The North Brunswick Water Treatment Plant has come a long way in 50 years. When the 1963 gravity filter system surpassed its useful life, leaders in the New Jersey township knew they had to upgrade to meet new turbidity standards.

In 2002, they contracted with American Water to operate the plant and coordinate a two-year, $19 million upgrade. The new 10 mgd plant, completed in 2010, includes six dual-media gravity filters, a new control room, office and laboratory, and new automation and control.

The staff ran the old plant while starting up the new one, meeting all regulations even as the old filters were failing and new ones were being tested, along with the chemical feed system and other equipment. Another challenge was converting the two existing filter backwash holding tanks to thickeners – that meant operating with one tank while the other was being retrofitted.

The effort was well worth it: Finished water turbidity has improved from 0.1-0.2 NTU to 0.01-0.02 NTU. Residuals handling has improved, and a 60 kW rooftop solar system supplies 5 percent of the plant’s electricity. Meanwhile, the operations team began working toward Partnership for Safe Water awards and developed a complete set of standard operating procedures. The plant signed on to the Partnership in 2012 and won the Phase III Directors Award in June 2015.

New ideas

When American Water stepped in, team members found the operations staff struggling to meet Department of Environmental Protection regulations with the old gravity filter plant and pressure filter plant, now mothballed. “We had no way to determine filter head loss or flow from each of our eight gravity filters,” says Jim Grootenboer, general manager. “Because they backwash automatically based on hydraulic conditions, operators had no way of knowing if a filter was backwashing.”

As a filter failed to meet turbidity standards, it was removed from service. “It was labor-intensive for operators to determine what caused the turbidity fluctuations,” recalls Grootenboer. “The pressure plant required the section head created by the gravity plant, so it was important to keep at least a few filters in service.” The gravity plant also posed a challenge. With no individual filter flow controls, the cleanest filter received most of the flow. The automated controls had failed, so two operators were required to wash the filters manually.

The new plant changed all that, with new gravity filters, sludge thickeners, sodium hydroxide chemical feeder, inline mechanical mixer, backwash equalization basins and SCADA system. The plant still uses the original clarifiers.

The new plant helped in meeting Partnership for Safe Water goals, but equally important is the plant’s culture. “We have an open-door policy between management and staff,” says Tony Cappa, plant supervisor. “The operators are always encouraged to discuss new ideas, findings and problems.”

During the self-assessment phase, management surveyed the staff. “We asked about plant culture, leadership, safety and operations,” says Grootenboer. “We got some great feedback.”
Standard operating procedures also helped. The operators walked through each process, then reviewed them in a staff meeting and offered input.

“Now, the operators have specific goals for each process and know what to do if things go outside specification,” says Grootenboer. “It’s a much more proactive approach.”

Many improvements

The new treatment plant was built to meet current regulations and serve a growing population. The plant serves 40,000 people with 11,700 metered connections in North Brunswick. New development includes townhomes, a mall and an Amtrak rail station.

Raw water from the Delaware and Raritan Canal flows by gravity through two traveling screens (Link-Belt) into a suction well. Three vertical turbine low-lift pumps (Flygt - a Xylem Brand) move water from there to three Permutit upflow clarifiers/precipitators (Evoqua Water Technologies). The water is treated with powdered activated carbon (Cabot Norit) if needed for taste and odor control, and with caustic soda if needed for pH and alkalinity control. It is then treated with aluminum chloride hydroxide sulfate as a primary coagulant. If required, operators can add a polymer for color removal.

The water is mixed with the inline mechanical mixer (Hayward Gordon) and sent to three upflow clarifiers, which remove most solids before filtration. A floc aid polymer is added before the water enters the precipitators. Sludge blow-off and filter backwash are fed to a sludge wet well and processed through sludge thickeners (Envirodyne Systems). Thickened sludge is dewatered in a press and land-applied.

Next, the water is filtered through the gravity, dual-media filters (Leopold - a Xylem Brand). Backwash water discharges to equalization basins and is gravity fed to the sludge wet well. The filtered water is treated with polyphosphate for sequestering and corrosion control, then treated with sodium hypochlorite. Filtered water enters the effluent wet well, is pumped to a 1-million-gallon clearwell, and is delivered to the distribution system with four horizontal split-case high-lift pumps (Flygt - a Xylem Brand).  

Better control

In late 2009 there was a rush to place the new plant online. Although the operators were familiar with gravity filtration, not all were comfortable with SCADA technology. “There was a learning curve, especially with running reports and changing alarm setpoints,” says Cappa. “The operators went to the manufacturer’s site (Emerson Process Management) in Connecticut for several days of training.”

Standard operating procedures for the SCADA system show the screen shots, and as operators go through the procedure each readout is fully explained. “In the past, we had to have a set of eyes on all the meters and monitoring equipment. Now, we have real-time control and can react immediately,” says Grootenboer. This is especially important in monitoring fluctuations in raw-water turbidity. The Delaware and Raritan Canal is shallow, and although turbidity averages 5 to 10 NTU, runoff during storms can raise turbidity to over 100 NTU.

