Microporous diffusion apparatus

Abstract

Apparatuses for removal of volatile organic compounds in a soil formation include a microporous diffuser for injecting air and gaseous ozone as bubbles into water in the soil formation. The gaseous ozone is present at concentrations to effect removal of volatile organic compounds by the gaseous ozone reacting with the volatile organic compound(s). Injection of air and gaseous ozone is controlled by a timer to allow separation of bubbles by size. In various embodiments, a plurality of microporous diffusers may be controlled by a single timer or each of the plurality of microporous diffusers may be controlled by one of a plurality of timers.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a reissue of U.S. Pat. No. 7,645,380, which is a continuation of U.S. patent application Ser. No. 10 / 997,452, filed Nov. 24, 2004, now U.S. Pat. No. 7,537,706, which is a continuation of U.S. patent application Ser. No. 09 / 943,111, filed Aug. 30, 2001, now U.S. Pat. No. 6,872,318, which is a continuation of U.S. patent application Ser. No. 09 / 606,952, filed Jun. 29, 2000, now U.S. Pat. No. 6,284,143, which is a continuation of U.S. patent application Ser. No. 09 / 220,401, filed Dec. 24, 1998, now U.S. Pat. No. 6,083,407, which is a continuation of U.S. patent application Ser. No. 08 / 756,273, filed Nov. 25, 1996, now U.S. Pat. No. 5,855,775, which is a-continuation-in-part of U.S. patent application Ser. No. 08 / 638,017, filed Apr. 25, 1996, now abandoned, which is a continuation-in-part of U.S. patent application Ser. No. 29 / 038,499, filed May 5, 1995, now abandoned. Each of these applications is incorporated by referenc...

AI Technical Summary

Benefits of technology

[0045]The need for vapor control exists when vapors of VOC's partitioned from the dissolved form into the microbubbles, reach the unsaturated zone, releasing vapors. Without reaction with a decomposing gas, such as ozone, a large mass can be transmitted in a short time, creating potential health problems near residential basement areas.

[0046]The combined extraction / decomposition process has the capacity to eliminate the need for vapor capture. If the ozone-mediated decomposition rate exceeds the vertical time-of-travel, vapors will either not be produced or their concentration will be so low as to eliminate the requirement for capture. By controlling the size of microbubbles and matching them to suitable slow rise times, the need for vapor control is eliminated.

[0047]The rise time of bubbles of different sizes was computed for water, producing the upwards gravitational velocity (Table 3). The upwards velocity provides the positive pressure to push the bubbles through the porous media, following Darcy's equation. By determining the rise rate in the field, the rise time, proportional to upwards pressure, can be calculated. The bubble size is very important. Once a bubble exceeds the pore cavity size, it is significantly retarded or trapped. Pulsing of the water phase provides a necessary boost to assure steady upwards migration and reduction of coalescence.

Problems solved by technology

However, an apparatus using micro-fine bubbles including a multi-gas oxidizing agent for the controlled remediation of a site containing poorly biodegradable organics, particularly dissolved chlorinated solvents, has not been shown.

Notwithstanding the teachings of the prior art, there has not been shown an apparatus for remediating a site contaminated with poorly biodegradable organics, particularly dissolved chlorinated solvents, with micro-fine bubbles including an encapsulated multi-gas oxidizing agent in a controlled manner.

None of the models to date are designed for explosive environments.

The major problem in effectiveness is ozone's short half-life.

In actual practice diffusion is rate-limiting, resulting in the most effective removal with PCE (tetrachloroethylene).

Without reaction with a decomposing gas, such as ozone, a large mass can be transmitted in a short time, creating potential health problems near residential basement areas.

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