Surfactants are considered promising and practical substances for enhancing polycyclic aromatic hydrocarbon (PAHs) removal from contaminated soil. In order to explore the effects of single and mixed surfactants on the removal of high-concentration PAHs from soil, a series of experiments have been conducted. In this study, Tween80-saponin (a mixed surfactant), Tween80 (a nonionic surfactant), and saponin (a biosurfactant) were used to remove two typical and high concentration PAHs (anthracene and pyrene) from contaminated soil. Results showed that the mixed surfactant had better performance on the solubilization of anthracene and pyrene than Tween80, but its performance was worse than saponin. When the proportion and concentration of the mixed surfactant were 1:9 and 800 mg L⁻¹ respectively, the elution rate of anthracene could reach 97.67%, it was better than that by Tween80 and saponin. In addition, the Tween80-saponin mixed surfactant had good performance on actual PAHs contaminated soil remediation. When the proportion and concentration of Tween80-saponin were 1:9 and 800 mg L⁻¹ respectively, the PAHs elution rate of actual contaminated soil could reach 81.31%.

As an important role in economic development in China, industrial parks have consumed plenty of energy, while emitting enormous air pollutants and discharging large quantities of waste heat. Energy cascade utilization is an effective way to improve the energy efficiency of industrial parks. The objective of this study was to assess the co-benefits of energy cascade utilization, including the energy savings potential, reduction potential of air pollutants, and air quality improvements, in an industrial park in China. Through an energy flow analysis of steam at different pressures and residual gas among various enterprises, this study identified the existing energy cascade utilization network in a baseline scenario and proposed an enhanced scenario. To evaluate the co-benefits of these two scenarios, the CALPUFF model was used to integrate energy savings and air pollutant mitigation for the park in 2017. The results show that energy cascade utilization can result in considerable co-benefits related to energy conservation, air pollutant emission reductions, and air quality improvements. In the enhanced scenario, the total energy savings potential is 11,425 TJ, with emission reductions of 859 tons of SO₂ and 910 tons of NOₓ. Based on the CALPUFF simulations of SO₂ and NOₓ diffusion in the four seasons, the concentrations of SO₂ and NOₓ in the study area considerably decreased in the enhanced scenario compared with those in the baseline scenario. This study demonstrates that the park should focus on the cascade utilization of waste heat and residual gas to improve the energy utilization efficiency and reduce atmospheric pollutant emissions.

The indirect carbon emission embodied in the intermediate input is also an important indicator of assessing a producer’s carbon emissions. Structural analysis of indirect carbon emissions is helpful to understand the responsibilities between producers and pay efforts to key areas. The aim of this study is to analyze indirect carbon emissions embodied in intermediate input between sectors and explore the distribution structure of indirect carbon emissions flow network (namely, ICEFN). Based on the modified input-output model and complex network theory, this study constructed four directed and weighted ICEFNs with 28 sectors from 1997 to 2012. The results show that indirect carbon emissions between sectors are significantly higher than direct carbon emissions, accounting for nearly 70% of the total carbon emissions of China. Second, we analyzed the embodied carbon emission intensity (namely, ECI) of each sector. Although the ECI has been decreasing over time, the decrease has increasingly diminished, which indicates that the additional carbon emission reductions are more difficult. Third, we identified the key sectors which play different roles in the ICEFNs. Meanwhile, we studied the key paths which show more closed relationships between some sectors in ICEFNs. Finally, based on the above analysis, we made policy recommendations.

Methylmercury (MeHg) in sediment is difficult to be determined due to its low concentration and binding compounds like sulfide and organic matter. Moreover, wet sediment samples have been suggested to behave differently from certified reference materials in MeHg analysis. Optimal pretreatment procedure for MeHg determination in sediments has not been ascertained and whether the procedure could apply to sediment samples with complex matrix merits further research. This work firstly compared recovery results of five pretreatment procedures for MeHg determination using ERM-CC580. Using the optimal pretreatment procedure, recovery results were analyzed in different sediment samples after manipulation of moisture content, organic matter, and acid volatile sulfide. The procedure using CuSO₄/HNO₃ as leaching solutions and mechanical shaking as extraction method was proved to produce the most satisfactory recovery results (100.67 ± 6.75%, mean ± standard deviation). And when moisture content varied from 20 to 80%, average recovery results in sediment samples ranged from 100 to 125%. Furthermore, before and after the manipulation of organic matter or acid volatile sulfide, spiking recovery results varied little and were all within acceptable limit (85~105%). Therefore, the procedure of CuSO₄/HNO₃-mechanical is proposed as a universal pretreatment method for MeHg determination in sediment samples with various characteristics.

