Perhaps no wastewater treatment facility blends old and new as well as the Kline’s Island Wastewater Treatment Plant operated by the Lehigh County Authority in Allentown, Pennsylvania.

On one hand, the staff at the 40 mgd (design) plant operates a fixed-nozzle rock media trickling filter that dates to 1931. On the other, Kline’s Island switched to sodium hypochlorite instead of gaseous chlorine for effluent disinfection and replaced old motor control centers and breakers with new equipment.

Future projects will upgrade process control and address wet-weather flows that affect plant capacity. They’re balancing old and new so well that the plant recently received the Operation and Maintenance Excellence Award for plants over 2.0 mgd from the Eastern Pennsylvania Water Pollution Control Operators Association.

It’s all the result of commitment and cooperation among the 50-person staff. “Teamwork is the key,” says Gary Saunders, plant manager. “We work well together, striving for a common goal and pursuing any new idea, as long as it makes our facility more efficient and safe.”

The plant also received the operator association’s 2020 Laboratory Excellence and Performance Award. Saunders received the 2020 Daniel H. Treat Award for sharing of wastewater knowledge with others, and the 2021 Mark B. Hannum Operator of the Year award from the Pennsylvania Water Environment Association.

Where streams meet

The Kline’s Island plant sits on a 33-acre site at the confluence of the Lehigh River, Little Lehigh Creek and Jordan Creek, near the center of Allentown. It serves that city and 14 surrounding communities.

Wastewater enters through 60-inch and 36-inch pipes and passes through two climber screens (SUEZ Water Technologies & Solutions) before Worthington pumps deliver it to the grit chamber. Then it settles in four circular primary basins, each about 1 million-gallon capacity.

Liquid oxygen is added just ahead of the grit chamber to help mitigate against odors and BOD.

From the primaries, the wastewater is pumped by five Johnston vertical turbine pumps to four 100-foot diameter, 32-foot-deep plastic media trickling filters (Dorr-Oliver Eimco). After passing through the filters, the flow is pumped to three circular intermediate clarifiers, each with a capacity of 1.54 million gallons.

The rock media tricking filter follows; nitrification-denitrification occurs as the flow passes through. It’s big — 5.32 acres with a depth of 10 feet. After the filter, the water flows by gravity to a series of 10 final clarifiers of varying sizes and then to the chlorine contact chamber. The Lehigh River is the receiving stream.

Biosolids

The plant maintains three anaerobic digesters. Two receive thickened primary sludge. After digestion, biosolids are transferred to the secondary digester where quiescent conditions promote liquid-solids separation.

The digested material is thickened and dewatered on three Winklepress belt presses (Alfa Laval) and produce biosolids cake at 19-22% solids. The authority’s trucks haul it to a site owned and operated by Synagro, which distributes the material for land application.

Biogas is fully used as an energy resource. It fuels a Biogen generator that produces electricity, which the plant exports to the Pennsylvania Power and Light grid. It makes up about half the total plant power draw. Heat from the generator is captured to heat the sludge in the primary digesters. If the BioGen system goes down, the plant can switch to natural gas.

The nearest homes to the plant are less than a quarter mile away and the plant used to experience frequent odor complaints. Since the 1980s those issues have disappeared thanks to an odor-control system consisting of 40-foot-high fiberglass towers that use an atomized sodium hypochlorite mist. The mist and odorous air react as they pass up through the tower. There are 12 towers, positioned at the settling tanks, the plastic media filters, the thickening tanks and the dewatering building.

Despite the age of the plant, it is fully automated and equipped with the latest data and information systems. The SCADA system is from Kapsch; CityWorks supplied the computerized maintenance management system, and the laboratory information management system is from Hach.

Plant performance is excellent. From an influent loading of 157 mg/L BOD and 166 mg/L TSS, Kline’s Island produces an effluent discharge with less than 6 mg/L each. Effluent ammonia nitrogen is 1.5 mg/L.

The authority’s 5.75 mgd regional pretreatment facility at Fogelsville pretreats high-strength waste from several large industrial customers, supporting high performance at Kline’s Island.

Dual licensing

Fifty employees staff the plant, some doing double duty. Saunders explains that about one-third of the staff is responsible for operation and maintenance of the authority’s 30 mgd drinking water treatment plant, as well as the wastewater facility.

Key team members are Joseph Westfall, assistant plant manager; Bryan Geissel, project manager; Justin Silberman, maintenance manager; Gretchen Schleppy, lab manager; Andrew Moore, compliance manager; John Parsons, chief operations officer; and Mark Kudera, maintenance crew leader. “We have 18 operators and two supervisors rotating between the two facilities every two months, working 12-hour shifts,” Saunders says.

Saunders says the split works well because many of the procedures, such as pump maintenance and chemical addition, are the same or similar, even though the treatment processes are not. The dual experience “helps greatly in covering shifts,” he says. “Our operators are certified and licensed in both wastewater and drinking water plant operations.”

Lots of ideas

Such an experienced and knowledgeable staff helps improve operations. “Our progression to move away from gaseous chlorine is a good example,” Saunders says. “We had 16 one-ton cylinders on site for use in the chlorine contact chamber, but now we’re moving to sodium hypochlorite, primarily for safety reasons. Our personnel were involved in the design and execution of the project.”

In another instance, operators identified reliability issues with the dewatering equipment. The most viable suggestion was to bring in a consultant to troubleshoot the process, identify issues and show operators how to deal with problems successfully.

And Kline’s Island is not stopping there. Faced with an old electrical distribution system installed in the 1970s, the plant is in the design phase for new motor control centers, along with new breakers and substations. Age and reliability are the reasons behind the changeout.

An electronic plant services site using Microsoft SharePoint helps keep the operators up to date on what is happening at both plants. “Operators at each plant can see the same shared page and will create a blog entry in the operators’ blog for each shift at each plant,” Saunders says.

“They document anything significant that happened on the shift that would be important for the other operators and management to know: pump changes, equipment failures, equipment rotation and any other irregularities during the shift. 

Management also writes announcement entries that are at the top of the webpage to convey important information that future shifts need to know. With all this information in one spot, an operator stationed at one plant can keep up to date on what’s happening at the other plant and can be ready when it’s their time to change plants.”

Dealing with weather

Wet-weather flows are another issue. Flows can reach 90-95 mgd in extreme conditions, causing the plant to bypass into a stream. “Once the influent flow reaches 84 mgd, a few of the key processes have reached their capacity,” says Saunders. “At that point we begin to throttle down our influent gates to maintain the 84 mgd flow rate in order to protect the facility.”

Any flow above this amount is diverted untreated to the Little Lehigh Creek through a 48-inch bypass line. “We do everything within our power to prevent this from happening, but Mother Nature doesn’t always play by our rules,” Saunders says. The authority, the City of Allentown and the Pennsylvania Department of Environmental Protection are discussing ways to mitigate the bypass flows.

Finally, the 90-year-old rock media trickling filter is performing well but will be evaluated for replacement. Although it has operated reliably for many years and has enabled the plant to meet nitrogen requirements, debris has never been cleaned out of the media, Saunders says.

As part of the regional sewage facilities planning now under way, the rock media filters will be evaluated for replacement, possibly by new plastic media filters and a new pump station. The progress continues.