This study refers to the development of hybrid briquettes using centrifuged sludge from the wastewater treatment of poultry and sawdust from furniture industry. The aim was to evaluate the performance of briquettes as a source of thermal energy, mitigating the risks of the current elimination and reducing the operational costs of their destination. To know the oxidizing characteristics of the briquettes and their mechanical resistance, superior calorific power, ash content, volatile materials, fixed carbon, and resistance to axial compression were evaluated. Thermogravimetric and differential exploratory calorimetry analyses were performed. Statistical treatments were carried out to verify the most significant factors to produce briquettes, the best proportions of the raw materials, and to evaluate whether there is interference from moisture and glue flour used as a binder. The best condition of the sludge-sawdust mixture was 15% and 85%, respectively, with 6.0% moisture. The best-case treatment had 23.82-MPa mechanical resistance, a calorific value of 17.20 MJ kg⁻¹, and a density of 1374.15 kg m⁻³.

Proper information regarding the performance of waste management systems from an environmental perspective is significant to sustainable waste management decisions and planning toward the selection of the least impactful treatment options. However, little is known about the environmental impacts of the different waste management options in South Africa. This study is therefore aimed at using the life cycle assessment tool to assess the environmental impact of the current, emerging, and alternative waste management systems in South Africa, using the city of Johannesburg as a case study. This assessment involves a comparative analysis of the unit processes of waste management and the different waste management scenarios comprising two or more unit processes from an environmental view. The lifecycle boundary consists of unit processes: waste collection and transportation (WC&T), material recycling facilities (MRF), composting, incineration, and landfilling. Four scenarios developed for the assessment are S1 (WC&T, MRF, and landfilling without energy recovery), S2 (WC&T, MRF, composting, and landfilling with energy recovery), S3 (WC&T and incineration), and S4 (WC&T, MRF, composting, and incineration). Based on the result of this study, MRF is the most environmentally beneficial unit operation while landfill without energy recovery is the most impactful unit operation. The result further revealed that no scenario had the best performance across all the impact categories. However, S3 can be considered as the most environmentally friendly option owing to its lowest impact in most of the impact categories. S3 has the lowest global warming potential (GWP) of 33.19 × 10⁶ kgCO₂eq, ozone depletion potential (ODP) of 0.563 kgCFC-11e, and photochemical ozone depletion potential (PODP) of 679.46 kgC₂H₂eq. Also, S4 can be regarded as the most impactful option owing to its highest contributions to PODP of 1044 kgC₂H₂eq, acidification potential (AP) of 892073.8 kgSO₂eq, and eutrophication potential (EP) of 51292.98 MaxPO4⁻³eq. The result of this study will be found helpful in creating a complete impression of the environmental performance of waste management systems in Johannesburg, South Africa which will aid sustainable planning and decisions by the concerned sector.

Schizolobium parahyba species can be found in all of South America, producing several residues that can be a major opportunity to develop activated carbon. This work presents the investigation regarding the development of a high specific surface activated carbon (981.55 m² g⁻¹) and its application in the adsorption of ketoprofen from the aqueous media. The ketoprofen molecules were better adhered to the adsorbent surface under acidic conditions (pH = 2), being the ideal adsorbent dosage determined as 0.7 g L⁻¹, resulting in satisfactory values. It was found that the system reached equilibrium in 200 to 250 min depending on the initial concentration studied, achieving an adsorption capacity of 229 mg g⁻¹. The general order was the most suitable model for describing the experimental data, with an R² ≥ 0.9985 and MSR ≤ 63.40 (mg g⁻¹)². The equilibrium adsorption found that the temperature increases the adsorption capacity, achieving 447.35 mg g⁻¹ at 328 K. Besides that, the Tóth model was the most suitable for describing the isotherms R² ≥ 0.9990 and MSR ≤ 25.67 (mg g⁻¹)², indicating a heterogeneous adsorbent. The thermodynamic values found that the adsorption of ketoprofen is spontaneous (average ΔG⁰ of − 32.79 kJ mol⁻¹) and endothermic (ΔH⁰ 10.44 kJ mol⁻¹). The treatment of simulated effluent with the developed adsorbent was efficient, removing 90% of ketoprofen, ibuprofen, and salts. It was found that the adsorbent is reaming its adsorption capacity up to the 5th cycle, progressively decreasing the adsorption capacity until the adsorption does not occur past the 12th cycle. Overall, the results demonstrated that the activated carbon from residual biomass of the Schizolobium parahyba species could be an excellent alternative in obtaining an effective adsorbent to treat wastewater-containing drugs.

