Researches
Coupled Anaerobic/Aerobic Treatment Of High-Sulfate Wastewater With Sulfate Reduction And Biological Sulfide Oxidation
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Engineered Nanomaterials for Water Treatment and Remediation
Water is one of the world’s most abundant resources, but less than 1% of the global supply of water is available and safe for human consumption [1]. According to the World Health Organization, over 760 million people were without adequate drinking water supply in 2011 [2]. Where it is available, the cost of potable water is rising due to increasing energy costs, growing populations, and climatic or other environmental issues [1,3]. In addition, an increasing number of drinking water sources are showing evidence of contamination, especially by emerging pollutants like pharmaceuticals and personal care products [4,5]. Many traditional water and wastewater treatment methods do not effectively remove these emerging contaminants, and/or are not capable of removing enough to meet increasingly stringent water quality standards [5,6]. Contamination of surface waters also constitutes a risk to water supplies because pollutants may penetrate into aquifers, where they can be transported to drinking water sources.
Engineered Nanomaterials for Water Treatment and Remediation
Water is one of the world’s most abundant resources, but less than 1% of the global supply of water is available and safe for human consumption [1]. According to the World Health Organization, over 760 million people were without adequate drinking water supply in 2011 [2]. Where it is available, the cost of potable water is rising due to increasing energy costs, growing populations, and climatic or other environmental issues [1,3]. In addition, an increasing number of drinking water sources are showing evidence of contamination, especially by emerging pollutants like pharmaceuticals and personal care products [4,5]. Many traditional water and wastewater treatment methods do not effectively remove these emerging contaminants, and/or are not capable of removing enough to meet increasingly stringent water quality standards [5,6]. Contamination of surface waters also constitutes a risk to water supplies because pollutants may penetrate into aquifers, where they can be transported to drinking water sources.
Current Advances in Membrane Technologies for Saline Wastewater Treatment A Comprehensive Review
ABSTRACT
The saline wastewater from various sources including agriculture and industrial activities, appears to have high salt concentration, organic content and other pollutants which can harm the environment. Thus, saline waste[1]water treatment has become one of the major concerns in many countries. Membrane technology offers great potential in saline wastewater treatment due to its high permeate quality, flexibility, and desalination capability. This paper highlights the current development in various types of membrane processes such as pressure driven[1]based membranes, forward osmosis, membrane distillation, electrodialysis and membrane bioreactor, either as a stand-alone or integrated process for saline wastewater treatment. The membranes performance in terms of water reclamation as well as resource recovery is discussed. Besides, the membrane fouling issue is highlighted, and the efficiency of various fouling mitigation strategies when dealing with real/challenging saline wastewater are reviewed. Finally, the future challenges and outlook in the context of membrane application for saline wastewater treatment are discussed.
Current Advances in Membrane Technologies for Saline Wastewater Treatment A Comprehensive Review
ABSTRACT
The saline wastewater from various sources including agriculture and industrial activities, appears to have high salt concentration, organic content and other pollutants which can harm the environment. Thus, saline waste[1]water treatment has become one of the major concerns in many countries. Membrane technology offers great potential in saline wastewater treatment due to its high permeate quality, flexibility, and desalination capability. This paper highlights the current development in various types of membrane processes such as pressure driven[1]based membranes, forward osmosis, membrane distillation, electrodialysis and membrane bioreactor, either as a stand-alone or integrated process for saline wastewater treatment. The membranes performance in terms of water reclamation as well as resource recovery is discussed. Besides, the membrane fouling issue is highlighted, and the efficiency of various fouling mitigation strategies when dealing with real/challenging saline wastewater are reviewed. Finally, the future challenges and outlook in the context of membrane application for saline wastewater treatment are discussed.
Nanotechnology in Water Treatment
ABSTRACT Drinking water is unfortunately becoming a rare luxury on our planet.On the other hand, with a trend of population growth, need for water which is essential to life,is becomingbigger every day.Practical application of nanotechnology in saving water worldwide is in using nanoparticles in detection of water pollution and water purification. This knowledge has importance in medicine and public health, so as in environment safety.Possible application areas of nanotechnology in field of purification and treatment of water are in filtration, catalytic and separation processes, ion exchanging, sensitive pollutant detection,etc.Nanotechnology could be the main solution in future fortreatment of surface water,groundwater, and waste water contaminated by toxic metal ions, organic and inorganic solutes, and microorganisms.
