The main problem in the reduction of river bottom sediments is to solve the dewatering of the sludge. The commonly used natural air drying method requires a large amount of time and economic cost. In this paper, different treatments were developed for the needs of the project, and related tests were carried out on the reduction of the sludge. Firstly, two or more flocculants were compounded according to the nature of the sludge. The 6 different treatments were determined according to the sedimentation and the turbidity value of the supernatant. Secondly, the dewatering test was carried out on river sediments after flocculation-vacuum preloading. The dewatering effect of different flocculants, water quality, dissipation of pore water pressure, vane shear strength, compression coefficient, and coefficient of consolidation have been analyzed after flocculation-vacuum preloading. The polysilicate aluminium ferric (PSAF) can greatly increase the dewatering efficiency of the filter press membrane, and the final dewatering amount could reach 310 g. The effect of purifying water quality was PSAF>PAM (polyacrylamide, PAM-1(18 million): PAM-2(23 million) = 3:7)>PAC (polyaluminium chloride). The PSAF and PAC could increase the pH of the water during the vacuum preloading test. The PAM has the best the vane shear strength. Lime could improve the vacuum preloading and the vane shear strength when it was added to other flocculants. The incorporation of PSAF could accelerate the dissipation and increase the final dissipation value of pores water pressure. Compared with PAM+PAC+lime, PAM+lime, PAM+PSAF+lime, PAM+PSAF, and PAM+PAC, the overall effect and price of the PAM is optimal.

Strict environmental laws have been put in place around the world to reduce the amount of sulfur in the fuel to reduce the emissions of harmful gases from fuel combustion and improve air quality. Therefore, extensive researches have been undertaken to devise effective processes or to improve the desulfurization processes. Among the desulfurization processes, the oxidative desulfurization (ODS) process is a promising method to achieve very low and near-zero sulfur content of the fuel. In this process, sulfur compounds are converted to the corresponding sulfone by a catalyst and in the presence of an oxidant. The obtained compounds by polar solvents or adsorbents are removed from the fuel. In recent decades, extensive studies have been carried out on the catalysts used in the oxidative desulfurization process. In this review, a comprehensive survey has been performed on heterogeneous catalysts used in the oxidative desulfurization process. According to the reported researches, the heterogeneous catalysts used can be divided into five groups: ionic liquids, carbon materials, polyoxometalates, transition metal oxides stabilized on porous solid substrates, and metal–organic frameworks. The proposed mechanisms with different catalysts have also been studied in this work.

The study was conducted to monitor concentration of six toxic metals in faecal pellets of blue rock pigeon from six industrial areas of Jaipur, i.e. Jhotwara, Malviya, Mansarover, Sitapura, Vishwakarma industrial areas and Sanganer industries, by using atomic absorption spectrophotometer. At the same time, trace metals were also analysed for a reference area so that a comparative impact of the metal pollution from the industries could be figured out. From the data obtained, the highest Cd, Cu, Ni, Pb and Zn concentrations were found in the faecal pellets from Sitapura industrial area (1.12 ± 0.60 μg/g; 128.9 ± 11.10 μg/g; 17 ± 2.87 μg/g; 79.6 ± 42.69 μg/g; 2250 ± 1390.16 μg/g) and the highest Cr (18.6 ± 3.65 μg/g) from Jhotwara industrial area. However, industrial environment has high deposition of studied trace metals (except Ni for Sanganer industries) as compared with reference area. The concentration of Cd was below the detectable level in faecal pellets from reference area. The trend of trace metals from Malviya, Sitapura, Jhotwara and reference areas was noticed as Zn > Cu > Pb > Cr > Ni > Cd and almost same for Sanganer industries and Mansarover industrial area as Zn > Cu > Cr > Pb > Ni > Cd. The excretion of heavy metals in fa1ecal pellets from Vishwakarma industrial area was noticed as Zn > Cr > Cu > Pb > Ni > Cd. Further levels of metals were varied significantly among different industrial areas, P ≤ 0.05, as well as between industrial areas and reference area. The observed high concentration of different heavy metals in faecal pellets of bird species shows their exposure to metal contamination which is warning to spiked environmental pollution.

