[en] With the development of clean coal technology, modern coal-fired power plants have achieved the similar emission standards as gas power plants. However, due to the impressions of high pollution and high emission in traditional coal-fired power plants, such projects are often opposed by local residents, which hinder the promotion of this technology. This manuscript aims to investigate public attitudes toward these projects and to analyze the influencing mechanisms of the factors of public support. The conceptual model was built with sense of place, trust and environmental attitude as the independent variables, benefit and cost perceptions as the mediating variables and public support as the dependent variable. The model was tested and modified by structural equation modelling. The results revealed that sense of place had a slight indirect impact (−0.043) on public support through benefit perception, whereas trust had a direct impact (0.332) on public support and indirect impacts (0.298) through benefit and cost perceptions. Environmental attitude had indirect impacts on public support through benefit perception (0.180) and cost perception (−0.115). In addition, policy suggestions on decision-making, project publicity and compensation strategy are proposed to enhance public support for similar projects. - Highlights: • This manuscript aims at eliminating the NIMBY effects on modern coal-fired power plant project. • A SEM model is proposed to explore how potential factors affect public support. • Trust is the dominant influencing factor to improve public support with both direct and indirect impacts. • Environmental attitude can also have positive effect on public support through rational compensation plans.

[en] Highlights: • The pesticide tebuconazole (TEB) removal was investigated in different CW designs. • Unsaturated CWs had higher TEB removal than saturated CWs. • Plant uptake and biodegradation were the main removal pathway in both designs. • System design, plant presence and hydraulic loading rate affected TEB removal. • TEB removal was accurately modelled through an artificial neural network model. Constructed wetlands (CWs) are a promising technology to treat pesticide contaminated water, but its implementation is impeded by lack of data to optimize designs and operating factors. Unsaturated and saturated CW designs were used to compare the removal of triazole pesticide, tebuconazole, in unplanted mesocosms and mesocosms planted with five different plant species: Typha latifolia, Phragmites australis, Iris pseudacorus, Juncus effusus and Berula erecta. Tebuconazole removal efficiencies were significantly higher in unsaturated CWs than saturated CWs, showing for the first time the potential of unsaturated CWs to treat tebuconazole contaminated water. An artificial neural network model was demonstrated to provide more accurate predictions of tebuconazole removal than the traditional linear regression model. Also, tebuconazole removal could be fitted an area-based first order kinetics model in both CW designs. The removal rate constants were consistently higher in unsaturated CWs (range of 2.6–10.9 cm d⁻¹) than in saturated CWs (range of 1.7–7.9 cm d⁻¹) and higher in planted CWs (range of 3.1–10.9 cm d⁻¹) than in unplanted CWs (range of 1.7–2.6 cm d⁻¹) for both designs. The low levels of sorption of tebuconazole to the substrate (0.7–2.1%) and plant phytoaccumulation (2.5–12.1%) indicate that the major removal pathways were biodegradation and metabolization inside the plants after plant uptake. The main factors influencing tebuconazole removal in the studied systems were system design, hydraulic loading rate and plant presence. Moreover, tebuconazole removal was positively correlated to dissolved oxygen and all nutrients removal.

[en] Highlights: • Six common materials were tested for adsorption of organic micro-pollutants (OMPs). • The adsorption capacities of the tested materials were low. • OMP removal in material-packed columns was mainly attributed to biodegradation. • Materials shaped differently the water and biofilm microbial communities. Constructed wetlands (CWs) are an eco-friendly and cost-effective technology to remove organic micro-pollutants (OMPs) from wastewater. The support matrix is an important component in CWs as it has a primary role in the growth and development of plants and microbes. However, the roles of the support matrix in CWs in removing OMPs have not been systematically studied. Therefore, in this study, six common materials (sand, zeolite, blast iron slag, petcoke, polonite and crushed autoclaved aerated concrete (CAAC)) as support matrixes were firstly investigated by batch tests to explore their adsorption capacities to selected OMPs (ibuprofen, iohexol, tebuconazole and imazalil). Results showed that the adsorption capacities of the materials were low (at the level of μg/g) compared to well-known sorbents (at the level of mg/g), such as activated carbon and carbon nanotubes. Columns packed with the six materials, respectively, were then built up to study the effects of different materials on microbial community. In the medium-term study (66 days), the removal of four OMPs in all the columns increased by 2–58% from day 25 to day 66, and was mainly attributed to microbial degradation. Furthermore, Community-level physiological profiling (CLPP) analysis indicates that material presence shaped the microbial community metabolic function not only in the interstitial water but also in the biofilm. Overall, all the findings demonstrate that although the adsorption capacities of the common materials are low, they may be a driver to improve the removal of OMPs by altering microbial community function in CWs.

