Grantee Research Project Results
Final Report: Non-Thermal Plasma Assisted Inactivation of AntibioticResistantBacteriain Wastewater
EPA Contract Number: 68HERD19C0007Title: Non-Thermal Plasma Assisted Inactivation of AntibioticResistantBacteriain Wastewater
Investigators: Bailey, Charles
Small Business: AAPlasma, LLC
EPA Contact: Richards, April
Phase: I
Project Period: May 1, 2019 through October 31, 2019
Project Amount: $99,998
RFA: Small Business Innovation Research (SBIR) - Phase I (2019) RFA Text | Recipients Lists
Research Category: Small Business Innovation Research (SBIR): Phase 1 (2019) , Small Business Innovation Research (SBIR) , SBIR - Water and Wastewater
Description:
Current wastewater treatment measures are ineffective at reducing the number of antibiotic-resistant bacteria (ARB), with some unit processes in wastewater treatment plants (WWTPs) even exacerbating the problem by offering a favorable environment for bacteria to thrive. Even while some wastewater treatment processes can lyse ARB, intact remnants of antibiotic resistance gene (ARG) containing DNA that are released into the environment from WWTP effluents can eventually be taken up by other cells through natural transformation; presently, the mechanistic effects of different wastewater treatment processes on intracellular and extracellular DNA is not well-studied. Furthermore, the removal efficiency of antibiotics during wastewater treatment is highly variable, depending on the physicochemical properties of the antibiotic and the design and operation conditions of the WWTP.
Antibiotic resistance in bacteria is an increasing threat to humans and wildlife, and the incidence of ARB in the environment is a growing public concern. The spread of contamination into the environment from water pollution sources such as untreated urban wastewater and industrial wastewater is a significant and increasing problem of public health. Antibiotics have been released into the environment since their introduction in society through human waste (medicated), animal waste (farming), and the pharmaceutical industry. The pharmaceutical industry is such a significant contributor to the increase in environmental ARB, a correlation can be found between the countries with the highest rate of active pharmaceutical ingredient (API) production and antibiotic resistant bacterial increases. China, for example, accounts for 90% of global API production and has demonstrated a 22% increase in ARB over the past 6 years, compare to the Unites States, with only a 6% ARB increase in 6 years.
Antibiotic resistance in bacteria predates the discovery of antimicrobial drugs by humans, yet the widespread use has increased the levels of ARB due to the process of evolutionary pressure placed on the bacteria. The reasons for this occurrence include:
- An increase in global antibiotic availability since the 1950s
- Inadequate treatment of wastewater from pharmaceutical manufacturing facilities leading to the release of large quantities of antibiotics into the environment
- Uncontrolled or over-the-counter antibiotic sales in mid to low income countries leading to use when not indicated
- Antibiotic use in livestock feed in industrialized countries to promote animal growth (although in low dose) is known to contribute to antibiotic resistance
- Some antibacterial agents lyse the microbe without destroying the genetic material, thus antibiotic resistant genes (ARGs) can still give rise to ARB
- Antibacterial soaps may contribute to the development of ARB in wastewater
AAPlasma is developing a novel and affordable integration of a non-thermal plasma treatment system into existing wastewater treatment infrastructure that offers better protection from the three largest factors that lead to antimicrobial risks: antibiotics, antibiotic-resistant bacteria ARB, and ARGs in industrial wastewater. Our technology uses electrical discharge in water to inactivate bacteria and dissociate antibiotics via advanced oxidation, UV radiation, charged particles, and mechanical disruption (shockwaves).
Summary/Accomplishments (Outputs/Outcomes):
Throughout this SBIR project Phase I period of performance (PoP), the project team investigated antimicrobial, antibiotic dissociation, and gene degradation activity of our pulsed spark system (replacing the original gliding arc plasma system) by performing water treatments with time ranges up to 2560 seconds to analyze the efficacy of the three major validation objectives of our technology. The transition from gliding arc discharge to pulsed spark discharge for our plasma system (Figure 1) stems from the realization that our original target water within wastewater treatment plants differed from the reality. As the water we plan to treat in industrial settings is relatively clean and therefore more transparent than we originally anticipated, the more energy intensive gliding arc discharge is an excessive solution for the target wastewater and a pulsed spark system appears to offer a more appropriate fit.
