International Journal of Environmental Science and Technology最新文献

Anaerobic digestion (AD) has become the technology of choice for organic waste treatment as an environmentally beneficial and sustainable waste treatment technology. However, the nitrogen content of these organic waste streams is generally high. Ammonia is produced in the biodegradation of nitrogenous organic matter. Low concentrations of ammonia favour AD, but high concentrations can lead to digestive system failure. To address the issue of ammonia inhibition and ensure the stability of the digestive system, numerous physical, chemical, and biologicalmethods aimed at controlling ammonia levels and/or strengthening the biological processes have been proposedand developed. Literature evidence suggests that differences in AD reaction conditions and microbial sources result in different tolerances of the digestive system to ammonia and nitrogen. This paper summarises and compares the inhibitory effects of ammonia nitrogen under different conditions and the existing regulatory measures to alleviate ammonia nitrogen inhibition. In addition, since the core of the digestive system is microorganisms, this paper explains the mechanism of ammonia stress especially at the microbial level, and in this way, it explores the future direction of research using biofortification. This review provides a theoretical reference for solving the problem of ammonia nitrogen inhibition.

The electrochemical performance of microbial fuel cells is conventionally assessed through linear sweep voltammetry at predefined potential scan rates. Nevertheless, this approach frequently falls short in representing the long-term behavior of microbial fuel cells under actual external loads, highlighting the need for a standardized evaluation method incorporating both linear sweep voltammetry and external loads. To address this gap, this study evaluates the performance of single-chamber microbial fuel cells under different loads and scan rates. The MFCs were tested with external loads of 1200, 470, and 270 Ω, derived from maximum power points of polarization sweeps at scan rates of 0.1, 0.5, and 1 mV/s at two operational phases. Power estimates at these scan rates were 61.96, 87.88, and 166.68 mW/m² at current densities of 116.5, 229.6, and 403 mA/m², respectively. In the initial two hours, average power densities with 1200, 470, and 270 Ω were 73 ± 16.7, 36.3 ± 42, and 88.5 ± 120.1 mW/m², respectively. Over the long term, the fuel cells under constant loading with resistance estimated at 0.1 mV/s showed average power 73.7% and 89.1% higher than those with resistances estimated at 0.5 mV/s and 1 mV/s, respectively, indicating that higher scan rates lead to overestimation of power. Although initially underestimated, the 0.1 mV/s scan rate more accurately reflected the true long-term performance of the fuel cells. This study emphasizes the importance of using appropriate scan rates for linear sweep voltammetry to obtain realistic long-term performance estimates of microbial fuel cells under real-time loads.

TiO₂ nanoparticle-loaded hydrogel bead material was prepared by the sol–gel method of alginate cross-linked in CaCl₂. TiO₂ hydrogel bead formulations were based on two methods: (1) sodium alginate mixed with polyvinylpyrrolidone (AP), together with nano TiO₂ powder (TiO₂–AP1), and (2) AP hydrogel bead soaked in solution of nano TiO₂ and CaCl₂ (TiO₂–AP2). The synthesized materials were characterized using X-ray diffraction, Fourier transform infrared spectrometer and field-emission scanning electron microscope. The photocatalytic performance of the synthesized materials was evaluated on the removal efficiency of oxytetracycline (OTC) and enrofloxacin (EFX) contained in an aqueous solution under ultraviolet (UV) light irradiation. TiO₂–AP1 beads, prepared using the first method, exhibited superior performance compared to TiO₂–AP2 beads. The porous structure of TiO₂–AP1 hydrogel beads effectively immobilized and dispersed TiO₂ particles, resulting in enhanced photocatalytic activity and stability. The best removal efficiency for OTC and EFX using TiO₂–AP1–0.4 within 240 min under UV light reached 89.5% and 82.9%, respectively. Although the photocatalytic activity of TiO₂–AP1 beads was slightly lower than that of TiO₂–P25, their separation and recovery ability from aqueous solutions were significantly better. TiO₂–AP1–0.4 maintained nearly unchanged photocatalytic activity after six degradation cycles (reduced by only about 3–4%).