[en] Highlights: • Intensified CWs effectively treated alkaline ammonia-stripped digestate effluent. • Biological N transformation consumed the majority of alkalinity and decreased pH. • NH₃ volatilization accounts for less than 5% of the total NH₄⁺-N removal. • Biodegradation was the main N removal pathway indicated by N-isotopic assessment. • Anammox showed high potential for N removal when treating highly alkaline effluent. This study investigated the treatment performance and nitrogen removal mechanism of highly alkaline ammonia-stripped digestate effluent in horizontal subsurface flow constructed wetlands (CWs). A promising nitrogen removal performance (up to 91%) was observed in CWs coupled with intensified configurations, i.e., aeration and effluent recirculation. The results clearly supported that the higher aeration ratio and presence of effluent recirculation are important to improve the alkalinity and pollutant removal in CWs. The influent pH (>10) was significantly decreased to 8.2–8.8 under the volumetric hydraulic loading rates of 0.105 and 0.21 d⁻¹ in the CWs. Simultaneously, up to 91% of NH₄⁺-N removal was achieved under the operation of a higher aeration ratio and effluent recirculation. Biological nitrogen transformations accounted for 94% of the consumption of alkalinity in the CWs. The significant enrichment of δ¹⁵N-NH₄⁺ in the effluent (47–58‰) strongly supports the occurrence of microbial transformations for NH₄⁺-N removal. However, relatively lower enrichment factors of δ¹⁵N-NH₄⁺ (−1.8‰ to −11.6‰) compared to the values reported in previous studies reflected the inhibition effect of the high pH alkaline environment on nitrifiers in these CWs.

[en] The use of bioscrubber is attracting increasing attention for exhaust gas treatment in intensive pig farming. However, the challenge is to improve the methane (CH₄) removal efficiency as well as the possibility of pig house wastewater treatment. Three laboratory-scale bioscrubbers, each equipped with different recirculation water types, livestock wastewater (10-times-diluted pig house wastewater supernatant), a methanotroph growth medium (10-times-diluted), and tap water, were established to evaluate the performance of CH₄ removal and wastewater treatment. The results showed that enhanced CH₄ removal efficiency (25%) can be rapidly achieved with improved methanotrophic activity due to extra nutrient support from the wastewater. The majority of the CH₄ was removed in the middle to end part of the bioscrubbers, which indicated that CH₄ removal could be potentially optimised by extending the length of the reactor. Moreover, 52–86% of the ammonium (NH₄⁺-N), total organic carbon (TOC), and phosphate (PO₄³⁻-P) removal were simultaneously achieved with CH₄ removal in the present study. Based on these results, this study introduces a low-cost and simple-to-operate method to improve CH₄ removal and simultaneously treat pig farm wastewater in bioscrubbers.

[en] Highlights: • China VI heavy-duty moving average window (MAW) method was evaluated quantitatively. • The cold-start occupied 40.82 ± 11.83% of the total NOx within 5.77 ± 1.34% of the duration. • The MAW method weakens the real driving tests due to its ineffective NOx supervision. • The power threshold and 90th percentile window bring large uncertainty to the result. • The MAW boundaries are closely coupled and they should be reconsidered together. The heavy-duty moving average window (MAW) method, used for heavy-duty diesel vehicle (HDDV) real driving emission certification, has been long criticized for its unreasonable results. To quantitively analyze the problem, causes, and impacts of the MAW method, five China VI HDDVs were tested under real driving conditions. The specific method and MAW method with different boundaries are applied for data analysis. The results illustrate that cold start occupied 40.82 ± 11.22% of the total NOx emission within 5.77 ± 1.21% of the duration. Compared to the specific method, the MAW result gap is observed varying from −16.92% to 100.24% and didn’t show any pattern. Three reasons could explain biased MAW results: the 20% power threshold excludes the cold data; the 90th accumulative percentile window brings large uncertainty to the result and leaves the highest 10% window without supervision; the initial data gets low utilization. The MAW method could lead to ineffective NOx supervision and exhaust cheating. The future emission limits and emission inventories based on these results are also less reasonable. The above-discussed three reasons and the cold start data exclusion should be considered together to consummate the MAW method. These results could be used for future emission legislation and NOx control optimization.