The SCADA system provides detailed filter profiles and enables monitoring of filter runtimes and turbidity. Operators still observe backwashing to make sure there are no air gaps and no bed rise. They also perform a quarterly filter inspection and an annual media core sampling.

Converting to thickeners

Residuals handling has improved. The old facility used backwash holding tanks and overflow lagoons. The lagoons were removed, and the tanks were converted to sludge thickeners. Supernatant overflow weirs allow continuous flow back to the head of the plant. The slope of the thickener floors was increased to allow settled solids to flow to the center discharge pipe, and the rake arm drive units were replaced.

This all posed an operations challenge. “We had to regulate flow through the one thickener and install turbidimeters on the supernatant return lines to monitor possible upsets,” says Grootenboer. “These were caused by the return of solids to the head of the plant during high flow and large volumes of solids accumulating in the thickener.” The team isolated one side of the equalization basin to act as a temporary backwash holding tank.

Until the SCADA system was installed, operators constantly monitored flow, sludge levels and return-water turbidity.

Now when operators perform a backwash, the waste and the sludge blowdown enter the thickeners, and the clear supernatant flows back to the head of the plant. The heavier solids settle to the bottom and are pumped to the existing belt press. “The thickener process is a continuous trickle operation that allows sludge to sit in the tank longer, so we end up with thicker solids,” says Grootenboer.

The process is now partially automated. The sludge pumps operate based on the level in the wet well. The sludge level in the thickeners is measured continuously using an ultrasonic device, and return turbidimeters are now alarmed.

Meeting challenges

Five certified operators and a lead senior mechanic keep the plant running smoothly. Besides Grootenboer (Level 4 water treatment and water distribution, Level 1 industrial waste treatment certifications, 10 years at the plant) and Cappa (Level 2 water treatment, four years), the team includes:

• James Connelly, Ronald Parsons, John Bryant, Alan LeFave and Anthony Liscio, operators
• Stephen Koblos, lead senior mechanic
• Peter Peterson, distribution supervisor
• David Soltis and Kameron Miller, distribution field service representatives
• Sammy Ferrante, meter reader
• Alisa White, senior secretary

They are not afraid of challenges, which include algae growth in the clarifiers (mainly April through June) and sludge thickening issues in winter. “Ultrasonic waves have been successful in killing algae, and we are looking at a possible test situation at our plant,” says Grootenboer. “We have also invested in a lab instrument called a FEEM (fluorescence excitation emission matrix) spectrophotometer to determine the species of algae and chlorophyll levels and estimate algae activity and growth.”

The staff also uses the FEEM device to help determine coagulant dosages. “Our current procedure based on previous testing is to raise our primary coagulant to remove both turbidity and algae,” Grootenboer says.

Plant staff has been testing sodium permanganate as a pre-oxidizer to help oxidize and destroy algae without using chlorine, which can cause disinfection byproducts. They also increased prefilter disinfectant to maintain a chlorine residual post-filtration.

Heavy ice on top of the thickeners and clarifiers in winter also affects operations. “We lose the use of our ultrasonic sludge level monitors in the winter and have to keep an opening in the ice so we can monitor this manually,” says Grootenboer.

To estimate the amount of sludge produced, operators use a formula based on raw-water quality and the amount of coagulant. “We do our best to keep up with production during the winter,” Grootenboer says. “We empty and clean each thickener before winter and again in the spring. We also monitor the belt press camera so the operator has eyes on the process. Polymer is added ahead of the belt press to help produce a heavier sludge.”

Taking ownership

The operators’ greatest strength is their sense of ownership and team involvement. “The operators don’t just run the plant according to management telling them what to do,” says Grootenboer. “They enjoy a project they can take ownership of.”

For example, the operators worked as a team to improve the polyaluminum chloride (PACl) dosing. In the past, they would continually perform jar tests on the raw water to determine the dosing rate, but that was time-consuming. “The team began plotting turbidities and dosages for both low-color and high-color turbid waters,” says Grootenboer. “They created a graph so they could look up the turbidity and determine a dosage rate.

Operator Jim Connelly was instrumental in developing that tool.”
Operators often go above and beyond. During a Christmas night snowstorm, the air compressor that runs the PACl pumps failed, and PACl from the underground storage tanks could not be pumped to the day tank. With the day tank level dropping, operator John Bryant and former distribution field service representative Dominic Carra unbolted the storage tank lid and used a bucket to fill the day tank. They also installed a temporary pump to operate until the compressor was repaired.

Future projects

The township and American Water are busy planning for future improvements, which include new clarifiers and a larger solar power system next to the plant. Distribution system improvements include new billing software, leak detection equipment, and water tank inspections.

In the meantime, the plant team will be busy optimizing filter performance and possibly applying for the Partnership Presidents Award. Says Cappa, “Ongoing communication and training as well as empowering the team to make operational decisions with confidence are going to make all the difference.”