Nanotechnology in Water Treatment
ABSTRACT Drinking water is unfortunately becoming a rare luxury on our planet.On the other hand, with a trend of population growth, need for water which is essential to life,is becomingbigger every day.Practical application of nanotechnology in saving water worldwide is in using nanoparticles in detection of water pollution and water purification. This knowledge has importance in medicine and public health, so as in environment safety.Possible application areas of nanotechnology in field of purification and treatment of water are in filtration, catalytic and separation processes, ion exchanging, sensitive pollutant detection,etc.Nanotechnology could be the main solution in future fortreatment of surface water,groundwater, and waste water contaminated by toxic metal ions, organic and inorganic solutes, and microorganisms.
Water Desalination Using Solar Thermal Collectors Enhanced by Nanofluids
Introduction
In the future, the world is confronted with energy and freshwater shortage. Desalination of brackish or seawater is one of the most important ways to solve the water scarcity issue [1, 2]. The use of solar energy or waste heat sources is acceptable for water-producing systems of such a small size [3–5]. The relevancy of nanomaterials is to realize the best attainable properties within the smallest possible loadings through homogenized distribution and stable suspension of these nanoparticles[6–11]. Often, heat transfer improvement in solar collectors is one of the basic problems in energy saving, compact designs, and different operating temperatures. Researchers also investigated the multiwalled carbon nanotubes (MWCNTs) and water nanofluids with a pH of 3.5, 6.5, and 9.5, and Triton X-100 as a surfactant (0.2 wt %) using flat-plate solar collectors. It was found that the nanofluids have better heat transfer performance in acidic and alkaline water due to the influence of the isoelectric point. The higher efficiency (67 %) was obtained at pH 9.5 and 3.5 with a water flow rate of 0.0333 kg s–1. A stable nanofluid based on ethylene glycol-containing nanosheets of graphene oxide was prepared by Yu et al. [12]. The improvement in thermal conductivity relies strongly on the volume fraction of the nanosheet of graphene oxide and increases with higher nanoparticle loading. The heat efficiency was enhanced up to 61.0 % using a nanosheet loading of 5.0 vol %. For seven days, the thermal conductivity of the fluids remained almost constant, which suggests their high stability. In the measured temperature range, the enhancement value was independent of the temperature. Peyghambarzadeh et al. [13, 14] studied force convection techniques in an excessively base water nanofluid, which was experimentally compared to water in a vehicle heat exchanger with different nanofluid loadings. It was experimentally investigated to improve the rate of heat transfer. The variable effect of the inlet temperature of the fluid in the heat exchanger on the heat transfer coefficient was evaluated. The findings showed that the incremental fluid circulation rate would increase the output rate of heat transfer, while the temperature of the fluid entering the heat exchanger had negligible effects. Meanwhile, water nanofluid subservience at low-volume loadings would increase the heat transfer rate efficiency by approximately 44 % compared to water
Water Desalination Using Solar Thermal Collectors Enhanced by Nanofluids
Introduction
In the future, the world is confronted with energy and freshwater shortage. Desalination of brackish or seawater is one of the most important ways to solve the water scarcity issue [1, 2]. The use of solar energy or waste heat sources is acceptable for water-producing systems of such a small size [3–5]. The relevancy of nanomaterials is to realize the best attainable properties within the smallest possible loadings through homogenized distribution and stable suspension of these nanoparticles[6–11]. Often, heat transfer improvement in solar collectors is one of the basic problems in energy saving, compact designs, and different operating temperatures. Researchers also investigated the multiwalled carbon nanotubes (MWCNTs) and water nanofluids with a pH of 3.5, 6.5, and 9.5, and Triton X-100 as a surfactant (0.2 wt %) using flat-plate solar collectors. It was found that the nanofluids have better heat transfer performance in acidic and alkaline water due to the influence of the isoelectric point. The higher efficiency (67 %) was