Environmental Technology & Innovation最新文献

Mixing inside high-solids anaerobic co-digestion (HS-AcoD) is essential for process feasibility and economic sustainability. This study developed a proper energy assessment for a high solids anaerobic digestion-combined heat and power (AD-CHP) system to clarify the impact of mixing on methane production, energy recovery and carbon emission reduction during HS-AcoD of food waste (FW) and sewage sludge (SS). Results indicated that intermittent mixing enhanced methane production and shortened the lag phase compared with unmixing and continuous mixing. The modified Gompertz model yielded better fitting than the logistic and transfer function models via kinetic analysis. In the case of a scaled-up AD-CHP system, intermittent mixing with 15 min/h boosted energy output (2.14 × 10³ kWh/tonne VS) at 21 d. Compared with continuous mixing, 15 min/h intermittent mixing at 13 d improved the energy recovery ratio from 31% to 45% and carbon emissions reduction from 0.25 t CO₂/t VS to 0.35 t CO₂/t VS. For a high availability of FW and SS in China, the AD-CHP system with intermittent mixing would have higher net energy output (128.4 × 10⁹ kWh) and carbon emission reduction (15.3 million tonnes) by the full utilization of these biomasses. These results are expected to provide theoretical support for the high solids AD-CHP system in determining the optimal mixing strategy with maximum energy production for FW and SS disposal.

Plastic film mulching and organic fertilisation result in the coexistence of mulch film residues of multiple sizes and antibiotic resistance genes (ARGs) in farmlands. However, the differential effects of large and small low-density polyethylene mulch film (LDPEM) and biodegradable mulch film (BDM) residues on ARGs have not yet been studied. In this study, we investigated the dynamic variations in soil ARGs induced by organic fertiliser application under treatments with different LDPEM and BDM residue sizes. The results indicated that the target ARGs could be divided into six clusters according to their variation characteristics with sampling time. The reduction rates of most target ARGs, including ermC, aadA-01, qacEdelta1-01, sul1, sul2, tetM-01, tetM-02 and tetPA in treatments with large mulch film residues were lower than those with small mulch film residues for both LDPEM and BDM, which resulted from the higher average degree and positive correlation ratio in the networks between the soil bacterial community and ARGs. The results of structural equation modelling indicated that soil bacterial communities directly affected soil ARGs, with a path coefficient of −0.6428. Soil physicochemical properties and soil enzyme activities affected soil ARGs through the soil bacterial community with path coefficients of 0.24 and 0.28, respectively. The results of the present study emphasise that the environmental impact of large mulch film residues should not be ignored.

Bisphenol A (BPA) is an emerging organic pollutant that can disturb endocrine systems at trace levels in water. This study constructed a photocatalyst of cobalt oxide modified bismuth vanadate (CoO${}_x$/BiVO₄) coupled with peroxymonosulfate (PMS) oxidation system to investigate its photocatalytic mechanism for degrading BPA in wastewater. The CoO${}_x$/BiVO₄ photocatalyst was fabricated through a precipitation-hydrothermal method and systematically characterized. The results showed that modifying BiVO₄ with CoO${}_x$ significantly improved the separation and migration efficiency of photogenerated electron–hole pairs, thereby enhancing the photocatalytic activity of the system. Through active species trapping experiments using different scavengers, singlet oxygen (¹O₂) and sulfate radicals (SO₄${}^{-}\cdot$) were identified as the predominant reactive oxygen species responsible for BPA degradation. BPA photocatalytic reaction intermediates were analyzed using HPLC-MS, which proposed three possible degradation pathways: (1) Initial hydroxylation of BPA by SO₄${}^{-}\cdot$ and $\cdot$OH radicals; (2) Ring-opening oxidation of hydroxylated intermediates into carboxylic acids; (3) Further mineralization of all intermediates into CO₂ and H₂O by ¹O₂ and $\cdot$OH. In summary, the CoO${}_x$/BiVO ₄-PMS system provides an efficient and promising technology for eliminating trace BPA in wastewater via synergistic effects of SO₄${}^{-}\cdot$ and ¹O₂. Further optimization of CoO${}_x$ loading and PMS dosage is still needed to maximize the overall photocatalytic performance.

