Advances in Environmental Technology (AET) Journal

The “river-sea” geochemical barrier is studied slightly in terms of the variety of pollutants, sedimentation, and degradation. At the same time, problems related to oil pollution, in particular the genesis of hydrocarbons, are almost never covered. This study was dedicated to the origin, concentration, and composition of hydrocarbons in the bottom sediments of the Chernaya River (Black Sea, Crimea) estuarine zone. The features of the marginal filter zone of the river were considered. N-alkanes in the range of C11-C36 were identified in the bottom sediments of the studied water area. It was noted that there was persistent oil pollution (degraded hydrocarbons) in the water area of Sevastopol Bay, adjacent to the confluence of the river. The accumulation of terrestrial material increased as it moved from the river to the sea. The application of various molecular markers displayed the predominately allochthonous origin of the hydrocarbons in the bottom sediments. As a result of the study of molecular markers by using principal component analysis (PCA) and analysis of variance (ANOVA) analysis, three leading factors responsible for hydrocarbon input to the bottom sediments water area were identified. The first one (36.53 % of the total variation) was associated with n-alkanes of natural and anthropogenic input. The second factor (19.52 % variation) was associated with allochthonous organic matter, including petroleum and bacterial destruction. The third factor (10.74 %) was associated with mainly allochthonous routes of organic substances entering the bottom sediments of the water area.

The photocatalytic degradation of Quinalphos, an organic pesticide, in the presence of modified ZnO metal composites, namely ZnO/MgO and ZnO/SnO2, was investigated at normal pH in the presence of sunlight. The structural and morphological properties of both the synthesized nanocomposites were characterised by different spectral techniques. The effect of pesticide concentration, catalyst dosage, and pH on the photocatalytic degradation efficiency was investigated. The photocatalytic activity of the respective nanocomposites on the degradation of Quinalphos was confirmed by UV-Visible spectroscopy. Moreover, the recycling ability of the prepared nanocomposites was also conducted and analyzed. However, the photocatalytic efficiency of ZnO/SnO2 nanocomposite was more efficient than the ZnO/MgO nanocomposite for the treatment of pesticide effluent, achieving 98 % and 95 % of total organic carbon (TOC) and chemical oxygen demand (COD) removals, respectively. The present study therefore concluded that the ZnO/SnO2 nanocomposite was the more stable and well organised composite, which could be the preferred treatment of industrial and agricultural wastewater containing organic contaminants within a short span of time.

Herein, a pilot study on the removal of ammonia from surface water using the integration of struvite precipitation and breakpoint chlorination is reported. A two staged pilot plant with a capacity of 1000 liters (1 m3) per run (LPR) was utilized, of which Stage 1 comprised struvite precipitation and Stage 2 comprised breakpoint chlorination. Optimum conditions (i.e., Stage 1) for struvite precipitation were 110 mg/L of Mg and P dosage (concentration), 150 rpm of mixing speed, 60 minutes of contact time, and lastly, 120 minutes of sedimentation, while optimum condition for the breakpoint chlorination (i.e., Stage 2) were 30 minutes of mixing and an 8:1 Cl2-NH4+ weight ratio. The synergistic effects of this hybrid system proved to be effective, with Stage 1 increasing the pH from 6.8 to 10.1, reducing Mn (≥97.0%) and Fe (≥99.6%) concentrations steeply, and concomitantly deactivated E coli and TPC to ≥ 99% and ≥91%, respectively, while ammonia was reduced from 5.4 mg/L to 2.7 mg/L-N (51.8 %). In Stage 2, i.e., breakpoint chlorination, ammonia was reduced from 2.7 mg/L to 0.02 mg/L-N whilst fully depleting residual microorganisms. Finally, the OPEX amounted to $ 0.31/m3; however, there is a potential for cost savings (≈53.2%) by replacing Kh2PO4 with waste phosphoric acid. Lastly, the results from this techno-economic evaluation study showed great potential compared to similar technologies, making this approach a game-changer towards the prudent management of elevated levels of ammonia amongst other problematic contaminants.

