Online sensors, which monitor the ammonia oxidation and the dissimilatory nitrate reduction process, can optimize aerobic and anoxic phase duration. The purpose of this study was to comparatively evaluate the effectiveness of online sensors that were in situ–located in an intermittently aerated and fed membrane bioreactor (IAF-MBR) system. Ammonium and nitrate nitrogen sensors equipped with ion-selective electrodes as well as pH and oxidation–reduction potential (ORP) sensors were employed to online monitoring and optimizing of ammonia oxidation and nitrate reduction processes. The “ammonia valley” or pH bending point, which is indicative of ammonia depletion, was effectively and repeatedly detected by measuring the pH profile, while the “nitrate knee” point, which indicates the completion of the denitrification process, was online-detected by obtaining the ORP profile. The “ammonia valley” and “nitrate knee” were detected at pH and ORP values of 6.47 ± 0.02 and – 162 ± 39 mV, respectively. The ORP and pH first derivatives (dORP/dt and dpH/dt) were found to be more suitable than the untransformed ORP and pH values in detecting pH and ORP inflection points and controlling the shift from the anoxic to the aeration phase. Specifically, the ORP and pH bending points were detected at dORP/dt and dpH/dt values of 1.64 ± 0.82 mV min⁻¹ and 0.005 ± 0.001 min⁻¹, respectively. Moreover, the ORP first derivative has appeared earlier than the ORP bending point.

Seaweeds rich in polysaccharides are considered commercially important because of their wide range of industrial applications. In this study, the red seaweed Kappaphycus alvarezii was used for bioplastic film production. Plasticizer polyethylene glycol (PEG) to seaweed biomass ratio was optimized and a thin bioplastic film with higher tensile strength was produced. The films obtained were characterized by its thickness, tensile strength, colour (L, a, b), elongation at break (EAB), water vapour transmission rate (WVTR) and oxygen transmission rate (OTR). TG-DSC, AFM, SEM and FTIR spectroscopy analysis were performed to assess the composition, phase transitions and chemical reaction capabilities of the film. The bioplastic film obtained from 4% K. alvarezii (whole seaweed) showed better physical and mechanical properties, whereas TG-DSC, FTIR and AFM showed similar kind of bioplastic properties in all the concentrations. Decrease in OTR was observed against decreasing wall thickness of the film. The present study suggests that the seaweed would be a potential alternate source for bioplastic production which may reduce the usage of non-degradable plastics.

β-Lactam antibiotics have been widely used in clinic due to strong antibacterial activity with mild adverse side effects and have been detected in the environment. In the enhanced biological phosphorus removal (EBPR) process, phosphorus-accumulating organisms (PAOs) play a major role. In this study, amoxicillin, aztreonam, and cefoperazone are the selected antibiotics that applied in investigating the interaction mechanism of β-lactam antibiotics and PAO. The effects of β-lactam antibiotics on PAOs were analyzed comprehensively from the aspects of antibiotic impacts on phosphorus removal rate, intracellular polymer, their toxicity to PAOs, and PAO impacts on the fate of β-lactam antibiotics. It was found that the phosphorus removal rate of PAO increased by 19.21% and 15.75%, respectively at 10 mg/L amoxicillin and aztreonam, while cefoperazone had certain inhibition effect on phosphorus removal efficiency. Quantitative analysis shows that in the aerobic stage, three kinds of β-lactam antibiotics could promote the synthesis of polyphosphates (poly-P). The degradation rates of three antibiotics were as follows: amoxicillin > aztreonam > cefoperazone. The fate characteristics of antibiotics provide a theoretical basis for environmental risk assessment. The toxic effects of three antibiotics were as follows: cefoperazone > aztreonam > amoxicillin according to the bacteriostatic test. It provided a scientific theoretical basis for systematically evaluating the biological toxicity of antibiotic pollutants.

