VOC Control in Wastewater Management

Release of Volatile Organic Compound (VOC) from wastewater can be hazardous towards the health of the plant workers and the environment. Usually VOC is characterized by chemical with low boiling point less than 100 degree Celsius and at current room temperature they will exist and released in gaseous form. And because in recent years whereby chemicals such as trichloroethylene (TCE) which is a common solvent used in industrial facilities including other aldehydes and ketones have been a major concern, VOC control needs to be put in place for a better wastewater management system.

Generally there are two physical mechanisms which commonly occurs in treatment plants such as “volatilization” and “gas stripping” whereby these processes will actually hasten the release of the Volatile Organic Compound. Places identified to be hazardous that will cause buildup of gas are those areas where we would expect heavy turbulence like the Grit Chambers and Aeration Tanks (Activated Sludge Reactor). Generally, stronger turbulence will actually promote the compound to turn into gas and as long as the equilibrium between two different states has not been reached, gas will continue to be released. The same thing applies as well when it comes to gas stripping processes involving diffusers and blowers happening in aeration tanks.

In order to contain and control the release of VOC in a safe manner, there are different approaches to deal with the problem. One of the simple strategies is to construct a cover over the grit chamber and the trapped off gases can later be removed using absorbent such as activated carbon and silica gel. For biological treatment processes involving aeration, replacing diffusers with submerged mixers can also be seen as a viable alternatives. In fact, a study can be conducted based on reduction in aeration rate to find out the impact of lower DO towards the biological processes. Basically once a value has been obtained, it is about balancing between less VOC release and compromised aeration rate.

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