In this work, the capacity of Trametes polyzona in degrading three textile dyes (amaranth, denim blue, and orange G) to three different concentrations (100, 150, and 200 mg/L) was evaluated. Two growth conditions were tested; in the first condition, the fungus was grown in a defined minimal medium with an initial glucose concentration of 10 g/L and adding the different concentrations of each of the dyes, and in the second condition, the same minimum medium was used but with a concentration of 3 g/L of glucose, after 7 days of fungus growth, at which time the glucose in the medium was completely consumed; each of the dyes was added at the three different concentrations. T. polyzona was able to decolorize the three dyes at the concentrations tested and a 200% increase in the decolorization rate was observed when the medium lacks glucose. Enzymatic activities of laccase, lignin peroxidase, and manganese peroxidase were detected; the enzyme laccase was the one that presented the greatest enzymatic activities in all the media tested. A simultaneous process of adsorption by the mycelium and degradation of extracellular enzymes was observed. A decrease of more than 90% COD was observed and the effluent generated showed no algal growth toxicity.

The current research outlines the course of eutrophication processes emerging when some critical physical and chemical factors interact altogether. For this purpose, investigations were carried out, where nitrogen [N as (NH₄)₂HPO₄ and KNO₃] and phosphorus [P as (NH₄)₂HPO₄] were added to three different water sources (double distilled water, DDW; tap water, TW; and lacustrine water, LW) and the solutions were incubated at two distinct temperatures (17 and 23 °C). Treatments were kept in 1 dm³ glass jars and the incubation time lasted 7 weeks. The eutrophication process emerged only at 23 °C and was stronger for the lacustrine water (LW). In the case of DDW treatments, this process was observed at N/P = 5.1 and even at 60.0, whereas for the TW, no algal blooming was detected (N/P ratio 17.7–640.0). The lacustrine water (LW) outlined patterns with strong eutrophication at N/P = 4.40, but also at ratios 20.9–71.1. Algal blooming significantly intensified according to LW > TW > DDW but was reversely dependent on the P/N ratios, which followed the range DDW (P/N, 1.6–3.78) > TW (P/N, 0.050–0.100) > LW (P/N, 0.016–0.023). At P = constant (P = 0.10 mg dm⁻³) and the N inputs varying from 0.010 to 2.0 mg dm⁻³, it appeared that the higher the N concentrations, the more intensive the eutrophication process. For N/P ratios, phosphorus regulated for most of the intensity of the process, whereas in the case of P/N, the role of N and P was interchangeable. The main finding of the research is that nitrogen revealed in many cases to be a powerful eutrophication-regulating factor than did phosphorus.

Inland waters are considered hotspots of greenhouse gas (GHG) emissions and have been extensively researched. Static chamber (STAT) and thin boundary layer (BLE) are two commonly used methods for analyzing diffusive GHG emissions from inland waters. However, the STAT method is often disturbed by GHG bubbles; meanwhile, many kinds of headspace gas are used in the BLE method, but the differences between their diffusive GHG emission analysis results are not understood. In this study, the chamber in the STAT method was modified to combat the disturbances from GHG bubbles, and the typically used gases for the BLE method, namely, pure nitrogen, air, and filtered air, were comparatively studied. Results demonstrated that the modified chamber could effectively prevent the invasion of GHG bubbles; it increased the success rate from 67 to 90% in the field test, with no obvious impacts on the results of the GHG emission analyses. The use of air and filtered air in the BLE method yielded the lower values of GHG emissions relative to pure nitrogen, and this finding was potentially attributed to the inhibition effects of the residual GHGs and high humidity in air and filtered air on the extraction of diffusive GHGs from the surface water. This study improved the commonly used methods for diffusive GHG emission analysis, and the current findings are beneficial to the study of GHG emissions from inland waters.