The adverse effects caused by the increase in nitrate concentration in drinking water have prompted researchers to find green and economical methods for nitrate removal. Mineral materials are suggested for this purpose due to their economic and environmental benefits. In this study, Iranian natural zeolite was used for this purpose. An organic surfactant, HDTMA-Br, was used to modify the natural zeolite. Fourier-transform infrared spectroscopy (FTIR) verified that the surfactant was loaded on the zeolite surface. The influence of various parameters on adsorption was studied using the Taguchi method. They were screened by Taguchi's L8 array, and four significant variables were determined: mass of adsorbent, particle size, contact time, and competing anion concentration. The Taguchi L9 array was used to determine the optimum condition of these significant variables. Analysis of the results showed that the concentration of the competing anion was the most significant variable on the nitrate adsorption by the surfactant modified zeolite (SMZ). In the optimum conditions, SMZ removed about 90% of nitrate from the aqueous solution obtained at a 20 mg/L initial nitrate concentration, 10 min contact time, 15 g adsorbent, and without any competing anion. The study of the adsorption isotherms showed that the nitrate adsorption process by SMZ from the aqueous solution fits well with the Freundlich and linear models.

Landfills in urban areas contribute to soil and water pollution with heavy metals. In Côte d'Ivoire, urban landfill soil is used to produce food, which presents health risks. This study evaluates the growth capacity of Acacia spp. trees-legumes (Acacia mangium, Acacia auriculiformis, and Acacia crassicarpa) and their potential for landfill soil remediation and restorations. These trees-legumes were grown under controlled conditions for six months in polluted soils sampled from urban landfills located in southeastern Côte d'Ivoire. The study used a simple, completely randomized design with four treatments (Acacia mangium, Acacia auriculiformis, Acacia crassicarpa, and control) and five replicates. Growth parameters, soil pH, metal contents (bulk soil, leachate), and plants were measured during this experiment. The results indicated that Acacia auriculiformis and Acacia mangium displayed better growth indicators (dry biomass, heights, and number of phyllodes) compared to Acacia crassicarpa. The soil pH under the trees-legumes indicated a significant decrease compared to the control (p < 0.05). In addition, heavy metal contents significantly decreased in the leached solutions of the planted soil compared to the control (p < 0.05). In the exchangeable soil fraction, only the Acacia auriculiformis treatment showed a significant decrease in Zn compared to the control. Regarding the plants, Acacia auriculiformis showed the highest amounts of Pb (111 µg plant-1) and Cd (54 µg plant-1) in total biomasses. Acacia crassicarpa had the highest metal extraction capacity from the polluted soil (Pb: 24 µg plant-1 , Cr: 11 µg plant-1 , Cd: 14 µg plant-1 , and Zn: 83 µg plant-1) compared to the two other species. The Acacia crassicarpa species appears to be the best one for the phytoremediation of landfill soils.

This study evaluated the ability of Chlorella vulgaris, a freshwater microalgae species, to remove nutrients from raw municipal wastewater. The wastewater was collected from the initial sedimentation-stage discharge of the treatment plant and used to cultivate the microalgae in both a shaker-incubator and a photobioreactor. The results showed that the microalgae effectively reduced the nitrate, nitrite, phosphate, and ammonium ion concentrations in the wastewater by over 90%. Phosphate removal was particularly efficient in the photobioreactor, with a removal rate of 91%, while the shaker-incubator had a removal rate of 44%. In addition to removing nutrients, the microalgae were also able to significantly reduce the wastewater's chemical oxygen demand (COD), with a reduction of over 90% from 264 to 23.1 mg/l. The microalgae also had a symbiotic effect on the bacterial colonies present in the wastewater, reducing their numbers by 99% while allowing the microalgae to thrive. The final biomass concentration in the photobioreactor was 2.03 g/l, a higher value compared to similar studies. These results demonstrate the potential of Chlorella vulgaris and other microalgae species for use in wastewater treatment systems.