To improve the carbon fixation capacity of crops, ${\mathrm{HCO}}_3^{-}$ is applied to the rhizosphere under a suitable pH value, which can enhance the utilization of CO₂ by crops. This study aimed to clarify the maximum fixation capacity of ${\mathrm{HCO}}_3^{-}$ in tomato plants by exploring the optimal concentration of ${\mathrm{HCO}}_3^{-}$ in their cultivation environment. The results showed that the tomato could maintain both the net increase of ${\mathrm{HCO}}_3^{-}$ fixation and normal growth, when the maximum concentration of ${\mathrm{HCO}}_3^{-}$ in the cultivation surroundings was discovered during the growth period: 25 mmol/L NaHCO₃-solution in seed germination, 14 g-NaHCO₃/kg-soil in the cotyledon development, 8 to 10 g-NaHCO₃/kg-soil during the seedling, 6 g-NaHCO₃/kg-soil in the flowering, and 9 g-NaHCO₃/kg-soil in the fruiting. However, excessive ${\mathrm{HCO}}_3^{-}$ could impair the development of tomato plants, especially the vegetative growth at seedling/flowering stages and the root growth at fruiting stage due to the increased soil pH and EC by ${\mathrm{HCO}}_3^{-}$. On the other hand, H${}_2$O produced by the decomposition of ${\mathrm{HCO}}_3^{-}$ by tomato plants could alleviate physiological stress under severe conditions. Therefore, ${\mathrm{HCO}}_3^{-}$ became the main inorganic carbon source of tomato assimilation under extreme stress. This study provides a data basis for selecting and optimizing the appropriate ${\mathrm{HCO}}_3^{-}$ application amount when CO₂ is used for agricultural eco-fixation in the form of ${\mathrm{HCO}}_3^{-}$ in the future.

Electrochemical oxidation (ECO) is a promising process that exhibits excellent performance in various wastewater treatment applications. Herein, the influence of operating parameters on the reduction of energy requirements for the electrochemical oxidation of various wastewater resources was investigated. The results revealed that pH significantly reduces the energy required for the removal of total nitrogen, unlike the chemical oxygen demand (COD) and NH₃ removal. Electrochemically-based hybrid technologies and low current densities also resulted in a decrease in the required energy. Additionally, pollutants with high concentrations had a positive effect on the electrical energy required. Besides, the comparative performance of three advanced electrochemical oxidation processes was reported as technological alternatives for the treatment of reverse osmosis (RO) concentrate applied to membrane bioreactor (MBR) effluent in livestock wastewater. The results revealed that advanced electrochemical oxidation-peroxide is the most effective process for treating RO concentrate among all advanced ECO technologies. The removal rates for total organic carbon (TOC) and COD were 82% and 96%, respectively, after only 60 min of treatment.

Accurate solubility prediction of hydrogen sulfide in aqueous electrolyte solutions is critical for gas exploitation and geological storage. However, there is a lack of electrolyte Equation of State model that can accurately calculate the solubilities of hydrogen sulfide in aqueous electrolyte solutions over wide ranges of temperature, pressure, and salt molality. This work presents a modeling study on the solubilities of hydrogen sulfide in pure water and several aqueous sodium salt solutions. The thermodynamic framework used in this work is an electrolyte version of Cubic-Plus-Association Equation of State. The model’s temperature-dependent ion-gas binary interaction parameters are obtained by regressing the experimental solubilities in the aqueous electrolyte solutions. The modeling results show that the electrolyte Cubic-Plus-Association Equation of State can satisfactorily correlate the solubilities of hydrogen sulfide in aqueous electrolyte solutions over wide ranges of temperature, pressure, and salt molality. For the typical water–sodium chloride–hydrogen sulfide system, the model can satisfactorily correlate the gas solubilities with the mean relative deviation being 6.2%, with the temperature up to 593.95 K, pressure up to 32.30 MPa, and salt molality up to 6.0 mol$\cdot$kg⁻¹ water. Moreover, the salting-out effects and model adaptability are analyzed and discussed.

Aim:

Generate fire susceptibility maps for the present and 2070, to identify the threat wildfires pose to koalas now and under future climate change.

Location:

Australia.

Time period:

Present and 2070.

Major taxa studied:

60 main tree species browsed by koalas.

Method:

The Decision Tree machine learning algorithm was applied to generate a fire susceptibility index (a measure of the potential for a given area or region to experience wildfires) using a dataset of conditioning factors, namely: altitude, aspect, rainfall, distance from rivers, distance from roads, forest type, geology, koala presence and future dietary sources, land use-land cover (LULC), normalized difference vegetation index (NDVI), slope, soil, temperature, and wind speed.

