per annum [commercial fisheries total output]). When considered in an additive fashion and standardised by habitat extent, the values attributable to coastal wetland productivity were as high as $86 459 per hectare per annum for saltmarsh, and $20 611 per hectare per annum for mangroves. These values reflect the dependency of fisheries activities on the extent and condition of coastal wetland habitats, and the framework presented here is widely applicable for considering the economic value of these activities i.e., fishing) as an indicator of habitat value.

The stability of pharmaceutical active ingredients (APIs) and their resistance to conventional treatment methods necessitates the development of degradation methods as point-source treatment before mixing with municipal wastewater. Advanced oxidation processes utilize oxidants such as H₂O₂ or persulfate (PS) to treat organic contaminants and have shown promising results for eliminating APIs from wastewater. This research investigated the degradation of tramadol (TRA), a fully synthetic opioid, in a UVC/PS system, which was selected after evaluating thermal and simulated solar activation techniques. Different concentrations of PS were tested, and the UVC/PS system with [PS]₀ = 0.4 mM achieved complete degradation of 10 mg L⁻¹ [TRA]₀ in 6 min with k_obs of 0.90 min⁻¹ and was chosen for this study. The system was evaluated under different conditions and showed a decrease in reaction rate under acidic conditions and in the presence of bicarbonates or competing natural organic matter. Additionally, high levels of chlorides and nitrates inhibited the degradation. Building on insights from batch treatment experiments, a pilot-scale treatment plant was developed utilizing elements from commercially available UV water-disinfection kits for continuous-flow treatment of pharmaceutical industry effluent. After optimization, the system achieved full degradation of 360 L per day of 10 mg L⁻¹ [TRA]₀ at a cost of $0.296 per m³.