Grantee Research Project Results

Final Report: Enhanced Decontamination of Wetted Pipe Material

EPA Contract Number: EPD14018
Title: Enhanced Decontamination of Wetted Pipe Material
Investigators: Ball, Raymond G.
Small Business: Enchem Engineering, Inc.
EPA Contact: Richards, April
Phase: I
Project Period: May 1, 2014 through April 30, 2015
Project Amount: $99,920
RFA: Small Business Innovation Research (SBIR) - Phase I (2014) RFA Text | Recipients Lists
Research Category: SBIR - Drinking Water and Wastewater Security , SBIR - Homeland Security , Small Business Innovation Research (SBIR)

Description:

The security of critical infrastructure is currently of high importance to the United States following the terrorist attacks on September 11, 2001. In particular, the potential for deliberate or accidental contamination of our water systems is a concern, considering the number of people potentially affected and the engineering difficulties with evaluating and treating contaminants in a subsurface network of pipes. The disadvantages of current pipe wall treatment methods such as surfactant or ozone flushing has led to research and application of innovative treatment methods. The advantages of the proprietary reactive agent OxyZone-C^® treatment are enhanced contaminant desorption and ozone delivery for improved contaminant destruction.

This project focuses on dissolution and destruction of adhered or trapped target compounds on wetted porous surfaces such as pipe walls. The innovative treatment approach is based on simultaneous (1) desorption from the pipe wall and (2) oxidation via radical formation. Developed by EnChem Engineering, Inc., OxyZone-C^® combines facilitated contaminant desorption and targeted delivery of ozone to the treatment zone. This technology has the potential to provide better treatment efficiency and significant cost savings relative to the most current pipe wall treatment methods, surfactant flushing and ozone water main flushing (Dahm and Schulz, 2006), because the combination of enhanced desorption, facilitated ozone transport and in-contaminant destruction significantly improves pipe wall treatment and decreases treatment times.

The specific objectives of this study were the following:

Determine the adherence tendency and persistence of target contaminants on different pipe materials.
Evaluate those parameters, such as OxyZone-C^® concentration, ozone concentration and contact sequencing order, that have the greatest effect on the solubilization and degradation rate of the target contaminants from the test material surface.

Using pipe coupon experiments under dynamic conditions, this study generated the data needed to assess the performance of the OxyZone-C^® treatment technology under a variety of test conditions. The proprietary reactive agent in OxyZone-C^® stabilized ozone to facilitate target compound desorption from the wetted porous surface and extend the life of ozone in the treatment zone.

EPA would like to identify nonhazardous technologies that could be applied over a wide water distribution network without damaging the water infrastructure. Contaminants of interest include chlorine-resistant pathogens such Bacillus anthracis (or surrogate) in spore form; persistent, soluble radionuclides (including stable surrogates); and common chemicals such as hydrocarbons, pesticides and inorganic compounds that adhere strongly to plumbing surfaces and that are not easily removed by conventional flushing. The complexities of both the water systems involved and the range of contaminants make preparing for such an attack challenging. For example, different types of piping are used in water systems (i.e., mortar-lined iron, unlined cast iron) with different surface structures (i.e., smooth, porous, weathered) and pipes may have varying types and amounts of biofilm growth covering them, depending on the chemical makeup of the water flow. These parameters may affect the extent to which a contaminant adheres to a surface and that contaminants persistence in the system once it adheres. Contaminants such as Bacillus anthracis, hydrocarbons and pesticides have varying chemical properties that determine how they will react in a water system with regards to sorption/desorption, solubilization, interaction with other compounds and degradation rates. Additional parameters such as flow rate and type (i.e., laminar, turbulent), pressure, pH and temperature of the water flowing through the pipes also will affect the behavior of contaminants in a water system.

This technology is high demand for decontamination of water infrastructure. EnChem Engineering, Inc., also expects that this decontamination technology will prove useful to the Department of Defense, public and private water companies, and the petrochemical industry, although additional funding is necessary to ready the technology for application. In addition, there may be applications within the Cleaning-In-Place industry.

Summary/Accomplishments (Outputs/Outcomes):

This Phase I investigation demonstrates that recalcitrant toxic organics, based on using a surrogate dye compound, can be effectively removed from a wetted pipe surface and destroyed with the innovative OxyZone-C^® treatment approach. Cement pipe coupons contaminated with a target compound, Coomassi Brilliant Blue G-250 dye, were treated under dynamic test conditions. The results of these tests indicate that (1) the addition of a relatively small concentration of OxyZone-C^® to the treatment solution removes the adhered target compound from a cement coupon surface; (2) treatment with OxyZone-C^® resulted in complete target compound destruction; (3) the treatment is most efficient during the initial hours after injection of OxyZone-C^® solution; (4) rates of destruction vary for different dosages; (5) a fraction of the OxyZone-C^® is destroyed during the treatment; and (6) OxyZone-C^® stabilizes ozone, which is an integral part of the formulation. Ozone released slowly from OxyZone-C^® extended the reactivity of the treatment solution.

Conclusions:

Based on cement coupon studies, OxyZone-C^® completely destroyed the target compounds under dynamic conditions in the laboratory bench-scale studies in a closed loop system. The technology can be implemented at a pilot or field scale in a closed loop piping system. OxyZone-C^® technology can be implemented in the field by using either the companys already proven treatment scheme, which relies on single or multiple injections of conventional, patented OxyZone-C^® treatment solution discussed here for pipeline injection, or via one or more enhancements. Typically, the treatment solution would be injected into a pipeline and withdrawn at the other end and then treated for contaminant destruction and possibly reagent regeneration.

COMMERCIALIZATION:

EnChem Engineering, Inc. has discussed use of the Test and Evaluation (T&E) facility in Cincinnati, Ohio with EPA Homeland Security to further evaluate decontamination of pipe materials under quasi-realistic conditions.
EnChem Engineering, Inc. has prepared a white paper and presentation for potential government or private commercialization partners.

Supplemental Keywords:

Homeland security, contamination, cyclodextrin, pesticide desorption, water, ozone, pipe walls

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