Mouhamed Ngounouno Ayiwouo; Felicite Obono Mba; Colins Leprince Kombou; Jules Metsebo
Abstract
This paper assesses the environmental impact of the wastewater treatment plant (WWTP) of the Cameroon Real Estate Company (CRE) camp in the "Cité-Verte" district in Yaoundé (Cameroon) and the causes of its malfunction. The study was carried out in two stages. The first stage consisted of ...
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This paper assesses the environmental impact of the wastewater treatment plant (WWTP) of the Cameroon Real Estate Company (CRE) camp in the "Cité-Verte" district in Yaoundé (Cameroon) and the causes of its malfunction. The study was carried out in two stages. The first stage consisted of describing the wastewater treatment steps of the WWTP, and analyzing the staff interviews in order to determine the causes of malfunction that had been suspected. The second phase consisted of collecting water samples at the entry of the WWTP (P1), inside the WWTP (P2), and at the outlet of the WWTP (P3). This, in order to produce a list of the WWTP's collecting systems, characterize the various types of wastewater (P1 and P2) and the treated wastewater (P3), and then determine the effect of effluent discharges on the environment. Finally, the structural and operational malfunctions of WWTP are identified using the Ishikawa and the Pareto diagrams. The results of water characterization show that the mean values of pH (7.7), EC (1059.3 μS/cm), TDS (524.6 mg/L), T° (23.6 °C), BOD5 (10.8 mg/LO2), NO3- (2.3 mg/L), and fecal coliforms (447.3 CFU/100 mL) are below the acceptable limit values of the Cameroonian standard of treated wastewater discharge. However, the mean values of TSS (269.3 mg/L), PO43- (1661.6 mg/L), K+ (1220.6 mg/L) and Escherichia coli (10133.3 CFU/100 mL) exceed the recommended values set by the Cameroonian standard of treated wastewater discharge. The values of the wastewater parameters at the sampling point P3 are globally lower than those at the sampling point P1 but higher than Cameroon’s standard for PO43- and K+. These results demonstrated that the current system (filters and plants) is appropriate but not optimal. The Pareto diagram reveals that the inadequate plant controls, unfavorable working conditions, lack of maintenance andsystematic control, and outdated equipment represent 20% of the causes responsible for 80% of the WWTP's malfunction. Therefore, the implementation of corrective and preventive measures is essential for better monitoring and determinization of the optimal performance of the WWTP of the CRE camp in the "Cité-Verte".
Fayazeh Rabanimehr; Mehrdad Farhadian; Ali Reza Solaimany Nazar; Elham Sadat Behineh
Abstract
In photocatalytic microreactors the catalyst layer is obtained by integration of nanostructure films of semiconductors. One of these nanostructures that have a good photocatalytic activity is ZnO nanowires. The photocatalytic degradation of methylene blue in a continuous flow microreactor with ZnO nanowires ...
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In photocatalytic microreactors the catalyst layer is obtained by integration of nanostructure films of semiconductors. One of these nanostructures that have a good photocatalytic activity is ZnO nanowires. The photocatalytic degradation of methylene blue in a continuous flow microreactor with ZnO nanowires deposited film is simulated. A finite element model is developed using COMSOL Multiphysics version 5.3 software to simulate the microreactor performance. The kinetic law of the photocatalytic reaction is assumed to be Langmuir–Hinshelwood. The kinetic constants kLHa and K are determined 1.43×10-7 mol/m2s and 7.5 m3/mol, respectively. The percent of average absolute deviation of the model in predicting the methylene blue outlet concentration obtained about 0.12% mol/m3. The model showed a very good agreement with the published experimental data. The effect of microreactor depth, methylene blue inlet concentration and flow rate on the methylene blue degradation is also investigated. The simulation results showed that the microreactor with shorter depth and lower values of inlet concentration and flow rate has higher efficiency. Thiele modulus and Damköhler number are both estimated lower than 1. It indicates that the photocatalytic reactions occur without internal and bulk mass transfer limitations.
Farhat Sadat Meibodi; Ebrahim Soori
Abstract
Crude oil is released into the water sources during exploration, extraction or displacement operations due to the partial dissolution, and it can remain as a layer on the surface of the water or become emulsive. Crude oil emulsion is very stable due to the presence of asphaltene and cannot be removed ...
