The critical parameters namely initial pH, time and current density largely impact the process efficiency of electrocoagulation (EC). Few works have been done on observing the interaction of these critical parameters and the possible combined effect on the overall pollutant removal efficiency. Therefore, the knowledge of the combined effect of critical parameter interaction would enhance the optimization of EC parameters to attain maximum efficiency with limited resources. Using aluminium electrodes with interelectrode distance of 10 mm on synthetic wastewater, representing biotreated palm oil mill effluent (BPOME), with a set range of initial pH, current density, and time of 3-8, 40-160 mA/cm2 and 15 to 60 minutes, respectively, the effect of the three critical variables was investigated. The optimum Chemical Oxygen Demand (COD) removal of 71.5% was determined at pH 6, current density of 160 mA/cm2 (with current 1.75 A) at EC time of 15 minutes. The experiment was validated with real BPOME, resulting in the removal efficiency of 60.7 % COD, 99.91 % turbidity, 100 % total suspended solids (TSS) and 95.7 % colour. Removal of a large quantity of pollutants in a time span of 15 minutes with optimized parameters in EC is notable for a wastewater treatment alternative that requires no extensive use of chemicals. The interaction of parameters observed in this study indicated a synergistic contribution of initial pH and current density in removing maximum wastewater COD in 15 minutes of EC.

Technology has made the life of Bangladeshi people very flexible with new inventions. In most cases, here the people depend on these technological devices. These devices, along with various facilities, have also invited a series of problems mostly due to the lack of proper management. The Bangladeshi citizens often leave electronic devices that went bad or became unusable, in landfills, rivers, canals, and open spaces. As these devices possess a variety of toxic substances, dumping huge amounts of electronic waste can pollute the environment and threaten human health. Around 2.7 million metric tons of e-waste are generated each year in Bangladesh. Only 20-30% of this waste is recycled while the rest amount is released in landfills, rivers, canals, and open spaces posing a serious threat to the health and environment. Bangladesh has experienced rapid advancement in the technological sectors over the years. Therefore, it is a must to take steps necessary for avoiding the future jeopardized situation because of e-waste. The present e-waste management in Bangladesh experiences a number of drawbacks such as challenges in incentivization, unhygienic conditions of informal recycling, insufficient law and policy, less awareness, and lack of enthusiasm on part of the corporate to address the critical issues. In spite of the alarming levels of e-pollution in the country, the concerned authorities are yet to take any effective step or formulate any legislation to prevent the existing e-pollution. Moreover, the prevailing environmental laws are not adequate to address the issue and its application is still largely absent.

In this study, the removal of nitrogen from effluent of ammonia plant by Chlorella vulgaris and Spirulina platensis was investigated. For this purpose, microalgae were cultivated in three diluting percentage of the wastewater (1, 3, and 5%) at 29±1 ◦C and light intensity at surface of culture were adjusted to 150 µmol photon / (m2. s). The results showed that Spirulina platensis is more capable than Chlorella vulgaris to grow in high levels of total nitrogen concentration. Also, maximum biomass production rate happened in 1% diluted samples for Chlorella vulgaris and 3% for Spirulina platensis. Furthermore, Chlorella vulgaris reduce total nitrogen concentration up to 55%. This value for Spirulina platensis was about 96%. However, for both species the removal of nitrogen in 1% diluted wastewater was maximum. According to the results of diluted wastewater of ammonia plant, it is a suitable culture medium for microalgae and it can be used to remove the nitrogen before entering the wastewater in nature.

Mineralogy studies can help understand the interactions of geographical, environmental, and geological factors. Considering frequent occurrence of urinary tract stones in the south and west of Iran, the present paper examines trace elements, like heavy metals, in 53 urine stone samples collected from patients in Lorestan Province. It investigates the mineralogy of the stones, using X-ray diffraction. The samples are then classified into five mineral groups (calcium oxalate, urate, cysteine, calcium oxalate-urate, and calcium oxalate/phosphate). Results from this analysis are confirmed by SEM images, showing the crystalline form of the mineral phases. The microscopic studies show that only the mineral group of calcium oxalate (whewellite) could be detected in thin sections, prepared from urinary tract stone samples. The main and trace elements in each group are determined through ICP-MS method with the results showing that calcium is the most abundant substance in urinary tract stones, compared to other elements. This is caused by the role of calcium in most basic functions of cell metabolism. The correlation between magnesium and strontium is 0.64, originated from the placement of high amounts of strontium in calcium oxalate minerals. The positive correlation between sodium and calcium also indicates that sodium is replaced by calcium due to the similarity of the ionic radius in the crystal structure. Results from this study can help us find the causes behind the frequent occurrence of urinary tract stones in Lorestan Province.