Antibiotics are generally applied for the treatment of infections in humans and animals due to their economic value, easy accessibility, and potency. The use of veterinary pharmaceuticals such as antibiotics for the treatment of various infections in aquaculture cannot be overemphasized; the discharge of aquaculture effluent without necessary remediation techniques leads to the toxicity of the ecosystem. In this work, zinc oxide hexagonal-nanorods were synthesized via a precipitation method and calcined at 5000C in a muffle furnace for the catalytic degradation of ciprofloxacin (CIP) formulated aquaculture effluent. The characterization of nano-sized ZnO (n-ZnO) was conducted using scanning electron microscopy-electron dispersive spectroscopy (SEM-EDS), transmission electron microscopy (TEM), x-ray diffraction (XRD), Fourier transmission infrared spectroscopy (FTIR) and Brunauer, Emmett and Teller (BET) surface area determination. The SEM micrograph depicted both hexagonal and rod-like structures. The TEM micrograph subjected to ImageJ software showed an average particle size of 42.69 nm. The weight percent of the elements from the electron dispersive spectroscopy (EDS) followed the trend of Zn>O>C>Cl. The sharp peak of the Zn-O band was observed around 463.12 cm-1. The results from XRD showed that pure n-ZnO was achieved at a temperature of 5000C with a BET surface area of 8.3 m2/g, pore volume of 0.072 cm3/g, and pore size of 184.77 A0. The percentage of chemical oxygen demand (COD) removal of CIP formulated aquaculture effluent followed the trend of 42.8%, 73.9%, and 94.8% for the ultrasound (US), US/n-ZnO, and US/n-ZnO/H2O2systems.The US/n-ZnO/H2O2system showed the highest removal efficiency of CIP from the aquaculture effluent. The kinetics best fit the pseudo-second order, while the mechanism of degradation followed the Langmuir-Hinshelwood model for the US/n-ZnO/H2O2system. Hence, the utilization of US/n-ZnO/H2O2for the degradation of CIP formulated aquaculture effluent has proven to be a sustainable system that is dependable, faster, less tedious, and does not generate additional waste superior performance compared to individual materials. As such, findings from this study confirmed the performance and effectiveness of the Mg-(OH)2-Ca-NPs nanocomposite on the removal of Mn from real river water. This will go a long way in curtailing the impacts of Mn in drinking water and further afield.

The raw and modified surface of agricultural waste of Avokado was investigated in the adsorption of textile dye Bemacid Red. Phosphoric Acid, sodium hydroxide, and Acetone were used to treat the adsorbent surface. Batch mode studied the effects of experimental parameters: solution pH, contact time, initial dye concentration and temperature. The fit of the kinetics data was performed by the pseudo-first and second-order models. Whereas the adsorption isotherm data was performed by the statistical physics models. The Batch results reveals that the contact time and initial concentration have a positive effect on adsorption capacity, however, the two other parameters have a negative effect. From the kinetic modeling results, it was observed that the pseudo-second order fit well the data with a height determination coefficient (0.971< R 2 < 0.984). On the other side the double layer with two energies from the tested physical models proves to be the best model to explain the Bemacid Red dye adsorption mechanism (0.0991<R 2 <0.999 for the raw and treated Avokado). The modeling analysis indicated that dye molecules occurred via parallel orientation onto raw and NaOH-treated Avokado at 20 °C and via non-parallel orientation at temperature greater than 20 °C. In summary the NaOH-treated Avokado gives an important affinity towards Bemacid Red dye and can be classified as a low and efficient adsorbent.

The current study focused on the charge and mass transport effect on the continuous electro-Fenton (EF) process treatment of synthetic Reactive orange 16 (RO16) dye using low-cost stainless-steel electrodes and sodium chloride (NaCl) supporting electrolytes, respectively. Lab-scale experiments were carried out in a 500 mL volume reactor cell at various initial RO16 dye concentrations (75-250 mg/L) and flow rates (0.05-0.4 L/h). The results showed that the decolorization rate increased quantitatively with an increment of the RO16 dye concentration and flow rate due to the mass transport limitation. Increasing the mass flow rate increased the mass transfer coefficient (km), improving the kinetics of the decay. It was found that regardless of inflow concentrations, the dye removal efficiency increased with the flow rate. Additionally, the degradation rate, elimination capacity, current efficiency (CE), and specific energy requirement were estimated for the process. A dimensionless current density relation was generated for the developed continuous stirred tank to describe the kinetics and mass transfer relationship towards the overall reaction rate contribution. It was found that the stainless-steel anode electrode proved to be preferable due to lower energy consumption (6.5 kWh m-3) and less iron sludge production. Additionally, the application of pyrite (FeS2) particulate electrode increased the process efficiency (~ 5%) for TOC removal and current mineralization while maintaining its sustainability for reuse.