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Crude oil is released into the water sources during exploration, extraction or displacement operations due to the partial dissolution, and it can remain as a layer on the surface of the water or become emulsive. Crude oil emulsion is very stable due to the presence of asphaltene and cannot be removed by the common methods. In this research, iron oxide nanoparticles were coated with oleic acid (OA), stearic acid (SA), sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), polyvinylpyrrolidone (PVP) and polyoxyethylene (POE), by using the same method. After synthesizing iron oxide nanoparticles and coating their surface with fatty acids and surfactants, we have tried to break the crude oil emulsion in water and remove the crude oil from the environment by adsorption via these nanoparticles. Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), scanning electron microscope (SEM), thermal gravimetric analysis (TGA), vibration sample magnetometer (VSM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Zeta potential devices were used to identify nanoparticles and their characteristics. Demulsification of crude oil in water (O/W) with nanoparticles coated with fatty acids and surfactants was studied. UV-Vis spectrophotometery was used to determine the amount of crude oil adsorption by nanoparticles. From the results, the nanoparticles coated with the fatty acids with smaller chains could more absorb the crude oil. The highest adsorption (98.03 %) was recorded for iron oxide nanoparticles coated with polyoxyethylene (Fe3O4@POE) and the lowest percentage (46.69 %) is related to the nanoparticles coated with palmitic acid in an alkaline medium. Alkalinization of the medium while coating the nanoparticles with fatty acid has increased only the efficiency in the case of oleic acid while led to a significant decrease in the efficiency for palmitic and stearic acids compared to the neutral state.
Nazanin Niknezhad; Neda Azimi; Shahin Ahmadi
Abstract
The purpose of this study was numerical and experimental investigations on the influence of ultrasound on Cr (VI) removal from aqueous solution by adsorption onto activated carbon nanoparticles. The effect of key factors on Cr (VI) elimination like media pH, absorbent mass, initial concentration of Cr ...
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The purpose of this study was numerical and experimental investigations on the influence of ultrasound on Cr (VI) removal from aqueous solution by adsorption onto activated carbon nanoparticles. The effect of key factors on Cr (VI) elimination like media pH, absorbent mass, initial concentration of Cr (VI) and the location of ultrasound transducers were considered. To perform CFD modeling of ultrasound propagation, the vibrations of 1.7 MHz piezoelectric transducers (PZTs) were defined based on the dynamic mesh model. The experimental results indicated that by pH raising from 2 to 8, Cr (VI) removal efficiency had a decreasing trend and at pH=8, it had the lowest value. The adsorption rate increased by augmentation in the adsorbent mass (AM) due to the enhancing its specific surface area. In comparison with using a shaker, ultrasound showed lower needed contact time for Cr (VI) elimination at identical conditions. In addition, CFD results depicted that the acoustic streams were induced in the direction of ultrasound propagation, which is caused to reach the better mixing and Cr (VI) removal efficiency. Finally, the experimental data were adopted with the Langmuir and Freundlich isotherms. The comparison of these models showed that both models were well suited to experimental findings and the data compatibility with Langmuir model was greater.
Joanes Ooko Odero; George Lukoye Makokha; Bancy Mati; Nathan Oduor Okoth
Abstract
Surface water pollution is a challenge due to effluent discharge from land-based factors like agro-based sectors, settlements, and poor sanitation. The research investigated the spatial and seasonal variation of physico-chemical and biological water quality due to land use changes along the Thika River ...
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Surface water pollution is a challenge due to effluent discharge from land-based factors like agro-based sectors, settlements, and poor sanitation. The research investigated the spatial and seasonal variation of physico-chemical and biological water quality due to land use changes along the Thika River sub-catchment, Upper Tana, Kenya. The study applied purposive sampling technique from the different zones within the catchment during the dry and wet season of 2021. The samples were tested for physico-chemical and microbial contaminants. R-studio was used to calculate the mean values and t-test performed at a 95% confidence interval to determine variation of the parameters in the two seasons and mean levels compared to the Kenya Bureau of Standards (KEBS) 2010 and the World Health Organization (WHO) acceptable quality for drinking water. There was significant variation in sulphate and nitrate concentration, total coliform and fecal coliform and no significant variations in physical parameters throughout the seasons. The total coliform and fecal coliform exceeded KEBS and WHO limits.
Zahra Mohebi; Maryam Nazari
Abstract
Disposal of waste products and residuals into the natural water bodies can havefatal consequences for aquatic ecosystems, posing severe threats to naturalhabitats and human health. Natural treatment systems are the most suitabletreatment technologies for various types of wastewaters, which has attracted ...
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Disposal of waste products and residuals into the natural water bodies can havefatal consequences for aquatic ecosystems, posing severe threats to naturalhabitats and human health. Natural treatment systems are the most suitabletreatment technologies for various types of wastewaters, which has attracted muchattention in recent years. Phytoremediation is a plant-based technique used toeliminate or recover surplus nutrients in contaminated environments. The use ofaquatic plants in wastewater phytoremediation is very efficient due to they have avery significant ability for assimilating and degrading contaminants (e.g., nitrates,phosphates, and heavy metals). Phytoremediation is a relatively new technologythat is considered as an operational, efficient, new, and environmentally friendlytechnology that is still in the early stages of development and optimization. Itsapplication on a large scale is still limited. It should also be noted that a clear visionof this innovation should be taken into account and, accurate data should be madeavailable to the public as it will enhance its efficiency as a manageable solution inthe worldwide. Additionally, phytoremediation has been evaluated as a separatelow-tech and environmentally friendly green option compared to the existingtechnologies. The present study attempts to review the recently published literatureto explain phytoremediation technology and its advantages in purifying water andwastewater.
