摘要 :
The main objective of this paper is to reach breakeven point between periodic planned maintenance and emergency maintenance, to reach this objective, periodic maintenance cost will be increased, then, it's necessary that emergency...
展开
The main objective of this paper is to reach breakeven point between periodic planned maintenance and emergency maintenance, to reach this objective, periodic maintenance cost will be increased, then, it's necessary that emergency maintenance should decreased and visa verse. The first step in this research was preparing a list of all maintenance activities to be done in water treatment plants according the history records of these plants, categorizing these activities into two main lists the first for periodic maintenance and the second for emergency. The next step is studying the effect of intensifying periodic maintenance on emergency maintenance. Using simulation model and starting intensifying periodic maintenance the effect will be determined calculating both periodic and maintenance cost and finally total maintenance cost. At the end of much iteration the result will be optimum maintenance cost. The suggested approach represents a flexible model to reach the optimal point for total maintenance cost through the process of balancing between and periodic and emergency maintenance costs.
收起
摘要 :
Background: Decentralized drinking water treatment methods generally apply membrane-based treatment approaches. Ozonation of drinking water, which previously has only been possible at large centralized facilities, can now be accom...
展开
Background: Decentralized drinking water treatment methods generally apply membrane-based treatment approaches. Ozonation of drinking water, which previously has only been possible at large centralized facilities, can now be accomplished on a small-scale using microplasma technology. The efficacy of decentralized solar-powered drinking water treatment systems has not previously been described. Methods: We established a 1,000L decentralized solar-powered water treatment system located in Kisumu County, Kenya. Highly contaminated surface water is pumped to the treatment system, which includes flocculation and filtration steps prior to ozonation. Turbidity, total coliform bacteria, and E. coli were measured at various stages of water treatment, and bacterial log reduction values (LRVs) were calculated. Results: Forty-seven trials were conducted in which1000L of water were flocculated, filtered, and ozonated for 180 minutes. Baseline turbidity and E. coli concentrations were reduced from a median of 238 nephelometric turbidity units (NTU) and 2,419.7 most probable number/100mL, respectively, in surface water to 1.0 NTU and undetectable E. coli after ozonation for 180 minutes. The median E. coli LRV was 3.99. Conclusions: The solar-powered, decentralized water treatment system that utilizes ozonation for disinfection was founded to reduce E. coli by more than 3 log-orders of magnitude despite the high turbidity of the raw water. Further research is needed to characterize limitations, scalability, economic viability, and community perspectives that could help determine the role for similar systems in other settings.
收起
摘要 :
Although commercial household water treatment (HWT) devices are presented and accepted as a complete and absolute solution in order to improve water quality both for chemical and microbiological aspects, their effects on microbial...
展开
Although commercial household water treatment (HWT) devices are presented and accepted as a complete and absolute solution in order to improve water quality both for chemical and microbiological aspects, their effects on microbial quality of water when they are used with municipal tap water were not investigated. We examined water samples taken from tap waters and corresponding HWT devices for heterotrophic plate and total coliform counts. Heterotrophic bacteria were seen in 12 (75.0%) processed water samples while five (41.7%) unprocessed tap water samples contained colonies. It was determined that 62.5% of the water samples processed by HWT devices contained coliform bacteria and were not potable. According to these results, it could be concluded that some of the HWT devices may be source of microbiological contamination rather than disinfecting it.
收起
摘要 :
Seit der Verschaerfung der Anforderungen an die Stickstoffelimination fuer groessere Klaeranlagen durch die Reduzierung des Ueberwachungswerts fuer anorganischen Stickstoff ist die Prozesswasserbewirtschaftung oder - behandlung fu...
展开
Seit der Verschaerfung der Anforderungen an die Stickstoffelimination fuer groessere Klaeranlagen durch die Reduzierung des Ueberwachungswerts fuer anorganischen Stickstoff ist die Prozesswasserbewirtschaftung oder - behandlung fuer die Praxis deutlich attraktiver geworden. Hierzu werden Verfahren dargestellt, die durch eine gezielte Einleitung oder separate Behandlung der Prozesswaesser eine kostenintensive Erweiterung der Klaeranlage vermeiden.
收起
摘要 :
The present study has been undertaken to evaluate performance efficiency of a water treatment plant. Water samples were collected at different stages of treatment units and analyzed for the major water quality parameters, such as ...
