Entropy analysis of water and wastewater treatment processes

• Published in: International journal of environmental studies 1985-06, Vol.25 (1-2), p.13-21
• Main Authors: Tai, Shingo, Goda, Takeshi
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Pollution; Water treatment and pollution
• ISSN: 0020-7233; 1029-0400
• DOI: 10.1080/00207238508710208

In the environment, due to its physicochemical properties such as action as a solvent in becoming a carrier to waste materials and waste heat, water especially as compared to other environmental media is very susceptible to pollution. Entropy is the measure of disorder of a system. In a closed system, entropy tends to increase. For example, if a compound is dumped in pure water, it is likely that the compound will be dissolved and diffused into whole water body. The meaning of a compound dissolved and diffusing in the water is twofold: (1) increase in entropy of the solution; (2) increase in the extent of pollution. It can be seen that an increase in entropy results in water pollution. Once water is polluted, input energy is required in order to remove the pollutants and purify the water and to decrease the entropy of polluted water. On the other hand, the entropy is created by the irreversibility. The author will show that if the efficiency of water treatment system (N) can be given by entropy production (?,S/?t), then the author can evaluate the thermodynamical efficiency of water treatment systems.