Alternative Treatment Technologies

Photocatalytic Destruction - Process Technologies Inc.

Photocatalytic Destruction is a process used to treat the chlorinated VOCs from soil vapor extraction (SVE) units. The photocatalytic destruction unit consists of a fluidized bed concentration unit and a photolytic destruction unit (PDU).

The fluidized bed concentration unit produces a low flow, high concentration VOC vapor through the use of an adsorber, desorber and chilled water condenser. The adsorber uses adsorbent “beads” to collect VOCs from the SVE waste stream. The desorber uses a heat exchanger operated at atmospheric pressure to vaporize adsorbed VOCs, and moves (or “sweeps”) these contaminants to the condenser. The condenser then uses chilled water to preferentially remove water vapor and non-halogenated organic compounds in the concentrated “sweep” vapor. The liquid condensate that remains is then sent off site for proper disposal.

Figure 1, below, shows a flow diagram of the Photocatalytic Process.

Figure 1: Flow Diagram of the Photocatalytic Process

Figure 1: Flow Diagram of the Photolytic Destruction Unit

This system is designed to run 24 hours per day, seven days per week. Operation and maintenance requirements for this type of unit require period replacement of reagent panels, UV lamp and caustic solution. In addition the concentrator requires period scheduled maintenance.

This unit also produces secondary waste streams. Preliminary testing suggests that these waste streams are non-hazardous. As a result, the most severe worker health and safety issues include the potential release of the concentrated VOC stream and/or the spill of the liquid condensate stream, which is a byproduct of this process.

For more detailed information or to view a report on an actual field application of this technique, please see PDURprt.