OCWA—Central New York’s Water Authority—has received inquiries from customers concerned about the potential impact of the coronavirus on our local drinking water supply.  The Authority certainly understands these concerns and we are pleased to report that we have a series of robust treatment processes in place to remove viruses/pathogens and other contaminants in the water.  In addition, we have a rigorous monitoring system to help identify and address any potential concerns before they arise.

Filtration

OCWA has two main sources of water supply—Otisco Lake and Lake Ontario—which provide 98% of our local drinking water.  Both sources are connected to sophisticated water treatment facilities which are designed to remove sediment, bacteria and viruses from the water.  The treatment process begins by filtering the water.  The water is pre-treated and adjusted for pH to aid with the filtration process.  A coagulant is added which helps remove particles during the filtration process.  The water is then filtered through multiple granular activated carbon filters which remove particles from the water along with bacteria, viruses, parasites, and chemicals.

Enhanced Filtration

An additional step in the filtration process can be added to enhance its effectiveness in the event that higher than normal contaminants are identified in the raw water.  This process involves adding a powered carbon slurry mix during the coagulation stage to help adsorb the additional contaminants during the filtration process.

Disinfection

After the water is filtered, it is treated with sodium hypochlorite (chlorine) to inactivate any remaining parasites, bacteria, and viruses.  The concentration of disinfectant is strictly monitored and controlled by OCWA staff to ensure it kills viruses while not negatively impacting taste or odor.  The water is then conveyed through onsite storage tanks allowing time for the chlorine to do its work and inactivate any remaining viruses and bacteria.

Because the coronavirus is a relatively new pathogen, complete data is not readily available on how it interacts in a waterborne environment.  However, experts believe that “…common disinfection methods used in water…treatment are expected to be effective for inactivation of coronaviruses….”  See Stantec Engineering whitepaper Introduction to Cornonaviruses dated February 21, 2020 (linked).  See also World Health Organization Technical Brief Water, sanitation, hygiene and water management for COVID-19, March 3, 2020 (linked).  Further, the USEPA has concluded that the coronaviruses are “one of the easiest [viruses] to kill with the appropriate disinfectant product.”  See EPA New Release Coronavirus Cases Trigger EPA Rapid Response dated January 29, 2020.

Supplemental Disinfection

Sodium hypochlorite booster systems have been installed in various locations throughout OCWA’s five-county service territory to add additional disinfectant in the event that monitoring (see below) reveals that levels are low.  In addition, mobile units are available for rapid deployment and placement in critical areas on an as-needed basis.

Monitoring

OCWA has implemented a robust monitoring and sampling program which exceeds federal requirements.  When it comes to viruses, the key data point is the amount of disinfectant in the system (also known as chlorine residual).  We take multiple samples for chlorine residual throughout our system four days per week.  All told, we collect 80-85 samples per week for this water quality parameter.  In addition, we electronically monitor the system continuously (24/7) for chlorine levels via our Supervisory Control and Data Acquisition (SCADA) system.  We can identify levels of disinfectant throughout our system and boost levels as necessary.  Finally, during summer months when concern about disinfectant levels is the greatest, we conduct random surveys of our system.  We turn on fire hydrants, test for chlorine levels and make adjustments accordingly.

City of Syracuse Water Supply (Skaneateles Lake)

For the roughly two percent (2%) of OCWA customers who are served by water from Skaneateles Lake, the City of Syracuse treats and delivers that water to us.  While the City does not filter its water, the system has a multi-step treatment process.  As an initial step, the City conducts an intensive watershed protection program to keep the lake water clean.  The City pre-treats the water with chlorine as it is drawn from the lake before it is conveyed into the City.  They then treat the water with an ultraviolet light disinfection process to kill parasites, bacteria, and viruses.  For further treatment the water is disinfected with sodium hypochlorite and as with other OCWA water, the chlorine is maintained as it is distributed through the water mains.

Conclusion

The threat of the coronavirus has raised the level of awareness for some customers about the safety and security of their drinking water.  Rest assured, OCWA has robust treatment and monitoring systems in place to help prevent the spread of the virus and keep our water safe.  If you have any additional questions about this or any other water quality issue, please do not hesitate to contact our Water Quality department at 315-455-7061 ext. 3157 or 3141, or at lyesensky@ocwa.org.