This study is carried out to investigate the effect of the cathodic contribution in the performance of electro-oxidation process for decolorization of the textile wastewater effluent pre-treated with a lab-scale moving bed-membrane bioreactor. For this purpose, titanium dioxide (TiO₂) was used as anode electrode and four different cathodic electrode materials: Graphite, TiO₂, TiO₂₋coated Platine, and TiO₂₋coated ruthenium dioxide (RuO₂) (namely RuO₂) were tested and compared for their color removal efficiencies. Besides, the optimization parameters that affect color removal in correspondence to the electrode materials, such as applied current, electrolysis time, and pH were studied. In this context, the optimum parameters for each electrode material were selected, and the color removal percentages were found as 92.95%, 91.58%, 91.40%, and 89.17% for TiO₂/Graphite, TiO₂/Platine, TiO₂/TiO₂, and TiO₂/RuO₂, respectively. Finally, the operational cost for each of the tested cathodic electrode materials was calculated in each of the studied optimization parameters making it easier and practical for the selection and evaluation of the electrode materials by the readers. The correlation coefficients (R²) were 81.2%, 87.1%, 86.7%, and 88.6% respectively as a result of the optimization study using the nonlinear regression modeling.

Hydrodesulfurization (HDS) of straight run light gas oil (SRLGO) using novel highly active two-dimensional (2D) MoS₂/graphene (G) nanohybrid catalysts is a precursor technology for the production of clean heavy fuel. The aim of this research is the synthesis of 2D MoS₂/G nanohybrid catalysts by use of exfoliation method from commercial bulky MoS₂ and graphite using hydrothermal ball milling system, which is a low-cost, high-yield, and scalable method. These nanohybrid catalysts were characterized by XRD, Raman spectroscopy, XPS, SEM, TEM, STEM, ICP, BET surface, TPR, and TPD techniques. Also, catalytic activities of 2D MoS₂/G nanohybrid catalysts were evaluated under different operating conditions such as temperature, pressure, LHSV, and H₂/Feed (SRLGO) ratio in the HDS reaction. The conversion of the HDS of SRLGO with 14000 ppm sulfur showed a considerably higher activity of 2D MoS₂/G nanohybrid catalyst (99.95% HDS efficiency) compared with the Co-Mo/γAl₂O₃ as a commercial catalyst (90% HDS efficiency) in the operation condition (340 °C, 40 bars, LHSV: 1 h⁻¹and H₂/oil: 600 NL L⁻¹) which is economically valuable. Using density functional theory calculations, the detailed mechanism of the HDS process over MoS₂/G catalyst was explored. It was found that sulfur coverage on the Mo edge of MoS₂ plays an important role in the hydrogenation of sulfur components.

Cadmium (Cd) is one of the most toxic contaminants, causing a lot of harm to environment and the human health. An outdoor pot experiment for 60 days was conducted to study the Cd(II) effects on growth, biomass, physiological properties, Cd uptake, and accumulation in Youngia japonica plants but also to evaluate the effect of Y. japonica growth on enzyme activity of Cd-contamination soils. Generally, the application of Cd(II) less than 120 mg kg⁻¹ stimulated the growth of the plants, whereas at 160 mg kg⁻¹ or higher levels, a significant reduction was observed. For all treatments > 10 mg kg⁻¹ Cd(II) in soil, values of Cd in roots and aboveground parts were more than the critical value of 100 mg kg⁻¹ and reached highest values of 252.51 and 314.29 mg kg⁻¹, respectively. The bioconcentration factors (BCF) and translation factors (TF) for all Cd treatments were more than 1.0, with the former ranging from 1.03 to 5.46 and the later from 1.04 to 1.33. The activities of peroxidase (POD) and superoxide dismutase (SOD), as well as the levels of glutathione (GSH) and proline in Y. japonica plants after exposure to 10–200 mg kg⁻¹ Cd(II) were stimulated, implying that they were defensive guards to the oxidative stress produced by Cd. The urease, dehydrogenase, and alkaline phosphatase activities under low Cd concentrations can be enhanced by planting Y. japonica species but inhibited under high Cd concentrations. Our data provide comprehensive evidence that Y. japonica has the typical properties of a Cd hyperaccumulator and thus may be practically employed to alleviate Cd from contaminated soils.

