Water left Halifax facility without final disinfection process for 66 minutes following power outage: preliminary report

Halifax Water has released a preliminary report on a power outage that caused a multi-day boil water advisory.

A preliminary report into a multi-day boil water advisory across Halifax says water left the J.D. Kline Water Supply Plant without its final disinfection process for more than an hour before the situation was resolved.

Halifax Water released its after-incident review of the Jan. 20 outage on Tuesday, laying out the timeline of events and possible corrective measures. The full report will be submitted to the Utility and Review Board by March 21.

The outage was the second interruption to primary chlorine disinfection at the J.D. Kline facility in the last six months (the first one happened on July 1, 2024). Both events resulted in boil water advisories for thousands of customers.

The report says Nova Scotia Power planned an outage near the facility the night of Jan. 20, but did not make direct contact with staff as “the phone numbers on file for the autodial notification process for the facility were not active.”

“Planned transition to backup power requires adequate advance notice to call and bring in additional staff to complete and monitor the transition to backup power,” the report reads. “The loss of utility power this night at the facility was no different than any unplanned loss of power that occurs from time to time for various reasons.”

Halifax Water knew about power outage: report

The report says an off-duty operator learned about the planned outage and notified someone at the facility roughly two hours before it was set to begin. The operator took steps to prepare the plant for the outage.

Once the outage started, the main generator at the low lift pump station was engaged. When power was restored, there were approximately 175 alarms that needed attention.

During the troubleshooting process, staff learned the service water pumps were not working, which meant the main chlorination system went offline. Staff learned control fuses on the transformers for the service water pumps were blown, preventing them from receiving run commands.

Staff replaced the fuses and brought the main chlorination system back online.

Due to the incident, the facility did not have a final disinfection with chlorine before leaving for 66 minutes. All other treatment requirements were met, but the boil water advisory was still issued.

The advisory lasted for two days and impacted more than 200,000 customers in Beaver Bank, Middle and Lower Sackville, Upper Hammonds Plains, Bedford, Fall River, Halifax, Timberlea, Spryfield and Herring Cove. Nova Scotia Premier Tim Houston labelled the incident a “complete embarrassment” and called for an investigation.

During the July 1 incident, the water did not receive the final disinfection treatment for 16 minutes.

The report says Halifax Water identified “fundamental design constraints as a root cause” of the July and January incidents. It notes flow cannot be isolated from the J.D. Kline plant during disinfection interruptions and there is no chlorinated water storage at the facility.

“As currently designed, the (facility) has constraints that prevent adequate treated water storage at the facility, directly impacting the ability to shut down without significant interruption to water quantity or quality,” the report reads. “As a result, staff could not prevent unchlorinated water from entering the distribution system. However, staff implemented operational adjustments to the distribution system to minimize the amount of water leaving the facility.”

Halifax Water says the point of chlorination has not changed since the facility was built in the 1970s.

Corrective measures

Based on the preliminary report, Halifax Water suggests 14 corrective measures such as:

-complete formal incident debriefs with various levels of staff

-addressing fundamental design constraints

-investigating feasibility of chlorine analyzer monitoring earlier in the distribution system

-improving communications with Nova Scotia Power

Halifax Water identified 16 corrective measures after the July incident; nine have been implemented to date.

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