Value Engineering for Low Voltage Networks
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Engineering Aspects of Reverse Osmosis Module Design
Abstract:
During the half century of development from a laboratory discovery to plants capable of producing up to half a million tons of desalinated seawater per day, Reverse Osmosis (RO) technology has undergone rapid transition. This transition process has caused signification transformation and consolidation in membrane chemistry, module design, and RO plant configuration and operation. From the early days, when cellulose acetate membranes were used in hollow fiber module configuration, technology has transitioned to thin film composite polyamide flat-sheet membranes in a spiral wound configuration. Early elements – about 4-inches in diameter during the early 70s – displayed flow rates approaching 250 L/h and sodium chloride rejection of about 98.5 percent. One of today’s 16-inch diameter elements is capable of delivering 15-30 times more permeate (4000-8000 L/h) with 5 to 8 times less salt passage (hence a rejection rate of 99.7 percent or higher).
This paper focuses on the transition process in RO module configuration, and how it helped to achieve these performance improvements. An introduction is provided to the two main module configurations present in the early days, hollow fiber and spiral wound and the convergence to spiral wound designs is described as well. The development and current state of the art of the spiral wound element is then reviewed in more detail, focusing on membrane properties (briefly), membrane sheet placement (sheet length and quantity), the changes in materials used (e.g. feed and permeate spacers), element size (most notably diameter), element connection systems (interconnectors versus interlocking systems). The paper concludes with some future perspectives, describing areas for further improvement.
Engineering Aspects of Reverse Osmosis Module Design
Abstract:
During the half century of development from a laboratory discovery to plants capable of producing up to half a million tons of desalinated seawater per day, Reverse Osmosis (RO) technology has undergone rapid transition. This transition process has caused signification transformation and consolidation in membrane chemistry, module design, and RO plant configuration and operation. From the early days, when cellulose acetate membranes were used in hollow fiber module configuration, technology has transitioned to thin film composite polyamide flat-sheet membranes in a spiral wound configuration. Early elements – about 4-inches in diameter during the early 70s – displayed flow rates approaching 250 L/h and sodium chloride rejection of about 98.5 percent. One of today’s 16-inch diameter elements is capable of delivering 15-30 times more permeate (4000-8000 L/h) with 5 to 8 times less salt passage (hence a rejection rate of 99.7 percent or higher).
This paper focuses on the transition process in RO module configuration, and how it helped to achieve these performance improvements. An introduction is provided to the two main module configurations present in the early days, hollow fiber and spiral wound and the convergence to spiral wound designs is described as well. The development and current state of the art of the spiral wound element is then reviewed in more detail, focusing on membrane properties (briefly), membrane sheet placement (sheet length and quantity), the changes in materials used (e.g. feed and permeate spacers), element size (most notably diameter), element connection systems (interconnectors versus interlocking systems). The paper concludes with some future perspectives, describing areas for further improvement.
