Journal of Environmental Management最新文献

Microalgal tolerance to emerging contaminants (ECs) such as 1,4 dioxane (DXN) and its impact on phycoremediation performance, algal growth, biomolecules generated, and recycling the produced biomass for biochar production has been rarely reported. Hence, Chlorella vulgaris was cultivated in DXN-free wastewater (WW1) and 100 mg L⁻¹ DXN-laden wastewater (WW2) in 1-liter photobioreactors with an operating volume of 800 ml under controlled conditions: temperature (25 ± 1 °C), light intensity (351 μmol m⁻²s⁻¹), and photoperiod (12 h light:12 h dark). Interestingly, this microalgal-based system achieved up to 32.79% removal efficiency of DXN in WW2. In addition, there was no significant difference in the removal of COD (90.6% and 86.8%) and NH₄-N (74.5% and 76.8%) between WW1 and WW2, respectively. Moreover, the variation in C. vulgaris growth, pigments, lipid, and carbohydrate contents between the two applied wastewaters was negligible. However, there was a significant increase in the protein yield upon exposure to DXN, suggesting the ability of C. vulgaris to secrete various antioxidant and degrading enzymes to detoxify the contaminant. These results were validated by FTIR, SEM, and EDX analysis of C. vulgaris biomass with and without DXN exposure. The harvested biomass was thermally treated at 350 °C for 60 min in an oxygen-free environment. The biochars generated from both algal systems were characterized by comparable morphologies and elemental profiles with sufficient C and N contents, indicating their applicability to enhance the soil properties. The economic evaluation of the combined phycoremediation/pyrolysis system demonstrated a net profit of 596 USD⋅y⁻¹ with a payback period of 6.2 years and fulfilled the objectives of several sustainable development goals (SDGs). This is the first study to point to C. vulgaris as a robust microalgal strain in remediating DXN-laden wastewater accompanied by the potential recyclability of the biomass produced for biochar production.

Human activities that involve diverse behaviors and feature a variety of participations and collaborations usually lead to varying and dynamic impacts on the ecological environment. Quantitative analysis of the dynamic changes and complex relationships between human activities and the ecological environment (eco-environment) can provide crucial insights for ecological protecting and balance maintaining. We proposed a two-dimensional four-quadrant assessment method based on the dynamic changes in Human Activity Index (HAI) - Environmental Ecological Condition Index (EECI) to analyze the dynamic trends and coupling coordination degree (CCD) between HAI and EECI. This approach was applied in an empirical study of Hainan Province. A comprehensive HAI at a resolution of 1 km × 1 km is established to measure human activities, while an EECI is developed to evaluate ecological environment quality. The eco-environment showed continuous improvement, with the HAI initially rising and then declining. Analysis of coupling coordination revealed a ratio of 6:1 between coordinated development regions and conflict regions, indicating a gradual improvement in overall coupling coordination. The interaction between the HAI and EECI is strengthening, though variations exist across different locations. Using the geodetector method, we identified Net Primary Productivity (NPP), Land use and land cover (LULC), and Particulate Matter (PM) as the primary factors influencing changes in coupling coordination between HAI and EECI. These factors indirectly affect the stability and carrying capacity of the ecological environment. This method facilitates a quantitative examination of the dynamic relationship between HAI and EECI in different regions, offering insights into ecosystem functionality, biodiversity maintenance, and the effect of HAI on the region.

Municipal solid waste (MSW) is a major anthropogenic contributor to climate change due to the substantial quantities of greenhouse gas (GHG) emitted by landfills and incineration. Circular waste management has shown promise in reducing GHG emissions; however, it is still in its early stages and requires further optimization. In this study, support vector machine models were developed to determine the compositional dynamics of MSW, which were then integrated to examine the interactions among composition, disposal routes, and GHG emissions. The results from analyzing large-scale transitions from traditional to circular waste management practices showed that GHG mitigation potential will be significantly enhanced as the coverage of circular waste management increases from 35% in 2025 to 100% in 2035 in China. However, these reductions will eventually decrease as waste quantities decline in response to population shrinkage. The results reveal both the GHG mitigation potential and limitations of the circular waste management mode, assisting policymakers and researchers in maximizing its mitigation potential.

