After six weeks of frustration, wading through wastewater and hard work done by the Yelm Water Reclamation Facility staff and public officials, the facility is now able to distribute reclaimed water to its customers as of Wednesday.
It was discovered on June 14 that Yelm’s Water Reclamation Facility (WRF) was not treating the water effectively. Public Works employees discovered the total kjeldahl nitrogen (TKN) levels to be higher than compliance of Class A water reclamation while doing routine maintenance to the reuse water skid. TKN is the sum of organic nitrogen and ammonia nitrogen.
“The ammonia levels are not a serious risk to human or animal safety but that is a risk we are not willing to take,” said Public Works Director Chad Bedlington on June 27.
What This Meant for Customers
Since the facility was not meeting Class A requirements, Longmire Park, Cochrane Park, Yelm Community Schools and many right-of-way landscapes have not been watered for about six weeks. Yelm Public Works tried to preserve the ball fields at Longmire Park by hauling 45,000 to 50,000 gallons of potable water to the park daily but deemed the effort unsuccessful within a few days.
Customers of reclaimed water were unable to tap into the Yelm Water supply because the infrastructure to water the parks and right-of-way areas was designed to pull water from the Water Reclamation Facility.
How the Facility Works
The facility is best described as a biological system in comparison to one’s stomach. The stomach uses oxygen with digestive enzymes to digest food and drink consumption much like the reclamation facility does to treat water.
The first step is the intake of murky water with liquids and solids (bacteria) from Yelm’s septic called influent. From the influent tank, wastewater is sent through sequential batch reactors (SBR) where it is oxygenated in one of three 500,000-gallon aeration tanks and then the sludge sits until the solids and liquids separate.
From the SBR, the solids and liquids are sent in different directions.
The liquids are sent to the equalizing basin where the liquids and solids further separate.
The solids are brought to the waste tank before they are brought to the gravity belt thickener where the liquid is almost completely removed from the solids. The liquid then goes back to the influent and starts the process over again while the solids are stored. The solids are then pumped from the tank and sent to Central Wastewater Treatment Plant in Tacoma.
From the equalizing basin, the liquid is pumped through sand filters and sent to the flash mixer where it goes into chlorine contact chambers.
From the chlorine contact chambers the liquid is sent through the reuse water skid and out for Yelm facilities to use or it will be stored in the reserve tank or discharged into the Centralia Canal and Nisqually River if the reserve tank is full.
What Went Wrong
The facility was one of the first water reclamation facilities in the state, built in 1999. It was state-of-the-art for its time period but years of inadequate maintenance, needed software and hardware updates have caught up to the facility. The WRF was unable to produce Class A reclaimed water until improvements were made.
“We inherited this and now we have to fix it,” VanBuskirk said.
There are multiple examples of deferred maintenance. The first example is the reuse water skid, a piece of equipment that is many years past its life expectancy and currently rotting from the inside. The second example is the equalizing basin. The equalizing basin was built as one big “lagoon” but has proven to be impossible to keep clean. The liquid had higher ammonia levels after the liquid left the equalizing basin than before the liquid entered it.
The solution proposed by VanBuskirk was to build two parallel walls creating three equal sized basins. The reason for this is to have a rotation of two fully functioning basins while one is being cleaned of solids.
Another example of failed maintenance is the sand used to filter water. The sand is supposed to be replaced every 10 years but it hasn’t been replaced for almost 20 years due to cost. The cost of the sand is $30,000 and it is an additional $20,000 to ship the sand from Florida.
“The bottom line is that there has been huge deferred maintenance to this facility,” said Yelm City Administrator Michael Grayum.
The Reason Behind the Deferred Maintenance
Since the facility was built, required upgrades have not been made along the way partly in an effort to cut spending and partly because the facility was run by consultants instead of a treatment plant manager with expertise in maintaining the facility.
The city now has multiple problems to fix at one time. Cost was the leading factor behind the lack of maintenance, said Yelm Mayor JW Foster. He cited the deferment of maintenance was an easy way for the previous city government to cut spending during the recession of 2008.
Immediate Phase One Improvement Plan
Immediate Phase One has five improvements and was designed in a collaborative effort between the city of Yelm, VanBuskirk and the Washington state Department of Ecology.
The first improvement is to replace the operating system and software to allow WRF operators better control of the setpoints of the system.
The second improvement will replace the hardware components of the Supervisory Control and Data Acquisition System, which will allow the system to operate safely, reliably and effectively.
The third will replace the pumps and pipes that are overdue for replacement due to current demand.
The fourth will include upgrading compressors for pressurization and airflow.
The fifth includes the construction of an underdrain system in the equalizing basin for efficient operations and maintenance of sludge.
The expected cost of Phase One is $2 million. The city of Yelm expects to pay for the project through the Department of Ecology Grant and Loans Program, Public Works Trust Fund, U.S Department of Agriculture loans, direct financing through bond insurance and direct legislative funding assistance.