Coliphage and Determining a Standard for Virus Removal and Identification from Wastewater

By Allison Plante

The treatment and disinfection of wastewater in the United States is a tedious process involving the removal of sediments, nutrients, and bacteria from previously contaminated influent wastewater. It requires a wastewater treatment plant to filter, oxidize, chlorinate, and neutralize the incoming wastewater into a regulated standard composition, making it safe enough for reintroduction to the environment via deep well injection or ocean outfalls.

Through this advanced treatment, options for water reuse arise, especially for areas experiencing water scarcity. Non-potable water reuse represents the largest potential reuse market. Yet, economic constraints for new water reuse infrastructure and safety concerns due to microbial water quality, especially viral pathogen exposure, limit the widespread implementation of water reuse.  Despite the increasing reliance on wastewater reuse, current wastewater treatment processes often focus on bacterial indicators and are lacking in virus-specific standards and monitoring. The United States has yet to establish federal regulations for virus levels in treated wastewater, leaving a critical gap in ensuring overall public health. Researchers are working to address this by developing innovative methods to detect and remove viruses for safer non-potable reuse options. 

Virus detection and removal options are limited at this time due to the complexity and expensive costs involved in quantifying viruses, especially in wastewater. The differences between bacteria and viruses are the basis of difficulty in viral investigation. Compared to the already implemented bacterial detection and removal, viruses are much smaller than bacteria, have higher environmental persistence, higher resistance to water treatments, and have very low infectious doses. With such inconsistent quantifying methods, there is no federally regulated standard to the allowable amount of pathogenic viruses within a given wastewater sample. 

One promising advancement in virus detection is the use of coliphages as indicator viruses. Coliphages, which infect E. coli, are being studied as surrogates for pathogenic viruses in wastewater. Their behavior closely mimics that of enteric viruses, making them valuable tools for assessing the effectiveness of treatment processes. Unlike direct detection of pathogenic viruses, which can be costly and time-consuming, coliphage monitoring offers a more practical and cost-effective approach. By incorporating coliphage analysis into wastewater monitoring programs, researchers can better evaluate the microbial safety of treated water and identify areas for improvement in virus removal technologies.

In addition to detection, advancements in virus removal technologies are also being explored. Techniques such as membrane filtration, UV disinfection, and advanced oxidation processes have shown promise in achieving higher virus removal rates. Researchers are combining these methods with statistical modeling and data analysis to optimize treatment processes and enhance efficiency.

The development of virus-specific standards is another area of focus. While current regulations often emphasize bacterial indicators, the inclusion of virus standards would provide a more comprehensive framework for ensuring water safety. Researchers are working to establish benchmarks for virus removal, using tools like coliphages to inform these standards. By aligning detection methods with regulatory requirements, these efforts aim to bridge the gap between research and policy, fostering greater confidence in wastewater reuse practices.

In conclusion, the commitment to formulating virus standards, improving detection methods, and advancing removal technologies represents a significant step forward in wastewater management. The use of coliphages as indicator viruses, combined with innovative treatment processes, offers a pathway to safer and more sustainable non-potable reuse options. As global water scarcity continues to increase, so does the need for such water treatment research to continue advancing in hopes that one day a rigid method of viral quantification and removal will become standard and ensure safe reuse options.

Citations

Jiang, Sunny C., et al. (2022) “Integrating Virus Monitoring Strategies for Safe Non-Potable Water Reuse.” MDPI, Multidisciplinary Digital Publishing Institute

 www.mdpi.com/2073-4441/14/8/1187. Paragraph 2, 4, 5.

Philo, Sarah E, et al. (2024) “Wastewater Surveillance for Bacterial Targets: Current Challenges and Future Goals.” Applied and Environmental Microbiology, U.S. National Library of Medicine 

www.ncbi.nlm.nih.gov/pmc/articles/PMC10807411/. Paragraph 3.

University of Queensland (2024)“What’s the Difference between Bacteria and Viruses?” Institute for Molecular Bioscience - University of Queensland, Institute for Molecular Bioscience

imb.uq.edu.au/article/2020/04/difference-between-bacteria-and-viruses. Paragraph 3.