obtained at pH 9.5 and 3.5 with a water flow rate of 0.0333 kg s–1. A stable nanofluid based on ethylene glycol-containing nanosheets of graphene oxide was prepared by Yu et al. [12]. The improvement in thermal conductivity relies strongly on the volume fraction of the nanosheet of graphene oxide and increases with higher nanoparticle loading. The heat efficiency was enhanced up to 61.0 % using a nanosheet loading of 5.0 vol %. For seven days, the thermal conductivity of the fluids remained almost constant, which suggests their high stability. In the measured temperature range, the enhancement value was independent of the temperature. Peyghambarzadeh et al. [13, 14] studied force convection techniques in an excessively base water nanofluid, which was experimentally compared to water in a vehicle heat exchanger with different nanofluid loadings. It was experimentally investigated to improve the rate of heat transfer. The variable effect of the inlet temperature of the fluid in the heat exchanger on the heat transfer coefficient was evaluated. The findings showed that the incremental fluid circulation rate would increase the output rate of heat transfer, while the temperature of the fluid entering the heat exchanger had negligible effects. Meanwhile, water nanofluid subservience at low-volume loadings would increase the heat transfer rate efficiency by approximately 44 % compared to water
Fouling and Cleaning Characteristics of Reverse Osmosis (RO) Membranes
Abstract:
This work deals with fouling and successive cleaning of RO membrane fouled by an organic foulant, sodium alginate using a laboratory-scale cross flow test unit. First, spiral-wound RO membrane was fouled with sodium alginate solution up to 10% and 15%, respectively at an applied pressure of 1380 kPa with flow rate of 10 lit/min. An anionic surfactant, sodium dodecyl sulfate (SDS) was used as a chemical cleaning agent for cleaning of RO membrane. The effect of cleaning chemical dose and cross-flow velocity on the membrane chemical cleaning duration to achieve 100% cleaning efficiency (i.e., to get original water flux) was also investigated. As the SDS concentration increases, the membrane chemical cleaning time decreases due to increase in the solubility of the foulant (when the surface tension decreases by an increase in the SDS concentration). Furthermore, the membrane chemical cleaning time decreases with increasing cross-flow velocity of the cleaning chemical solution (SDS). Higher cross-flow velocity enhances the turbulence at the fouling layer and hence the mass transfer of the foulant from the fouling layer to the bulk solution is improved, then the SDS has weakened the structural integrity of the fouling layer. It is observed that better cleaning is occurred with higher concentration of SDS and flow rate. The obtained results clearly reveal that SDS cleaning is proved to be an efficient cleaning method for RO membranes fouled with organic foulant.
Fouling and Cleaning Characteristics of Reverse Osmosis (RO) Membranes
Abstract:
This work deals with fouling and successive cleaning of RO membrane fouled by an organic foulant, sodium alginate using a laboratory-scale cross flow test unit. First, spiral-wound RO membrane was fouled with sodium alginate solution up to 10% and 15%, respectively at an applied pressure of 1380 kPa with flow rate of 10 lit/min. An anionic surfactant, sodium dodecyl sulfate (SDS) was used as a chemical cleaning agent for cleaning of RO membrane. The effect of cleaning chemical dose and cross-flow velocity on the membrane chemical cleaning duration to achieve 100% cleaning efficiency (i.e., to get original water flux) was also investigated. As the SDS concentration increases, the membrane chemical cleaning time decreases due to increase in the solubility of the foulant (when the surface tension decreases by an increase in the SDS concentration). Furthermore, the membrane chemical cleaning time decreases with increasing cross-flow velocity of the cleaning chemical solution (SDS). Higher cross-flow velocity enhances the turbulence at the fouling layer and hence the mass transfer of the foulant from the fouling layer to the bulk solution is improved, then the SDS has weakened the structural integrity of the fouling layer. It is observed that better cleaning is occurred with higher concentration of SDS and flow rate. The obtained results clearly reveal that SDS cleaning is proved to be an efficient cleaning method for RO membranes fouled with organic foulant.