The impact of a novel sawdust-modified carrier on the performance of aerobic sequencing batch reactor (SBR) was examined. Compared with the conventional polyethylene (PE) carrier, the sawdust-modified carrier had coarse surface and porous side wall, which was beneficial for the rapid formation of biofilm. The biomass of sawdust-modified carrier was 3.4 ± 0.7 times more than those of PE carrier at the end of this study. The biofilm gotten from suspended carrier had higher extracellular polymeric substances (EPS) concentrations than activated sludge (AS). The EPS from biofilm contained higher proportions of polysaccharides compared to those from AS. The SBR with addition of sawdust-modified carrier exhibited higher ammonia nitrogen removal efficiency (84.8%) than the one with addition of conventional PE carrier (73.1%) in a typical cycle at 12 h. The volumetric nitrification rates of modified carrier were higher than those of conventional PE carrier. High throughput sequencing revealed that sawdust-modified carriers exhibited greater microbial richness and diversity compared with traditional PE carriers. Saccharimonadales was the most predominant genus that removed organic matter under aerobic condition, whereas Nitrospira was the dominant nitrifying genus. The present study verifies the advantage of sawdust-modified carrier, which has the potential for the full-scale application in the future.

Hydraulic conditions exert a comprehensive and vital influence on constructed wetlands (CWs). However, research on this subject is relatively limited. Hydraulic parameters can be categorized into design and operational parameters based on their properties. The design parameters are represented by the hydraulic gradient, substrate porosity, and aspect ratio, while operational parameters are represented by the hydraulic retention time, hydraulic loading rate, and water depth. These parameters directly or indirectly affect the operational lifespan and pollutant removal performance of CWs. Currently, the primary measures for optimizing the hydraulic conditions of CWs involve hydraulic structure and numerical simulation optimization methods. In this review, we aimed to elucidate the impact of hydraulic conditions on CW performance and summarize current optimization strategies. By highlighting the significance of hydraulic parameters in enhancing pollutant removal and extending operational lifespan, this review provides valuable insights for improving CW design and management. The findings will be useful for researchers and practitioners seeking to optimize CW systems and advance the application of nature-based solutions for wastewater treatment.

Protected areas such as national parks constitute an increasing land mass globally, but these areas are under increasing threat from climate change events such as drought, flooding, and bushfires. The recent Yosemite National Park fires in California provide an example of this issue. After any such disaster, authorities will need to restore those protected areas to their former state at significant costs within any public funding cycle. To corroborate that request, clear economic assessments of total costs and benefits will be required. However, in previous studies of these issues a complete set of government cost and/or benefit data may not be provided, skewing assessment results accordingly. Using South Australia's Kangaroo Island protected areas—which were significantly destroyed by bushfire in 2019–20—as a case study with a unique set of State government cost data we calculate a set of analyses via economic methods. Despite significant restoration costs the study found the discounted net present value of returning tourists to the Island is 3.15 over ten years for park tourism and regional economic impacts, providing an internal rate of return of 22%. The rebuild work is also expected to support around 430 full time equivalent (FTE) jobs during construction, with a return to full tourism supporting another 744 FTEs across relevant sectors (e.g. accommodation, retail) of the Kangaroo Island economy. This robust assessment makes it far easier for protected area managers to argue their funding case.

The inverted U-shaped relationship between economic growth and environmental degradation is known as environmental Kuznets curve (EKC) and has been tested in many empirical studies since more than 3 decades. Technological change is one of the tools that can be used to examine the existence of EKC in CGE models. The objective is to extract EKC for G7 countries using a multi-regional CGE model and investigate the effects of some key factors affecting EKC using historical data for the period of 1861–2021. First, we have considered the effects of energy efficiency, on CO₂ emissions, on carbon intensity and on economic growth. Then, EKC was extracted based on the obtained results. In addition, the effects of factors such as carbon tax, revenue recycling schemes and various types of substitution elasticities are evaluated on EKC. Our results show that, with a 3% improvement in productivity, by 2050, GDP will increase by nearly 12% and carbon emissions will decrease by 4.4%. The combination of such two effects has led to an inverted U-shaped relationship between economic growth and carbon emissions. Among the elasticity of substitutions, the elasticity of substitution of capital and energy, as well as the substitution elasticity of energy inputs has the greatest effect on EKC. The slope of EKC becomes negative if a carbon tax is imposed. The EKC moves downwards if carbon tax income is transferred to the production tax-cut in renewable sectors. The results suggest that carbon tax and its allocation to renewable sectors will improve environmental effects.