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Taking the natural water in Anhui Polytechnic University as the research object, the removal of micro-pollutants in water body by KMnO₄ pre-oxidation enhanced polyaluminium chloride (PAC) coagulation process was studied. Firstly, the ability of different experimental schemes to remove turbidity, TP (Total Phosphorus) and UV₂₅₄ was investigated to determine the pre-oxidation scheme. Then, on the basis of the selected pre-oxidation scheme, the effects of the dosage of KMnO₄, dosage of PAC, pre-oxidation time and pH on the removal of pollutants were investigated. Taking removal rate of turbidity, UV₂₅₄ and TP as the response values, the response surface method (RSM) was used to investigate the independent and interactive effects of the dosage of KMnO₄ (A), PAC dosage (B) and pre-oxidation time (C). The technological parameters of KMnO₄ pre-oxidation enhanced coagulation treatment of micro-polluted water were optimized. The results showed that adding KMnO₄ for 5 min followed by adding PAC had the best treatment effect. The influence order is as follows: turbidity (B > A > C), UV₂₅₄ (B > C > A), TP (A > B > C). The optimal technology parameters predicted by the model are as follows: A is 0.886 mg/L, B is 47.498 mg/L, and C is 13.1 min. Under these conditions, the best removal rates of turbidity, TP and UV₂₅₄ were 92.43%, 86.25% and 40.6%, respectively, and the validated values were 92.51%, 88.67% and 41.32%, respectively. The deviation values from the model prediction are 0.07%, 2.42% and 0.72%.

Perchlorate (ClO₄⁻), which is a powerful endocrine disruptor affecting iodine fixation in the thyroid gland in humans and in biota, is a pollutant of natural and anthropogenic origin. For this reason, this pollutant must be eliminated from the ecosystems. It has been found in extreme environments such as Antarctica. ClO₄⁻ reduction can be achieved with physicochemical treatments in small concentrations and through bacterial degradation. This is a cost-effective method, easy to implement, which makes it a viable method for the removal of perchlorate contamination in ecosystems. This review provides an updated discussion of reducing perchlorate contamination; that includes different perspectives of investigations related to its origin, use, effects on living beings; as well as the technologies used to eliminate this pollutant from the environment; its environmental fate in strategic ecosystems such as Antarctica in particular and astrobiological perspectives.

The study examined the feasibility of utilizing the mixture of ceramic sludge and roller kiln wastes, to produce low-cost ceramic-based membranes designated for use in wastewater treatment applications. In recent years, the treatment of wastewater contaminated with humic acid has posed significant challenges due to its complex nature and resistance to conventional treatment methods. To improve the physical, mechanical, and filtration qualities of the membranes, the study involved preparing them using a blend of five distinct composition ratios of totally recycled ceramic sludge and roller kiln wastes, which were then sintered at temperatures ranging from 900 °C to 1300 °C. The most effective membrane showed the best permeate flux and humic acid separation efficiency for the wastewater samples when it was sintered at 1000 °C using only ceramic sludge waste. The produced membranes were thoroughly examined to reveal their structural and chemical characteristics. This confirmed the effective integration of functionalized multi-walled carbon nanotubes (f-MWCNTs) and their influence on the membranes’ functionality. f-MWCNTs were added to the membrane’s surface via wet impregnation and drop casting methods. This resulted in a notable improvement in the membrane’s humic acid separation efficiency, which increased to 92.61%, and the flux increased to 128.46 L/m²/h at a concentration of 100 mg L⁻¹ as well. The opportunity to develop effective and environmentally sustainable ceramic membranes for water treatment using industrial ceramic wastes is highlighted by this study.

The Northwest Minas Gerais is a significant grain-producing region in Brazil. Center pivot irrigation in the region increased by 84% from 2010 to 2020, and records of conflicts over water use have occurred since 2000. This study carries out a hydroclimatic analysis of water resources in the Northwest Minas Gerais, using orbital and field data related to 567 pivots, considering the expansion of the irrigated area in the region over the years, the rainfall regime, and the flow of rivers. The time series of precipitation from 1982 to 2022 and river flows from 1978 to 2015 show a significant decrease in rainfall of up to 14.4% since 2012 and a reduction in river flow in all sub-basins analyzed. Furthermore, there was a 99.4% growth in irrigated areas in the last ten years. Due to this scenario, using outdated information to define water allocation rights can escalate conflicts in the use of water resources in the Northwest Minas Gerais region. The results show the need to implement sustainable and contemporary water use management in the Northwest Minas Gerais region. Implementing effective policies, advocating the efficient use of water in agriculture, and promoting collaboration between various sectors are vital to facing current and future challenges.

