Calcite/zeolite mixture (CZ) can be used to construct a capping layer for the simultaneous management of phosphorus (P) and nitrogen (N) liberation from sediments into the overlying water (OVER-water). However, its control efficiency of sedimentary P release still needs to be improved. To address this issue, an iron-modified CZ (Fe-CZ) was synthesized, characterized, and employed as a capping material to simultaneously prevent P and N release from sediments into OVER-water. Batch and microcosm incubation experiments were performed to study the efficiency and mechanism for the control of P and N release from sediments by capping Fe-CZ. Results showed that sediment capping with Fe-CZ resulted in the significant reduction of soluble reactive P (SRP) and ammonium-N (NH₃-N) in OVER-water, with reduction rates of 77.8–99.7% and 54.0–96.7%, respectively. Furthermore, the Fe-CZ capping layer decreased the SRP concentration in the pore water (PORE-water) at depth of 0–30 mm and reduced the concentration of PORE-water NH₃-N at depth of 0–50 mm. Moreover, the Fe-CZ capping layer gave rise to the great decrement of the concentration of the labile P measured by DGT (diffusive gradient in thin films) technology (P-DGT) in the profile of OVER-water and sediment. Additionally, the Fe-CZ capping resulted in the reduction of redox-sensitive P (P-BD) in the 0–50 mm sediment and caused the transformation of P-BD to calcium-bound P (P-HCl) and residual P (P-RES) in the 0–10 mm sediment as well as to P-RES in the 10–20 mm sediment. Results of this work indicate that the Fe-CZ capping has a high potential for the simultaneous management of P and N release from sediments, and the decrease of the contents of sediment P-DGT, sediment P-BD, PORE-water SRP and PORE-water NH₃-N as well as the conversion of mobile P to more stable P in the top sediment should have a significant role in the simultaneous interception of sedimentary P and N liberation into OVER-water by the Fe-CZ capping.

In this paper, we present a comparative review of the externalities of electricity production. First of all, the environmental impact is considered. A discussion of the influence of various electricity production processes on human health follows. The studies are conducted in the context of historical development. Current trends, as well as a historical background that resulted in the changes that can be observed today, are presented. The considerations are supported by a few case studies. Analysis of perspectives for the development of electricity generation methods, in particular the indication of clean energy sources and the perspectives of their exploitation, is the main aim of this paper.

This work is scrutinizing the development of metallized biochar as a low-cost bio-sorbent for low temperature CO₂ capture with high adsorption capacity. Accordingly, single-step pyrolysis process was carried out in order to synthesize biochar from rambutan peel (RP) at different temperatures. The biochar product was then subjected to wet impregnation with several magnesium salts including magnesium nitrate, magnesium sulphate, magnesium chloride and magnesium acetate which then subsequently heat-treated with N₂. The impregnation of magnesium into the biochar structure improved the CO₂ capture performance in the sequence of magnesium nitrate > magnesium sulphate > magnesium chloride > magnesium acetate. There is an enhancement in CO₂ adsorption capacity of metallized biochar (76.80 mg g⁻¹) compare with pristine biochar (68.74 mg g⁻¹). It can be justified by the synergetic influences of physicochemical characteristics. Gas selectivity study verified the high affinity of biochar for CO₂ capture compared with other gases such as air, methane, and nitrogen. This investigation also revealed a stable performance of the metallized biochar in 25 cycles of CO₂ adsorption and desorption. Avrami kinetic model accurately predicted the dynamic CO₂ adsorption performance for pristine and metallized biochar.

Chlorotoluene rectification residual liquid (CRRL) from chlorotolune industry is hard to dispose of because of its high chlorine concentration, which poses high dioxin risk once it is subjected to incinerate. This research employed a chemical approach by using Williamson ether synthesis (WES) method for CRRL dechlorination. It shows that the sodium dosage, the ethanol dosage, and the ultrasonic time are the key factors in chlorine removal. The highest removal rate of chlorine was observed when the sodium dosage, the ethanol dosage, and the ultrasonic time were 0.35 g mL⁻¹, 0.8 mL mL⁻¹, and 15 min, respectively. The further optimization tests indicate that the highest chlorine removal efficiency of 39.06% was observed when the ultrasonic time was 15 min, the sodium dosage and the ethanol dosage were 0.5 g mL⁻¹ and 1.1 mL mL⁻¹, respectively. It suggests a feasible chlorine removal process for organic hazardous waste with high chlorine content before incineration.