Climate change and human activities are affecting the ecological health of rivers and the economic value of its ecosystem services. Taking water quantity as the intermediate variable, we proposed a quantitative calculation method for the impact of climate change and human activities on the economic value produced by the ecosystem service functions of rivers. The framework mainly consists of three steps: firstly, we quantitatively determined the changes in the amount of water coming from rivers due to climate change and human activities; secondly, combining the theory of resource and environmental economics to calculate the economic value generated by ecological service functions of rivers; finally, we quantitatively identified and analyzed the impact of climate change and human activities on the economic value produced by the ecosystem service functions of rivers. Taking Baoji section of Weihe River (BSWR) as an example, we quantitatively analyzed and calculated the impact of climate change and human activities on the economic value produced by ecosystem service functions of rivers. The main conclusions of this paper are as follows: in recent 52 years, the economic value produced by the ecosystem service functions of rivers decreased by 3.57 billion yuan due to the climate change and human activities; the total economic value has been reduced by an average of 68 million yuan per year. This useful work can not only reveal the impact of climate change and human activities on the economic value of ecosystem services of rivers but also can provide an important basis for the reasonable management model of water resource of ecosystem of rivers watershed.

Landfilling is a critical method in managing massive generated C&D waste, and the appropriate selection of C&D waste landfill sites can reduce the impacts of landfilling. This study proposes an approach combined F-AHP and GIS to select suitable C&D waste landfills. The proposed model considers multiple factors from environmental, social and economic aspects. A case study of Shenzhen, China, is undertaken to showcase the implementation of the proposed model. It is found that about 25 million m² of land has the potential to be used for C&D waste landfills in the study case, but the actual usable land is limited as some lands are too small for a landfill site. The study contributes to the waste management discipline as it provides an improved framework for selecting a landfill site. Besides, the landfill site selection procedure and results have practical implications for urban planning.

With the extensive mining of vanadium (V) ore, much attention has been focused on soil V pollution and its hazards. This study was conducted to investigate the adsorption-desorption properties of V on silica under various conditions, such as initial vanadate (V(V)) concentration, reaction time, pH, ionic strength, and temperature. The Langmuir and Freundlich isotherm models were applied to describe the adsorption of V(V) on silica and the results indicate that the adsorption was mainly monolayer adsorption. The kinetic studies show that the mechanisms of V adsorption on and desorption from silica were different from one another. The main adsorption-desorption-controlling step was chemical reaction, whereas V adsorption on silica also involved the diffusion. The adsorption-desorption procedure was highly dependent on the initial V(V) concentration and solution pH. Adsorption of V(V) increased with an increase in initial concentration and the maximum adsorption capacity was observed at solution pH 3.0–5.0. At 29.1 mg L⁻¹ initial V(V), and silica dosage 36.4 g L⁻¹ at 25 °C, the adsorption amount reached maximum of 82.7 mg kg⁻¹ and the corresponding desorption rate was 5.44%. Therefore, silica is an effective adsorbent which can fix V in the soil.

Retrotransposons, as vital regulator of male fertility, are essential for spermatogenesis. Cadmium (Cd) is an environmental toxicant and endocrine disruptor, targeting the reproductive system. Growing evidence shows that Cd exposure can induce male infertility in mammals. In this study, we generated a male C57BL/6 J mice model with consecutive 35 days cadmium chloride (CdCl₂) in different concentrations of 0, 0.25, 0.5, 1.0, and 2.0 mg/kg. The results indicated that 1.0 and 2.0 mg/kg CdCl₂ significantly affected the body weight. Meanwhile, the highest dose group with 2.0 mg/kg CdCl₂ presented low fertility. Furthermore, the expression of retrotransposon mRNA was markedly increased in the higher doses group. We examined methylcytosine (mC) levels of the three active LINE-1 subfamilies TfI, A, and GfII in testis. Conclusively, Cd exposure probably undermines the male mice fertility by disrupting DNA methylation to regulate the retrotransposons. Further studies are required for identifying whether retrotransposon activation has any significant impacts on genome structure, stability, and expression in Cd-induced testicular injury, laying foundation for the treatment for male infertility.