How To Add Value To Your Estimates With Value Engineering
A Brief History
During World War II, value engineering was first introduced in the manufacturing industry by General Electric. In the beginning, they actually called it “value analysis” because of the shortage of supplies, skilled labor, parts, and materials during the war. Interestingly enough, this time of scarcity allowed the AEC industry to apply value engineering methods to a variety of projects. This eventually grew into a highly efficient and valuable process that is still practiced today.1 A
How To Add Value To Your Estimates With Value Engineering
A Brief History
During World War II, value engineering was first introduced in the manufacturing industry by General Electric. In the beginning, they actually called it “value analysis” because of the shortage of supplies, skilled labor, parts, and materials during the war. Interestingly enough, this time of scarcity allowed the AEC industry to apply value engineering methods to a variety of projects. This eventually grew into a highly efficient and valuable process that is still practiced today.1 A
Development Of An Engineered Wetland System For Sustainable Landfill Leachate Treatment
ABSTRACT
Sustainable and effective treatment of landfill leachate has become one of the most important environmental problems due to the fluctuating composition and quantity, as well as its high concentrations of pollutants. High-tech solutions applied for the leachate treatment are expensive and energy consuming, and in addition they are not suitable at many landfill sites, especially those in rural areas. Hence there is need to develop novel and sustainable low-energy systems for the effective treatment of landfill leachates. Constructed wetlands (CWs) are inexpensive simple to operate and they have the potential to remove not only organic carbon and nitrogen compounds, but heavy metals. This study focussed on the design, development and experimental investigation of a novel CWs for the treatment of landfill leachate. The CWs employed dewatered ferric waterworks sludge (DFWS) as the main substrate. The overall aim of the study was to design and assess the novel configuration of the CWs, whilst also contributing to advancing the understanding of pollutant removal from the landfill leachate in the CWs, through the development of models to explain the internal processes and predict performance. The key design and operational variables investigated were: the primary media used, i.e. the DFWS, and the wetting and drying regimes. The CWs was configured as 4- stages in series which was operated for 220 days. Thereafter, an additional unit was added due to clogging and the CWs was operated for 185 days in this second period. Results and experimental observations indicate that the chemical treatment processes (adsorption and precipitation) contributed to the clogging. The DFWS used served as adsorbent for heavy metals removal in the system. Results of heavy metals, organic matter (COD), ammonia and total nitrogen removal indicate average removals of 99%, 62%, 83% and 81%, respectively in first period; and 100%, 86%, 90% and 82% in second period, with an average heavy metals loading rate 0.76 g m-2 day-1 , organic loading rate 1070 g m-2 day-1 , ammonia loading rate of 178 g m-2 day-1 and total nitrogen loading rate 192 g m-2 day-1 . Results were supported through mathematical analysis using STELLA model for heavy metals transformation in CWs and numerical modelling using HYDRUS CW2D, which enhanced understanding of the internal processes for organic matter and nitrogen 3removal. The result from STELLA modelling showed that up to 90% of the removal of heavy metals was through adsorption, which is highly significant. While HYDRUS CW2D results showed that the main path of nitrogen removal was through simultaneous nitrification and denitrification. Overall, results have shown that CWs design has great potential for reduction of metals and nutrients in landfill leachate. Results of this study can contribute to future CW research and design for landfill leachate treatment, through the increased understanding of long-term pollutant removal in these systems. In time, this may result in the wider application of CWs for landfill leachate treatment to better protect the environment.
Development Of An Engineered Wetland System For Sustainable Landfill Leachate Treatment
ABSTRACT
Sustainable and effective treatment of landfill leachate has become one of the most important environmental problems due to the fluctuating composition and quantity, as well as its high concentrations of pollutants. High-tech solutions applied for the leachate treatment are expensive and energy consuming, and in addition they are not suitable at many landfill sites, especially those in rural areas. Hence there is need to develop novel and sustainable low-energy systems for the effective treatment of landfill leachates. Constructed wetlands (CWs) are inexpensive simple to operate and they have the potential to remove not only organic carbon and nitrogen compounds, but heavy metals. This study focussed on the design, development and experimental investigation of a novel CWs for the treatment of landfill leachate. The CWs employed dewatered ferric waterworks sludge (DFWS) as the main substrate. The overall aim of the study was to design and assess the novel configuration of the CWs, whilst also contributing to advancing the understanding of pollutant removal from the landfill leachate in the CWs, through the development of models to explain the internal processes and predict performance. The key design and operational variables investigated were: the primary media used, i.e. the DFWS, and the wetting and drying regimes. The CWs was configured as 4- stages in series which was operated for 220 days. Thereafter, an additional unit was added due to clogging and the CWs was operated for 185 days in this second period. Results and experimental observations indicate that the chemical treatment processes (adsorption and precipitation) contributed to the clogging. The DFWS used served as adsorbent for heavy metals removal in the system. Results of heavy metals, organic matter (COD), ammonia and total nitrogen removal indicate average removals of 99%, 62%, 83% and 81%, respectively in first period; and 100%, 86%, 90% and 82% in second period, with an average heavy metals loading rate 0.76 g m-2 day-1 , organic loading rate 1070 g m-2 day-1 , ammonia loading rate of 178 g m-2 day-1 and total nitrogen loading rate 192 g m-2 day-1 . Results were supported through mathematical analysis using STELLA model for heavy metals transformation in CWs and numerical modelling using HYDRUS CW2D, which enhanced understanding of the internal processes for organic matter and nitrogen 3removal. The result from STELLA modelling showed that up to 90% of the removal of heavy metals was through adsorption, which is highly significant. While HYDRUS CW2D results showed that the main path of nitrogen removal was through simultaneous nitrification and denitrification. Overall, results have shown that CWs design has great potential for reduction of metals and nutrients in landfill leachate. Results of this study can contribute to future CW research and design for landfill leachate treatment, through the increased understanding of long-term pollutant removal in these systems. In time, this may result in the wider application of CWs for landfill leachate treatment to better protect the environment.