Penicillin is one of the emerging pollutants that has toxic effects on food chains and aquatic environments. It creates many problems for human health and other living organisms. Conventional wastewater treatment methods cannot remove penicillin; therefore, modern approaches are necessary to remove it from sewage. In this study, we examined the ability of TiO2 photocatalysis in the degradation of penicillin in aqueous solutions. The effects of different factors such as adsorption, pH, catalyst dosage, the initial concentration of penicillin, and time were examined. The results showed that photolysis and adsorption had negligible effects on penicillin degradation. The maximum degradation (94.5%) was observed at an ambient pH of 5, 0.1 g/l of TiO2, and 20 mg/l of penicillin for 90 min. The photodegradation of penicillin followed a first-order kinetic reaction, and the rate constant (k) was 0.0213 min-1. A TOC analysis was conducted to determine the fate of the pollutant. The results showed that 41% of the organic carbon was removed in 120 min. Based on the results, TiO2 photocatalysis is an economically feasible procedure with good efficiency in removing penicillin from the aquatic environment.

The present work investigates the aeration pressurization effect by monitoring the airflow (Qg) variations during its injection at various diffuser arrangements in an activated sludge (AS) system and its impact on the overall energy-saving strategy. To this extent, a laboratory pilot-scale system (450 mm in length, 400 mm in width, and 470 mm high) was built to conduct the experiments with an effective volume of 84.6 L. To determine the optimum operating conditions, an experimental design combined with the grey method was used to establish the optimal tests to minimize the process’s energy footprint based on the pressurization effect due to various diffuser arrangements. Successful implementation of this operation confirmed that controlling the local diffuser densities (DDL) benefits the power consumption value by experiment ( ) savings and the mixing performances at a DDL = 0.0144. Undoubtedly, increasing the DDL improved the mixing performance of the AS and reduced the inhibition of the oxygen mass transfer coefficient by the mixed liquor suspended solids (MLSS). Furthermore, an empirical model was built to describe the nature of the power consumed accurately. The outcomes showed that the coefficient of determination was R² = 0.9856 with a significant corresponding probability (P-values) < 0.05. As a result, the multiple linear regression model (MLR), which means that the model’s reliability to predict the data revealed an R² > 80 %, confirmed that the model is reliable at a 95% confidence interval (CI).

The foibles in extant wastewater treatment technologies release untreated nitrate and ammonia containing compounds into different potable water sources. The toxicity and fatal effects of entrained nitrate and ammonia produce lethal health consequences upon being consumed. Novel methods obtained by combining light, electrical, and chemical energy have opened new frontiers of pronounced efficiency and reduced demerits. These methods lead to the destruction of nitrate instead of just removing it by adsorption on the surface of another material. Photochemical (PC) and electrochemical (EC) reactions offer a vast scope for degrading harmful ammonia and nitrates from wastewater. The catalyzed form of these processes has been found to be meritorious over non-catalyzed techniques due to several advantages like improved efficiency, lower energy input, lower reaction time, and product selectivity towards N2 gas over nitrate and nitrite. This paper presents a review of significant research that has been performed using PC, EC, and photoelectrochemical (PEC) to remove ammonia and nitrate from wastewater. Not much research is available on the combined and simultaneous use of PC and EC oxidation and reduction processes which have immense potential as future methodologies for treating municipal and industrial wastewater to remove these toxic inorganic nitrogenous compounds. High ammonia and nitrate removal efficiencies at the laboratory scale have been reported using specific combinations of catalysts, pH, cell composition, electrodes, electrical input, and reaction time by electrochemical denitrification. However, they lack practical viability. Catalyzed photochemical processes are successful in removing ammonia and nitrate to a large extent and are practically viable if carried out using natural sunlight. Combined PC and EC, i.e., PEC oxidation and reduction processes, eliminate the occurrence of toxic intermediates and give about 90 % to 98 % conversion of ammonia and nitrate in the form of nitrogen gas.

Gas flaring in the petrochemical industries is an important issue due to the significant economic value of the emitted gases and the detrimental effects on the environment and workers’ health through gas combustion. Iran has the second largest gas reservoir in the world, with an extensive facility for gas exploitation in the Persian Gulf, indicating its significant role in the environmental conditions of the Persian Gulf. Therefore, this investigation, for the first time, endeavored to evaluate the design of offshore flares and model the amount of produced radiation and noise in the South Pars gas platforms using Flaresim software. The field data were obtained from Phase 7 of the South Pars platform. The results indicated that the amount of radiation from the flare flame in the surrounding area and the receptor points was less than the American Petroleum Institute (API) standard 521 regarding the stack length of 305 ft. The estimated values were 286 (0.9021 kW/m2) and 283.9 btu/h/ft2 (0.8955 kW/m2) in the base-flare and helideck areas, respectively. Moreover, the noise level in the receptors was less than the standard of the Occupational Health Organization of Iran. The current investigation can provide a practical framework to assess the compatibility of flare systems with environmental standards towards achieving sustainable development.