Mohammad Sadegh Talebi
Abstract
This research was conducted with the aim of investigating temporal and spatial changes in the quality of underground water in Marvast plain in order to be used in planning for these resources. For this reason, the underground water quality data of Marvast Plain was prepared and selected for the research ...
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This research was conducted with the aim of investigating temporal and spatial changes in the quality of underground water in Marvast plain in order to be used in planning for these resources. For this reason, the underground water quality data of Marvast Plain was prepared and selected for the research through the review and test of Run Test and Makos for the statistical period of 21 years (2001 to 2021). By performing trend analysis, the presence of trend in all data was determined and during the implementation of geostatistical methods, the trend was removed. Also, for the implementation of geostatistical methods, half-variable and half-variable cross-plot were chosen and due to the higher R2, lower RSS and stronger spatial structure, the best model was selected, and the exponential model was found to be suitable for most of the parameters. Then RBF, IDW with powers of 1 and 2, normal kriging and normal cokriging were used to perform interpolation. The most accurate method was selected for each parameter with the mutual evaluation method and three error estimation indices MAE, MBE and RMSE. The results showed that the normal cokriging method is the best method for most parameters (cation, anion, Ec, Cl, Ca, K, Mg, Na and TH). For the SAR, So4 and pH parameters, the normal kriging method and for the Na percentage parameter, the radial basis function was found to be the most suitable method. The results showed that the concentration of most parameters has an upward trend from west to east and south to north. Also, with the passage of time, the trend of reducing the quality of underground water was observed.
Nafise Jamialahmadi; Sepideh Rahimi; Ali Esmaeili
Abstract
Healthcare facilities are vital establishments to improve the public health, but with poor waste and wastewater management, may turn into a potential health risk. The fecal-oraltransmission potential of SARS-CoV-2 and the role of the wastewater as a potential sourceof infection, more than ever highlights ...
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Healthcare facilities are vital establishments to improve the public health, but with poor waste and wastewater management, may turn into a potential health risk. The fecal-oraltransmission potential of SARS-CoV-2 and the role of the wastewater as a potential sourceof infection, more than ever highlights the importance of proper wastewater managementduring the COVID-19 pandemic. This systematic review represents a picture of the currentstate of hospital wastewater (HWW) management in Iran; an upper-middle income countrywith a paucity of proper data concerning HWW management and further provides suggestions for hospital wastewater management during COVID-19 pandemic in the country. We reviewed 31 papers that published from 2005-2020 evaluated 163 hospitals from 82 cities and 17 provinces. HWW generation in Iran varies from 354 to 1892 liter per bed per day (839±363 L/bed/d). BOD, COD and TSS in the raw HWW were in the range of 119-1270, 205-1611 and 58-464 mg/L, respectively. Total coliforms and/or total fecal coliforms were in the range of 105-108 (MPN/100 mL). 44.2 % of hospitals had an active WWTP at the time of the study from which, only 15.3 % complied with discharge standards. More than 55 % of the hospitals in Iran use no disinfection, and less than 7 % comply with the discharge requirements. HWW management in Iran is very poor and there has been no improvement in HWW management within the last decade. To best respond to this pandemic, responsible authorities should address wastewater management in hospitals.
Fatemeh Asnad; Hossein Fakhari
Abstract
The occurrence of global environmental crises, combined with population growth and increased global water demand, highlights the pressing need for effective management of water resources. This includes comprehensive attention to water administration, consumption, and reporting. The objective of this ...
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The occurrence of global environmental crises, combined with population growth and increased global water demand, highlights the pressing need for effective management of water resources. This includes comprehensive attention to water administration, consumption, and reporting. The objective of this research is to investigate the frameworks of global water reporting and provide a robust and comprehensive model for water reporting in Iranian listed companies. To achieve this goal, a survey was conducted in 2023 involving sixteen experts in water reporting. The participants consisted of engineers and managers from prominent companies in the water consumption and sustainability reporting sector, as well as university professors specializing in sustainability studies and research. The aim was to identify the appropriate components of water reporting for companies listed on the Iran Stock Exchange. Subsequently, the Best-Worst Method (BWM), a multi-criteria decision-making approach, was employed to determine the importance of each reporting item and establish the priorities of the reporting components. The results revealed that the main components of water reporting, ranked in order of importance, are as follows: performance, business strategies, water-related impacts, metrics, water governance, risks and opportunities, and finally regulations and rights. These findings hold valuable implications for stock market policymakers and company managers. By recognizing these critical indicators and components, they can effectively mandate water reporting for Iranian listed companies. Furthermore, they can ensure that water reporting accurately reflects the significant aspects of corporate operations related to water resources.
Tooba Naveed; Niaz Ahmed; Shahid Bhutto; Nazeer Tunyo; Durdana Rais Hashmi
Abstract
Presently, Pakistan is the 8th largest exporter of textile products in the world andthis sector is considered the backbone of Pakistan’s economy. Due to intensifieduse of dyes, chemicals, and water, the textile sector is also listed as the highestcontributor to environmental pollution. Therefore, ...