In current study, the enhanced efficiency of copper (Cu) phytoremediation potential of Calendula officinalis L. was investigated in a Cu-spiked calcareous soil, using foliar and soil application of humic acid. For this purpose, in a greenhouse experiment, seedlings of C. officinalis were transferred to Cu-spiked soils (0, 250 and 500 mg/kg) and treated separately with soil (soil drench) and foliar (spraying plant leaves) humic acid applications at different levels (0, 10, 20 μM). The humic acid treatments were applied 2 weeks after transferring plant, and eventually the various biochemical-physiological traits and phytoremediation indices of Cu in C. officinalis were measured at (specific) time points. According to the results, C. officinalis grew normally without any toxicity signs in Cu-spiked soils, however with increasing the Cu levels, the dry weight biomass decreased and antioxidant enzymes activities increased. Both foliar and soil humic acid application in Cu-spiked soils increased dry weight biomass, photosynthetic pigment contents, Cu concentration, and bioconcentration factor (BCF). Furthermore, the application of this organic substance, obviously moderated the Cu stress since the antioxidant enzymes activities reduced compared to the control. Based on the results, the obtained translocation factor (TF) and BCF values of Cu, which were >1, indicated that this plant is a Cu-hyperaccumulator, which could extract Cu via phytoextraction mechanism. Generally, the results of this study showed that, among the humic acid treatments, application of 20 μM (especially soil drench application) had the best effect on increasing Cu phytoremediation efficiency in the studied soil and it recommended to enhance the efficiency of Cu phytoremediation in calcareous soils.

The Air Pollution Tolerance index (APTI) of six plants located within Ikpoba Okha gas flaring site in Oredo Local Government Area of Edo State, Nigeria during wet and dry seasons were assessed. Plant samples for this research work were randomly collected from the vicinity of the flaring site. Six (6) sample of each plant was used for laboratory analysis. The plant parameters assessed include relative water content (RWC), the ascorbic acid content (AAC), total leaf chlorophyll (TLC) and pH extract of the leaves and were used to compute the Air pollution tolerance indices (APTI). Based on the analyzed result, the RWC in Drypetes leonensis, Ficus exasperata Vahl, Chromolaena odorata (Linn) and Gmelina arborea Roxb. ex Smith   species in dry season were higher than those in wet season. Icacina tricantha showed a relatively high level of acidity when compared to others. A. boonei De Wild has the highest ascorbic acid content in the leaves in both seasons. The highest level of chlorophyll contents was recorded in the dry season with Drypetes leonensis having the highest, followed by Icacina trichantha. There was no statistically significant difference in pH and total chlorophyll contents between samples collected in wet and dry season; however, there were significant difference observed in ascorbic acid and RWC in both seasons. APTI in wet and dry season showed a statistically significant difference. This study recommends planting of tolerant species that can acts as bio-indicators especially in gas flaring stations in Nigeria.

Two lab-scale electrodialysis (RED) stacks with different intermembrane spacing were used in this study. Each stack consists of two membrane pairs. Thick intermembrane spacing stack was made of four identical plexiglass sections, with outer dimensions 5 cm * 5 cm * 1.5 cm and an inner cross-section of 3 cm diameter each to construct two diluted solution compartments and two concentrated solution compartments. For the thin intermembrane spacing configuration, four rubber spacers with a thickness of 1 mm and an inner opening of 3 cm each were used instead of these sections. Two copper sheets were used as anode and cathode electrodes. Different solutions with NaCl concentrations of 15,000, 30,000 and 200,000 mg/l were used as a concentrated solution and different solutions with relatively low NaCl concentrations of 25, 1000 and 3600 mg/l were used as a diluted solution. A 30,000 mg/l NaCl solution was used as a diluted solution when the concentrated stream was with NaCl concentration of 200,000 mg/l. The electrode solution was of 15,000 mg/l (~0.25 M) NaCl and 8,000 mg/l (~0.05 M) CuSO4.5H2O. The results of this study confirmed the validity of using RED technology to harvest energy from salinity gradient using saline and freshwater available abundantly particularly in Iraq. An experiment on a synthetic hypersaline oil field co-produced water as a concentrated stream and seawater as a diluted stream showed that the system performance is reproducible and stable. A maximum power density of 0.029 W/m2 could be harvested.