Photo-treatment of water is a promising environmentally friendly process that provides clean water and makes wastewater reusable in industry. Thus, efforts toward finding highly efficient photocatalysts have gained a huge attention to remove the organic contaminants in water. Quantum dots (QDs) are extensively utilized for photocatalytic remediation regarding their prominent optical, electrical, and chemical properties. Herein, we report the highly efficient and environmentally friendly synthesis of Co₃O₄-QDs-based graphene quantum dots (GQDs) and infinite coordination polymer comprising Zn nodes (Zn-ICP) nanocomposites as active and robust photocatalysts for photo-assisted water treatment. The pristine Co₃O₄-QDs, GQDs, and Zn-ICP showed lower activity under visible light. However, after functionalization of GQDs and Zn-ICP with Co₃O₄-QDs, the activity increased, and more photocatalytic efficiency was achieved. For instance, Zn-ICP, GQDs, Co₃O₄-QDs, Co₃O₄-QDs/Zn-ICP, and Co₃O₄-QDs/GQD degraded 21, 19, 52, 73, and 83% of rhodamine B (RhB) and 34, 46, 50, 73, and 76% of methylene blue (MB) after 60 min. The high photocatalytic efficiency was ascribed to the conjugation of Co₃O₄-QDs with GQDs and Zn-ICP which causes efficient absorption of visible light. The existence of Co₃O₄-QDs was found to be essential not only for effective charge separation but also widening the region of light absorption followed by increase in photocatalytic performances. Charge separation in photocatalytic reactions, energy levels of nanocomposites, and mechanism of the photocatalytic process were investigated by photoluminescence spectra (PL), Mott-Schottky, electrochemical impedance (EIS), and diffuse reflectance UV–Vis spectroscopy (DRS).

Due to limited groundwater resources in arid and semi-arid areas, conjunctive use of surface water and groundwater is becoming increasingly important. In view of this, there are needs to improve the methods for conjunctive use of surface and groundwater. Using numerical models, optimization algorithms, and machine learning, we created a new comprehensive methodological structure for optimal allocation of surface and groundwater resources and optimal extraction of groundwater. The surface and groundwater system was simulated by MODFLOW to reflect groundwater transport and aquifer conditions. The important Marvdasht aquifer in the south of Iran was used as an experimental study area to test the methodology. In this context, we developed an optimal conjunctive exploitation model for dry and wet years using two new evolutionary algorithms, i.e., whale optimization algorithm (WOA) and firefly algorithm (FA). These were used in combination with the group method of data handling (GMDH) and least squares support vector machine (LS-SVM) to estimate sustainable groundwater withdrawal. The results show that the FA is more efficient in calculating optimal conjunctive water supply so that about 61% of water needs were met in the worst scenario for surface water resources, while it was 52% using the WOA. By applying the optimal conjunctive model during the simulation period, the groundwater level increased by about 0.4 and 0.55 m using the WOA and FA, respectively. The results of Taylor’s diagram, box plot diagram, and rock diagram with error evaluation criteria, i.e., root mean square error (RMSE), mean absolute error (MAE), and Nash–Sutcliffe efficiency (NSE), showed that the GMDH (RMSE = 6.04 MCM, MAE = 3.89 MCM, and NSE = 0.99) was slightly better than LS-SVM (RMSE = 6.36 MCM, MAE = 4.50 MCM, and NSE = 0.98) to estimate optimal groundwater use. The results show that machine learning models are cost- and time-effective solutions to estimate optimal exploitation of groundwater resources in complex combined surface and groundwater supply problems. The methodology can be used to better estimate sustainable exploitation of groundwater resources by water resources managers.

Mono(2-ethylhexyl) phthalate (MEHP) is a primary metabolite of di(2-ethylhexyl) phthalate (DEHP), which is widely used in industry as a plasticizer. Both DEHP and MEHP have been identified as endocrine disruptors affecting reproduction systems in natural aquatic environments. However, the effects of MEHP exposure on aquatic invertebrates such as Daphnia magna are still poorly understood. In the present study, lipid alterations caused by MEHP in D. magna were identified by analyzing lipid accumulation and nontarget metabolomics. In addition, reproductive endpoints were investigated. MEHP exposure under any conditions upto 2 mg/L was not associated with mortality of D. magna; yet, the number of lipid droplets and the adult female daphnids reproduction rates increased after 96 h of exposure and 21 days of exposure, respectively. MEHP also enhanced lipid metabolism, as evident from 283 potential lipid metabolites, including glycerolipids, glycerophospholipids, and sphingolipids, identified following 48 h of exposure. The MEHP-treated group exhibited significantly higher ecdysone receptor (EcR) and vitellogenin 2 (Vtg2) expression levels at 6 and 24 h. At 48 h, EcR and Vtg2 expression levels were downregulated in the 1 and 2 mg/L MEHP exposure groups. Our data reveal that the EcR pathway changes over MEHP exposure could be associated with lipid accumulation, owing to increased lipid levels and the subsequent increase in the reproduction of MEHP-exposed D. magna.