展开
The present study has been undertaken to evaluate performance efficiency of a water treatment plant. Water samples were collected at different stages of treatment units and analyzed for the major water quality parameters, such as pH, conductivity, turbidity, alkalinity, hardness and total dissolved solids (TDS). The performance efficiency in treating the pollutants was calculated. Results suggested that the parameters studied were within the standard range. The company has implemented treated water quality monitoring standards to ensure quality, sustainability and to develop and improve source water management practices across the plant.
收起
摘要 :
New regulations in Vietnam will prevent the current practice of returning water treatment plant residual
solids back to the environment. Therefore, the Saigon Water Corporation (SAWACO) and CDM are evaluating
alternatives that are...
展开
New regulations in Vietnam will prevent the current practice of returning water treatment plant residual
solids back to the environment. Therefore, the Saigon Water Corporation (SAWACO) and CDM are evaluating
alternatives that are both cost-effective and meet all environmental requirements.
收起
摘要 :
Selenium is a trace element that can be poisonous in small quantities. The aim of this study was to analyze the change in the content of selenium in drinking water, raw water, as well as treated and raw wastewater in an annual cyc...
展开
Selenium is a trace element that can be poisonous in small quantities. The aim of this study was to analyze the change in the content of selenium in drinking water, raw water, as well as treated and raw wastewater in an annual cycle in the city of Szczecin. The concentration of Se in samples was determined using the spectrofluorometric method at a 518 nm emission wavelength and a 378 nm excitation wavelength. The amount of selenium in drinking water ranged from <LOD to 0.007 μg/mL, in raw water, from 0.001 to 0.006 μg/mL, in raw wastewater, from 0.001 to 0.008 μg/mL, and in treated wastewater, from 0.001 to 0.009 μg/mL. The selenium content did not exceed the maximum allowable concentration (MAC), 0.010 μg/mL, in any of the water samples tested.
收起
摘要 :
Water resources in a country such as South Africa constitute a very precious asset to be managed usefully. Water is one of the most important resources for human life used domestically and industrially, therefore, water scarcity c...
展开
Water resources in a country such as South Africa constitute a very precious asset to be managed usefully. Water is one of the most important resources for human life used domestically and industrially, therefore, water scarcity can seriously affect the country's economy because manufacturing and industrial sectors are known to the biggest water consumers. Furthermore, water can be a key component in generating clean, renewable and environmentally friendly energy reducing sensibly the impact of environmental pollution. South Africa is not a water-rich country, despite its well performing and growing economy, water situation remains a concern. Being among the world driest countries, the country relies on rain water and rivers to harvest the necessary amount of water to face various challenges due to water scarcity. There is a necessity to manage adequately existing water resources and develop efficient technologies. In this regard, the current wastewater treatment infrastructure including the technology need to be upgraded to face high demand of water for use at industrial and domestic levels. An urgent need to develop innovative ways for efficient treatment of water resources in order to prevent a crisis in the next decade is required. Therefore, analyses from preliminary, physical, biological up to chemical treatment is important to model and design appropriate system and monitor them for an optimal efficiency. This analysis focuses on various aspects such as treatment methods for industrial and domestic wastewaters, the current water situation and state of water infrastructures in South Africa.
收起
摘要 :
Water resources in a country such as South Africa constitute a very precious asset to be managed usefully. Water is one of the most important resources for human life used domestically and industrially, therefore, water scarcity c...
展开
Water resources in a country such as South Africa constitute a very precious asset to be managed usefully. Water is one of the most important resources for human life used domestically and industrially, therefore, water scarcity can seriously affect the country's economy because manufacturing and industrial sectors are known to the biggest water consumers. Furthermore, water can be a key component in generating clean, renewable and environmentally friendly energy reducing sensibly the impact of environmental pollution. South Africa is not a water-rich country, despite its well performing and growing economy, water situation remains a concern. Being among the world driest countries, the country relies on rain water and rivers to harvest the necessary amount of water to face various challenges due to water scarcity. There is a necessity to manage adequately existing water resources and develop efficient technologies. In this regard, the current wastewater treatment infrastructure including the technology need to be upgraded to face high demand of water for use at industrial and domestic levels. An urgent need to develop innovative ways for efficient treatment of water resources in order to prevent a crisis in the next decade is required. Therefore, analyses from preliminary, physical, biological up to chemical treatment is important to model and design appropriate system and monitor them for an optimal efficiency. This analysis focuses on various aspects such as treatment methods for industrial and domestic wastewaters, the current water situation and state of water infrastructures in South Africa.
收起
原文获取