Advancement in the Fluid Dynamics Research of Reversible Pump-Turbine
Advancement in the Fluid Dynamics Research of Reversible PumpTurbine
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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.
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.
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.
Comparison of Wastewater Treatment Using Activated Carbon from Bamboo and Oil Palm
Abstract
Developing country causes growth of industries sectors. Despite that industrial sectors releases massive amount of waste water into the environment. At the same time, the increasing number of vehicles in Malaysia promotes the development of automobile workshop that produces huge amount of wastewater as well. Wastewater contains high level of suspended total solids and leave untreated. For instance oil, grease, dyestuff, chromium, phosphate in washing products and colouring, as well as heavy metals such as lead, cadmium, barium and others potential metals. All these hazardous wastes directly pollute the environment especially the groundwater and harm the ecosystem. In order to minimize and reduce the impact to the environment, the wastewater needed to be treated using technology such as permeable reactive barrier (PRB). Activated carbon is one of the PRB utilised. It is a compromised material for treatment of wastewater where there are varieties of sources to produce activated carbon. Malaysia as an active agricultural country, massive amount of agriculture wastes can be turned into activated carbon. They are two methods used to produce activated carbon, namely furnace heat processing and microwave processing. The usage of furnace and microwave instruments can produce different quality of activated carbon due to different mechanism involves. Furnace heat processing transferred the heat from external to the internal but microwave processing is vice versa. In this article, a brief overview of activated carbon usage for wastewater treatment is highlighted.
Comparison of Wastewater Treatment Using Activated Carbon from Bamboo and Oil Palm
Abstract
Developing country causes growth of industries sectors. Despite that industrial sectors releases massive amount of waste water into the environment. At the same time, the increasing number of vehicles in Malaysia promotes the development of automobile workshop that produces huge amount of wastewater as well. Wastewater contains high level of suspended total solids and leave untreated. For instance oil, grease, dyestuff, chromium, phosphate in washing products and colouring, as well as heavy metals such as lead, cadmium, barium and others potential metals. All these hazardous wastes directly pollute the environment especially the groundwater and harm the ecosystem. In order to minimize and reduce the impact to the environment, the wastewater needed to be treated using technology such as permeable reactive barrier (PRB). Activated carbon is one of the PRB utilised. It is a compromised material for treatment of wastewater where there are varieties of sources to produce activated carbon. Malaysia as an active agricultural country, massive amount of agriculture wastes can be turned into activated carbon. They are two methods used to produce activated carbon, namely furnace heat processing and microwave processing. The usage of furnace and microwave instruments can produce different quality of activated carbon due to different mechanism involves. Furnace heat processing transferred the heat from external to the internal but microwave processing is vice versa. In this article, a brief overview of activated carbon usage for wastewater treatment is highlighted.
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.
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.
A Pilot Study of an Electromagnetic Field for Control of Reverse Osmosis Membrane Fouling and Scaling During Brackish Groundwater Desalination
Abstract: This study investigated the effects of an electromagnetic field (EMF) on control of membrane
fouling and scaling during desalination of brackish groundwater using a pilot reverse osmosis (RO)
skid. The groundwater was primarily CaSO4 type with a total dissolved solids concentration of
5850 mg/L and hardness of 2500 mg/L as CaCO3. Two EMF devices were installed in the pipeline
before a cartridge filter and in the RO feed inlet to induce an electric signal of ±150 kHz to the
groundwater. The effects of EMF on membrane scaling were evaluated under accelerated conditions,
i.e., without pH adjustment and addition of antiscalant. Two-phase experiments were conducted:
Phase 1 (376 h) with the EMF devices turned on after 150 h baseline operation; and Phase 2 (753 h)
with the EMF devices turned on from the beginning of testing. The EMF significantly reduced
membrane scaling and improved RO performance by 38.3% and 14.3% in terms of normalized water
permeability decline rate after 150 h and 370 h operation, respectively. Membrane autopsy results
indicated that the fouling layer formed under the influence of EMF was loose with a low density and
was easily removed by hydraulic flushing
A Pilot Study of an Electromagnetic Field for Control of Reverse Osmosis Membrane Fouling and Scaling During Brackish Groundwater Desalination
Abstract: This study investigated the effects of an electromagnetic field (EMF) on control of membrane