Refineries are amongst the most energy-intensive and polluting industries in the world. Biotechnology may serve as an alternative low-cost and environmental-friendly tool to the current costly, toxic and hazardous refining processes. In this study, the compositional redistribution of a heavy hydrocarbon cut is investigated under biological conversion using native microbial consortia. The native consortia were obtained by batch enrichment method applied on oil-polluted soil samples from oil refineries of Iran. The bioconversion experiments were conducted with 20% and 40% (v/v) of the heavy cut as the sole carbon source and 10% (v/v) of the consortia broth in 250 ml flasks containing a mineral medium. The samples kept at 30C stirring at 120 rpm for one week. The biotreated hydrocarbons were then separated and analyzed for determination of saturate, aromatic and resin fractions using column chromatography and gravimetric measurements. The results showed that the amounts of saturates increased by 6% to 92% while the resins decreased by 10% to 70% in most cases, compared to the blank. The GC-Mass analysis of the saturate fractions also revealed an increase in the cyclic and branched alkanes and a decrease in the S-containing and N-containing compounds.

The electrospinning technique is utilized to physically load Fe3O4/TiO2/Ag nanoparticles on polycaprolactone/polyethylene glycol (PCL/PEG) nanofibers scaffold for oxidative decomposition of 2, 4-dichlorophenol as a model organic pollutant. The scaffold is used in order to eliminate the need for separation of the catalyst after treatment, thus, making the catalyst system recyclable and reusable. Prepared nanofibers were thermally processed to change the morphology to crystalline form to make them transparent to visible light, which is a necessity for the function of photocatalysts. Different analysis techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), UV/Vis spectrophotometry (UV–Vis), and field emission electron microscopy (FESEM) were implemented to identify and characterize the presented products. Kinetic performance of both the particulate system and nanofiber system was determined. The prepared products demonstrated good catalytic activity by 53%, decomposing the target pollutant in 180 minutes of visible light exposure. The new catalyst-loaded nanofiber system maintained the decomposition performance of the particulate system and improved its reusability. Although this scaffold nanofiber-based system demonstrates slightly lower pollutant removal performance in the first run compared to the ternary non-fixed particle system (53.12% vs 54.74%), it outperforms the non-fixed particulate system in the 2nd and 3rd runs. The decomposition rate improved from 52.37% to 52.81% in the 2nd run and from 48.08 to 51.02% for the 3rd run. This photocatalytic system can be used as a reusable efficient catalyst for oxidative decomposing of 2, 4-dichlorophenol.

Diesel engines are critical to economic mobility. Because of the increasing scarcity of petroleum resources and the strict administrative rules, engine manufacturers and users must follow environmental regulations to avoid undesirable emissions. Vegetable oil could be used in diesel engines due to its high fluidity, poor stratification, ineffective ignition, and carbon buildup in the fuel system. The transesterification method reduces the viscosity of vegetable oil by converting it into methyl ester or ethyl ester, which is also known as biodiesel. This research examined the productivity, combustion, and output of zinc oxide nanoparticle disseminated canola oil biodiesel. The canola oil biodiesel was produced using the traditional transesterification process. The experimental hydrocarbons were produced using a magnetic agitator and ultrasonication, with a scattering of zinc oxide nanoparticles at a dosage of 50mg/l. The experiments were conducted at 1500 rpm. The use of zinc oxide nanoparticle dispersed canola oil biodiesel improved the specific fuel consumption, heat release rate, and other parameters. When compared to diesel, the brake thermal efficiency, nitrogen oxide, and hydrocarbon emissions were all lower. This study provides critical guidance on the use of sustainable energy, resulting in lower conventional oil consumption.

