The reduction of wet desulfurization wastewater is one of the important tasks of coal-fired power plants, and it is important for achieving “zero emissions.” Evaporation and concentration (E&C) with waste heat is an effective way to reduce wastewater. Here, two typical types of industrial desulfurization wastewater are used to study the change rule of pH and total dissolved solids during wastewater concentration in a circulating evaporation tower. The results indicate that with the increase of concentration ratio, the pH of desulfurization wastewater is decreased rapidly and then is gradually stabilized at 2–3 when SO₂ or SO₃ is contained in flue gas, and the increase in conductivity is less for wastewater with higher SO₄²⁻ content. The characteristics of various ions are also analyzed, and the composition and microscopic morphology of the precipitates are characterized during concentration. The growth pattern of Ca²⁺ concentration is dependent on the ratio of Ca²⁺ and SO₄²⁻ in raw wastewater. When the concentration ratio is 7.21, the insoluble and slightly soluble substances undergo precipitation and the solid content is approximately 20%, which can help realize the concentration and reduction of desulfurization wastewater.

With the adding of tourist volume in China, carbon emissions from hotel sector increased greatly. Environmental efficiency of hotel sector considering technology heterogeneity is mainly analyzed across different regions of China from 2000 to 2013. Metafrontier global Malmquist-Luenberger (ML) is implemented to evaluate environmental efficiency of hotel sector. Furthermore, we analyze whether technology heterogeneity of different regions increased or not through technological gap ratio. The empirical analysis revealed that the east had the highest environmental efficiency under metafrontier after 2009. After 2009, technological gap ratio (TGR) in the east ranked highest among four regions in China. Environmental regulation positively impacts environmental efficiency under group frontier of hotel sector in the model of nation, east, and middle. Urbanization has U-shaped link with environmental efficiency of hotel sector for the east. It is important to strengthen environmental regulation to reduce carbon emissions. Last, it is important to enhance consciousness of energy abating and carbon emissions reduction of hotel customers.

The aim of this study was to investigate the impact of incorporating Walnut leaves (WL) and their biochars produced at three temperatures (200, 400, and 600 °C) on fractionation, availability and maize indices in a naturally calcareous highly contaminated soil of Central Iran. A pot experiment was conducted considering soils treated with 0, 0.5, 1, and 2% (w/w) of WL and their derived biochars. After maize (Zea mays L.) planting, shoot and root dry matter and Pb and Zn concentration in shoots and roots and DTPA-extractable and fractions of Zn and Pb in soils were determined. Results showed showed that biochar amendments substantially modified the partitioning of Zn and Pb from easily available forms to less available forms. The results showed that DTPA-extractable of Zn and Pb and their bioaccumulation were reduced upon the addition of biochars produced at different temperatures and application rates in a calcareous soil. Treating soil with 2% biochar produced at 600 °C increased significantly shoot and root dry matter by 131.4% and 116.7%, respectively and reduced the bioavailability of Zn and Pb (DTPA-TEA extraction) by 49.1%, and 34.9%, respectively (P < 0.05) in comparison to the control. Therefore, biochars were able to reduce metals contamination in treatments and increase maize dry matter. Biochar decreased Zn and Pb concentration in plant tissues and promoted gradual maize growth responses through changing metals fractions. Therefore, biochar as a sorbent for contaminants can assist in maize to mitigate and phytostabilize Zn and Pb in highly contaminated soils.

Excessively high concentration of inorganic salts in the groundwater is the main threat for residents to drink directly in the remote areas of northwestern China. In this paper, nano-porous membrane process was proposed to removal of diverse ions in such raw water. Through the response surface methodology (RSM), the effects of multiple factors on permeate flux and ion rejection rates were analysed, and the application scope of nanofiltration for various water resource was evaluated. It was found that the factors affecting permeate flux, chloride removal and nitrate removal (response value) followed some typical sequences, and the operating pressure was always the most influential factor. Besides, nanoporous membrane process showed predominant performance in the removal of sulphate, chloride and fluoride; the rejection rates were over 99%, 97% and 95%, respectively, and the produced water could completely satisfy the relevant national standards for drinking water. However, nitrate removal rate was seldom over 80%, and it reduced obviously with the increasing initial concentration of nitrate, thus the nitrate content of raw water should be controlled within 40 mg.L-1.