A high-efficient method for determining the total petroleum hydrocarbon (TPH) was established by gas chromatography-flame ionization detection, coupled with an efficient 10 m short chromatographic column; the analyzing period was narrowed to 5 mins. The limits of detection of the method included 1.47, 4.02, and 0.69 mg/kg, and the corresponding limits of quantification reached 4.45, 12.2, and 2.10 mg/kg for the three fractions C₁₀–C₁₆, C₁₇–C₃₄, and C₃₅–C₄₀, respectively. The method was employed to real samples to achieve the routine environmental monitoring of TPH in polluted sites from Fushan oilfield, China. As revealed from the analysis of 30 soil samples in the study area, a wide range of TPH concentrations were achieved: 61.6–7300 mg/kg (average, 1055 mg/kg) for ΣC₁₀–C₁₆, 438–14,280 mg/kg (average, 4544 mg/kg) for ΣC₁₇–C₃₄, 25.4–638 mg/kg (average, 250 mg/kg) for ΣC₃₅–C₄₀, and 617–15,348 (average, 5848 mg/kg) for ΣC₁₀–C₄₀, respectively. According to the Nemerow integrated pollution index, the Fushan oilfield has been slightly polluted by TPH. As suggested from the distribution of TPH concentrations, the main sources of TPH in soil samples of Fushan oilfield included oil spills during temporary storage, transportation, and oil exploitation. Adopting the developed method to delve into oilfield soil samples further verifies the effectiveness of the method, indicating that the method can well meet the growing demand of regulatory guidelines for related risk assessment and environmental monitoring and remediation strategy formulation.

Nowadays, humanity is consuming unsustainably the planet’s resources. In the scope of energy resource consumption, e.g., the intense use of fossil fuels has contributed to the acceleration of climate changes on the planet, and the overriding need to increase energy efficiency in all sectors is now widely recognized, aiming to reduce greenhouse gases (GHG) emissions by 69% in 2030. Largely due to climate changes, water has also become a critical resource on the planet and hydric stress risk will rise significantly in the coming decades. Accordingly, several countries will have to apply measures to increase water efficiency in all sectors, including at the building level. These measures, in addition to reducing water consumption, will contribute to the increase of energy efficiency and to the decrease of GHG emissions, especially of CO₂. Therefore, the nexus water energy in buildings is relevant because the application of water efficiency measures can result in a significant contribution to improve buildings’ energy efficiency and the urban water cycle (namely in abstraction, treatment, and pumping). For Mediterranean climate, there are few studies to assess the extent and impact of this nexus. This study presents the assessment of water-energy nexus performed in a university building located in a mainland Portugal central region. The main goals are to present the results of the water and energy efficiency measures implemented and to assess the consequent reduction of water, above 37%, and energy (30%) consumption, obtained because of the application of water-efficient devices and highly efficient light systems in the building. The water efficiency increase at the building level represents at the urban level an energy saving in the water supply system of 406 kWh/year, nearly 0.5% of the building energy consumption, with a consequent increase in the energy efficiency and in the reduction of GHG emissions. Complementarily, other energy-efficient measures were implemented to reduce the energy consumption. As the building under study has a small demand of domestic hot water with no hydro pressure pumps and has a small water-energy nexus, it was concluded that the significant reduction of the building energy consumption did not influence the indoor comfort.

This paper analyzes the factors explaining the slight decrease of CO₂ emissions in the European Union (EU), recorded during the last period. With a focus on 12 EU countries, we apply a panel data analysis over the period 1990 to 2017 and we investigate the impact of renewable energy share in energy production, and the role of EU environmental regulations, in explaining the level of CO₂ emissions. Our static and dynamic panel data analysis points to a negative impact of an increased renewable energy share on CO₂ emissions, while there is no clear evidence about the role of environmental regulations. It appears that the 2020 climate and energy package contributed to the reduction of pollution level, while the ratification of the Kyoto protocol by the EU countries had no significant influence. At the same time, our findings validate the environmental Kuznets curve (EKC) hypothesis and the pollution halo (PH) hypothesis, showing that foreign companies export eco-friendly technologies. Our results prove to be robust regarding the use of static fixed and random effects models, of two-stage least square models and the use of difference and system generalized method of moments (GMM) frameworks.

