Climate change seriously affects habitat suitability for coldwater fish. Amur whitefish (Coregonus ussuriensis) is a commercially important coldwater fish species found in northeast China that is particularly sensitive to water temperature. We use water temperature models for Songhua (Harbin to Yilan) and Mayi rivers to predict habitat suitability for Amur whitefish and other coldwater fish species during the months of July and August in 2014 and 2100—2 months during which river temperatures can reach extremes. The predict-results showed that fish habitat was to deteriorate over time, and to be less suitable for survival of coldwater fish species in 2100 than that in 2014. Under scenario RCP4.5 (Representative Concentration Pathway 4.5), the time period during which habitat for Amur whitefish was unsuitable increased continually; under scenario RCP8.5 (Representative Concentration Pathway 8.5), Amur whitefish might even disappear from the river basin. A significant increase in river water temperature will compromise coldwater fish survival and possibly lead to their disappearance. Practical measures to control greenhouse gas emissions and reduce the impact of global warming on aquatic ecosystems must be taken.

High retention membrane bioreactors (HR-MBR) combine a high retention membrane separation process such as membrane distillation, forward osmosis, or nanofiltration with a conventional activated sludge (CAS) process. Depending on the physicochemical properties of the trace organic contaminants (TrOCs) as well as the selected high retention membrane process, HR-MBR can achieve effective removal (80–99%) of a broad spectrum of TrOCs. An in-depth assessment of the available literature on HR-MBR performance suggests that compared to CAS and conventional MBRs (using micro- or ultra-filtration membrane), aqueous phase removal of TrOCs in HR-MBR is significantly better. Conceptually, longer retention time may significantly improve TrOC biodegradation, but there are insufficient data in the literature to evaluate the extent of TrOC biodegradation improvement by HR-MBR. The accumulation of hardly biodegradable TrOCs within the bioreactor of an HR-MBR system may complicate further treatment and beneficial reuse of sludge. In addition to TrOCs, accumulation of salts gradually increases the salinity in bioreactor and can adversely affect microbial activities. Strategies to mitigate these limitations are discussed. A qualitative framework is proposed to predict the contribution of the different key mechanisms of TrOC removal (i.e., membrane retention, biodegradation, and sorption) in HR-MBR.

Eggshell ash was used as an adsorbent to remove phosphorus from wastewater. Adsorbent dose, initial phosphorus concentration, and contact time were investigated to determine the optimum conditions. Results indicate that 5 g of eggshell ash adsorbent with 1.5 mg L⁻¹ of initial phosphorus concentration removed over 90% of the phosphorus. When the temperature was increased, phosphorus removal potential also increased. Specific surface area, morphological features, and structure of the adsorbent were characterized by Brunauer-Emmett-Teller (BET) surface area analysis, scanning electron microscopy with energy dispersive X-ray spectrometer (SEM-EDS), and X-ray diffraction (XRD). Results showed prominent calcium, magnesium, and phosphorus in the eggshell ash surface after adsorption. The elemental composition of eggshell ash surfaces before adsorption did not contain phosphorus, revealing that calcium carbonate-based eggshell ash was co-precipitated with calcium phosphate. The adsorption mechanism was studied by applying Langmuir and Freundlich isotherm models. Experimental data fit well with the Langmuir model, which indicates monolayer adsorption. Eggshell ash was also applied as an adsorbent in wastewater at Srinakharinwirot University dormitories, resulting in 80% phosphorus removal within 2 h. These findings indicated that eggshell ash could be applied as an adsorbent for phosphorus treatment and removal from domestic and industrial wastewater.

In this work, two recyclable phosphotungstic acid salts/reduced graphene oxides were successfully prepared. The prepared samples were characterized by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), thermo-gravimetric analysis (TGA), Raman spectroscopy, and photoluminescence spectroscopy (PL). The structure and catalytic performance of two composites were comparatively investigated, and the reduced graphene oxide mass ratios in K₃[PW₁₂O₄₀]/reduced graphene oxide (denoted as KPW-RGO) and (NH₄)₃[PW₁₂O₄₀]/reduced graphene oxide (denoted as NH₄PW-RGO) were optimized and their roles in them were explored. The results indicate that the Keggin structures of KPW and NH₄PW are still kept after being anchored on the RGO surface, but their morphologies change a lot in composites. The photocatalytic activities of KPW-3RGO (0.01989 min⁻¹) are 5.42 times than that of KPW (0.00367 min⁻¹), and NH₄PW-1RGO (0.0184 min⁻¹) is 2.26 times than that of NH₄PW (0.00814 min⁻¹). The enhanced photocatalytic activity is mainly ascribed to photo-induced interfacial charge transfer on the heterojunction between RGO and NH₄PW or KPW and strong adsorption ability of RGO towards MO. Moreover, NH₄PW-1RGO and KPW-3RGO had much better photocatalytic activity, good recyclable ability, and stability compared to HPW-RGO, which cannot be recycled.

