Grantee Research Project Results

Final Report: An Electroporation Drinking Water Disinfection System

EPA Contract Number: 68D00250
Title: An Electroporation Drinking Water Disinfection System
Investigators: Schlager, Kenneth J.
Small Business: Bioelectromagnetics Inc.
EPA Contact:
Phase: I
Project Period: September 1, 2000 through March 1, 2001
Project Amount: $70,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2000) RFA Text |  Recipients Lists
Research Category: Watersheds , SBIR - Water and Wastewater , Small Business Innovation Research (SBIR)

Description:

Electroporation (EP) is the occurrence of transient and permanent changes in cell porosity caused by the presence of an electric field. At lower field strengths, the effects are useful in improving the efficiency of chemical disinfection, as in chlorination. At higher field strengths, EP is capable of inactivating bacteria and other pathogens in water without the use of any chemical disinfectant. The primary purpose of the project was to demonstrate EP disinfection of water-with and without chlorine-in a flow-through environment. A secondary purpose was to demonstrate the potential cost-effective use of the system in a full-scale operating environment.

Two flow-through EP systems were developed and tested during the Phase I project. A Micro-Flow EP System was designed and built for bench testing of 100 mL samples of water contaminated with coliform-indicated bacteria and Cryptosporidium parvum oocysts. A much larger Macro-Flow EP System was built as a potential pilot plant demonstrator to address the challenge of full-scale electroporation system design.

In initial microflow testing, equal emphasis was placed on electroporation alone and electroporation/chlorination modes of operation. In later experimentation, however, priority was placed on the electroporation/chlorination mode because of the needs of potential customers with problems related to chlorination byproducts. Development efforts focused on reducing chlorine dosage while still providing 3-log water disinfection. Extensive testing of coliform-indicated bacteria demonstrated the ability of electroporation to significantly reduce chlorine dosage levels (see findings below) for the same 3-log level of disinfection. Electroporation treatment and testing of C. parvum also indicated great potential for disinfection capability.

Based on the Macro-Flow development experience, a full-scale EP design was formulated that compared very favorably with ultraviolet radiation water disinfection, the probable important technological alternative. This EP design emphasized wide electroporation pulsing for very high disinfection efficiency.

The primary potential markets identified in Phase I for EP technology were:

• Utilities with chlorination byproducts violations.
• Surface water utilities desiring C. parvum oocyst disinfection.
• Wastewater treatment utilities.

Summary/Accomplishments (Outputs/Outcomes):

Electroporation demonstrated 3-log water disinfection of coliform-indicated bacteria with an 80 percent (5:1) reduction in chlorine dosage.

Electroporation combined with only 1 mg/L dosage of chlorine demonstrated C. parvum oocyst disinfection of 97.1 percent as evaluated by an in vitro fluorogenic dye assay that consistently underestimates C. parvum inactivation.

A full-scale electroporation system design based on bench-scale system experience and data indicated a potential system competitive in both capital and operating costs.

Conclusions:

Electroporation water disinfection technology is ready for pilot plant development/demonstration as part of a Phase II SBIR project. It is ideally suited to the needs of water utilities with recurring microbiological contamination and/or those exceeding limits for trihalomethanes and other chlorination byproducts.

Supplemental Keywords:

electroporation, water/wastewater disinfection, chlorination byproducts reduction, Cryptosporidium inactivation., RFA, Scientific Discipline, Water, Chemical Engineering, Environmental Chemistry, Analytical Chemistry, Drinking Water, Environmental Engineering, Engineering, Chemistry, & Physics, alternative disinfection methods, monitoring, electrochemical technology, exposure and effects, drinking water filtration plants, exposure, microorganisms, community water system, pulsed electric field, alternative drinking water disinfection, Other - risk management, treatment, microbial risk management, contaminant removal, drinking water contaminants, drinking water treatment, Giardia, electroporation, drinking water system, cell membrane permeability