The establishment of S-scheme heterojunctions represents an effective strategy for enhancing the transfer and separation of charge carriers, thereby bolstering redox capacities and consequently benefiting subsequent photocatalytic reactions. In this study, the pristine Bi₇O₉I₃ underwent a facile vulcanization process to in-situ produce various composites. Systematical characterizations confirmed the simultaneous generation of Bi₇O₉I₃/Bi₂S₃ (BI-BS) heterojunctions with surface oxygen vacancies (OVs). Under visible light, these BI-BS composites exhibited improved NO removal efficiencies with reduced NO₂ generation compared to bare Bi₇O₉I₃. Particularly, the best candidate BI-BS2 possesses the highest NO removal (43.02%) and lowest NO₂ generation (5.44%) among all tested samples. The improvement was primarily attributed to synergetic effects of heterojunction and surface OVs, including enhanced charge separation, heightened light responsiveness, and improved generation of reactive oxygen-containing species through an S-scheme mode. Furthermore, the Density Functional Theory (DFT) calculations had demonstrated that the establishment of BI-BS heterojunctions with surface OVs not only optimized the electronic structure to facilitate the transfer and separation of charge carriers, but also significantly enhanced the adsorption of NO, H₂O, and O₂ molecules, ultimately favoring the generation of NO₃⁻ species. These as-synthesized composites indicated sufficient structural stability and hold potential for the photocatalytic removal of NO at ppb levels.

This review examines various modification techniques, including metal doping, non-metal doping, multi doping, mixed doping, and the construction of heterojunction photocatalysts, for enhancing the performance of pure TiO₂ and ZnO in the photodegradation of antibiotics. The study finds that mixed and multi doping approaches are more effective in improving photodegradation performance compared to single doping. Furthermore, the selection of suitable semiconductors for constructing heterojunction photocatalysts is crucial for achieving an efficient charge carrier separation. The environmental impacts, recent research, and real application of photocatalysis process have been discussed. The review also investigates the impact of operating parameters on the degradation pathways and the generation of by-products for different antibiotics. Additionally, the toxicity of the by-products resulting from the photodegradation of antibiotics using modified ZnO and TiO₂ photocatalysts is explored, revealing that these by-products may exhibit higher toxicity than the original antibiotics. Consequently, to enable the widespread implementation of photodegradation systems, researchers should focus on optimizing degradation systems to control the conversion pathways of by-products, developing innovative photoreactors, and evaluating toxicity in real wastewater matrices.

Fuel management is undertaken to mitigate the adverse consequences of wildfire. Finite mitigation budgets demand selective prioritization of forest stands for targeted fuel reduction treatments. A range of modeling methods have been used to identifiy optimal fuel treatment plans at various spatial and temporal scales of investigation; however, strategic analysis of fuel management alternatives can involve a range of limitations and challenges, including the prevalence of one-time solutions, static models lacking dynamic adaptability, and challenges in accounting for the stochastic nature of fire behaviour. To navigate these complexities, our study combines remote sensing-based analysis with a random search optimization algorithm to inform strategic fuel management and wildfire mitigation planning. For two communities in Alberta, Whitecourt and Hinton, we assessed landscape fire exposure within and around the built environment and rated hazardous fuels by the number of buildings they exposed (i.e., Building Exposure load, BEL). Through the assessment of BEL and the outcomes of the optimization algorithm, our model identified key areas for intervention, enabling a more informed allocation of mitigation resources. We found good alignment between expert-derived fuel treatment areas and our model-derived fuel reduction areas, PFRs, confirming the utility and relevance of our findings. The methodology is adaptable to diverse regional fuel characteristics and it also offers a phased implementation to assisting communities with financial constraints. The suggested systematic approach aids communities that lack local expertise in developing proactive fuel treatment strategies. Additionally, this study emphasizes the need to combine fuel treatment prioritization with community involvement, acknowledgment of potential local limitations, and financial planning to enhance its effectiveness and adaptability.