Concentration of trace metals (TMs) is one of the most crucial factors determining the quality of cereal grains. The aim of this study was to evaluate the effect of digestate, manure, and NPK fertilization on TM concentration in grains and straw of two cereal crops—winter wheat (WW) and spring barley (SB)—and TM transfer from soil to plants. The experiment was carried out between 2012 and 2016. Every year, the same treatment was used on each plot: control (without fertilization), digestate, digestate + straw, cattle slurry, and mineral NPK fertilization. In general, fertilization increased the concentration of TMs that belong to the micronutrient group (Zn, Cu, Fe), particularly after application of digestate and cattle slurry. At the same time, fertilization, regardless of the fertilizer type, led to an increase in Cd concentration in the grain of WW in comparison with the control. Despite the increase in Cd and micronutrient content as a result of fertilization, the concentration of elements remained below the applicable standards. Among TMs, only Pb content exceeded the European Union limits. The increased concentration of Pb was, however, an effect of other factors, rather than fertilization. The results clearly indicated that the biogas digestate from anaerobic codigestion of cattle slurry and agricultural residue could be utilized as fertilizer in agricultural applications without a risk of contaminating the food chain with TMs.

The spent biological activated carbon (BAC) should be disposed properly; regeneration was a better choice. Performances of thermal and ultrasonic regeneration to the BAC with various service time (3 years, 5 years, and 10 years) were compared comprehensively; the recovery of the BAC’s pore structure, variation of mechanical hardness, influence of bioactivity, and removal efficiency of typical pollutants in the reuse were examined. The results showed that thermal regeneration was an utterly regeneration, and almost all the pore structure was restored, whose recovery rate was above 90% for BAC used 3 years and disfavored by the longer BAC’s service time (83% for the BAC used 5 years). Ultrasonic regeneration could recover part of the BAC’s pores (including micropores) and the restoration mainly focused on the BAC’s surface, so the recovery rate was not influenced by the BAC’s service time, and the recovery values of specific surface areas and iodine value were kept at 120 m²/g and 200 mg/g, respectively. In addition, the ultrasonic treatment enhanced the BAC’s biological activity even with a significant decrease of the biomass on the BAC. The mechanical hardness of BAC decreased from 95 to 89% for the first regeneration and further to 79% for the second regeneration, whereas relatively lower decrease happened for the ultrasonic regeneration (less than 10% after 5 regeneration cycles). The mass losses in the thermal and ultrasonic regeneration were about 13%, 0.5%, and 25%, 3% for the first and second regeneration, respectively. The thermal-regenerated activated carbon (AC) exhibited excellent adsorption ability, good adherence of biofilm, and maintain higher removal rate for more than 2 years, which were similar with that of the fresh AC, but relatively lower removal performance was found. However, the ultrasonic regenerated BAC retained the biodegradation ability, restored the fast-adsorption ability, and the higher removal process lasted about 6 months. Taking the regeneration cost, operation, variation of the AC’s characteristics, and the removal performance in reuse, ultrasonic regeneration was more suitable for the BAC filter and better used as a regular measure to maintain the higher removal performance, whereas thermal regeneration was more applicable to the activated carbon adsorption tank.

The present study aims to study the effect of low viscous biofuel, namely pine oil (PO) and orange oil (O) blending with Jatropha methyl ester (JOME) along with exhaust gas recirculation (EGR) on NO-smoke tradeoff in a single-compression ignition (CI) engine. Two blends of pine oil and orange oil (30% by volume) with JOME were prepared and tested at 10%, 15%, and 20% EGR rates for various load conditions and compared with base fuels. JOME operation increased NO emission by 4% and reduced smoke opacity by 10% in comparison to diesel at maximum load condition. Poor physical properties of JOME, namely high viscosity and inferior volatility leads to reduced brake thermal efficiency with higher HC and CO emissions. Blends of JOME with low viscous biofuel reduces smoke emission with a further increase in NO emission in comparison to JOME as a result of combustion enhancement. Addition of EGR with JOME70 + PO30 and JOME70 + O30 aids in the reduction of NO emission with a slight increase in smoke opacity. Considering the NO-smoke tradeoff, JOME70 + O30 + EGR (10%) is optimum, NO emission is reduced by 14% and 11% in comparison to JOME and diesel and smoke opacity is reduced by 5% and 15% in comparison to JOME and diesel at maximum load, respectively.