Showing papers by "P.K. Tewari published in 2008"
TL;DR: A mathematical model has been developed based on the input parameters of feed salinity, basic membrane characteristics, feed temperature, desired product quality and quantity to predict the operating recycle ratio at constant operating parameters as mentioned in this paper.
22 citations
TL;DR: In this article, the authors reported the development of self-standing tubular geometry of aligned carbon nanotubes with very high surface area (∼ −90m 2 /g).
21 citations
TL;DR: In this paper, the authors assess the potential of carbon nanotubes (CNTs) as an emerging technology in water purification system, particularly with respect to its potential for the removal of arsenic, fluoride, heavy metals and toxic organic components.
Abstract: The problems of water shortages and lack of access to safe drinking water have been and will continue to grow as major global problems. To alleviate these problems, water purification technologies are being updated. Recent years have witnessed impressive breakthroughs towards practical application of nanostructured materials such as Carbon Nanotubes (CNTs) in the field of water purification owing to their unique thermal, electrical and mechanical properties. These nanoscale structures need to be arranged into well-defined configurations in order to build integrated systems with high efficiency (the nanotubes being reusable, whereas the traditional membranes foul easily and require frequent replacements), high flux (owing to the hydrophobic super smooth inner surface of nanotubes), and with improvements in chemical selectivity (through suitable chemical functionalisation of the CNTs), so that the idea of using CNTs in separation technology can be made realistic and the potential benefits of practical application of these unique materials can be exploited. This paper assesses the CNTs as an emerging technology in water purification system, particularly with respect to its potential for the removal of arsenic, fluoride, heavy metals and toxic organic components.
19 citations
TL;DR: In this paper, the dosing of pretreatment chemicals, ferrous sulphate and polyelectrolytes was done at optimum levels to keep the Silt Density Index (SDI) value between 3 and 4.
Abstract: A 1800 m³/day Seawater Reverse Osmosis (SWRO) plant was commissioned in October 2002 at Kalpakkam, India, as part of the Nuclear Desalination Demonstration Project (NDDP). The conventional pretreatment scheme was adopted consisting of a lamella clarifier, pressurised sand filter, activated carbon filter and cartridge filter. The dosing of pretreatment chemicals, ferrous sulphate and polyelectrolytes was done at optimum levels to keep the Silt Density Index (SDI) value between 3 and 4. Experimental trials indicated that the dosing of chemicals may not be necessary below a particular turbidity level. Similarly, the dosing of proprietary antiscalant chemicals instead of sodium hexametaphosphate to control the sulphate scaling did not affect the process performance. Rather it helped the operation, as the antiscalant is in liquid form and the addition of hydrochloric acid could be eliminated. The overall cost per unit water production was also reduced.
1 citations
TL;DR: In this paper, high priority research areas in all the above technological areas are discussed to help make decisions about the research direction that will address our nation's future water supply challenges, which will offer a promise of'step reduction' in the cost of producing water.
Abstract: By 2020, desalination and water purification technologies are expected to contribute significantly to ensure a safe, sustainable, affordable and adequate water supply in India. The cost of producing water from the current-generation desalination technologies has declined over time at a rate of only approximately 4% per year. Hence the need to accelerate our Research and Development (R&D) activities with a near and long-term objectives for evolution of current generation desalination technology along with the creation of revolutionary next-generation advanced desalination and water purification technologies that will offer a promise of 'step reduction' in the cost of producing water. There are five broad technological areas (thermal technologies, membrane technologies, alternative technologies, concentrate management technologies, reuse and recycle technologies) that encompass the spectrum of desalination technology. In this paper, high-priority research areas in all the above technological areas are discussed to help make decisions about the research direction that will address our nation's future water supply challenges.