Results:

We found a general increase in susceptibility of Australian vegetation to bushfires overall. The simulation for current conditions indicated that 39.56% of total koala habitat has a fire susceptibility rating of “very high” or “high”, increasing to 44.61% by 2070.

Main conclusions:

Wildfires will increasingly impact koala populations in the future. If this iconic and vulnerable marsupial is to be protected, conservation strategies need to be adapted to deal with this threat. It is crucial to strike a balance between ensuring that koala habitats and populations are not completely destroyed by fire while also allowing for forest rejuvenation and regeneration through periodic burns.

Biocathodes in bioelectrochemical systems (BESs) have been reported to enhance nitrogen (N) removal. However, the complex multi-parameter variables in BESs have increased the difficulty of studying the enhanced mechanism of nitrification using biocathodes. This study aimed to construct a range of potentiostatic biocathodes (−400, −200, ＋200, and ＋400 mV vs Ag/AgCl) with a dissolved O₂ concentration of 2–3 mg L⁻¹ using a potentiostat to further clarify the mechanism. The mechanism of how biocathodes influence microorganisms was elucidated from multiple perspectives, including variations in N concentration, electrochemistry, high-throughput sequencing, and PICRUSt2 prediction. The biocathodes were found to increase the nitrification rate by improving the abundance of nitrification-related bacteria (unidentified_Nitrospiraceae, Thauera, Nitrosomonas, Prosthecobacter, and Stenotrophomonas), the expression of genes related to ammonia oxidation and nitrite oxidation (pmoABC, hao, nirk, ncd2, and npd), and the activity of ammonia oxidase (AMO) and nitrite oxidase (NOR) in the biocathodes. The results of this study might provide crucial academic support and demonstration in facilitating the application of BESs and realizing the deep treatment of wastewater.

Oilseed rape (Brassica napus L.) planting could be a promising approach for the safe utilization of cadmium (Cd) contaminated soil. However, comprehensive evaluation on safe utilization potential of oilseed rape was lacked, including phytoextraction efficiency, health risk, and economic benefits. In this study, ten oilseed rape cultivars were planted in Cd-contaminated soils immobilized with limestone and a comprehensive evaluation was performed on the safe utilization potential. Results showed that the highest biomass of rapeseed (1363-1569 kg ha⁻¹) was found in Zhongshuang 11, Xiangzayou 787, and Luoyouza 101. Zhongyouza 19, Zhongshuang 11 and Dadi 199 had the highest Cd phytoextraction efficiency (3.31-3.76 g ha⁻¹). The Cd concentrations in all the rapeseeds ranged from 0.18–0.45 mg kg⁻¹ and were lower than the limit of food security standards, but oil Cd concentrations of three cultivars (Fengyou 730, Dadi 199, and Yangguang 50) were 0.90-1.56 times higher than those in the reference oils (0.04-0.05 mg kg⁻¹). Target hazard quotient (THQ) suggested that the Cd in all the oils were under the acceptable level for adults and children, whereas only of three cultivars (Huihaoyou 26, Luoyouza 101, and Zhongshuang 11) were at acceptable level at incremental lifetime cancer risk (ILCR) value. Based on the yields and market price of rapeseed, Luoyouza 101, Xiangzayou 787, and Zhongshuang 11 had the highest economic benefits (9812-11300 CNY ha⁻¹). Overall, the comprehensive evaluation indicates that Zhongshuang 11 is the most suitable for the safe utilization of Cd contaminated soil.

There is a growing recognition that illegal dumping or global transfer of solid waste poses an environmental challenge. The dearth of effective tracing source techniques exacerbates the difficulty in the identification of unknown wastes, thus further complicating the environmental and management challenges. To this end, we developed tracing source processes for unknown waste, leveraging similarity models to facilitate identification. With a dataset of waste features, we established a matching function for single waste feature, as well as a cross entropy model for multiple waste features. Both the similarity models were applied to the tracing source process, enabling the identification of the source or category of unknown waste. The similar probability value between known waste and unknown waste can be obtained by those two models. The process of source tracing in the study was shown by examples of aluminum dross. If the known waste feature dataset is sufficiently accurate, the accuracy rate of tracing source will be correspondingly high in practical applications. Therefore, when using the similarity models, it is imperative to improve the known waste dataset to satisfy the demands of actual tracing source.