During wastewater collection and treatment, an array of chemicals, solvents, and byproducts — many of them volatile organic compounds (VOCs) — are combined. As a result, VOC emissions produced or liberated during onsite wastewater collection and treatment are often a major contributor to overall pollution at the facility. This article¹ discusses common end-of-pipe methods for treating VOCs encountered during wastewater treatment.

Downstream VOC control
In general, there are two basic approaches to handling VOC-laden wastewater:

1. Transfer the VOCs from the wastewater into a second phase, then recover or destroy them in the second phase. Tables 1a and 1b show several widely used methods for transferring VOCs from wastewater into a second phase (The reader should note that the characterizations shown in these tables are application-specific). Tables 2a–d show the various methods that are available to recover or destroy VOCs that have been transferred to a second, intermediate phase.

In general, biological-treatment methods, such as those shown in Table 2b, are among the more effective and economical approaches to VOC control. While space constraints prevent elaboration here, the VOC Biotreater² is one of the more promising biological-treatment systems to be proposed in recent years.

2. Destroy the VOCs in the wastewater itself. Many technologies that are available to destroy VOCs in the wastewater itself are described in Table 3, which, due to space constraints here, can be found online at www.che.com. However, this author is unaware of any that are able to recover VOCs from the wastewater itself, without first transferring them to a second, intermediate phase.

Since there are so many control options available, the following section offers some recommendations for selecting the best site-specific approach.

Note: This article is the second in a two-part series. Part 1, which discussed regulations and source-reduction strategies impacting VOCs in wastewater, appears on pp. 66-68 of this book.
2. Due to space constraints, the references and Table 3 (Methods for Destroying VOCs in Wastewater Without Initial Phase Transfer) can be found online at www.che.com/ceextra/.

During wastewater collection and treatment, an array of chemicals, solvents, and byproducts — many of them volatile organic compounds (VOCs) — are combined. As a result, VOC emissions produced or liberated during onsite wastewater collection and treatment are often a major contributor to overall pollution at the facility. This article¹ discusses common end-of-pipe methods for treating VOCs encountered during wastewater treatment.

Downstream VOC control
In general, there are two basic approaches to handling VOC-laden wastewater:

1. Transfer the VOCs from the wastewater into a second phase, then recover or destroy them in the second phase.