The aim of this study was to evaluate changes in hematological parameters of O. niloticus exposed to sublethal concentrations of the imidacloprid in order to utilize these parameters as biomarkers of exposure. Fish with an average weight of 68.5 ± 2.0 g were exposed to sublethal concentrations of imidacloprid (1.405, 2.810, 14.050, and 28.1 mg L⁻¹) for 7 days. Blood samples were collected by puncture of the tail vein. Blood samples were used to determine the number of erythrocytes, hemoglobin level, hematocrit number, total plasma protein concentration, total and differential leukocytes count, and thrombocytes number. All tested concentrations caused changes in fish leukogram. Concentrations from 14.050 mg L⁻¹ reduced the number of erythrocytes and total plasma proteins. The tilapia exposed to 28.1 mg L⁻¹ had a significant increase in the number of thrombocytes. Although considered slightly toxic to fish, sublethal concentrations of imidacloprid in aquatic environments, even if it does not cause immediate death, may compromise the health and long-term survival of these animals. The sublethal responses adopted for evaluation toxicity in this study were sensitive and adequate to show the extent to which pesticide can affect non-target organisms. This study recommends the use of blood parameters as biomarkers of exposure of fish to pesticides.

The trade-off between energy savings and emission reductions of an activated sludge process is a multi-objective problem relating to several potentially conflicting objectives. Therefore, the optimal modification of an anaerobic–anoxic/nitrifying/induced crystallization (A2N-IC) process by multi-objective optimization method was studied in this work. The multi-objective optimization model comprised three evaluative indices, (effluent quality (EQ), operation cost (OC), and total volume (TV) of structures), and 14 process parameters (decision variables) solving by non-dominated sorting genetic algorithm II (NSGA-II) in MATLAB. The trade-off relationships among EQ, OC, and TV were investigated under 30 days of dynamic influent with different constraint conditions. A series of Pareto solutions were obtained, and one Pareto solution was selected for further analysis. Results showed improved effluent concentrations of chemical oxygen demand (COD), total nitrogen (TN), ammonia-nitrogen (NH₄⁺-N), and total phosphorous (TP) under the optimized strategy compared to the original strategy, where the average effluent concentrations decreased by 2.22, 0.47, 0.13, and 0.02 mg/L, respectively. The values of EQ and OC decreased from 0.015 kg/day and 0.15 ¥/m³ to 0.0023 kg/day and 0.12 ¥/m³, respectively, while the TV increased from 0.31 to 0.33 m³. These results indicated that the multi-objective optimization method is useful for modifying activated sludge processes.

The olive mill wastewater (OMW) properties impose substantial practical and fiscal difficulties for effective management and dumping. A feasible and practical option is a regulated spreading of OMW into the soil. This study aimed to investigate the sustainable reuse of OMW through land application to enhance soil quality and wheat growth performance under rain-fed conditions. OMW was spread at 20, 40, 60, 80, and 120 m³ ha⁻¹ at two sites. Soil physical and chemical properties were measured after OMW application and after harvest. Wheat growth performance and leaf nutrient content were determined. This study revealed no deleterious influence of OMW application on soil properties and wheat growth at the two locations for all OMW application doses. The OMW land spreading improved significantly wheat growth by increasing the biological yield (BYLD) (8.4 to 36.5%), grain yield (GYLD) (20.1 to 79.4%), and harvest index (HI) (4.2 to 60.2%). Based on the measured soil chemical parameters and wheat grain yield, we can suggest that OMW application rate at 60 m³ ha⁻¹ could improve significantly wheat growth without significant negative impact on soil properties. In conclusion, we recommend using OMW as suggested in this study for wheat. However, still the long-term application of OMW assessment and local legislative adaptation of saving use are necessary.

A novel furnace throat structure was designed to reduce dust particle concentration in the flue gas emitted from the copper smelting industry. A two-stage turbulence model of the furnace throat based on the RNG k-ε model combined with the stochastic trajectory model was developed to analyze the gas flow and particle trajectories in this furnace throat structure. The resulting turbulent flow fields and particle trajectories under different operating conditions were shown and discussed. It indicates that the furnace throat plays an important role in separating the dust particles from the flue gas by applying centrifugal force and subsequent resistance force. Moreover, the effects of the radius of the inner flue, the number of the spiral plate, and the number of the spiral plate turns on the particle collection efficiency were analyzed to optimize the throat structure. The simulation results show that the furnace throat with inner flue radius of 0.05 m, two spiral plates, and two spiral plate turns has the highest particle collection efficiency. Furthermore, a series of experimental tests were conducted to validate the accuracy of the simulation results, and the measured experimental data show a good correlation with the numerical results.

The presence of heavy metals in food is a threat to human health. Exposure to heavy metals as a result of consumption of contaminated vegetables, as well as their toxicity, is a serious problem.Different branches of industry and the road traffic have a significant impact on environmental pollution with heavy metals. Municipal and industrial sewage also is an important source of those substances. Furthermore, the mineral content of vegetables depends on factors such as the natural content of trace elements in the environment, their levels in mineral fertilizers, and fertilizer doses. In the soil, a natural source of these metals is bedrock. In soils used for agricultural purposes, some quantities of metals are introduced together with fertilizers, both organic and mineral. Additionally, another sources of the metals are plant protection products.Heavy metal dynamics in the soil and their uptake by plants are influenced by soil properties, which play a key role in the bioavailability of these metals. Metal mobility and assimilation are also influenced by the addition of organic and inorganic matter. A significant body of evidence also suggest that the age of the soil plays an important role in modulation of metal bioavailability to plants.Apart from being influenced by the soil-related factors, absorption of metals differs in different types of plants. A significant variation in metal concentrations was also found depending on their location in plant tissues, on plant species, or even on varieties of the same species.