Source Correction

Impairment to the watershed that supplies the Bellingham Water Treatment Plant challenges the county, the city and plant operators in delivering high-quality water.
Source Correction

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The City of Bellingham, Wash., relies on Lake Whatcom to supply drinking water for its 87,700 residents. Also popular for swimming, boating and fishing, the 10-mile-long lake is divided into three basins, and the city draws water from the shallowest, called Geneva Basin.

In 1998, the lake was placed on the U.S. EPA's list of impaired water bodies because of low dissolved oxygen from phosphorus contamination, which has caused seasonal algae blooms. While that has not affected the Bellingham Water Treatment Plant's water quality, it has affected operations by clogging filters.

During summer 2009, the plant's filter run times were reduced, requiring more frequent backwashing and greatly reducing plant capacity. This led to mandatory outdoor watering restrictions for the first time in the city's history.

In 2011, the city hired engineering firm CH2M HILL to perform a pretreatment evaluation study to determine the best solution. As part of this study, a six-week pilot test at the water treatment plant found that an upgrade to dissolved air flotation pretreatment would solve the problem.

The city is considering the upgrade, but for now, operators at the 44-year-old, 29 mgd plant are easily meeting water quality requirements. As a participant in the Partnership for Safe Water program, the plant received five-year and 10-year Director's Awards in 2004 and 2009, and the team is working toward the 15-year award in 2014.

To the source

While treatment plant personnel deal with their own challenges, the city is looking upstream, seeking ways to protect the drinking water supply by reducing phosphorus loadings to the lake.

In 1998, Bellingham, Whatcom County and the Lake Whatcom Water and Sewer District established the Lake Whatcom Management Program to manage and implement programs affecting the watershed. In 2000, an inter-jurisdictional coordinating team (ICT) was created to develop and coordinate the program's activities.

Even with these initiatives, the lake's water quality continues to deteriorate, primarily from phosphorus entering by way of residential development and other human and natural sources. A 2008 state Department of Ecology (DOE) total maximum daily load (TMDL) study concluded that some 86 percent of developed acreage in the watershed would have to return to natural conditions to reduce phosphorous to an acceptable 2,400 pounds per year.

In 2013, the DOE plans to include TMDL compliance as part of new NPDES stormwater requirements. Lake stakeholders know that meeting the TMDLs for phosphorus and dissolved oxygen will take many years.

Improving the watershed

Meanwhile, the Lake Whatcom Management Program continues to monitor lake water quality and take steps to reduce phosphorus levels. Nine tributaries to the lake are routinely monitored, as is the lake itself in the deepest part of each of the three basins. Monitoring is also conducted at the city intake and at an additional point in Basin 3 (the largest).

Raw water samples are collected at the city screen house and at various points in the water plant.

The Lake Whatcom Management Program's 2011 Annual Progress Report, prepared by the ICT in March 2012, highlights accomplishments and provides recommendations for 2012. Accomplishments for 2011 include a cost benefit study by CH2M HILL of activities that can prevent or reduce phosphorus loadings.

Other highlights are stormwater capital improvement projects in the watershed and community education efforts that include a bimonthly e-newsletter and a new Lake Whatcom Management Program website.

"The city, county and Lake Whatcom Water and Sewer District cooperate to implement annual work plans to improve and protect lake water quality," says Clare Fogelsong, environmental resources manager for the city Public Works Department. "The annual plans are comprehensive and include a wide range of actions that address several threats to the lake. The recent focus has been to reduce nutrient loading into the lake."

A five-year work plan describes a number of tasks to be pursued, dealing with program areas that include watershed ownership, land development, stormwater management, data and information management, utilities and waste management, spill response, transportation, recreation, and community outreach.

Clogged filters

Today, the water treatment plant team deals regularly with the consequences of phosphorus. Algae in Lake Whatcom has been steadily increasing for the past decade, and it peaked in the summer of 2009, when a slime produced by the blue-green algae clogged the water plant's filters.

Contributing factors included a heavy January rainstorm that delivered a huge load of phosphorus-laden sediment, and a wet spring that washed more sediment and nutrients than usual into the lake — just in time for record-setting hot summer weather.

Treatment plant operators saw decreases in the Unit Filter Run Volumes (UFRVs) — a measure of how much water passes through each square foot of filter media before it clogs and needs backwashing. "The UFRVs are typically 6,000 gallons per square foot during winter and 3,000 during summer," says Bill Evans, chief plant operator. "In the summer of 2009, the UFRVs decreased to 900 gallons per square foot for several days."

Filter run times decreased from 12 hours to 3 1/2 hours, and clean filters were placed online every 30 minutes to replace the ones being backwashed. "It became difficult for the operators to keep up," says Evans. "As soon as we backwashed a filter, the next one would come due."

All this cut plant capacity to below customer demand and below the volume required to maintain fire flows. When voluntary water conservation measures proved inadequate, the city enacted mandatory watering restrictions, reducing demand sufficiently in just two days. "Fortunately, the algae did not cause any taste and odor issues with the city's drinking water," says Evans.

Operational headaches

While frequent backwashing was taxing, a power failure on July 29, 2009, during the hottest day on record, made things even worse. "We called the power company to report the outage," recalls Evans. "Our generator ran for about 20 minutes before it overheated and shut down, which was the operators' worst nightmare. When power company staff finally showed up at the plant, they said there was nothing they could do because we owned the service equipment into the plant."

When Evans asked the power company to check to see if power was even coming into the plant, power plant staff found and repaired a loose wire that had caused the outage. "The power was out for an hour, causing us to lose an estimated 2.3 million gallons of water in our gravity reservoir," says Evans.