India is the second-largest sugarcane producer and consumer in the world, with 29.66 million tonnes of annual production and 25.51 million tonnes of consumption, along with a high degree of contaminated wastewater from sugar industries. Sugar industries in India generate about 1,000 litres of wastewater for one tonne of crushed sugarcane. The effluent discharged from sugar industries contains high concentration of biochemical oxygen demand, chemical oxygen demand, total dissolved solids, nitrogen, and phosphorous, causing serious environmental pollution problems. A combination of suspended and attached growth wastewater treatment systems can be used by integrating a moving bed biofilm reactor (MBBR) with a sequencing batch reactor (SBR) known as the moving-bed biofilm sequencing batch reactor (MBSBR), which is an aerobic treatment method. It is a promising technology as it has no requirement for sludge recirculation and requires lesser reactor volumes. In this study, the moving-bed biofilm sequencing batch reactor has been modelled for treating sugar industry wastewater. At a cycle time of 2 h, the biochemical oxygen demand removal efficiency is around 87% at 500 mg/L, sludge loading rate is 13 kg BODm-2d-1, chemical oxygen demand removal efficiency is 84.2%, food to micro-organism ratio is 1.09, and the mixed liquor volatile suspended solids and mixed liquor suspended solids values are around 2909 mg/L and 3639 mg/L, respectively. The economic viability of this technology is still to be established for treating sugar industry wastewater. This study can guide scientists, researchers, designers, and consultants when selecting wastewater treatment technology for the sugar industry. This technology has the potential to be replicated in other industries with similar wastewater characteristics.

This research deals with the sequent sulfonation and magnetization of waste polystyrene to form a novel adsorbent. The novelty is assigned by an anionic surface that can adsorb cationic dye and by a magnetic property allowing it to be separated quickly and practically. The sulfonation was conducted using H2SO4, and the magnetization was performed by the coprecipitation of Fe3O4. The prepared adsorbents were characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), and Scanning Electron Microscope (SEM) machines. The adsorption capacity was evaluated for the removal of methylene blue (MB) dye from aqueous media conducted by batch experiment. The contact time, adsorbent weight, and solution pH were optimized. The parameters of kinetic and isotherm adsorptions were also determined. The characterization data showed evidence that sulfonated magnetic polystyrene was successfully produced. The adsorbent with 50 wt% of Fe3O4 showed good adsorption capacity and separability effectiveness. The optimum condition of the adsorption of 10 mg/L MB in a 40 mL solution was reached by 15 mg of the adsorbent weight within 45 minutes and at pH 7 with an effectiveness of about 98%. The adsorption kinetics is best suited to a pseudo-second-order with an adsorption rate constant of 0.364 g mg-1 min-1 and is well explained by the Langmuir isotherm model with an adsorption capacity of 46.56 mg/g.

Domestic wastewaters are one of the main sources of contamination and diseases. However, they can be treated and potentially reused if certain organic and inorganic compounds and molecules are eliminated. Novel environmentally friendly proposals are available, such as the use of bioremediation mediated by microalgae capable of efficiently upcycling different quantities of phosphates and nitrates. Thus, in the present study, we evaluated the consumption capacity of nitrates and phosphates present in samples of domestic wastewater by cultures of Chlorella sp. and Desmodesmus sp., two microalgae with nutrient removing abilities, to propose novel wastewater treatment alternatives. For this purpose, we assessed the microalgae growth in domestic wastewater, cultured using the batch system, under greenhouse conditions by reading the wavelength and obtaining the cell density using a multiparameter photometer and two equations for each type of microalgae. Then, the rate and mean percentage of nitrate and phosphate removal were obtained and compared using two previously reported equations applied in similar culture conditions. Both microalgae grew in wastewater samples mostly by day three to four, showing similar growth tendencies without alterations and having a progressive increase in cellular density. Nitrate concentrations in all experimental groups were reduced to up to 90% on the fourth day; the initial phosphate concentration of 30.0 mg/L was reduced to 3.5 ± 2.1 mg/L with the Desmodesmus sp. treatment and to 9.2 ± 1.0 mg/L in the Chlorella sp. group. Desmodesmus sp. was the most efficient in the consumption of nitrates and phosphates, obtaining 96.5 ± 8.91 % and 88.3 ± 4.29 % of removal, respectively, while Chlorella sp. obtained 95.0 ± 8.0% and 69.3 ± 2.8%. Likewise, representative values of removal were obtained with the targets used in the laboratory tests.