Uncertainty in future availability of irrigation water and regulation of nutrient amount, management strategies for irrigation and nitrogen (N) are essential to maximize the crop productivity. To study the response of irrigation and N on water productivity and economic return of maize (Zea mays L.) grain yield, an experiment was conducted at Water Management Research Center, University of Agriculture Faisalabad, Pakistan in 2015 and 2016. Treatments included of full and three reduced levels of irrigation, with four rates of N fertilization. An empirical model was developed using observed grain yield for irrigation and N levels. Results from model and economic analysis showed that the N rates of 235, 229, 233, and 210 kg ha⁻¹ were the most economical optimum N rates to achieve the economic yield of 9321, 8937, 5748, and 3493 kg ha⁻¹ at 100%, 80%, 60%, and 40% irrigation levels, respectively. Economic optimum N rates were further explored to find out the optimum level of irrigation as a function of the total water applied using a quadratic equation. The results showed that 520 mm is the optimum level of irrigation for the entire growing season in 2015 and 2016. Results also revealed that yield is not significantly affected by reducing the irrigation from full irrigation to 80% of full irrigation. It is concluded from the study that the relationship between irrigation and N can be used for efficient management of irrigation and N and to reduce the losses of N to avoid the economic loss and environmental hazards. The empirical equation can help farmers to optimize irrigation and N to obtain maximum economic return in semi-arid regions with sandy loam soils.

The rice husk ash (RHA) was used as an alternative source of silica for the synthesis of the functionalized mesoporous material, which was used in the removal of the PAHs naphthalene (Nap), benzo[b]fluoranthene (B[b]F), benzo[k]fluoranthene (B[k]F), and benzo[a]pyrene (B[a]P) from aqueous media. The PABA-MCM-41 (RHA) was characterized using FTIR, TGA, SAXS, and N₂ adsorption–desorption analyses. Removal experiments were performed to determine the initial concentrations, individual adsorption in comparison with the mixture of the PAHs, PABA-MCM-41 (RHA) amount, pH, time, and temperature, and the results obtained were statistically analyzed. The PABA-MCM-41 (RHA) presented the SBET, VT, and DBJH values of 438 m² g⁻¹, 0.41 cm³ g⁻¹, and 3.59 nm, respectively, and good thermal stability. The qₑ values found in the kinetic equilibrium for the PAHs mixture followed increasing order: Nap < B[a] P < B[k]F < B[b]F, with removal percentages of 89.08 ± 0.00, 93.85 ± 0.28, 94.54 ± 0.10, and 97.80 ± 0.05%, respectively. Graphical abstract

Better cotton is introduced with the aim of a reduction in the use of environmentally detrimental farm inputs in order to attain sustainable cotton production. The present study is designed to assess the environmental and economic effects of better cotton in Pakistan using panel data comprising of two cropping seasons, 2015 and 2016. Panel methods were used in the present study. Findings show that better cotton increases the gross margin by 37% and yield by 9%, whereas it results in decreasing seed rate by 6%, fertilizers by 7%, pesticides by 7%, and irrigation by 14%. Since better cotton involves more labor use due to higher yield, labor increases by 3%. The study concludes that better cotton is more economically and environmentally sustainable than conventional cotton. The study suggests that public private partnership will be a good strategy to diffuse better cotton technologies among the farming communities.

A growing body of research has investigated the vital effects of urban greening. However, the green space on campus, also recognized as an important element of urban greening and providing many benefits to college students, has gained very limited attention. In developing China, after nearly 20 years of campus construction climax, the speed of expansion has dropped significantly and the focus of a sustainable and optimized green campus has emerged. Improving the accessibility, availability, and attractiveness is a control determining if the green spaces can realize their values. Therefore, this study, taking a case, aims to explore and better understand students’ usage conditions, perceptions, and demands about campus green spaces. On Yijin campus in Hangzhou, China, through the questionnaire among 590 students, and accessibility analysis based on Space syntax theory, we have revealed that the negative usage condition of green spaces: most students rarely or occasionally visit the green space, and the visit time is concentrated in the afternoon and after class but rarely in the morning. Besides, students’ gender and growth surroundings have little influence on the perception of campus green space, but the plant configuration, seasonal color richness, and facilities required at different spaces will affect. In addition, the ranking of accessibility analyzed by Space syntax theory is similar to campus convenience considered by students. In the conclusions, suggestions are made about how to fulfill students’ requirements and improve the attractiveness and accessibility of campus green spaces so that they may inform to the growth of emerging colleges and universities in other cities and countries undergoing campus construction climax.

Most sulfonamides, widely used around the world, are excreted via feces and urine along with their metabolites in humans and animals. Therefore, understanding the potential removal pathway of sulfonamides and their metabolites in wastewater treatment systems is of importance. The occurrence and fate of four sulfonamides and their acetyl metabolites in wastewater and sludge in a biological aerated filter in Xiamen city were evaluated. Six of the target compounds were detected in wastewater, but only parent compounds were detected in sludge. The highest concentration in wastewater was acetyl-sulfamethoxazole (Ac-SMZ) with a concentration of 75.2 ng/L. Removal efficiency and mass load in wastewater treatment systems were calculated. In terms of the overall removal efficiency, they ranged from 24.4 to 100%. The removal efficiencies of sulfamerazine (SM1), sulfamethazine (SM2), and sulfadiazine (SD) were up to 100% while N-acetyl sulfamerazine (Ac-SM1) showed the lowest removal efficiency. Biodegradation was the dominant remove pathway according to the mass balance analysis while SD and SM2 were sludge adsorption. The results can provide an insight into the fate of target sulfonamides in BAF systems and provide data to assess their potential ecological risks.