Applications of Nanotechnology in Wastewater Treatment
Abstract:
Waste water treatment issues have been a growing problems these days. Its treatment is becoming must in this Industrial world. Nanoparticles have a great potential to be used in waste water treatment. Some of the unique characteristics of it having high surface area can be used efficiently for removing toxic metal ions, disease causing microbes, inorganic and organic solutes from water. The different classes of nanomaterials also have the authority to be efficient for water treatment like metal-containing nanoparticles, carbonaceous nanomaterials and zeolites. The review includes recent development in nanotechnology for water and wastewater treatment. The paper covers nanomaterials that enables the applications, advantages and limitations as compared to existing processes. Nanotechnology has led to various efficient ways for treatment of waste water in a more precise and accurate way on both small and large scale.
Applications of Nanotechnology in Wastewater Treatment
Abstract:
Waste water treatment issues have been a growing problems these days. Its treatment is becoming must in this Industrial world. Nanoparticles have a great potential to be used in waste water treatment. Some of the unique characteristics of it having high surface area can be used efficiently for removing toxic metal ions, disease causing microbes, inorganic and organic solutes from water. The different classes of nanomaterials also have the authority to be efficient for water treatment like metal-containing nanoparticles, carbonaceous nanomaterials and zeolites. The review includes recent development in nanotechnology for water and wastewater treatment. The paper covers nanomaterials that enables the applications, advantages and limitations as compared to existing processes. Nanotechnology has led to various efficient ways for treatment of waste water in a more precise and accurate way on both small and large scale.
Correlation Between BOD5 and COD for Al- Diwaniyah Wastewater Treatment Plants to Obtain The Biodigrability Indices
ABSTRACT
The present study aims to establish an empirical correlation between biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) of the sewage flowing in Al-Diwaniyah wastewater treatment plant. The strength of the wastewater entering the plant varied from medium to high. High concentrations of BOD5 and COD in the effluent were obtained due to the poor performance of the plant. This was observed from the BOD5 /COD ratios that did not confirm with the typical ratios for the treated sewage. Regression equations for BOD5 and COD removal percentages were suggested which can be used to evaluate rapid effluent assessment after the treatment processes or optimal process control to improve the performance of wastewater treatment plants. The average Biodegradability indices (B.I) of Al-Diwaniyah wastewater plants was found to be 0.69. The equations relating the percentage removal of BOD5(y) with influent BOD5(x), y= 0.044x + 80.66 and the percentage removal of COD (y) with influent COD (x), y= 0.045x + 55.15 were found with high correlation R2 =0.72 and 0.86 respectively. Keywords: BOD5, COD, BOD5/COD ratio, Biodegradability indices, BOD5 and COD correlations
Correlation Between BOD5 and COD for Al- Diwaniyah Wastewater Treatment Plants to Obtain The Biodigrability Indices
ABSTRACT
The present study aims to establish an empirical correlation between biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) of the sewage flowing in Al-Diwaniyah wastewater treatment plant. The strength of the wastewater entering the plant varied from medium to high. High concentrations of BOD5 and COD in the effluent were obtained due to the poor performance of the plant. This was observed from the BOD5 /COD ratios that did not confirm with the typical ratios for the treated sewage. Regression equations for BOD5 and COD removal percentages were suggested which can be used to evaluate rapid effluent assessment after the treatment processes or optimal process control to improve the performance of wastewater treatment plants. The average Biodegradability indices (B.I) of Al-Diwaniyah wastewater plants was found to be 0.69. The equations relating the percentage removal of BOD5(y) with influent BOD5(x), y= 0.044x + 80.66 and the percentage removal of COD (y) with influent COD (x), y= 0.045x + 55.15 were found with high correlation R2 =0.72 and 0.86 respectively. Keywords: BOD5, COD, BOD5/COD ratio, Biodegradability indices, BOD5 and COD correlations
Removal of Escherichia Coli from Domestic Wastewater Using Electrocoagulation
ABSTRACT
The objective of this study was to evaluate the efficiency of electrocoagulation in the removal of Escherichia coli from domestic and urban wastewaters and to determine the effects of the main operational parameters on the process. An electrocoagulation reactor with aluminum and iron electrodes was built for this purpose. A factorial design was applied, where amperage, treatment time, and pH were considered as the factors and E. coli percent removal was the response variable. After 20 min of treatment, >97% removal efficiency was achieved. The highest E. coli removal efficiency achieved was 99.9% at a neutral pH of 7, amperage of 3 A, and treatment time of 60 min. However, the removal efficiency of close to 99% was also achieved at natural wastewater pH of 8.5. The statistical analyses showed that the three tested factors significantly affected the E. coli removal percentage (p < 0.05). These results indicate that electrocoagulation has a high disinfection power in a primary reactor in removing water con[1]taminants as well as simultaneously removing pathogenic microorganisms when compared to biological treatment processes. This represents an additional benefit, because it will considerably reduce the use of chlorine during the final disinfection stage.