Plastic pollution is a threat to the environment because of its slow degradation rate and high usage. The continuous accumulation of these synthetic plastic wastes poses an ever-increasing threat to animals, humans, and the environment. The use of microorganisms to effectively degrade plastic waste can provide a solution to this problem. This study aims to isolate plastic degrading microorganisms from soils taken from the Alimosho local government area of Lagos State, Nigeria. The soil samples were collected from dumpsites filled with plastic and plastic materials. The effectiveness of the degradation of plastic materials was studied over six (6) weeks in broth and agar culture under laboratory conditions by the weight determination method. Physicochemical and microbiological analysis was carried out on the various soil samples using standard protocols. The biodegradation of polyethylene and polystyrene was done in-vitro using the microorganisms isolated from the soil. The following microorganisms were able to degrade a higher percentage of the plastic materials; Staphylococcus aureus, Streptococcus sp, Bacillus sp, and Escherichia coli. The total viable count for bacteria was within the range of 11.8×105 to 2.0×1010CFU/g.  Staphylococcus aureus, Streptococcus sp, Bacillus sp, and Micrococcus sp degraded plastic up to 25%, 31.2%, 25%, and 31.2%, respectively. These isolates may be used to actively degrade plastics, thereby reducing the rate of plastic pollution in our ecosystem.

The purpose of this study is to compare the environmental risks arising from two models of drilling operations of single-ring and clustered wells in the land area, and finally, to select the most appropriate drilling operations to reduce environmental risks. For this purpose, after identifying the most important drilling activities of oil and gas wells and collecting the opinions of the statistical community, the risks arising from the activities in this field for both drilling models were identified and evaluated using the failure modes and effects analysis (FMEA) method. Then, the best option was selected using the hierarchical analysis process technique, which is useful in prioritizing and selecting the best option. The location of drilling risks in the high and medium risk matrix was determined using the FMEA method for both models with 1<RPN<30. And using the analytic hierarchy process (AHP) technique in the range of zero and one and between the single ring and cluster prioritized the techniques, and the best drilling technique for oil and gas wells, namely cluster drilling, was selected.

This study evaluated the effects of different operating conditions and the air-to-water ratio (G/L) on the kinetics and the mass transfer coefficient of ammonia (KL) in the air stripping method for removing ammonium ions (NH4+) from wastewater with low concentrations in municipal wastewater treatment plants (WWTPs). The impact of operating conditions including the temperature, initial ammonium ion concentration, pH, and air-to-water ratio (G/L) of <2000:1 (60:1, 70:1, and 80:1) on KL in the air stripping method was investigated using artificial wastewater at laboratory scale. The NH4+ concentrations in the wastewater samples were determined with the Nesslerization method (the standard method for the examination of water and wastewater). According to the results, the minimum (0.0528 h-1) and maximum (0.64825 h-1) of KL were obtained within 1 to 4 h in the operating status that included an initial ammonium ion concentration of 33.63-52.81 mg/l, a temperature of 34-45.7 °C, a pH of 9.48-12.2, and an air-to-water ratio of 60:1-80:1. A comparison of the results of three regression models showed that the air-to-water ratio was the most effective factor on KL. Furthermore, in Model 3 (multivariate linear regression model/comparing four parameters), the effects of the air-to-water ratio, pH, and temperature increased, leading to the acceleration and conversion of ammonium ions (NH4+) to a gaseous form (NH3). Also, the initial NH4+ concentration and pH in Model 4 (multivariate linear regression model by subgroup) at a low (60:1) and high (80:1) G/L ratio were the most influential factors on KL, respectively. The results of this study revealed that the air-to-water ratio (60:1, 70:1, and 80:1) could be used successfully for the elimination of ammonium ions from municipal WWTPs, leading to lower energy costs for the required aeration in the air stripping method.

Iran is located in the Earth’s arid zone, and a drought crisis imperils the country as a result of declining water resources. Khuzestan Province, located in the south of Iran, is in critical condition due to water shortages; many of its groves have been destroyed. It also has many respiratory and pulmonary patients due to the constant presence of dust. The pandemic and this dust have caused acute problems for those diagnosed with COVID-19. Due to the importance of water deficit in this province, the present research calculated the Standardized Precipitation Index (SPI) and Standard Precipitation Evaporation Index (SPEI) in a thirty-year statistical period from 1984 to 2014; 12 stations were selected during the months when rainfall was more likely. This study utilized a geostatistical method to prepare zoning maps of SPI and SPEI. Then, various spatial statistics techniques in ArcGIS software were used to identify and locate the exact areas that were the sources of drought with the help of drought hot spots and strong drought clusters. Anselin Local Moran's maps indicated that the high-high precipitation clusters were located in the northeastern regions of Khuzestan. The hot and cold drought spots, which were identified by Getis-Ord G* spatial statistics based on both SPI and SPEI, showed that the hot spots were formed in the southern and southwestern regions; the cold spots were formed in the northwestern regions. Furthermore, the drought hot spots were identified with a 99% confidence level in places where the total ten-year precipitation was less than 270 millimeters.

