End-of-pipe Antipollution Measures

When a production-integrated approach cannot be applied and the amount of waste is relatively small, then end-of-pipe solutions may be employed. Examples are  

Obviously, the end-of-pipe measures can fix tbe problem temporarily, but not remove tbe cause. Sometimes tbe problem is shifted or masked into another one. For this reason, an end-of-pipe solution should be examined from a plantwide viewpoint and beyond. For example, sour-gas scrubbing by chemical absorption may cut air pollution locally, but involves tbe pollution created by the manufacture of chemicals elsewhere. In this case, physical processes or using green (recyclable) solvents are more suitable. The best way is tbe reduction of acid components by changing the chemistry, such as for example using a more selective catalyst. 

End-of-pipe measures are implemented in the short term and need modest investment In contrast, production-integrated environmental protection necessitates longer-term policy committed towards sustainable development. 

Summing up, tbe following measures can be recommended for improving tbe environmental performances of a process  

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Here we mention as advanced technique the use of supercritical water oxidation (SCWO) for destroying organic impurities. Note that organic species become highly soluble in supercritical water. For example, highly harmful PCBs can be converted in benign small molecules, as COj, HCl and NH by oxidation is supercritical water. However, this is a typical end-of-pipe antipollution measure. 

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