Anaerobic bioconversion of methanol was tested in the presence of selenate (SeO₄²⁻), thiosulfate (S₂O₃²⁻), and sulfate (SO₄²⁻) as electron acceptors. Complete SeO₄²⁻ reduction occurred at COD:SeO₄²⁻ ratios of 12 and 30, whereas ~ 83% reduction occurred when the COD:SeO₄²⁻ ratio was 6. Methane production did not occur at the three COD:SeO₄²⁻ ratios investigated. Up to 10.1 and 30.9% of S₂O₃²⁻ disproportionated to SO₄²⁻ at COD:S₂O₃²⁻ ratios of 1.2 and 2.25, respectively, and > 99% reduction was observed at both ratios. The presence of S₂O₃²⁻ lowered the methane production by 73.1% at a COD:S₂O₃²⁻ ratio of 1.2 compared to the control (no S₂O₃²⁻). This study showed that biogas production was not preferable for SeO₄²⁻ and S₂O₃²⁻-rich effluents and volatile fatty acid production could be a potential resource recovery option.

The surface of the earth is rapidly changing every day due to certain natural reasons and other impacts by society. Over the last few decades, the hottest topics in the field of remote sensing and GIS (geographic information system) environments have evolved from observing the nature of the earth. Owing to the enlargement of several worldwide modifications related to the nature of the earth, land use/land cover (LU/LC) change is considered as the matter of utmost importance in the natural atmosphere, and it has also become an interesting area to be studied by the researchers. As there is a lack of review articles in the land use/land cover change analysis process, we presented a comprehensive review which may help the researchers to proceed further. This paper deals with the most frequent methods used by researchers on various processes like pre-processing, classification, and prediction of time series satellite images for analyzing the LU/LC changes using satellite images. The generic flow of the LU/LC change analysis process and the challenges faced during each process by the researchers are discussed. Varied resolutions of the environmental image captured by remote sensing satellites for analyzing the LU/LC changes are discussed. Various LU/LC classes depending on change in the earth’s surface are also studied and the constraint used in each application is stated. The importance of this review lies in the motivation for future researchers to work on the LU/LC change analysis problem effectively.

The study aims to address the dynamic common correlated effects of trade openness, FDI, and institutional performance on environmental quality in OIC countries. Mostly, pollutants like CO₂ and SO₂ emissions are considered as the environmental indicators. However, for this study, we have selected ecological footprint as the indicator of environmental quality. The new econometric approach Dynamic Common Correlated Effects (DCCE) by Chudik and Pesaran (2015) has been used to measure the cross-sectional dependence among cross-sectional units. Results confirm that previous techniques for long panel data, like MG and PMG, give ambiguous outcomes in the presence of cross-sectional dependence. According to DCCE estimation, trade openness, FDI, and urbanization have a positive and significant relationship with ecological footprint while a significant and negative association is found between institutional performance and ecological footprint. The OIC countries must encourage green technology, clean production, and improved institutions for sustainable development and better environmental quality.

Extensive construction of dams by humans has caused alterations in flow regimes and concomitant alterations in river ecosystems. Even so, bacterioplankton diversity in large rivers influenced by cascade dams has been largely ignored. In this study, bacterial community diversity and profiles of seven cascade dams along the720 km of the Lancang River were studied using Illumina sequencing of the V3-V4 hypervariable region of the 16S rRNA gene. Spatiotemporal variations of bacterial communities in sediment and water of the Gongguoqiao hydroelectric dam and factors affecting these variations were also examined. Microbial diversity and richness in surface water increased slightly from upstream toward downstream along the river. A significant positive correlation between spatial distance and dissimilarities in bacterial community structure was confirmed (Mantel test, r = 0.4826, p = 0.001). At the Gongguoqiao hydroelectric dam, temporal differences in water overwhelmed spatial variability in bacterial communities. Temperature, precipitation, and nutrient levels were major drivers of seasonal microbial changes. Most functional groups associated with carbon cycling in sediment samples decreased from winter to summer. Our findings improve our understanding of associations, compositions, and predicted functional profiles of microbial communities in a large riverine ecosystem influenced by multiple cascade dams.

This study investigates techno-economic aspects of wastepaper recycling to optimize process efficiency and operating cost. The deinking was carried out using pulping followed by froth flotation. The development of a waste management process was achieved employing refinery wastewater to provide chemical reagents in pulping. Ozone was also used as a gas media in flotation to improve brightness and number of ink-spot and to reduce chemical oxygen demand (COD) simultaneously. An enhancement in the brightness was observed from 50.1 to 64.1% ISO that was superior to the brightness of virgin newspaper before printing (61.0% ISO). It was equivalent to a reduction of 55% (from > 100,000 to 45,058) in number of ink-spot. The quality of flotation effluent was assessed by measuring the COD and phthalocyanine concentration. The COD reduction of 67% (from 3250 to 1072 mg/L) and phthalocyanine reduction of 85% (from 2 to 0.3 mg/L) were achieved after 30 min ozonation. According to the obtained results, approximately 67% of the direct (variable) cost reduced while the wastewater was used in pulping because of saving NaOH and water consumption. Associating the refinery and paper recycling wastewater treatment units, while taking into account the environmental and economic benefits of ozone, results in a quality paper and significantly preserves the environment.