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Presently, Pakistan is the 8th largest exporter of textile products in the world andthis sector is considered the backbone of Pakistan’s economy. Due to intensifieduse of dyes, chemicals, and water, the textile sector is also listed as the highestcontributor to environmental pollution. Therefore, to approach the demand of newglobal trend towards sustainability, the textile industry along with others need tofocus on resource recovery and reuse. The present study was therefore plannedfor the treatment of textile effluent composed from 04 textile mill samples. Thetextile effluent is treated by employing coagulation, ozone oxidation, andultrafiltration techniques. All the samples exceeded the standard limits as given inSindh Environmental Quality Standard (SEQS 2016). Each individual treatmentprovided promising results in terms of reduction in pollution load. Overall findingsrevealed a remarkable decrease in total suspended solid (TSS) (96 %), totaldissolved solid (TDS) (78 %), chemical oxygen demand (COD) (93 %), BiologicalOxygen Demand-BOD (93 %), oil & grease (96 %) and heavy metals (HM) (98 %).It is suggested that combined techniques are the best option for textile effluenttreatment.
Saliha Bouranene; Khaled Djeffal; Lotfi Zeghadnia; Abdalhak Gheid
Abstract
The objective of this study was to evaluate the coagulation-flocculation process inthe clarification of leachate from the landfill Technical Center of Souk-Ahras cityusing three coagulants based on iron: ferrous sulfate FeSO4.7H2O; ferrous chlorideFeCl2.4H2O and ferric chloride FeCl3. The influence of ...
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The objective of this study was to evaluate the coagulation-flocculation process inthe clarification of leachate from the landfill Technical Center of Souk-Ahras cityusing three coagulants based on iron: ferrous sulfate FeSO4.7H2O; ferrous chlorideFeCl2.4H2O and ferric chloride FeCl3. The influence of some parameters namelypH leachate, dose and nature of coagulant and nature of flocculant was studied.The best treatment efficiency was obtained at 20 % of FeCl3 giving a turbidity of4.09 NTU with pH adjustment of the raw leachate at acidic pH (3.5 ± 0.2) beforecoagulant addition and at a basic pH (7.5 ± 0.2) after addition of coagulant. Theiron valence and the nature of anion at which is linked, played a determinant rolein the clarification of leachate. The treatments made with ferric chloride in thepresence of a flocculant have proved that the starch was more efficient than limegiving abatement rates of 99 % for COD and 85 % for BOD5.
Mojtaba Karimaei Tabarestani; Atabak Feizi
Abstract
In this study, a probabilistic method was proposed to determine the stable riprap as a scour control measure downstream of a stilling basin, using the Monte Carlo Simulation Technique. The Kan diversion dam in Iran was selected as a case study, and various uncertainties in the model, including hydraulic ...
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In this study, a probabilistic method was proposed to determine the stable riprap as a scour control measure downstream of a stilling basin, using the Monte Carlo Simulation Technique. The Kan diversion dam in Iran was selected as a case study, and various uncertainties in the model, including hydraulic parameters for different design flood events, were taken into account during the analysis. Moreover, the relationship between the probability of failure, structure lifespan, and riprap sizing was also investigated. The results indicated that the estimates for riprap data followed a normal distribution. By utilizing the characteristics of this distribution, such as the mean and coefficient of variation, the stable riprap sizes were calculated based on the desired probability of failure and the structure lifespan. For instance, when considering a 5% probability of failure, the riprap size was determined to be 0.203 m for a 50-year design flood. Similarly, for larger floods, such as a 200-year design flood, the riprap size needed to be increased by 65%. Furthermore, as the structure lifespan increased from 25 years to 200 years, the riprap stone size saw an approximate 25% increase for a 200-year design flood.
Fábio Ivan Ivan Seibel; Guilherme Otávio Moraes Giubel Giubel; Vandré Barbosa Brião; Mehri Shabani; Maxime Pontié
Abstract
As a result of population growth and potable water scarcity, an increasing number of reverse osmosis desalination plants are being installed and operated (more than 15,000 in the world). Reverse osmosis membranes tend to reach the end of the life cycle in around two to five years, becoming a solid waste. ...
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As a result of population growth and potable water scarcity, an increasing number of reverse osmosis desalination plants are being installed and operated (more than 15,000 in the world). Reverse osmosis membranes tend to reach the end of the life cycle in around two to five years, becoming a solid waste. Recycling/repurposing these aged membranes could be a sustainable and profitable solution. This project aimed to transform end-of-life reverse osmosis membranes through the oxidation of their active layer using chlorine into nanoporous/microporous membranes, while searching possible applications for the resulting membranes. The results show that membranes oxidized at 10,000 ppm.h had a significant increase in permeability (3.1x), reaching NF-like capacity. On the other hand it was observed a decrease in the rejection of salt (4.35x) and acetaminophen (1.5x). Scanning Electron Microscopy (SEM) shows the positive effect of chlorine in the complete removal of particles deposited over the membrane. This oxidation condition also increased the average roughness (2.42x) of the membrane, as shown by Atomic Force Microscopy (AFM). Analysis by Fourier Transform Reflectance Spectroscopy (FTIR) suggests that chlorine oxidation replaced the hydrogen in the amide nitrogen. Both FTIR and SEM suggests the polyamide layer was not fully degraded. Application tests suggests that the recycled membrane can be used for the treatment of brackish and surface waters. The recycling of reverse osmosis membranes can be an alternative to simple landfill disposal, allowing owners to shift from disposal cost to revenue, as well as being a sustainable solution. The high permeability achieved on these oxidized membranes suggest many other NF/UF functions could potentially use recycled RO membranes.