Process Design Engineering
PROCESS ENGINEERING AND THE ROLE OF PROCESS ENGINEER
Process design is the design of processes for desired physical and or chemical transformation of materials. Process design is central to chemical engineering and it can be considered to be the summit of chemical engineering, bringing together all of the components of that field. Process Engineering involves the design of unit operations & equipment design.
Role of Process Engineer: Chemical engineers (or process engineers) are responsible for developing new industrial processes and designing new process plants and equipment or modifying existing ones. The processes that they come up with are used to create products ranging from oil and gas, chemicals, petrochemicals, and specialty chemicals to food and drink. It is a vocation wherein the process engineer is supposed to perform any one or all of the activities mentioned below to provide documentation for a safe, reliable, and profitable design
Design new equipment/unit/plant as per good and internationally accepted engineering practices (Greenfield)
Rate or checks the adequacy of existing equipment/unit/plant for changed operating conditions (e.g. pressure, temperature, flow, etc.) as per good and internationally accepted engineering practices (Brownfield)
Process Design Engineering
PROCESS ENGINEERING AND THE ROLE OF PROCESS ENGINEER
Process design is the design of processes for desired physical and or chemical transformation of materials. Process design is central to chemical engineering and it can be considered to be the summit of chemical engineering, bringing together all of the components of that field. Process Engineering involves the design of unit operations & equipment design.
Role of Process Engineer: Chemical engineers (or process engineers) are responsible for developing new industrial processes and designing new process plants and equipment or modifying existing ones. The processes that they come up with are used to create products ranging from oil and gas, chemicals, petrochemicals, and specialty chemicals to food and drink. It is a vocation wherein the process engineer is supposed to perform any one or all of the activities mentioned below to provide documentation for a safe, reliable, and profitable design
Design new equipment/unit/plant as per good and internationally accepted engineering practices (Greenfield)
Rate or checks the adequacy of existing equipment/unit/plant for changed operating conditions (e.g. pressure, temperature, flow, etc.) as per good and internationally accepted engineering practices (Brownfield)
Wastewater Engineering In Questions And Answer
In Palestine, the existing water and wastewater/sanitation infrastructure suffers from inadequate level of skills in planning, designing, managing, operating and maintaining of the infrastructure to ensure its sustainability. Furthermore, there is no coordinated effort on human resources development aimed to build the needed managerial and technical capacity among water and wastewater service providers. So far, this sector lacks any needs-based capacity building and systematic training arrangements.
Wastewater Engineering In Questions And Answer
In Palestine, the existing water and wastewater/sanitation infrastructure suffers from inadequate level of skills in planning, designing, managing, operating and maintaining of the infrastructure to ensure its sustainability. Furthermore, there is no coordinated effort on human resources development aimed to build the needed managerial and technical capacity among water and wastewater service providers. So far, this sector lacks any needs-based capacity building and systematic training arrangements.
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