fouling and scaling during desalination of brackish groundwater using a pilot reverse osmosis (RO)
skid. The groundwater was primarily CaSO4 type with a total dissolved solids concentration of
5850 mg/L and hardness of 2500 mg/L as CaCO3. Two EMF devices were installed in the pipeline
before a cartridge filter and in the RO feed inlet to induce an electric signal of ±150 kHz to the
groundwater. The effects of EMF on membrane scaling were evaluated under accelerated conditions,
i.e., without pH adjustment and addition of antiscalant. Two-phase experiments were conducted:
Phase 1 (376 h) with the EMF devices turned on after 150 h baseline operation; and Phase 2 (753 h)
with the EMF devices turned on from the beginning of testing. The EMF significantly reduced
membrane scaling and improved RO performance by 38.3% and 14.3% in terms of normalized water
permeability decline rate after 150 h and 370 h operation, respectively. Membrane autopsy results
indicated that the fouling layer formed under the influence of EMF was loose with a low density and
was easily removed by hydraulic flushing
Perspectives And Applications Of Nanotechnology In Water Treatment
Abstract
Industrialization and excessive use of pesticides for boosting agricultural production have adversely affected the ecosystem, polluting natural water reserves. Remediation of contaminated water has been an area of concern with numerous techniques being applied to improve the quality of naturally available water to the level suitable for human consumption. Most of these methods, however, generate by-products that are sometimes toxic. Heterogenous photocatalysis using metal oxide nanostructures for water purification is an attractive option because no harmful by-products are created. A discussion on possible methods to engineer metal oxides for visible light photocatalysis is included to highlight the use of solar energy for water purification. Multifunctional photocatalytic membranes are considered advantageous over freely suspended nanoparticles due to the ease of its removal from the purified water. An overview of water remediation techniques is presented, highlighting innovations through nanotechnology for possible addressing of problems associated with current techniques.
Perspectives And Applications Of Nanotechnology In Water Treatment
Abstract
Industrialization and excessive use of pesticides for boosting agricultural production have adversely affected the ecosystem, polluting natural water reserves. Remediation of contaminated water has been an area of concern with numerous techniques being applied to improve the quality of naturally available water to the level suitable for human consumption. Most of these methods, however, generate by-products that are sometimes toxic. Heterogenous photocatalysis using metal oxide nanostructures for water purification is an attractive option because no harmful by-products are created. A discussion on possible methods to engineer metal oxides for visible light photocatalysis is included to highlight the use of solar energy for water purification. Multifunctional photocatalytic membranes are considered advantageous over freely suspended nanoparticles due to the ease of its removal from the purified water. An overview of water remediation techniques is presented, highlighting innovations through nanotechnology for possible addressing of problems associated with current techniques.
Overview Of The Main Disinfection Processes For Wastewater And Drinking water Treatment Plants
Abstract: The use of water disinfection as a public health measure reduces the spread of diseases. Various disinfection technologies can be used to meet the pathogen inactivation demand in water. This work is an overview of the main disinfection technologies of wastewater and drinking water that reports for the conventional processes the action mechanism, the possible formation of by-products, the operative conditions, the advantages and disadvantages. For advanced and natural processes the action mechanisms are reported. Advanced technologies are interesting but are still in the research state, while conventional technologies are the most used. There is a tendency, especially in Italy, to use chlorine-based disinfectant, despite in some forms could lead to production of disinfection by-products.
Overview Of The Main Disinfection Processes For Wastewater And Drinking water Treatment Plants
Abstract: The use of water disinfection as a public health measure reduces the spread of diseases. Various disinfection technologies can be used to meet the pathogen inactivation demand in water. This work is an overview of the main disinfection technologies of wastewater and drinking water that reports for the conventional processes the action mechanism, the possible formation of by-products, the operative conditions, the advantages and disadvantages. For advanced and natural processes the action mechanisms are reported. Advanced technologies are interesting but are still in the research state, while conventional technologies are the most used. There is a tendency, especially in Italy, to use chlorine-based disinfectant, despite in some forms could lead to production of disinfection by-products.
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.
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