Amirhossein Khourshidi; Farhad Qaderi
Abstract
In the realm of industrial development, a variety of organic pollutants, including petroleum compounds, have emerged as persistent environmental concerns due to their non-degradable nature. To effectively address this issue, plasma technology has garnered significant attention as a promising approach ...
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In the realm of industrial development, a variety of organic pollutants, including petroleum compounds, have emerged as persistent environmental concerns due to their non-degradable nature. To effectively address this issue, plasma technology has garnered significant attention as a promising approach for wastewater treatment, offering the capability to eliminate a wide spectrum of contaminants. This research capitalizes on Response surface methodology (RSM) to explore the independent and combined effects of key factors such as initial concentration, pH, applied voltage, and time on the degradation of a specific pollutant known as PNP, utilizing non-thermal discharge plasma technology. The outcomes of this investigation unveiled several noteworthy trends. Enhancing the initial pH, applied voltage, and reaction time while reducing the initial concentration exhibited a positive influence on the removal efficiency. Additionally, the study examined the interactions among these variables, revealing both antagonistic and synergistic effects. Specifically, antagonistic relationships were observed between initial concentration and initial pH, initial concentration and applied voltage, as well as applied voltage and time. On the other hand, a synergistic effect was noted between initial concentration and time. By employing an optimization approach, the optimal conditions for achieving PNP degradation were determined to be as follows: an initial concentration of 50 mg/L, pH of 9.7, applied voltage of 13.75 kV, and a reaction time of 8 min, resulting in an impressive removal efficiency of 96.503%. The findings of this study underscore the immense potential of non-thermal discharge plasma technology and the utilization of RSM in advancing the optimization of advanced oxidation processes for effective wastewater treatment.
Mohammad Hesam Falsafi; Mohsen Moghaddas; Jafarsadegh Moghaddas
Abstract
In this study, removal of heavy metals from synthetic wastewater has been investigated using silica aerogel-activated carbon composite. The synthesized adsorbent was characterized by FE-SEM, FTIR and BET techniques. The effect of amine functional groups embedded on the surface of silica aerogel-activated ...
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In this study, removal of heavy metals from synthetic wastewater has been investigated using silica aerogel-activated carbon composite. The synthesized adsorbent was characterized by FE-SEM, FTIR and BET techniques. The effect of amine functional groups embedded on the surface of silica aerogel-activated carbon 0.5 wt. % composite, optimal initial pH of removal of ions, impact of initial concentration of the solution containing heavy metal ions, adsorbent amount and contact time on removal percentage of ions were investigated. The results showed the optimal pH of 8, optimal adsorbent amount of 0.3 g for the removal of cadmium ion and 0.06 g for the removal of lead ion and optimal contact time of 80 min for cadmium and 60 min for lead ions. Adsorption data were investigated using Langmuir and Freundlich isotherms and maximum adsorption capability for cadmium and lead was obtained at 38.16 and 175.44 mg/g adsorbent, respectively.
Dlpak Ahmed Hamaamin; Amjad Maleki; Arash Azari; Azzadeen Darwesh; Mohammed Ahmadi
Abstract
Flood is inherently an uncertain phenomenon and the certainty and credibility of flood forecasting and warning systems will cause errors regardless of the sources of uncertainty. Extreme rainfall events are one of the most important input data to rainfall-runoff models, which always have uncertainty. ...
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Flood is inherently an uncertain phenomenon and the certainty and credibility of flood forecasting and warning systems will cause errors regardless of the sources of uncertainty. Extreme rainfall events are one of the most important input data to rainfall-runoff models, which always have uncertainty. Considering this issue the uncertainty of the design flood hydrograph can be investigated for different return periods. In this research first to simulate the flood hydrograph the HEC-HMS model was calibrated and validated based on the hourly flood hydrographs recorded at the basin outlet. Historical data were collected on the 24-hour maximum rainfall of Gharesoo Basin stations with 30-year statistics and the affected basins were identified. Then in each station 30 series of 30 years of artificial data with a maximum 24-hour rainfall were produced. For each of these produced stochastic series the best statistical distribution was fitted and in each series extreme values with a return period of 25 50 100 and 1000 years were calculated. Finally in each return period by combining 30 different amounts of rainfall obtained from stochastic series, the uncertainty bandwidth of the flood hydrograph was obtained during this return period. The results indicated that the highest predicted peak discharge for different return periods was between 1.2 and 1.7 times the historically recorded discharge during that return period. Generally the maximum discharge of different return periods was between 1.5 and 3 times the minimum discharge.
