This study mainly focuses on welfare impacts from improving considerably degraded river stretches of Heihe river basin and to determine the impact of spatial heterogeneity on willingness-to-pay (WTP) for integrated river basin management (IRBM). The significant WTP values for ecological attributes improvement revealed that the respondents of Heihe river basin significantly support the integrated ecological restoration program. However, socioeconomic characteristics and residential location have a significant impact on WTP values for different ecological attributes. The results demonstrate that water quality is the most preferred variable among all the river attributes in the study area. For example, in Zhangye, Gaotai, Ejinaqi, Minle, and Sunan the respondents were willing to pay 90.6, 160.44, 377.15, 65.40, and 139.21 Yuan per year, respectively, for a one-grade improvement in current water quality. Our findings also show that all the major counties of the basin concern more about water quality representing the relative importance of river water and express the maximum WTP for its improvement, while all major counties also share a low WTP for improvements in conditions of the leisure and entertainment. The differences in socioeconomic characteristics and ecological status of the respondents partially explain the disparity in utility from IRBM. In conclusion, the results based on only specific sub-basin of river basin may over or underestimate the welfare estimate.

The thickening performance of CO₂ fracturing fluid was poor because of the low apparent viscosity. In this paper, the thickening performance of a modified silicone on liquid CO₂ is measured, and a rheology was investigated according to the consistency coefficient K and rheological index n. Meanwhile, a reservoir model was established to evaluate the fracturing property. Results showed that the modified silicone contributes to improve the apparent viscosity of liquid CO₂ and decrease the rheology of liquid CO₂. With the thickener content or pressure increase, the apparent viscosity of liquid CO₂ increases, and the rheological index n decreased obviously. A reduced apparent viscosity is shown as the flow rate or temperature rises, but the rheology increased gradually. The fracturing simulation herein shows that thickened CO₂ fracturing fluid could improve obviously the fracture property. This modified thickener possesses the potential as a thickener and could be a reliable alternative to the thickener in CO₂ fracturing technology, and the large contact angle improved the backflow property of this CO₂ thickener from rock surfaces. The development of CO₂ fracturing technology provides basic data for the improvement of greenhouse effect and clean mining of energy.

A vegetable oil–fueled diesel engine operation is characterized by low brake thermal efficiency and relatively high smoke emission. Conversion of vegetable oil to biodiesel results in slight improvement in efficiency and smoke emission, but the values are not comparable with diesel. In this work, a single-cylinder diesel engine’s performance is evaluated by inducting hydrogen in small quantities in the intake manifold along with Deccan hemp oil (DHO) and its methyl ester (DHOME) as the pilot fuel. The tests were conducted at part-load and full-load conditions at an engine speed of 1500 rpm. Results indicate an increase in brake thermal efficiency from 29.7 to 32.6% and from 27.3 to 29.6% at full load with hydrogen-induced DHOME and DHO engine operation. Unburned-hydrocarbon emissions, carbon monoxide emission, and smoke emission reduced for both the fuels. However, NOx levels increased for the two fuels because hydrogen induction causes high combustion rates and high temperature in the combustion chamber. Hydrogen induction leads to high premixed combustion resulting in high peak pressures.

In many years, the nickel electroplating technique has been applied to coat nickel on other materials for their increased properties. Nickel electroplating has played a vital role in our modern society but also caused considerable environmental concerns due to the mass discharge of its wastewater (i.e. containing nickel and other heavy metals) to the environment. Thus, there is a growing need for treating nickel electroplating wastewater to protect the environment and, in tandem, recover nickel for beneficial use. This study explores a novel application of membrane distillation (MD) for the treatment of nickel electroplating wastewater for a dual purpose: facilitating the nickel recovery and obtaining fresh water. The experimental results demonstrate the technical capability of MD to pre-concentrate nickel in the wastewater (i.e. hence pave the way for subsequent nickel recovery via chemical precipitation or electrodeposition) and extract fresh water. At a low operating feed temperature of 60 °C, the MD process increased the nickel content in the wastewater by more than 100-fold from 0.31 to 33 g/L with only a 20% reduction in the process water flux and obtained pure fresh water. At such high concentration factors, the membrane surface was slightly fouled by inorganic precipitates; however, membrane pore wetting was not evident, confirmed by the purity of the obtained fresh water. The fouled membrane was effectively cleaned using a 3% HCl solution to restore its surface morphology. Finally, the preliminary thermal energy analysis of the combined MD–chemical precipitation/electrodeposition process reveals a considerable reduction in energy consumption of the nickel recovery process.

This study aims to investigate the dynamic relationship between renewable and non-renewable energies, CO₂ intensity and economic growth for the period of 1990–2016 using a case study of Myanmar. Autoregressive distributed lag, dynamic OLS, fully modified OLS and Gregory–Hansen co-integration are applied to analyse a time series dataset over the specified time period. The analysis shows that total energy use plays an insignificant role in promoting economic growth. However, decomposition analysis reveals that only renewable energy use significantly promotes, whereas non-renewable energy negatively influences, economic growth. Furthermore, non-renewable energy use is counterproductive in the presence of technological inefficiency, and the size of the overall labour force fosters economic growth. Overall results are robust under different estimation scenarios, including structural break, endogeneity and mixed order of integration. This study presents a new avenue of knowledge by investigating the role of decomposed energy use and technological efficiency in promoting economic growth in the context of Myanmar. Results emphasise the production and use of renewable energy to achieve sustainable economic development in Myanmar.