Industry and civic society are unaware of polluted water’s quality, quantity, and environmental impact. On the other hand, unregulated extraction of groundwater, inefficient use of water at various stages of production, structural challenges in plumbing, lack of low-cost reliable meters, inaccurate data and tampering issues, inability of environmental regulation, and a manpower shortage to inspect the unit at regular intervals across thousands of factories necessitate the development of an automated system for effluent treatment plant monitoring. In this study, we design a cost effective, realistic water quality and quantity monitoring system for different stages of industrial production, with real time data for underground water extraction. All the collected data will be uploaded to a server and displayed on an online dashboard in real-time. The dashboard will be shared by both industries and government officials. We deployed machine learning to provide real-time predictive analytics on water quality and quantity. We automated the effluent treatment plant processes by testing the water quality and quantity in real time and sending appropriate instructions to the respective stakeholders. The industries can be aware of the water quality and quantity in each stage of production by monitoring the data before releasing the water in the environment. This project will help to achieve current and future national and international water compliance, and several sustainable development goals.

This composite study presents detailed instructions on the applicability of the results of a sequential extraction method (SE), coupled with statistical analyses, a Secondary Phase Enrichment Factor (Kspef), risk assessment indices, and, for the first time, the Chemical Index of Alteration (CIA). The study gives important data on the current risk of mobility of the elements and the methodology of appropriate measures before establishing an effective mitigation strategy and predicting the risk of mobility after changing environmental conditions, such as the harmful effects of ongoing climate change. The combination of techniques is used to assess the origin and contamination level of potentially toxic elements in the roadside agricultural soil impacted by traffic at Highway E75 (Serbia). The results show that B, Ni, Co, V, Ba, Cr, As, and Mo at most localities are of natural origin, sourced by a protracted decomposition of the geological matrix. Cu, Zn, Pb, Hg, Sb, and Cd have natural and anthropogenic origins (traffic and agricultural activities). Ba has the highest bio/geoavailability and belongs to the group of elements with a higher environmental risk. Groups with a moderate environmental risk include the elements As, Cd, Co, Ni, and V. A moderate to high-risk level of contamination of the soils with Pb, Cu, Zn, Sb, and Hg is documented exclusively at particular localities. The results of SE, coupled with the CIA coefficient, are applicable to predict the processes of chemical alteration of the mineral components of soils, including evaluating a degree of natural soil contamination.

Even though when the COVID-19 pandemic started, in 2020, the urban cleaning and solid waste management services were not disrupted in Goiânia, Brazil, they were directly affected by social distancing measures. Therefore, the goal of this study was to determine the environmental impacts of municipal solid waste management in the municipality of Goiânia, through life cycle assessment. For this purpose, quantitative data was requested to Companhia de Urbanização de Goiânia regarding waste collection (commingled and source-separated) and final disposal in the unlicensed landfill of Goiânia, between 2016 and 2020. To quantify the environmental impacts, six different scenarios were assessed with EASETECH, a specific life cycle assessment tool for waste, using 12 impact categories. Comparing the data of 2020 with 2019, commingled collection increased 2.2%, while source-separated collection decreased 7.6% than in 2019, mainly due to the changes in eating habits and lifestyle imposed by the pandemic. Concerning environmental impacts, the results indicated that scenario 2, which has the lowest of potentially recyclable waste diversions and relies on an unlicensed landfill, has presented the worst environmental result. Conversely, only by replacing the unlicensed landfill with a licensed one, reduces the environmental impacts between 68.5% and 75%. And when the amount of recycling was gradually increased in Scenario 6, the reduction in environmental impacts exceeded 84%.