Neshat Etedali; Monir Doudi; Ladan Rahimzadeh Torabi; Mohammad Hossein Pazandeh
Abstract
Industrial activities present a significant threat to the environment and natural ecosystems like water and soil due to the release of toxic metals. This article primarily concentrates on the identification and isolation of bacteria, with the goal of effectively eliminating pollutants from industrial ...
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Industrial activities present a significant threat to the environment and natural ecosystems like water and soil due to the release of toxic metals. This article primarily concentrates on the identification and isolation of bacteria, with the goal of effectively eliminating pollutants from industrial wastewater. In order to achieve this goal, the study was conducted to assess the ability of bacterial strains to tolerate copper (Cu) and zinc (Zn), as well as their antibiotic resistance and ability to tolerate elevated metal concentrations. The resistance of the isolates to various metals and antibiotics were assessed using the minimum inhibitory concentration (MIC) values and disc diffusion (DD) method, respectively. The technique of colony PCR was employed to determine the identity of the bacteria that were separated. Resistance to multiple antibiotics was assessed, including Penicillin, Sulfamethoxazole, Tetracycline, Erythromycin, Amoxicillin, Cefoxitin, Streptomycin, Chloramphenicol, Vancomycin, Gentamycin, Cephalothin, Rifampicin, and Novobiocin. In the current investigation, a total of 5 bacteria with a positive gram stain and 7 bacteria with a negative gram stain were identified. The study found that the effluent from the wastewater treatment plant in Razi industrial town showed resilience to copper ions, especially at a concentration of 7mM. The effluent wastewater from the refinery unit exhibited the greatest level of tolerance towards zinc, with a concentration as high as 6mM. The rise in copper and zinc levels in industrial wastewater treatment plants causes microorganisms to develop resistance to these heavy metals. The study of Gram-positive resistant bacteria conducted in this research focused on the examination of their susceptibility to zinc and copper. Notably, Staphylococcus hominis displayed resistance to a majority of the antibiotics evaluated. However, Kocuria rosea demonstrated sensitivity to all antibiotics. Agrobacterium fabrum exhibited susceptibility to all antibiotics as opposed to other Gram-negative bacteria resistant to zinc and copper. The findings of this study indicated that some strains displayed a degree of resistance to both antibiotics and heavy metals. The presence of heavy metals in bacteria isolated from a wastewater treatment plant exhibited the capability to restrict antibiotic resistance.
Mahya Samari; Sirus Zinadini; Ali Akbar Zinatizadeh; Mohammad Jafarzadeh; Foad Gholami
Abstract
new polyethersulfone (PES) microfiltration (MF) membrane was fabricated via phase inversion method using a melamine-modified zirconium-based metal-organic framework (MOF). The wettability and permeability of the membrane were measured using water contact angle and pure water flux (PWF), respectively. ...
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new polyethersulfone (PES) microfiltration (MF) membrane was fabricated via phase inversion method using a melamine-modified zirconium-based metal-organic framework (MOF). The wettability and permeability of the membrane were measured using water contact angle and pure water flux (PWF), respectively. By introducing the MOF additive (0.1 wt. %) to the membrane matrix, the performance of the membrane in the separation of the oil-water mixture (different oil concentrations of 300 and 500 mg/L) was enhanced. The flux recovery ratio (FRR) of the modified membrane was significantly increased to 90.76 % compared to that in the bare membrane (20.41 %). Furthermore, the antifouling property was considerably improved.
Nima Asadi; Hamid Soleimanimehr; Ali Alinia-ziazi
Abstract
Although during the last two decades many studies have proved the effectiveness of the reverse osmosis system and this system has been used as a suitable and efficient method to treat drinking and industrial water and to desalinate the seawater, salt water, as well as sewage, it has some shortcomings, ...
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Although during the last two decades many studies have proved the effectiveness of the reverse osmosis system and this system has been used as a suitable and efficient method to treat drinking and industrial water and to desalinate the seawater, salt water, as well as sewage, it has some shortcomings, including sensitivity to ions, microorganisms, and organic matter in feed water causing problems such as scaling, fouling, as well as biofouling. Acidification of the permeate and its low pH are also other drawbacks of this system. This study is designed based on a two-pass reverse osmosis system, and each pass includes two stages (to provide higher system recovery). Moreover, ion exchange resin and AMBERPACK tank are used as pre-treatments considering the common problems of reverse osmosis system. Such fouling has been done to provide the required quality. It should be noted that by using the exchange resin system instead of the acid injection system, the TDS rate changed from 3.15 to 1.27 mg/L, which is equivalent to 59.68 % improvement, the LSI parameter, which in previous cases indicated severe fouling, ideally changed to -1.35 and -2.01. Also, the working pressure decreased from 13.7 bar to 12.5 bar, which indicates an 8.76 % improvement in working conditions.