The purpose of the paper was to determine the factor of mercury emission into the atmosphere by households in Poland. Research for a home coal-fired boiler typical of Polish conditions was carried out, which was conducted throughout the heating season. On the basis of assessment of the quantity of coal burned and mercury content contained therein, as well as of the mercury content in bottom ash, chimney soot, boiler deposits and their quantities, annual mercury emissions and its factor of emission into the atmosphere were defined. It was defined that the mercury emission factor for the investigated case of a single-family house is at a level of 0.56 μg/MJ. It was shown that 41.4% of the mercury contained in coal burned in a home heating boiler is emitted into the atmosphere, 57.0% is adsorbed by chimney soot, 0.3% by boiler heater deposits and 1.3% passes into bottom ash. Annual mercury emissions into the atmosphere from the single-family house concerned was 79 mg. Mercury emissions can be significantly reduced by households by separating any overgrowths with pyrite from coal. The solution proposed would enable a reduction in annual mercury emissions into the atmosphere in Poland from the domestic user sector by 58.5% (0.351 Mg). The factor of emission of mercury into the atmosphere would be 0.23 μg/MJ.

The harbor sediment containing high concentration of heavy metals may pose serious impacts on the marine ecosystem and environmental quality. The bioleaching process has been considered as an environmentally friendly and cost-effective alternative for removing heavy metals from contaminated sediments. In this study, a series of experiments were performed to investigate the feasibility of bioleaching process for removing heavy metals from the contaminated harbor sediments. The performance of the bioleaching process inoculated with sulfur-oxidizing microflora acclimated from the native harbor sediment was compared with that acclimated from the exogenous soil. In the bioleaching experiment with inoculants from native sediment, the efficiency of Zn, Cu, Cr, Pb, and Ni (30 days) reached 39–100%, 21–94%, 8–63%, 5–74%, and 19–77%, respectively. While 59–100% of Zn, 22–100% of Cu, 0–95% of Cr, 0–100% of Pb, and 22–100% of Ni were respectively removed in the bioleaching experiment with inoculants from exogenous soil after 30 days of reaction time. The results show that the rate and efficiency of metal removal in the bioleaching process decreased with an increase of sediment solid content from 10 to 40 g/L. The efficiency of metal removal in the bioleaching process with inoculants from the native sediment was lower than those from the exogenous soil due to the bacterial activity. By the fractionation of metal in the harbor sediment, exchangeable, carbonate-bound, and Fe/Mn oxide-bound metals (mobile fractions) were found to be apparently reduced and even organic matter/sulfide-bound and residual metals (stable fractions) were slightly removed after the bioleaching experiment.

With decades of high-speed economic miracle, China inevitably encountered with environmental pressure and sustainable development problem. As the main carrier of the environmental responsibility, Chinese government set series of regulations and standards to supervise and guide enterprise to fulfill this challenge emission reduction task. Based on data envelopment analysis (DEA) approach, this paper focuses on air pollutant highly emission manufacturing tycoons to figure out “whether the yearly billions environmental input really worth it?” during 2014 to 2016. Unlike previous studies mainly from consumption perspective and got macro-regional evidence, we choose micro-enterprise to analyze individual environmental performance and draw general conclusions. Possible suggestions are also proposed for various industries and some salient enterprises.

The treatment of airport sewage has posed many novel challenges because of its huge impact on the surrounding environment. This paper proposes a multi-objective decision model to optimize the scale design and process selection of sewage treatment plants in airports. In this model, we consider the conflict among the process cost, environmental protection, and benefits of recycled water. In addition, the uncertainty in influent concentration and passenger throughput is also incorporated. Airport sewage treatment has its own unique features, such as the concentration of airport sewage is higher than that of ordinary urban sewage, the change in passenger throughput impacts the volume of the airport sewage treatment, and the utilization rate of the entire sewage treatment plant must be higher than or equal to 70%. Only in this case can the airport sewage treatment plant pass the acceptance test. The Tianfu International Airport, the largest civil transportation hub airport project in southwestern China, is used to prove the efficiency of the proposed model. Finally, some significant insights are suggested for the design of wastewater treatment plants in airports.

Renewable resources are playing a key role on the synthesis of biodegradable polyols. Moreover, the incorporation of covalently linked additives is increasing in importance in the polyurethane (PU) market. In this work, previously epoxidized grape seed oil and methyl oleate were transformed into phosphorylated biopolyols through an acid-catalyzed ring-opening hydrolysis in the presence of H₃PO₄. The formation of phosphate polyesters was confirmed by FT-IR and ³¹P-NMR. However, the synthesis of a high-quality PU rigid foam was not possible using exclusively these polyols attending to their low hydroxyl value. In that way, different rigid PU foams were prepared from the phosphorylated biopolyols and the commercial polyol Alcupol R4520. It was observed that phosphorylated biopolyols can be incorporated up to a 57 wt.% in the PU synthesis without significant structural changes with respect to the commercial foam. Finally, thermogravimetric and EDAX analyses revealed an improvement of thermal stability by the formation of a protective phosphorocarbonaceous char layer.