Removal of Escherichia Coli from Domestic Wastewater Using Electrocoagulation
ABSTRACT
The objective of this study was to evaluate the efficiency of electrocoagulation in the removal of Escherichia coli from domestic and urban wastewaters and to determine the effects of the main operational parameters on the process. An electrocoagulation reactor with aluminum and iron electrodes was built for this purpose. A factorial design was applied, where amperage, treatment time, and pH were considered as the factors and E. coli percent removal was the response variable. After 20 min of treatment, >97% removal efficiency was achieved. The highest E. coli removal efficiency achieved was 99.9% at a neutral pH of 7, amperage of 3 A, and treatment time of 60 min. However, the removal efficiency of close to 99% was also achieved at natural wastewater pH of 8.5. The statistical analyses showed that the three tested factors significantly affected the E. coli removal percentage (p < 0.05). These results indicate that electrocoagulation has a high disinfection power in a primary reactor in removing water con[1]taminants as well as simultaneously removing pathogenic microorganisms when compared to biological treatment processes. This represents an additional benefit, because it will considerably reduce the use of chlorine during the final disinfection stage.
Adsorption Characteristics of Multi-Metal Ions by Red Mud, Zeolite, Limestone and Oyster Shell
Abstract
In this study, the performance of different adsorbents—red clay, zeolite, limestone, and oyster shell—for adsorption of polymetallic ions (Cr3+, Ni2+, Cu2+, Zn2+, As3+, Cd2+, and Pb2+) were investigated from aqueous solutions.
Adsorption Characteristics of Multi-Metal Ions by Red Mud, Zeolite, Limestone and Oyster Shell
Abstract
In this study, the performance of different adsorbents—red clay, zeolite, limestone, and oyster shell—for adsorption of polymetallic ions (Cr3+, Ni2+, Cu2+, Zn2+, As3+, Cd2+, and Pb2+) were investigated from aqueous solutions.
Analysis of the Flux Performance of Different RO/NF Membranes in the Treatment of Agroindustrial Wastewater by Means of the Boundary Flux Theory
Abstract:
Dynamic membrane system behaviour must be adequately addressed to avoid process unfeasibility. The lack of proper analysis will mean relying on erroneous permeate flux values in the system design, which will lead to quick and/or steady high fouling rates. In this paper, the authors present additional data supporting the boundary flux theory as a helpful tool for membrane engineers to carefully avoid process failures. By fitting the dynamic permeate flux data to the
boundary flux model, it was possible to calculate the β fouling index for the three selected membranes (one nanofiltration (NF) and two reverse osmosis (RO) ones). The dynamic flux given by the low-pressure RO membrane did not follow sub-boundary operating conditions, since a sharp flux loss was measured throughout the whole operating cycle, pinpointing that supra-boundary flux conditions were governing the system. This was supported by the calculated value of the β fouling parameter, which resulted to be in the order of ten times higher for this membrane. However, the values of β→0 for the SC-RO and DK-NF ones, supported by the very low value of the sub-boundary fouling parameter α (0.002 and 0.007 L·h −1·m−2 ·bar−2 , respectively), ensure nearly boundary operating conditions for these membranes.
