There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

An introduction to heat transfer

Emerging desalination technologies for water treatment: a critical review.

Energy is consumed at every stage of the cycle of water supply, treatment, use and disposal. The intensity of energy consumption (kW h/m 3 ) depends upon the specific technologies applied at each stage of the water cycle. For some technologies, the intensity may be relatively low, whereas the intensity of other technologies is substantially greater. This report surveys the available literature on energy intensity for water use in the municipal and agricultural sectors and separates the process into several stages. Water supply, water treatment, residential end use, wastewater treatment, and agriculture end use are considered. Representative values of the energy consumed per unit water are given for a broad range of processes. Water extraction and pumping from ground and surface sources is considered. The energy intensity of treatment required for different types of water source is found to vary widely between the extremes of relatively fresh surface waters, which use energy mainly in pumping, and seawater, which requires desalination. Energy usage for different methods of irrigation including pressurized as well as surface irrigation is studied. The energy intensity of residential end use is very high relative to other parts of the water supply cycle. Processes such as heating water, washing clothes and dishes, and cooking are briefly studied within the water end-use stage. Hot water usage is responsible for making end use the most energy intensive stage of the water cycle. Hot water use in different buildings is briefly reviewed. Wastewater treated with various processes is considered, and the energy intensity is found to be highest when advanced wastewater treatment methods are applied. Energy consumption in the agricultural sector, which is principally related to irrigation pumping, is generally of lower energy intensity than for the municipal treatment or end use.

Energy requirements for water production, treatment, end use, reclamation, and disposal

Water plays an important role in all our day to day activities and its consumption is increasing day by day because of increased living standards of mankind. Some regions of the globe are under severe stress due to water scarcity and pollution. The fresh water needs of mankind can be only satisfied if saline water which is available in plenty is converted to potable water by desalination. Desalination industry has shown increased threats of CO2 emissions and severe environmental impacts. Desalination industry can be made sustainable if they are integrated with renewable energy and if proper brine disposal methods are followed. In this review different desalination units integrated with renewable energy with special emphasis given to solar energy is discussed. The problems associated with desalination units and their remedies have been presented. Apart from this some novel methods of desalination process has also been explained. This review will allow the researchers to choose appropriate desalination technology for further development.

Young-Deuk Kim

Papers

Adsorption desalination: An emerging low-cost thermal desalination method

Performance investigation of a solar-assisted direct contact membrane distillation system

Experimental investigation on the optimal performance of Zeolite–water adsorption chiller

A hybrid multi-effect distillation and adsorption cycle

Numerical simulation and performance investigation of an advanced adsorption desalination cycle