The aim of this study was to recycle dredged sediments as an alternative raw material in the production of ceramic tiles. The effect of the substitution of kaolin by raw sediment (HDS) and calcined sediment (HDSC) in the mixture of the ceramic tile samples sintered at 1100 and 1200 °C was studied. The samples were prepared with different proportions of HDS and HDSC (0, 10, 20 and 30 wt.%) substituting kaolin. The mineralogical analysis of the samples shows that mullite phase disappears in the samples incorporating raw sediments (HDS) and fired sediments (HDSC) leading to the formation of new crystalline phases such as anorthite and diopside.Moreover, ceramic tile samples with 20 wt.% of calcined sediment improve its densification and hence the compressive strength (171 MPa) and thermal conductivity (0.555 W/mK). An evaluation of the leaching was carried out in the ceramic samples, finding that the concentrations of heavy metals in the leachate were within the safety limit established by the USEPA. The heavy metals were immobilised in the ceramic matrix. Therefore, the results showed that dredged sediment (HDS) and calcined sediment (HDSC) could be used as substituent of kaolin to produce eco-friendly ceramic building materials as floor tile ceramics.

The relationship between environmental regulation and firms’ total factor productivity (TFP) has always been a hot topic in environmental economics, but the conclusions are still mixed. Employing a sample of 14,375 firm-year observations in China from 2010 to 2018, our research explores whether and when environmental regulation could trigger firms, to enhance TFP. The available evidence leads us to cautiously conclude that: (1) Environmental regulation notably improves firms’ TFP, the conclusion still holds after alleviating the endogenous problems and a battery of robustness tests. (2) Firms’ bargaining power significantly weakens the effect of environmental regulation on firms’ TFP. (3) Compared with non-state-owned firms and non-heavy-polluting industries, environmental regulation has a greater impact on state-owned firms and heavy-polluting industries; higher executive compensation does not motivate firms to improve TFP. Compared with firms headquartered in non-provincial capital cities, environmental regulation has a greater impact on firms’ TFP in provincial capital cities. Overall, the findings of our research are extremely relevant for the governments, investors, and firms’ managers; this paper provides China’s micro-firm-level evidence for the Porter hypothesis.

Fluid catalytic cracking (FCC) unit is one of the means to lighten heavy oil in refineries, and its regenerated flue gas is also the main source of air pollutants from refinery. However, it is not clear about the type and amount of pollutants discharged from FCC units in China. The emissions of regenerated pollutants in the stack flue gases of three typical FCC units in China were investigated in this study, including a partial regeneration unit without a CO boiler (U1), a partial regeneration unit with a CO boiler (U2), and a full regeneration unit (U3). Different monitoring methods were used to analyze the concentration of sulfur dioxide (SO₂) and nitrogen oxides (NOₓ), and the results showed that Fourier transform infrared spectroscopy (FTIR) monitoring results of SO₂ and NOₓ are approximately 10 times and 5 times larger than those of the continuous emission monitoring system (CEMS) data, respectively. Also, the contents of characteristic pollutants such as NH₃, C₆H₆, HCN, C₈H₈, C₂H₄, CH₄, and CO were also monitored by FTIR, and the emission factors based on coke burn-off rate and throughput were investigated. The pollutants in U1 exhibited relatively higher contents with the NH₃, HCN, and C₆H₆ of 116.99, 71.94, and 56.41 mg/Nm³ in flue gas, respectively. The emission of regenerated pollutants in U2 and U3 are significantly different from U1. Regeneration processes (including coke properties, operating modes, and presence or absence of CO boilers) affected pollutants’ emission factors in varying degrees. At last, reasonable emission factors based on the different FCC regeneration processes contribute to the prediction, assessment, and control for the pollutant emission.

Fecal carriage of bacteria is a major source of antibiotic resistance genes (ARGs) and a public health risk, but the antibiotic resistance of Escherichia coli (E. coli) in Chinese pig farms remains a major gap in the available literature. Our goal was to conduct a meta-analysis of studies reporting antibiotic resistance of fecal carriage of E. coli from pig farms in China, calculating the pooled resistance rates and summarizing factors associated with it. We searched PubMed and Web of Science for studies published in English up to February 28, 2021. We also searched bibliographic indices and corresponded with the authors. We chose ciprofloxacin, gentamicin, tetracycline, ampicillin, and florfenicol from five major types of antibiotics to comprehensively evaluate the resistance rate of E. coli. We used a random-effects model and Freeman-Tukey double arcsine transformation to calculate the resistance rate and 95% confidence interval. Among the 120 retrieved manuscripts, 16 studies (1985 E. coli isolates) were deemed eligible for our analysis. The combined resistance rate of E. coli from feces was 58.8% (95% CI: 45.3–71.7%) to ciprofloxacin, 54.3% (95% CI: 35.3–72.6%) to gentamicin, 91.0% (95% CI: 83.1–96.7%) to tetracycline, 81.4% (95% CI: 62.0–95.1%) to ampicillin, and 65.4% (95% CI: 33.9–90.9%) to florfenicol. In conclusion, fecal carriage of E. coli in Chinese pig farms shows high resistance to ciprofloxacin, gentamicin, tetracycline, ampicillin, and florfenicol. Subgroup analysis showed that the resistance of E. coli to antibiotics was closely related to the sample size and the health condition of the pigs. Specifically, ESBL-producing E. coli has a higher ratio of resistance to other antibiotics. Future collection of antibiotic resistance and other information in pig farms should be more precise and depend on local surveys.