Analysis of the Flux Performance of Different RO/NF Membranes in the Treatment of Agroindustrial Wastewater by Means of the Boundary Flux Theory
Abstract:
Dynamic membrane system behaviour must be adequately addressed to avoid process unfeasibility. The lack of proper analysis will mean relying on erroneous permeate flux values in the system design, which will lead to quick and/or steady high fouling rates. In this paper, the authors present additional data supporting the boundary flux theory as a helpful tool for membrane engineers to carefully avoid process failures. By fitting the dynamic permeate flux data to the
boundary flux model, it was possible to calculate the β fouling index for the three selected membranes (one nanofiltration (NF) and two reverse osmosis (RO) ones). The dynamic flux given by the low-pressure RO membrane did not follow sub-boundary operating conditions, since a sharp flux loss was measured throughout the whole operating cycle, pinpointing that supra-boundary flux conditions were governing the system. This was supported by the calculated value of the β fouling parameter, which resulted to be in the order of ten times higher for this membrane. However, the values of β→0 for the SC-RO and DK-NF ones, supported by the very low value of the sub-boundary fouling parameter α (0.002 and 0.007 L·h −1·m−2 ·bar−2 , respectively), ensure nearly boundary operating conditions for these membranes.
Removal Of Polar Organic Micropollutants By Pilot-Scale Reverse Osmosis Drinking Water Treatment
Abstract : The robustness of reverse osmosis (RO) against polar organic micropollutants (MPs) was investigated in
pilot-scale drinking water treatment. Experiments were carried in hypoxic conditions to treat a raw anaerobic riverbank filtrate spiked with a mixture of thirty model compounds. The chemicals were selected from scientific literature data based on their relevance for the quality of freshwater systems, RO permeate and drinking water. MPs passage and the influence of permeate flux were evaluated with a typical low-pressure RO membrane and quantified by liquid chromatography coupled to high-resolution mass spectrometry. A strong inverse correlation between size and passage of neutral hydrophilic compounds was observed. This correlation was weaker for moderately hydrophobic MPs. Anionic MPs displayed nearly no passage due to electrostatic repulsion with the negatively charged membrane surface,
whereas breakthrough of small cationic MPs could be observed. The passage figures observed for the investigated set of MPs ranged from less than 1%e25%. Statistical analysis was performed to evaluate the relationship between physicochemical properties and passage. The effects of permeate flux were more pronounced for small neutral MPs, which displayed a higher passage after a pressure drop.
Removal Of Polar Organic Micropollutants By Pilot-Scale Reverse Osmosis Drinking Water Treatment
Abstract : The robustness of reverse osmosis (RO) against polar organic micropollutants (MPs) was investigated in
pilot-scale drinking water treatment. Experiments were carried in hypoxic conditions to treat a raw anaerobic riverbank filtrate spiked with a mixture of thirty model compounds. The chemicals were selected from scientific literature data based on their relevance for the quality of freshwater systems, RO permeate and drinking water. MPs passage and the influence of permeate flux were evaluated with a typical low-pressure RO membrane and quantified by liquid chromatography coupled to high-resolution mass spectrometry. A strong inverse correlation between size and passage of neutral hydrophilic compounds was observed. This correlation was weaker for moderately hydrophobic MPs. Anionic MPs displayed nearly no passage due to electrostatic repulsion with the negatively charged membrane surface,
whereas breakthrough of small cationic MPs could be observed. The passage figures observed for the investigated set of MPs ranged from less than 1%e25%. Statistical analysis was performed to evaluate the relationship between physicochemical properties and passage. The effects of permeate flux were more pronounced for small neutral MPs, which displayed a higher passage after a pressure drop.
A Review of Reverse Osmosis Membrane Fouling and Control Strategies
Introduction
This paper reviews membrane contamination and dirt Control strategies, focusing on the latest developments.
The first goal From this paper is to illustrate the types of dirt.
The second goal is To discuss the latest pollution mitigation strategies, including pre-treatment, monitoring, cleaning, and surface modification as well as updates.
A Review of Reverse Osmosis Membrane Fouling and Control Strategies
Introduction
This paper reviews membrane contamination and dirt Control strategies, focusing on the latest developments.
The first goal From this paper is to illustrate the types of dirt.
The second goal is To discuss the latest pollution mitigation strategies, including pre-treatment, monitoring, cleaning, and surface modification as well as updates.
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