Use of the high-rate vermicomposting system and its relevant technology were successfully applied to accomplish direct vermicomposting of coral vine leaves - devoid of any pre-treatment/composting or amended with cow dung as earlier proclaimed protocols for the vermicomposting of various phytomass had necessitated. Three earthworm species tested were Eisenia fetida, Eudrilus eugeniae and Perionyx excavatus, and they had shown efficient vermicast recovery with few instances of mortality and good reproduction over the 150-day experiment. In this duration, all vermireactors were run in semi-continuous mode at the solid retention time of 15 days. This process enabled us to improve process efficacy of the reactor by the required pointers and systematic process monitoring. This paper substantiates the potential of the high-rate vermicomposting system in direct and potential vermicomposting of coral vine without any pre-treatment/composting or cow dung amendments. The observations have significance for enhancing process economics and therefore, process utility.

Despite its small share of 0.15% in the global market, the oil palm production in the Philippines is being contested with environmental issues on continued deforestation, increased emissions from illegal burning of trees, and the marginalization of indigenous communities. As a developing industry, there is a need to further conduct of social and environmental impact studies to gain more acceptance, thereby, pursue growth and expansion. In view of the environmental concerns, this study aimed to conduct a life cycle assessment of the crude oil palm with North Cotabato, Philippines as the case study. Using cradle to gate approach, the potential environmental impacts were established: non-renewable energy of 0.394 MJ/kg oil, carbon footprint of 1.150 kgCO2/kg oil, ozone creation potential of 2.429×10-3 kg NOx /kg oil, acidification potential of 0.0138×10-3 kg SO2 /kg oil and water footprint of 5,797.3 L/kg oil. Compared to six locations in Indonesia, Malaysia and Thailand, the environmental impacts and performance of the oil palm production in North Cotabato were satisfactory given the same topographical conditions. Opportunities to mitigate and decrease the impacts were also identified, namely improving oil extraction rates; increasing ratio of shell as biomass fuel; prudent application of nitrogen fertilizers and optimizing delivery loads and schedules. The results of this study can be a reference for future environmental assessments in other locations.

Chlorpyrifos is one of the toxic organophosphate insecticides that is often used by farmers in West Sumatra Province. This research was conducted with the aim to analyse the level of consumption, conversion ratio, and growth rate in fish cultivated in the twin lakes of West Sumatra. The concentration variations are 1/7 and 1/14 LC50-96h of chlorpyrifos. The study was conducted for 14 days. Research data analysis found the values of R = 0.75-1 for the relationship of oxygen level, conversion ratio, and growth of tilapia to the duration of exposure which means having a strong correlation. The results obtained were due to chlorpyrifos insecticide exposure on day 1 to day 14. At a concentration of 0.0054 mg/L, there was a decrease in the level of oxygen consumption of 0.0159 mgO2 /L, an increase in feed conversion ratio of 0.8253, and the deviation flow of 2.7048%. Whereas at a concentration of 0.0108 mg/L, there was a decrease in the oxygen level of 0.0213 mgO2 /L, increase in feed conversion ratio of 0.8201, and deviation growth by 2.7048%.

The estimation of carbon sequestration in forest ecosystem is necessary to plan for mitigating the impacts of climate change. The present study was conducted in the Cedrus deodara (CD) forests of Mandi district in Himachal Pradesh to estimate the biomass and soil organic carbon stock at various sites of the study area. Overall, 18 plots of 0.1 ha were laid at six sites randomly in the year 2014-15. In CD forest, the mean stem density was 354 trees/ha and the mean basal area and mean volume were 62.28 m2/ha and 719.71 m3/ha respectively. The mean carbon stock for tree aboveground, tree belowground, understorey and litter were 189.93 ton/ha, 37.99 ton/ha, 1.71 ton/ha and 0.72 ton/ha respectively. The soil organic carbon percentages varied from 1.98-2.83%, 1.72-2.11% and 1.56-1.74% at soil depth of 0-15cm, 15-30cm and 30-45cm respectively, and the soil organic carbon stocks ranged from 24.41-32.22 ton/ha, 21.59-29.03 ton/ha and 19.17-26.78 ton/ha at soil depths of 0-15cm, 15-30cm and 30-45cm respectively. The total mean soil organic carbon (SOC) stock up to a depth of 0-45cm was found to be 76.16 ton/ha. The organic carbon percentage showed a decreasing trend with increasing soil depth.