Air pollution is a significant concern for both managers and disaster decision-makers in megacities. Considering the importance of having access to correct and up to date spatial data, it goes without saying that designing and implementing an environmental alerting and monitoring system is quite necessary. A standard infrastructure is needed to utilize sensor observations so as to be ready in case of critical conditions. The use of sensor web is regarded a fundamental solution to control and manage air quality in megacities. The proposed system uses the SWE framework of OGC, the reference authority in spatial data, to integrate both sensors and their observations, while utilizing them in the spatial data infrastructure. The developed system provides the capability to collect, transfer, share, and process the sensor observations, calculate the air quality condition, and report real-time critical conditions. For this purpose, a four-tier architectural structure, including sensor, web service, logical, and presentation layer, has been designed. Using defined routines and subsystems, the system applies web sensor data to a set of web services to produce alerting information. The developed system, which is assessed through sensor observation, measures the concentration of carbon monoxide, ozone, and sulfur dioxide in 20 stations in Tehran. In this way, the real-time air quality index is calculated, and critical conditions are sent through email to those users, who have been registered in the system. In addition, interpolation maps of the observations along with time diagrams of sensors’ observations can be obtained through a series of processes, carried out by the process service.

The present study simulates the frontal dust storm by means of WRF-Chem model and AFWA emission scheme between April 23 and 24, 2019. It then applies reanalysis data (ERA5) to analyze this case from a synoptic perspective. The simulation results show that the model have been accurately characterized first by the onset of dust from the south-east of the country in Kerman Province and then via its transmission to large areas of the east and south-east. The model output also fits well with satellite images. A quantitative comparison of PM10 concentration of the model with actual values shows that the PM10 model estimates are larger than actual values, though it predicts the trend of concentration changes well. Examining the synoptic maps, the isobars’ curve, wind direction change, and temperature advection in the area reveals the presence of atmospheric fronts within a strong dynamic low-pressure system. This causes high temperature and pressure gradients, in turn speeding up the wind within the region. Results from the synoptic analysis show that by passing the frontal system and behind the cold front, a dust mass is formed, which gradually spreads in eastern and the southeastern regions of Iran. In this case, extreme pressure gradient, cold front passage, low-level jet, wind gust on dry areas of dry Hamoon wetland, and cold air advection over flat area of the Lut Desert are important factors in storm formation and emission, east of the country.

Because of the pinch of air pollution on human health and its environment, it has become necessary to monitor and map out the peaks and lows threat places of air pollution in different land use across a city. In this regard, air pollution exposure mapping of Kano metropolis based on land use classifications namely industrial, residential, commercial and institutional was carried out for interpretive and assessment of health hazard associated with the selected pollutants. The observations for ambient air quality parameters (CO, SO2, H2S, NO2, and PM10) monitored with portable digital air pollution detecting devices for creation of data. Geographic Information Systems (GIS) technique was applied to create spatial distribution maps of urban air quality of the metropolitan area. The results of pollution index map of ArcGIS extrapolation indicated that neighbourhoods in the vicinity of Bompai and Sabon Gari industrial and commercial zones, respectively were found to be highly exposed and liable to ailments associated with air pollution, while places nearby Dorawa and School of Technology were air pollution-ease zones but could experience bioaccumulation over long exposure time. Therefore, the study reveals that variability of air quality was strongly related to predominant land use in particular areas within the metropolis and could help in estimate and valuation of likely health challenges associated with poor air quality due to air pollution. Besides, the observed spatial variation for air quality could serve as hot spot identifier and as an informant for rational decision on air quality control strategies for environmental management.