How A Pennsylvania Plant Met Turbidity Goals

A Pennsylvania water treatment plant improves operations to meet stringent turbidity goals and receives Partnership for Safe Water Presidents Award.
How A Pennsylvania Plant Met Turbidity Goals
Scott Sharp, water quality supervisor with Pennsylvania American Water, performs a particle analysis using a microscope connected to a Zeta-Meter.

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When the Philipsburg Water Treatment Plant received its first Partnership for Safe Water Directors Award in 1999, it already met combined filter effluent turbidity goals.

Still, the operations staff wanted a better way to analyze individual filter turbidity information from the SCADA system. The team developed a report that automatically analyzed the data to show the percentage of time individual filters met the turbidity goal of <0.1 NTU, a requirement for the Partnership Presidents Award.

“Our water quality supervisor, Scott Sharp, and our SCADA manager, Roger Sandak, developed the report, which calculates the 95th and 99th percentile for turbidity,” says Jane Moore, production supervisor. “That gave us a better way to accumulate the data so we could show that we were meeting the turbidity requirements.”

Source-water turbidity changes from drought and rain used to be a challenge. The Partnership program changed that. “It made us more equipped to handle source-water changes,” says Moore. “We added shutdown parameters in the SCADA and alarms that allow operators to troubleshoot problems before the system automatically shuts down.”

The changes paid off. With consistent individual filter turbidities of less than 0.1 NTU, and typically in the range of 0.04 NTU or lower, the plant received the Presidents Award in March 2014. It was only the fourth plant in the state to do so.

Adsorption process

Owned and operated by Pennsylvania American Water, the 2.3 mgd Philipsburg plant was built in 1988 and serves 20,000 people in the boroughs of Philipsburg, Osceola Mills, Chester Hill and Wallaceton, and portions of Rush, Morris, Graham, Decatur, Bradford and Boggs townships.

The heart of the system is a Microfloc Trident adsorption clarification packaged treatment plant (WesTech Engineering), chosen after a pilot study to determine the best treatment option for the new facility.

Other equipment includes four mixed-media filters (WesTech), liquid chemical feed pumps (LMI Pumps), Wallace & Tiernan chlorinators (Evoqua Water Technologies), Depolox chlorine analyzers (Evoqua), 1720E turbidimeters (Hach Company), streaming current detector (Milton Roy) and actuators (AUMA) on the filter and clarifier flow control valves.

The water source is Cold Stream, a tributary to Moshannon Creek via one reservoir, along with a spring and three wells. Raw water is monitored for turbidity, treated with chlorine gas and alum, then monitored for pH, residual chlorine and streaming current. Treated raw water flows through two adsorption clarifiers, which contain 4 feet of buoyant plastic granular media that traps and removes coagulated particles. Contact flocculation and clarification occur as the coagulated particles move through the media.

Clarifier effluent is monitored by turbidimeters and flows to the mixed-media filters. Combined filter effluent is treated with chlorine, caustic soda, fluoride and corrosion inhibitor before flowing to an underground clearwell.

Wastewater from filter backwash and clarifier flushes is collected in the wastewater clarifier. Settled solids are pumped to a drying bed, and the clarifier supernatant is recycled to the head of the plant each day.

Small team

Three operators and a maintenance/relief operator run the Philipsburg plant and the chemical-only 1.5 mgd Penn 5 treatment plant, which treats Trout Run well water with chlorine, caustic soda, corrosion inhibitor and fluoride. Both plants feed into the same pressure gradient so if one plant shuts down, the other delivers water.

“There is a 1-million-gallon tank in the pressure gradient,” says Moore. “When both plants are operating, the excess water fills that tank when demand is low, and water from that tank provides water when demand is high. We determine what flow rate to set at each plant by the level in the tank.”

Philipsburg operators test for turbidity, pH, chlorine residual, fluoride, hardness, alkalinity, chloride, iron, manganese, aluminum, zinc, conductivity and odor. The Penn 5 plant lab is equipped to analyze process chemicals for proper feed calibration; microbiological samples are analyzed at the Philipsburg lab.

Operators analyze grab samples from the clarifier and filter every day and check coliform levels in the reservoir. They also flush the clarifiers and filters and fill the day tanks. “They make treatment decisions based on water quality and operational issues,” says Moore. “For example, if we know we are going to get a lot of rain, we will probably run the plant harder and make sure all the tanks in the system are full so we can slow down when the water is more difficult to treat.”

Weekly, the operators inspect booster pump and pressure relief valve stations. They collect all compliance samples in the distribution system and handle customer water-quality inquiries in the field. “Typically, Scott and I get the service order that a customer has a question or problem with water quality,” says Moore. “One of us talks to the customer to understand the problem, and then an operator will go out and get a sample. Most of the time, the solution requires flushing a line.”

Operators also inspect the reservoir, wells and spring, collect samples, maintain equipment and keep an eye on the overall health of the watershed.