It is a debated issue that the influence of information and communications technologies (ICTs) on the environment is positive or negative in the literature. For instance, usage and disposal of ICTs may lead to environmental degradation and it may also increase carbon emission arising from electricity generation. However, ICT applications may contribute to environmental quality creating great opportunities for smarter cities, transport systems, electrical grids, and industrial processes. These two effects reveal the possible relationship of an inverted U-shaped association also known as the environmental Kuznets curve (EKC) hypothesis relationship between ICT and CO₂. The objective of this study is to determine the structure of the relationship between environmental degradation and ICTs in Turkey for 1980–2017. The findings of the autoregressive distributed lag (ARDL) analysis indicate the validity of inverted N-shaped EKC hypothesis. However, the results of the quantile regression test are inconsistent with those of ARDL. When the coefficients from 30th to 95th quantiles are examined, it is observed that there is an inverted N-shaped relationship between ICT and CO₂, but these coefficients are not statistically significant. In addition, in the 95th quantile, coefficients of the square of ICT and ICT are statistically significant, contrary to the cube of ICT which is not. This reveals that the relationship between the variables is U-shaped.

The present study aims at a detailed experimental study of a passive-type solar air heater (SAH) on the effect of coating the absorber plate with higher thermal conductive black paint under forced circulation method and studied under the climatic conditions of Chennai. Furthermore, to enhance the thermal performance index of conventional SAH, additional enhancement such as coating and staggered fins are fixed to the absorber plate of duct which simultaneously increases the turbulent intensity, kinetic energy to enhance the temperature of outlet air. Comparisons are made with a solar air heater without coating and staggered fin in order to assess the thermal performance. Experiments were conducted on a continuous basis and the flow rates of air flowing through the duct are varied. Experimental results revealed that the effect of coating improved the plate temperature to a maximum of 102 °C while the modified SAH coated with ordinary black paint and staggered fin arrangement is found as 95 °C for the flow rate of mf = 0.03 kg/s. The difference in temperature between exit and inlet of conventional SAH with coating alone is found as 13.09 °C at a flow rate of mf = 0.03 kg/s whereas the average thermal efficiency is found as 22.3%. Similarly, increasing the mass flow rate from 0.13 to 0.22 kg/s has no significant improvement in average daily thermal efficiency, whereas the temperature difference decreases. The coating of absorber plate with higher thermal conductivity paint and increased turbulence created between the duct by using staggered fin improved the temperature of exit air by 63, 64, 38 and 35% for air flow rates of 0.03, 0.04, 0.13 and 0.22 kg/s respectively. On a flat absorber with coating, the average increase in temperature is found at 6.3% compared to that of SAH coated with ordinary black paint. The hourly thermal efficiency of the conventional type SAH with coating exhibited an enhancement of about 5% in thermal efficiency as compared to that of conventional type with black paint coating alone for the same climatic condition, whereas the thermal efficiency of staggered fin SAH with coating alone is enhanced by 7.5%. With staggered fin arrangement in the absorber plate, heat absorption by the air is increased with CNT-coated absorber and excessive turbulence produced by the fins enhanced the average temperature difference from 13.5 to 20.3 °C. The cost per unit kW of conventional type SAH with CNT-doped black paint reduced from 0.01754 $ to 0.00832 $/kW while varying the flow rate from 0.031 to 0.22 kg/s.

This study presents a detailed mathematical model of the pyramid solar still which is not performed in most of the previous studies. Computer programs (in Pascal language) are developed for both studying thermal performance of the square pyramid solar still and estimating the hourly variations of the solar intensity incident on the tilted still’s covers. Comparisons between the obtained theoretical results and experimental results (from previous work) are performed to validate the proposed mathematical model. The daily productivity of the pyramid solar still (Pd) varies from 4.22 to 4.43 kg/m² day with values of the glass cover’s tilt angle of 10°–60°. Pd decreases from 3.88 to 1.52 kg/m² day with increasing the depth of the still’s water (dw) from 0.01 to 0.30 m. Values of the top losses of the still decrease from 8.8064 to 8.2304 W/m² K with increasing glass cover surface area from 0.063 to 0.125 m², which correspond to values of tilt angles of the still covers changing from 10° to 60°, respectively.

The catalytic performance of Fe supported on nickel phosphate (NiP) was evaluated for the removal of bisphenol A (BPA) by catalytic wet air oxidation (CWAO) at 140 °C and 25 bar of pure oxygen pressure. The prepared NiP and Fe/NiP materials were fully characterized by XRD, N₂-physisorption, H₂-TPR, TEM, and ICP analysis. Iron (Fe/NiP) impregnation of NiP support enhanced the BPA removal efficiency from 37.0 to 99.6% when CWAO was performed. This catalyst was highly stable given the operating conditions of acidic medium, high temperature, and high pressure. The Fe/NiP catalyst showed an outstanding catalytic activity for oxidation of BPA, achieving almost complete removal of BPA in 180 min at a concentration of 300 mg/L, using 4 g/L of Fe/NiP. No iron leaching was detected after the CWAO of BPA. The stability of Fe/NiP was performed over three consecutive cycles, noting that BPA conversion was not affected and iron leaching was negligible. Therefore, this catalyst (Fe/NiP) could be considered as an innocuous and effective long-lasting catalyst for the oxidation of harmful organic molecules.

The petrol station location selection problem is taken into consideration in this study. In order to identify the main and sub-criteria for evaluation, the literature is reviewed and five experts from different companies are interviewed. After that, thirteen different alternative locations are for specified to evaluation. Then, the novel spherical fuzzy AHP-integrated spherical WASPAS methodology is structured in a fuzzy environment, and the petrol station location selection problem is evaluated with this methodology. In this study, a real application is presented for Istanbul to show the applicability of the proposed methodology. Subsequently, a sensitivity analysis is performed to explain and analyze the proposed methodology results. Finally, the results are presented and discussed with future directions.