Hassan Ranjbar; Mohsen Tabasi
Abstract
Consumption and drinking of healthy and high-quality water is considered an important matter in human life, so monitoring of drinking water pollution including radioactive contamination and assessing the amount of radiation exposure of people through water consumption is very important. The purpose of ...
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Consumption and drinking of healthy and high-quality water is considered an important matter in human life, so monitoring of drinking water pollution including radioactive contamination and assessing the amount of radiation exposure of people through water consumption is very important. The purpose of this investigation was to measure the concentration of gross beta and alpha activities in water samples collected from Tehran water sources. In the present study, the gross beta and alpha activity concentrations of 35 water samples in Tehran were analyzed and measured to evaluate their radiological quality using liquid scintillation method. The results of the analysis showed the activity concentration of gross alpha ranges from 48 mBq/L to 227 mBq/L with a mean of 137.5 mBq/L. the activity concentration of gross beta in the samples ranged from 49 mBq/L to 328 mBq/L with a mean of 184.7 mBq/L. Also, the correlation coefficient between the results were very strong and equal to 0.87. The results showed that the gross beta and alpha activity concentrations in all waters was lower than the standard limit of the World Health Organization (WHO) and the Institute of Standards and Industrial Research of Iran, which is 500 mBq/L and 1000 mBq/L, respectively and also waters are radiologically healthy.
Salah Meddah; Imene Djeghader; Mohamed El-Hadi Samar; Fadhel Ismail
Abstract
The objective of this work was to model and optimize the degradation of black azodye Naphthol Blue Black (NBB) by the Fenton process (advanced oxidation)using a minimum of experiments. A Plackett-Burman screening design was firstapplied to determine the main factors influencing the process. The dyediscoloration ...
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The objective of this work was to model and optimize the degradation of black azodye Naphthol Blue Black (NBB) by the Fenton process (advanced oxidation)using a minimum of experiments. A Plackett-Burman screening design was firstapplied to determine the main factors influencing the process. The dyediscoloration efficiency gave a yield approximately equal to 97 % in the bestconditions of several operating parameters used. The variance analysis (ANOVA)showed the effects of all different factors and deduced the most important ones.Subsequently, a second quadratic design of experiments central composite type(CCD) was applied using the response surface methodology (RSM) to optimizethe most important parameters deduced by the first design cited above, in order toobtain the best performance of the discoloration of NBB with this process. So from the contour plots and the response surfaces, the discoloration yield enhanced to the maximum and the optimization plot given by the Mnitab software, showed the following optimized parameters [NBB]=37.5 mg/L, [H2O2]=66.5 mg/L, [Iron]=3.5 mg/L and pH=3.4 for a yield of 100 % with a desirability of 1.0000. At last, to confirm that the discoloration was due to the degradation of the dye, the chemical oxygen demand (COD) was studied and in the optimized conditions, the degradation reached 94.78 % after 120 min of treatment. The kinetics of the dye degradation showed by the COD abatement was relatively slow compared to the kinetics of the dye discoloration.
Robert Ikechukwu Uroko; Obioma Uzoma Njoku
Abstract
This study evaluated the impact of heavy metal contents in vegetables grown in a palm oil mill effluents (POME) irrigated farmland on the biomes and well-being of humans that consume the vegetables. In this study, POME, a soil sample from POME irrigated farmland, and selected vegetables were evaluated. ...
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This study evaluated the impact of heavy metal contents in vegetables grown in a palm oil mill effluents (POME) irrigated farmland on the biomes and well-being of humans that consume the vegetables. In this study, POME, a soil sample from POME irrigated farmland, and selected vegetables were evaluated. The results showed high cadmium (Cd), chromium (Cr), lead (Pb), nickel (Ni),) and arsenic (As) and lower zinc (Zn) and copper (Cu) concentrations in POME relative to their respective permissible limits. The soil irrigated with POME had elevated levels of metals, comparable to the control soil, whereas vegetable growing in POME irrigated farmland contained increased amounts of most of the heavy metals above their respective permissible levels in edible vegetables. The plant concentration factors (PCF) of heavy metals detected in the vegetables were less than one except for V. amygdalina with PCF>1 for cobalt. The pollution load index of Cd, Cr, Cu, Co, and As in the POME soil were above 50, while high enrichment factors were obtained for Cd, Cr, Pd, Co, and arsenic. The geoaccumulation index indicated that the POME soil was strongly contaminated by Zn, Fe, Pb, Mn, Ni and extremely contaminated with Cd, Cr, Zn, Cu, and Co. The metals levels ingested daily from the vegetables were low, comparable totheir respective oral reference doses except for Mn in V. amygdalina and As in most of the vegetables. There was a high target hazard quotient for Mn, and As in most of the vegetables with hazard index (H.I.) >1 in each of the vegetables and increased cancer risk for Cd, Cr, Pb, Ni and As toxicity coupled with very high total cancer risks. These findingsshow that irrigation of farmlands with POME raises the heavy metal levels in vegetables and the risk of heavy metal toxicity.
