RICHMOND, Va. — As the city has revealed limited information about what caused the third significant issue to impact its drinking water system within a matter of months, records reviewed by CBS 6 could shed light on the problems at Richmond's Water Treatment Plant leading up to the current boil water advisory.
An apparent maintenance request dated May 12 showed that plate settlers, a type of sediment filter at the plant, were noted as needing be cleaned to "remove alum sludge."
The maintenance request stated cleaning the plates could "prolong the use" of the sedimentation basins "with increased flow going throughout" and indicated that the plates may have been "clogged."
According to engineering expert Joel Paulsen, these plates are critical to settling out particles like dirt and soil in the water entering the plant from the river. He said the plates will take out bigger particles of sediment before water enters the filters, which take out finer particles.
Depending on the sediment load in the water, he said plates should be cleaned at least every seven days.
“If those plates get overloaded with too much algae growth, sludge attached to them, they're no longer doing their job, and all of that sediment that should be settling out is now going into the filters, and the filters are not designed to handle all of that sediment load, and so they clog up and you have operational issues," Paulsen said.
But it appears the May 12 maintenance request was not immediately fulfilled.
The work order was updated with an action item that stated an employee requested on May 14 for plate settlers to be "thoroughly washed and cleaned" but they were "informed by operations this was not a good time" and it would need to be done at a later date.
“That should be a fairly high priority. Losing a filter within your system and not being able to provide that drinking water quantity out to the system is a pretty major impact. And so these plates are very closely monitored, or should be, and they should be cleaned on a regular basis," Paulsen said.
When asked about the maintenance request, Department of Public Utilities (DPU) spokesperson Rhonda Johnson said she was still working to verify the record as of Wednesday afternoon but added she would not speculate on a contributing cause.
She said the city is focused on recovery efforts, and once the advisory is lifted, will conduct an after-action investigation. Johnson did not answer questions about how the delayed cleaning could have impacted operations and why it was apparently determined it was "not a good time" for them to be cleaned.
All that officials have revealed so far about the root cause is that filters at the plant became clogged up due to "high turbidity," or extra sediment in the source water, which caused water production to slow down.
But Paulsen said the source water is constantly changing and dependent on the weather, so that can't be the only factor at play.
“This plant should be able to handle any sort of high turbidity, high sedimentation within the source water. That does change all the time, and it should be monitored at the water treatment plant. It really sounds like the plates themselves failed in this case, because they weren't cleaned in a timely enough fashion," Paulsen said.
DPU Director Scott Morris said he won't have a root cause analysis completed for another couple weeks, but he did tell councilmembers during a Wednesday committee meeting that he's already looking at developing a "plethora" of new standard operating procedures because of this incident that include addressing backwashing filters and maintenance protocols.
“If there's any particular maintenance items that we warrant, we would also implement basically a standard operating or preventative maintenance item to correct any deficiencies we note in the system," Morris said.
During the meeting, Morris explained that routine maintenance of the plant's filters generally includes "purging the sediment and debris off."
Councilmember Kenya Gibson asked Morris whether the plant had been performing that maintenance as it should have been. Morris responded that the plant "was doing that process on a routine basis" but in this particular instance, the "raw water source that had a high potential to cause reduced effectiveness in the filters."
Some councilmembers also expressed frustration with the problems and said they hope to receive answers about what happened sooner rather than later.
“I think being able to answer this is the first step to starting to rebuild the trust in the city, because no one wants to see this happen again. I know you guys didn't want to have it happen again. I'm grateful for everyone who's sticking it out, working through the problem, but the sooner we understand what happened and how we're working to prevent it, obviously the more comfort we will all have," said Councilmember Katherine Jordan.
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