[en] Highlights: • Oxygen nanobubble is a potentially promising technique to mitigate hypoxia/anoxia. • Oxygen nanobubble modified zeolite can effectively deliver oxygen to bottom water. • The oxygen-locking surface sediment layer is crucial in reducing sediment anoxia. • Oxygen-locking sediment layer can switch the anoxia sediment from P source to sink. Combating hypoxia/anoxia is an increasingly common need for restoring natural waters suffering from eutrophication. Oxygen nanobubble modified natural particles were investigated for mitigating hypoxia/anoxia at the sediment-water interface (SWI) in a simulated column experiment. By adding oxygen nanobubble modified zeolites (ONMZ) and local soils (ONMS), the oxygen nanobubble concentrations (10⁵–10⁷ particles/mL) were several orders of magnitude higher in the water than the original water solution (10⁴ particles/mL) within 24 h. In the column experiment, an oxygen-locking surface sediment layer was formed after capping with ONMZ and ONMS particles. The synergy of diffusion of oxygen nanobubbles and retention of oxygen in this layer contributes to both the increase of DO and reversal of hypoxic conditions. The overlying water had significantly higher dissolved oxygen (DO) values (4–7.5 mg/L) over the experimental period of 127 days in ONMZ and ONMS compared with the control systems (around 1 mg/L). Moreover, the oxidation-reduction potential (ORP) was reversed from −200 mV to 180–210 mV and maintained positive values for 89 days in ONMZ systems. In the control systems, ORP was consistently negative and decreased from −200 mV to −350 mV. The total phosphorus (TP) flux from sediment to water across the SWI was negative in the ONMZ and ONMS treated systems, but positive in the control system, indicating the sediment could be switched from TP source to sink. The oxygen-locking capping layer was crucial in preventing oxygen consumption caused by the reduced substances released from the anoxic sediment. The study outlines a potentially promising technology for mitigating sediment anoxia and controlling nutrient release from sediments, which could contribute significantly to addressing eutrophication and ecological restoration.

[en] Highlights: • Identification of amorphous elemental selenium in SO₂ bubbled simulated WFGD slurry. • Reveal of the reduction of selenite by SO₂ and the influences of reaction conditions. • The mutual inhibition of oxidation effect of S₂O₈²⁻ and the reduction effect of SO₂. Selenium is one of the hazardous trace elements emitted from coal-fired power plants. The distribution of selenium in Wet Flue Gas Desulfurization (WFGD) process is still unclear and even in controversial, impeding the development of selenium removal technologies. This research has found that the selenite in simulated slurry could be reduced by SO₂ while selenate has not been affected. Characterization methods including X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to provide an evidence that the product of the reduction reaction is amorphous elemental selenium. Meanwhile, the influences of other gaseous components, pH, temperature and S₂O₈²⁻ in simulated slurry has also been considered in this research. It is found that with the increase of SO₂ concentration in flue gas, the reduction of selenite increased and the reduction reaction is an exothermic reaction. Meanwhile, the oxidation effect of S₂O₈²⁻ competes with the reduction effect of SO₂. This study introduced the influence of flue gas into the research of the conversion of selenium in FGD slurry and indicate the effect of flue gas on the potential emission treatment techniques of selenium in FGD slurry.

[en] Highlights: • Model with particle radius and porosity changes for metal hydride tank is proposed. • Hydrogen absorption rates at different particle radii and porosities are studied. • Effect of volume expansion is coupled in mass, heat transfer and kinetics completely. • Simulation results of the models with and without volume expansion are compared. • Hydrogen absorption time is optimized from 1394.12 to 474.83 s without components. -- Abstract: Slow hydrogen absorption rate and low capacity of a metal hydride tank are the main bottlenecks restricting the practical applications of hydrogen energy. It is crucial to avoid of reducing system gravimetric/volumetric capacity by the additional components for enhancing the hydrogen absorption rate. In this work, we present a new method to increase the hydrogen absorption rate on the basis of the influence of particle radius and porosity to the performance of a LaNi₅ tank. A model considering the effects of volume expansion on mass, heat transfer and kinetics is proposed and solved by the finite element method, which constructs the relationship of the hydrogen absorption rate of a metal hydride tank with particle radius and porosity. The results indicate that larger particle radius and higher porosity is of benefit to the hydrogen absorption reaction. Compared with the model without volume expansion, a slightly slower hydrogen absorption rate is given by the model with volume expansion, which is attributed to the decreased thermal diffusivity. The simulation results obtained by the model with volume expansion agree well with the experimental data. The LaNi₅ tank is further optimized based on the model with volume expansion, from which the hydrogen absorption time at 90% of maximum hydrogen capacity can be reduced from 1394.12 to 474.83 s when the particle radius is 100 μm and porosity is 0.63.