In the present study, the integration of the electrochemical process with a membrane bioreactor was used as a new technology for leachate treatment. In the electro-membrane bioreactor (EMBR), aluminum electrodes were used as anodes and cathodes. The EMBR was operated at a current density of 0.5 mA/cm2 and a solids retention time of 90 days to remove common contaminants such as ammonia-nitrogen (NH3-N), chemical oxygen demand (COD), phosphate (PO43--P), and ultraviolet absorbance at 254 nm (UV254). The maximum removal efficiencies of COD and NH3-N were above 98%. The average removal efficiency of PO43--P by the EMBR system was 93%, which was significant compared to previous studies. The removal rate of humic substances based on UV254 was provided at approximately 96.95%. The trans-membrane pressure rate was acceptable for 80 days in the EMBR, which could be related to sludge size improvement and filtration resistance through the occurrence of electrocoagulation, electrophoresis, and electroosmosis mechanisms. The mean removal efficiencies in the EMBR were 90, 91.25, 96, and 87.5 % for chromium (Cr), cadmium (Cd), zinc (Zn), and iron (Fe), respectively. The slight change of mixed liquor-suspended solids (MLSS) in the leachate treatment reactor showed that the microorganisms in the new EMBR system had high adaptation. Based on the results, the EMBR is a promising technology to improve leachate treatment performance due to its excellent removal efficiency of common contaminants, metal removal, and reducing fouling.

Cdo-TiO2 nanocomposites were synthesized by varying the molar ratio of CdO: TiO2 as 1:1, 1:2, and 2:1 using the sol-gel method. The pH value for all the CdO-TiO2 nanocomposites was controlled at two different values, pH-3 and pH-13. The nanocomposites were used for facilitating photolytic degradation of azo dye (Reactive Green-19). The surface morphology, crystallinity, and properties related to interactions with the light of the prepared catalyst were examined by scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and ultraviolet-visible (UV-Vis) spectrophotometer, respectively. The nanocomposites for all molar ratios synthesized at pH-3 showed rod-like structure and some irregular shapes, while those synthesized at pH-13 were spherical. From XRD patterns, composites at pH-3 and pH-13 were crystalline; however, those at pH-3 were more crystalline. The parameters, namely initial dye concentration, pH of dye solution, and catalyst concentration, affecting photocatalytic activities were examined and optimized at 75 ppm, pH-7.5, and 1g/L, respectively. The progress of the degradation process of Reactive Green-19 was observed by monitoring the change in the concentration of the dye after a certain time interval by measuring the absorbance by UV-Vis spectrophotometer. Catalyst A1:1 (The nanocomposites obtained at pH-3 with 1:1 mol% of CdO:TiO2)  showed maximum degradation (94.53 %) at a catalyst concentration of 1 g/L.

Petroleum sludge is typically caused by petroleum contaminants, effluents, and wastes from various stages of hydrocarbon separation. In this study, samples of oily sludge were collected from heavy fuel storage tanks in Sirjan Petrochemical Company in order to investigate the bioremediation of oily sludge by Eisenia fetida earthworms. The effects of oily sludge content, soil ratio, and sawdust weight percentage on total petroleum hydrocarbon (TPH) removal and reproduction of earthworms were evaluated. According to the design of the experiment (DOE), 17 samples with different combinations of petroleum sludge, soil, cow manure, and sawdust were selected to be tested. Also, to determine the effectiveness of the bioremediation process, some properties of samples including pH, total organic carbon (TOC), total Kjeldahl nitrogen (TKN), carbon to nitrogen ratio (C/N), and electrical conductivity (EC) were measured. The results showed that all properties, except for the electrical conductivity, decreased. Besides, in the presence of worms, the TPH could reduce by 66% after 90 days for samples containing up to 40 g oily sludge. Moreover, a statistical model was proposed using the response surface methodology (RSM) to predict the TPH removal and earthworm population as the targeted responses.