During the height of the algae problem, filter backwashing used about two million gallons of water per day. Operators optimized the amount of treated water used to clean the filters, and adjusted raw water screen wash times to reduce raw water turbidity, which was above 1.0 NTU, rather than the usual 0.45 NTU. The operators also increased chemical coagulation doses to maintain treated water quality.

Even with the water use restrictions, operators had to backwash more often than normal. "The frequent backwash issue lasted from July through October, and returned to normal levels when the cooler fall weather reduced algae growth," Evans recalls. Since then, the plant has gone through several upgrades to help the situation:

New 75 hp vertical pump motors (U.S. Motors/Nidec Motor Corporation) for redundancy, and new electrical service equipment, including an automatic transfer switch to reduce outage risks.Air scour system (HSI blower and AWI underdrains) to reduce backwash water use.New motor control cabinet (Allen-Bradley/Rockwell Automation) and plant main switchgear (Schneider Electric) to update the electrical system and reduce failure risk.New 1,000 kW emergency generator (Baldor).

Many tasks

The Bellingham plant's seven operators are responsible for water and wastewater operations, including monitoring and operation of 14 storage reservoirs (29 million gallons of storage) and 14 pump stations. Two operators run the water plant and two run the wastewater plant during normal business hours. After hours, one operator monitors both treatment plants with the SCADA system.

Water plant operators report to Evans, who sets performance goals. They make production-change, filter-backwashing and disinfection-dose-rate decisions, make all process control adjustments and checks, and handle customer service calls after hours.

Evans, who reports to superintendent of operations Bob Bandarra, holds Class 4 water treatment plant and water distribution licenses and has been with the city for 33 years. His team includes lead operator Karl Lowry (Class 3, 19 years) and operators Gary Hess (Class 3, 41 years), Randy Osborn (Class 3, 38 years), Gary Gilfilen (Class 4, 33 years), Sally Pytel (Class 3, 12 years), Keith Fredrickson (Class 3, 9 years), and Shayla Frances (Class 3, 7 years).

Well-trained

"Training the operators on both the water and wastewater facilities gives them a broad background," says Evans. "They know both systems well, and even though it takes longer to train them, it makes them much more knowledgeable." The operators appreciate the variety of work at the two plants, and cross-training allows more flexibility when operators take vacation.

The plant team conducts annual tours for groups, including Western Washington University water-quality classes and Bellingham elementary school students. "It used to be part of the fifth grade curriculum," says Peg Wendling, laboratory supervisor for the Bellingham plants. "They still use a video series on water resources and treatment that the city developed 10 years ago. Bill Evans is featured prominently in that series as Bill Y the Water Guy."

Each year, the operations staff members attend the regional AWWA conference and take classes at the Washington Environmental Training Center (WETRC) to complete mandatory annual licensing credits. "We have an ongoing training program for all new operators, called skills standards, which covers the water treatment plant, distribution system and lake diversion system," Evans says.

Partnership for Safe Water

Another initiative is the Partnership for Safe Water program. "We started the program by completing the Phase III self-assessment of our plant in September 1998," says Evans. Since then, the plant has maintained Partnership goals each year.

"When we started the program, our first thought was how can we improve plant performance better than it already is," says Evans. "After the self-assessment stage, we discovered that by making simple operational changes on how the filters were placed in service, and using particle counter sensors to optimize chemical coagulation, we were able to improve performance and learn more about plant operations in the process."

The plant is active in the AWWA Pacific Northwest section and the Pacific Northwest subsection. The Pacific Northwest Section awarded Evans a certificate for his service as a state trustee from 2008 to 2010, and a certificate of appreciation as a water treatment committee chairperson from 1999 to 2009.

Future pretreatment

The 2011 pretreatment evaluation study considered different mechanical pretreatment options. It also considered extending the existing intake pipe into a deeper part of lake Basin 3, adding a second intake in a deeper section of Basin 2, or adding another over-the-ground pipeline to a deeper section of Basin 3.

"Options 2 and 3 would have provided redundancy to our intake system," says Evans. "But upon detailed analysis, the pipeline alternatives were not as attractive as adding pretreatment ahead of our inline filtration plant."

A pilot study of the dissolved air flotation (DAF) system (Roberts Filter Group) in summer 2011 showed that pilot filters fed with DAF-clarified water had significantly higher UFRVs (more than 8,000 gallons per square foot) than the existing filters, which had averaged about 3,000 gallons per square foot.

"The highest algae counts during the pilot testing period were 32,000 colonies per 50 mL of raw water," says Evans. "The DAF system removed 80 to 90 percent of that, which greatly extended filter runs." The system also effectively removed total organic carbon and reduced trihalomethane (THM) formation by up to 25 percent. (THM removal is a lesser concern, as the plant easily meets disinfection byproduct requirements.)

The city is examining the capital cost of DAF systems from 16 to 30 mgd capacity. A three-train DAF system offers maximum redundancy and the capacity to meet future water demand. A two-train system is also being considered. Regardless of size and capacity, a new DAF facility would be designed for easy expansion.

"We hope the city approves the upgrade so that construction can start in the near future," says Evans. "We also may upgrade the screen house, which was built in the 1940s. The preliminary review of this upgrade will include new raw water screens and potential bypassing of the structure with new water mains to the plant."

Continued diligence

In the long run, the city will continue its two-pronged approach to water quality: protecting the source while providing appropriate treatment to maintain the highest-quality product possible.

"In my 33 years in this field, the job of being a plant operator has changed," says Evans. "It has transitioned from pumps, piping and treatment to a profession that includes water resource management, watershed activities and education."



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