Majid Baghdadi; Mohammad Javan; Tahere Taghizade Firozjaee; Nioushasadat Haji Seyed Javadi; Mahshid Mortazavi; Ali Torabian
Abstract
In this study, the effect of antibiotic wastewater containing 20 common pharmaceuticals (14 antibiotics and 6 non-steroidal anti-inflammatory drugs (NSAIDs)) individually as well as their combination was investigated on activatedsludge in batch reactors. The chemical oxygen demand (COD), the ammonium ...
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In this study, the effect of antibiotic wastewater containing 20 common pharmaceuticals (14 antibiotics and 6 non-steroidal anti-inflammatory drugs (NSAIDs)) individually as well as their combination was investigated on activatedsludge in batch reactors. The chemical oxygen demand (COD), the ammonium concentration, the inhibition rate and toxicity index of COD and ammonium were investigated in wastewater. The inhabitation for COD and ammonium removal was variable for each drug so that the pharmaceuticals are applied simultaneously had such a greater adverse effect on inhibition rate than individual compounds. The pretreatment of wastewaters containing drugs was performed by powdered activated carbon PAC to reduce the adverse effect of these drugs on activated sludge. The appropriate method for separation of PAC from wastewater before introducing to activated sludge process and the optimized adsorption and contact time during the pretreatment process were studied. The pretreatment of pharmaceuticals wastewater with activated carbon improved well COD and NH4+ removal to 71 % and 55 %, respectively, that demonstrate the activated carbon can be considered as a suitable pretreatment option for the activated sludge.
Saeed Khanlari; Faranak Akhlaghian
Abstract
Herbicides such as 2, 4-dichlorophenoxyacetic acid (2, 4-D) are generally carcinogenic and their existence in water cause many problems. In this work, Fe3O4/FexCuyWzOt core/shell magnetic photocatalyst was used to remove 2, 4-D. The statistical analysis of the results of the Box-Behnken experimental ...
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Herbicides such as 2, 4-dichlorophenoxyacetic acid (2, 4-D) are generally carcinogenic and their existence in water cause many problems. In this work, Fe3O4/FexCuyWzOt core/shell magnetic photocatalyst was used to remove 2, 4-D. The statistical analysis of the results of the Box-Behnken experimental design method revealed that among the constituents of the photocatalyst shell, iron had the highest effect on 2, 4-D photodegradation. The photocatalyst composition was optimized using the response surface method. The photocatalyst formulation was determined using ICP method: Fe3O4/Fe0.874Cu0.349W0.004O1.525. XRD analysis confirmed the formation of Fe3O4, CuO, and WO3 in the photocatalyst shell. TEM images showed the photocatalyst core/shell structure. Fe3O4/Fe0.874Cu0.349W0.004O1.525 photodegraded 2, 4-D under ultraviolet light irradiation with the maximum yield of 90%. The photocatalyst was also active under sunlight and LED. The kinetics of the 2, 4-D photodegradation reaction under ultra violet light irradiation was studied. It followed first order kinetic model. The rate constant of the reaction was 0.0118 min-1. The photocatalyst activity of Fe3O4/Fe0.874Cu0.349W0.004O1.525 remained constant after the fourth cycle of reuse, which is the good advantage.
Masumeh Heidarzadeh; Nourollah Abdi; Javad Varvani Farahani; Abbas Ahmadi; Hamid Toranjzar
Abstract
A mixture of urban and industrial wastewater is discharged into the Meighan wetland, Arak, Iran. The heavy metals containing wastewater leads to environmental hazards whereby phytoremediation can be used for removing pollutants from contaminated water. An essential native plant that is abundant in the ...
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A mixture of urban and industrial wastewater is discharged into the Meighan wetland, Arak, Iran. The heavy metals containing wastewater leads to environmental hazards whereby phytoremediation can be used for removing pollutants from contaminated water. An essential native plant that is abundant in the Meighan wetland is Typha Latifolia L. The effect of T. Latifolia L. was investigated on the removal of heavy metals (aluminum, zinc, copper, and nickel) at the inlet of Arak wastewater treatment plant into Meighan wetland. The soil (0-30 cm in depth) and plants (aerial and root biomass) were sampled in September 2019. In the laboratory, heavy metal accumulation in samples was measured via atomic absorption method. The results of analysis of variance (ANOVA) revealed that the concentrations of all four metals were significantly different across the soil, root, and aerial biomass. The results of mean comparison by Duncan's test indicated that the highest concentration of aluminum was in the soil, while the lowest in aerial parts. Copper was maximum in the root, and the minimum was found in the aerial parts. Also, the concentration of zinc was the highest in the root, and the lowest in the soil. And, nickel was maximum in the soil while being minimum in the root. Data showed that the concentrations of aluminum in the soil, root, and aerial biomass of T. Latifolia L. were multiple times higher than permissible limit. The concentration of nickel in the soil was slightly higher than the acceptable limit, but the concentrations of other heavy metals in the soil, in aerial biomass, and in the root of T. Latifolia L. were within the acceptable range. The results indicated T.Latifolia L. is a suitable plant for the phytoremediation and water treatment in the Meighan wetland.