Non-thermal plasmas have long been known to inactivate bacteria, however, this project looked specifically at submerged pulsed spark plasma’s ability to not only inactivate rifampicin resistant E. coli (part of the Phase I validation objective), but its ability to dissociate rifampicin antibiotics themselves in addition to destruction of intracellular and extracellular genetic material. The destruction of DNA expressing potential antibiotic resistant traits is a key component of our proof of concept, as this genetic material has the potential to pass on antibiotic resistance to other bacteria.
Using this updated system, we have verified the antimicrobial, antibiotic dissociation, and gene degradation efficacy of the pulsed spark plasma system utilizing Rifampicin resistant E. Coli O157:H7, Rifampicin, and Rifampicin-resistant genes and plan to scale-up this technology and optimize the successful plasma regimes used in Phase I to develop a pilot-scale prototype system for field testing in our industrial partner facility.
Figure 1. Submerged Spark Water Treatment Phase I System
Conclusions:
The Phase I period of performance successfully demonstrated that non-thermal plasma can reduce antibiotic resistant bacterial, antibiotic, and antibiotic-resistant genes (intracellular and extracellular) loads in water. Further, the system used throughout the Phase I period of performance has demonstrated minimal electrical power requirements with high robustness, as no moving parts are utilized in our technology. This shows promise for an affordable water cleaning option compared to commercially available methods in addition to other emerging technologies. We plan to scale-up and optimize this technology in Phase II of the EPA SBIR program, resulting in a pilot-scale system ready for field demonstration.
Alongside our technical investigations, Foresight Science and Technology, Inc probed commercial interest within the medical industry (ranging from hospital systems to small private practices), the meat industry, and wastewater treatment industry to determine the market interest of our technology and potential challenges we will have to overcome prior to developing a successful commercial product. They provided AAPlasma with a full report detailing the initial investigation efforts of Foresight. This report provided new information regarding the applicable market for this technology, industry players, and recommendations for ways in which AAPlasma could take full advantage of market opportunities.
With the help of Foresight Science and Technology Inc, AAPlasma has a better understanding of the wastewater treatment industry and key end users targeted for interest in our technology to reduce the 3 major factors in antibiotic resistance. The report provided by Foresight furnished new information regarding the applicable market for this technology, industry players, and recommendations for ways in which AAPlasma could take full advantage of market opportunities.
Presently, there are four main technologies utilized within the wastewater treatment industry to combat antibiotic resistant bacterial load: chemical agents, filtration, ultraviolet (UV) radiation, and ozone. The prevailing solution currently used to reduce microbial proliferation in wastewater is the addition of chemicals (predominantly chlorine). With a compound annual growth rate (CAGR) of 7.01% estimated between 2018-2022, the global water treatment chemicals market will likely be our greatest competition. The Foresight report has provided detailed information for two major companies in this sector: Rex-Bac-T Technologies and LanXess.
The second noteworthy potentially competitive technology comes from filtration approaches where ultra-fine filtration technology can remove bacteria and even viruses. According to Foresight, this technology is likely to become a significant competitor as material science permits smaller pore sizes and anti-fouling technologies to improve filtration effectiveness. Foresight provided one example of a filtration company in their report and has encouraged us to maintain a relationship with the group for possible collaboration.
An additional approach that competes with our technology are UV and UV systems. UV radiation is effective for disinfecting clear water, with several UV companies in the sector.
Finally, ozone producers and ozone producing equipment appear to provide a competitive product for water disinfection.
During one of our discussions, Foresight also suggested that it would be wise to partner with one or more of the companies listed to develop a combined approach to water disinfection. This would potentially benefit these industry players by improving the effectiveness of antibiotic resistant bacteria, genes, and antibiotic reduction in wastewater and, especially in the case of chemical agent additions, possibly cost.
To date, we have contacted several companies within the wastewater treatment industry and have even begun joint efforts with Biocleaner, Inc. It is possible, however, that some of these companies may also be reluctant to make significant changes to their operations which could lead to substantial installation costs.
Despite the low interest expressed by some of the industry players that Foresight reached out to, we remain optimistic that the industry will see the value in our technology’s ability to render wastewater completely safe from antibiotic resistant genetic material in addition to the bacteria itself, which has been identified as a major shortcoming of current wastewater treatment methods. We will continue to develop our technology with these ideas in mind as we segue into our scale up and optimization efforts of this water treatment technology throughout our Phase II schedule. Relationships with the companies provided by Foresight in addition to other industrial entities will continue to be developed throughout Phase II and beyond. Our full commercial plan is summarized in the Final Report.
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.