Optimizing the process

To continually meet Partnership for Safe Water goals, Philipsburg operators diligently collect and record the turbidity data and regularly clean and calibrate the turbidimeters. They use alum as a coagulant, and a streaming current detector to control the dose. When the source-water turbidity changes, they adjust the detector setpoint.

Under the Partnership, the staff began analyzing clarifier runtimes and pressure to optimize flushing. “When I started in 1992, the clarifiers flushed automatically based on time,” recalls Moore. “We were getting 16-hour runtimes and pressures less than 1.0 psi. Now, we look at pressure and performance to decide when to flush.”

In normal conditions, the plant now achieves 72-hour runtimes. Operators typically flush at 1.5 psi for about 30 minutes. “They have complete control of each step and can make adjustments based on what they are seeing, which has been a tremendous improvement,” says Moore.

Typically less than 1.0 NTU, the raw water turbidity has sometimes increased to 5 or even 10 NTU.  “One year we had 2 feet of snow followed by a spring rain that melted the snow overnight,” says Moore. “The resulting high turbidity in the reservoir made the water very difficult to treat. 

“The first time this happened was in March 1993, and I had only been working as an operator for a few months. We already had a lot of snow from multiple storms. The turbidity was around 20 NTU, and the plant kept shutting down because we couldn’t treat the water.”

Although the plant’s permit allows it to operate the filters at 4 gpm/square foot, operators had to run at 1.5 gpm/square foot. “We didn’t have generators then, so when we did get the plant going, the power would go out and it would shut down again,” says Moore. “This happened 11 times during that March storm.”

Now, the plant has automatic generators, and under high-turbidity conditions the operators minimize water drawn from the reservoir by slowing the plant down and using more water from the wells and spring. They can also increase the Penn 5 plant’s flow to make up the difference.

“Because we’ve optimized treatment with clarifier flushing and SCADA setpoints, we can achieve a higher removal percentage through the clarifiers,” says Moore. “We were getting 30 to 40 percent removal, and now we get around 75 percent during storms.”

Meeting challenges

Although the plants are automated, the numerous tanks, pumping stations and pressure-reducing stations keep operators on their toes. “Their biggest challenge is making sure all the systems are working properly,” says Moore. “They must do preventive maintenance and troubleshoot, and since we’re in a very rural area, sometimes just getting to the site can be a challenge, especially in winter.”

Pennsylvania American Water maintenance and water-quality groups lend support when needed, but Philipsburg operators are the first on site during a problem. “I am extremely fortunate to have such a great group of operators,” says Moore. “When there’s a problem, they work as a team to fix it. Each situation can require different skills. They combine their talents to come up with solutions we never would have thought of otherwise.”

Moore has been with the plant for 22 years. She began as an operator and was promoted to supervisor in 1998. Sharp, with Pennsylvania American Water for 20 years, is responsible for compliance sampling and reporting and assists with water treatment issues. Operators Charles Jones (28 years), Dale Warner (14 years) and Dave Wildman (six years) and maintenance/relief operator Harry Foster (seven years) report to Moore.

Jones has been with the Philipsburg plant since the beginning and has done everything from installing water mains and fixing leaks to reading meters and plant operations. Foster began as an operator before moving to his current position. The Philipsburg plant is staffed seven days a week from 7 a.m. to 11 p.m. Operators rotate on the second shift. The unmanned Penn 5 plant is remotely monitored.

Always improving

The Philipsburg and Penn 5 plants are constantly upgrading equipment to keep up with changing technology. “We find that the equipment we use rapidly becomes obsolete and should be replaced with the newer version,” says Moore. “For example, we upgraded to radio communication a few years ago. It is much more dependable with no wires to go down during a storm. I get paged and receive an email to let me know if there are tank level issues or a communication failure.” 

Radio communication has saved time and money. Moore used to get an autodialed call for a plant alarm: “It could be at 3 a.m. and would just say ‘check water treatment.’ I had no idea what was wrong and had to call an operator to check it out. Now, I receive a text message that says ‘raw water turbidity high,’ and I can check on my home computer to see if the clarifiers and filters are working properly. So, it’s a great tool when deciding what action to take.”

As for future regulatory changes, the company’s water-quality group keeps an eye on what is happening. Says Moore, “We are usually in compliance with new regulations long before they actually take effect.”

Plant staff will continue to evaluate procedures to improve the treatment process. “The objective of the partnership is to challenge the industry to continuously improve the drinking water quality, and that is our goal,” says Moore. “My team is really interested in their work, and they get excited when they figure out how to solve a problem or how to do something better. If we have a really bad storm, the operators who are off that day will call in just to check and see if everything is OK.”

Moore also sees dedication in her team members’ personal lives: “They all have different interests that they’re passionate about, whether it’s Little League with their kids, working on or riding their motorcycles, or just being out in the woods. They’re excited about life.”   



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