The COVID-19 lockdown has been reported as a “ventilator” for the reinstatement of natural resources across the globe. Hence, the present study attempts to evaluate the impact of COVID-19 lockdown on the water quality of River Gomti across its stretch of ~960 km through the assessment of ‘Water Quality Index’ (WQI). The study also highlights the potential risk of faecal-oral transmission of COVID-19 through intake of river water facing the issue of direct discharge of domestic sewage. A deterioration in the water quality was witnessed at ~69% sampling locations during the lockdown period (May 2020). Interestingly, none of the water samples during the pre-lockdown, lockdown, and post-lockdown periods across the whole stretch belonged to the “excellent” category (WQI<25). The DO levels fell across ~69% and ~88% of the sites during the lockdown and post-lockdown periods, respectively. Moreover, there was an increase in the BOD₅ levels across ~69% and 75% of the sites during lockdown and post-lockdown periods, respectively. These findings indicate that the release of sewage without or with partial treatment is a chief contributor of water pollution in the groundwater fed River Gomti. Thereby, highlighting the possible risk of faecal-oral transmission of the corona virus, and creating a major concern for the residents across its stretch. The urban sprawl and riverfront development in Lucknow city also emerge as potential causes of water quality deterioration in River Gomti, considering that the water quality at five sites within the city was under the “unfit” category regardless of the lockdown situation. Thus, the urgent need of management of domestic sewage release into the river and further research on the potential risk of faecal-oral transmission of COVID-19 have been suggested in the study.

With the growing awareness of the linkage among open defecation (OD), environment, and health, it is important to understand the factors responsible for OD. It is a necessary step toward developing a strategy to end open defecation for ensuring a better environment and human health. There is no such study available for Pakistan. The study, therefore, aims to bridge this gap. Using household data of Pakistan Demographic and Health Survey (PDHS) 2017–2018, an association of OD with potential predictors, analysis of variance, and a logistic regression model are employed to develop the evidence. The results suggest that place of residence, education, poverty status, social norms, geopolitical regions, and living space significantly predict the OD behavior in Pakistan. This study recommends two things: first is to facilitate the households and communities to own latrines, second is to change the behavior through intervention. However, political commitment and effective administration will be key to ascertain ending OD.

In order to increase the knowledge about crop tolerance to air pollutants in the different agroclimatic zones of the world, so that they can be efficiently considered for improving peri-urban agriculture, increasing the success of restoration projects, or enhancing air quality in polluted sites, the suitability of four economical valuable tree crops of the Mediterranean agriculture were studied under field conditions: date palm tree (Phoenix dactylifera L.), pomegranate (Punica granatum L.), fig tree (Ficus carica L.), and olive tree (Olea europaea L.). The measurement of biochemical markers such as ascorbic acid content, leaf relative water content, leaf total chlorophyll and leaf extract pH, at two contrasted air quality sites, a polluted site located around Gabes (Tunisia) industrial area and a control site, allowed the assessment of the air pollution tolerance index (APTI) and anticipated performance index (API) for the assayed species. Results showed obvious differences between the evergreen and the caducifolious tree crops assayed. Phoenix dactylifera tree (API = 6) was classified as an excellent performer for growing under poor air quality, followed by Olea europaea tree (API = 2) which was classified as a moderate performer. Both of trees can be recommended for successful results in peri-urban agriculture and restoration projects of polluted areas in the Mediterranean climate; on the contrary, the suitability of the Punica granatum (API = 1) was very poor, but still potentially interesting as a biological indicator of air pollution. Regarding the Ficus carica tree (API = 0), this species is not suitable for growing in air-polluted areas.

Methane is one of the main greenhouse trace gases and seriously affects the radiation balance of Earth systems due to its strong heat absorption capacity and long atmospheric retention time. Based on the methane stratification data simulated by the community atmospheric model with chemistry (CAM-chem), near-surface methane concentrations were estimated by utilizing the Gaussian function, and the spatiotemporal variation in the near-surface methane concentration in China from 2001 to 2019 was discussed in this research. The results show that (1) based on the methane stratification concentration data simulated by the atmospheric chemical model, the near-surface CH₄ concentration estimated by Gaussian function model is reliable, which provides a new method to estimate the near-surface CH₄ concentration over China; (2) from 2001 to 2019, the near-surface methane concentration in China showed an increasing trend with an annual growth rate of 7.20±0.23 ppb·a⁻¹. The annual maximum near-surface methane concentration was measured in winter, and the minimum was measured in summer; (3) the spatial distribution differences are obvious: the methane concentration in the east was higher than that in the west, and the methane concentration in the north was higher than that in the south. Moreover, the distributions of methane in the east and west are consistent with the division of Hu Huanyong population line.