This paper is an “Editorial Perspective” published in the Royal Society of Chemistry (RSC) journal “Environmental Science: Water Research & Technology”*. The authors are Vincenzo Naddeo (University of Salerno Italy) and Haizhou Liu (University of California at Riverside, USA). The paper is made free to all readers as part of the RSC collection on corona virus research.
The authors provide a perspective on the fate of SARS-CoV-2 in urban water cycles and associated risks to public health. They remind us that previous studies have shown that coronaviruses (including SARS-CoV) can exist and maintain viability in sewage and hospital wastewater, originating from the faecal excretions of infected patients. Previous studies have also highlighted the persistence of (other surrogate) coronaviruses in aquatic environments and wastewater treatment plants.
The authors speculate that if a coronavirus did contaminate a drinking water supply system (perhaps one with low disinfection residual), survival might be enhanced by colonising bacteria in biofilms. If this were to occur, there could be exposure risks from the production of aerosols during activities such as showering.
The theoretical possibility of such exposure risks highlights the need to properly manage water supply systems to ensure that such risks are maintained at safe levels. Current water and wastewater disinfection strategies, using chlorine and UV irradiation are anticipated to be very effective for SARS-CoV-2 inactivation, but proper operational control is always essential.
The authors point out that some particular wastewater treatment processes, such as membrane bioreactors may also play an important role since they have been shown to be effective for virus removal, including for some enveloped viruses (such as coronaviruses) and some non-enveloped viruses (e.g. norovirus) that are known to be more resistant than enveloped viruses.
This Editorial Perspective highlights a number of water-cycle related research needs. These include:
- Decentralised virus inactivation treatment for wastewater discharged from potential hot-spots, such as hospitals, community clinics and nursing homes. This could reduce the environmental loading of viruses and risks of secondary transmission.
- Portable point-of-use disinfection devices for drinking water in individual households. For example, LED-based UV systems for decentralised disinfection. Such systems could be of value in countries where water treatment and/or distribution integrity is not reliable.
- Improved understanding of the efficacy of emerging disinfection technologies for coronavirus inactivation, especially treatment steps that are integrated into potable water reuse, including UV-based advanced oxidation processes (UV/AOPs) and ozone/biologically activated carbon (O3/BAC).
- Review of regulatory guidelines for virus removal in potable reuse systems for possible more stringent requirements in the event of a major coronavirus outbreak.
- Understanding the role of drinking water distribution systems in potentially harbouring coronaviruses, including the potential role of bacterial colonies and biofilm growth.
- An improved understanding of relationships between measures to control pandemic viral outbreaks (e.g., widespread use of disinfectants) and impacts on chemical pollution and the proliferation of antibiotic resistant bacteria.
In concluding comments, the authors consider how increasing globalisation enhances the significance of shared global health risks. They argue that the governments of developed countries must support and finance water and sanitation systems in developing countries, in order to also protect the citizens of their own countries.
Naddeo V and Liu H (2020) Editorial Perspectives: 2019 novel coronavirus (SARS-CoV-2): what is its fate in urban water cycle and how can the water research community respond? Environmental Science: Water Research & Technology*.
*The author of this blog post (Stuart Khan) is an Associate Editor of this journal and thus declares and interest in the promotion of work published in it.