Industrial Flows Are a Daily Challenge That the Norfolk Plant Team Meets Consistently

A meticulous focus on process and maintenance keeps a Nebraska plant in compliance and the office walls lined with plaques for excellence awards

Industrial Flows Are a Daily Challenge That the Norfolk Plant Team Meets Consistently

Travis Kollath services a pump (Moyno products by NOV).

The Nebraska city of Norfolk is home to 24,000 people, but the Water Pollution Control Plant treats a BOD loading typical of a population four to six times that size.

That’s because the plant receives wastewater from several major industries, most notably two dairy processors. The Norfolk team handles it all just fine with a consistent focus on the process, aided by extensive lab testing that includes microbiological examination.

Todd Boling, wastewater superintendent, leads a nine-member team that keeps the equipment in top shape and the facilities clean and neat. Besides consistently meeting its permit — no violations since the early 1990s — the plant has been repeatedly recognized for excellence. In 2018 alone, it received the:

Nebraska Water Environment Association Scott Wilbur Outstanding Facility Award for medium-sized plants (14th consecutive year)

Nebraska Water Environment Association Gold Safety Award (14th consecutive year)

Water Environment Federation George W. Burke Jr. Facility Safety Award.

Boling says simply, “We’re proud of what we do, and the staff works hard at it.”

Sequential upgrades

The original Norfolk plant, built in 1960, consisted of just two primary clarifiers. It was upgraded to an activated sludge process in 1980. The current sequencing batch reactor (Aqua-Aerobic Systems) was added in 1994. Four years later, the old activated sludge train was taken offline, after a meatpacking plant closed down.

There have been several upgrades along the way. In 2003, the plant added a TrojanUV3000 UV disinfection system. “We went away from chlorine to UV because the state Department of Environmental Quality couldn’t put chlorine residual into the Elkhorn River anymore,” Boling says. In 2007, influent grinders were removed and quarter-inch bar screen (Vulcan Industries) was added.

After a flood in 2010 collapsed two of three influent clay sewer lines, a single 54-inch HOBAS Pipe USA concrete influent pipe was installed. “In 2012, we upgraded our SBR blowers to high-speed turbos (Howden),” Boling says. “In 2015 we added a Vulcan Industries grit wash system. We went from 30 tons a month of sloppy material to 3 tons a month of clean sand and gravel.”

SBR process

Wastewater enters through the influent screen; six lift pumps (Pentair - Fairbanks Nijhuis) deliver it to a Parshall flume that measures flow. The wastewater then goes through two grit collectors followed by three preaeration basins to freshen the wastewater.

Half of the flow goes to the largest of three primary clarifiers and from there to a roughing trickling filter and on to the SBR. The other half goes to two smaller primary clarifiers original to the plant, then to another roughing trickling filter and on to the SBR. UV disinfection is the final step before discharge to the Elkhorn River.

All solids pass through two gravity thickeners (WesTech Engineering) that raise the solids content from 1% to 4% before delivery to an aerated holding tank. Then two belt filter presses (including one from Komline-Sanderson) dewater the material to 22% solids.

Lime kiln dust is added to raise the pH to 12.0 for two hours and to 11.5 for an additional 22 hours to satisfy federal standard for Class B biosolids. Average production is 4.5 tons of biosolids per day. The material is land-applied by plant staff using two high-flotation trucks equipped with Knight ProTwin side-discharge spreaders (Kuhn North America). The city has 2,500 acres of cropland permitted for application, all within a 10-mile radius of the plant.

Dealing with industry

Norfolk, in northeastern Nebraska, is an industrial community, home to a steel plant, a rubber hose manufacturer, a bottling facility for soft drinks and flavored waters, and a plant that dehydrates meat products for ramen noodles.

The industries that contribute the most to the Water Pollution Control Plant are an ice cream and milk products producer and a company that dehydrates organic milk into powder. These plants send wastewater containing 7,000 to 10,000 mg/L of BOD. “We don’t require them to pretreat,” Boling says. “We sample them every week in order to bill them.

“Sixty percent of our loading is industrial and is largely high BOD. The primary clarifiers and the roughing trickling filters knock the BOD down substantially, and then the SBR takes it the rest of the way. We upgraded the trickling filters in 2016 with new two-arm rotating distributors. They remove 70% of the BOD.” One filter has fiberglass media (Brentwood Industries), and the other uses stacked redwood pallet as media.

High-quality team

The Water Pollution Control Plant’s performance is built on process rigor. Boling, a Grade 4 (highest) operator, and Marsha Louthan, chemical technician, Grade 2, make the ongoing operational changes. “Marsha does a great job of monitoring the bugs and making sure they’re happy,” Boling says.

“She runs all the industrial samples in the lab: CBOD, COD, TSS, pH, TKN. For plant processes, we run the influent samples. We have an intermediate sampler for what is going into the SBR and then a final effluent sampler that she runs analysis on for permit purposes. We also run settleometers and look under the microscope.

“In the SBR, sensors feed back to the SCADA system and tell us the DO and TSS levels in the mixed liquor. Marsha runs the samples and makes comparisons to ensure the sensors are accurate.” Dissolved oxygen is on automatic feedback with the blowers, and the TSS level is used to automatically adjust wasting to the mixed liquor suspended solids setpoint (2,250 mg/L).

Boling is proud of a multitalented operations team, which includes Lonnie Tucker, plant supervisor (Grade 3 license); Kevin Endorf, Jesse Smith, Tom Schwedhelm and Travis Kollath, operators (all Grade 2); Zach Behnke, maintenance worker; and Twyla Hurlburt, secretary. The collections system is maintained by the Water and Sewer Department, headed by Dennis Watts.

Keeping it running

New team members at Norfolk usually come from farm backgrounds and have a variety of mechanical skills. They start by learning basic plant maintenance. “The senior staff members train them how to do all the planned maintenance and the overhauls of pumps and other equipment,” Boling says. “They drive the trucks to spread the biosolids on farm ground. They dewater it with the belt presses.

“The rest of the staff — every morning we do a walk-around to make sure all the equipment is running. Then we do the maintenance and the painting and cleaning as necessary. We have a computerized maintenance management system (eMaint from Fluke) that spits out PM work orders every week for team members to complete.”

The SBR is highly automated with programmable logic controllers that feed back to the SCADA system. Boling and some colleagues have earned degrees in the electromechanical program at Northeast Community College.

The plant is staffed during the day shift; operators rotate on-call duty during nights and weekends. “Because of excellent plant maintenance and housekeeping, they only get called out 10 times a year after hours on average,” Boling says. Staff members can use tablets to monitor the SCADA system and answer alarms from home.

Stressing safety

Safety is a long-standing priority for the Norfolk team. “We haven’t had any lost-time accidents in 15 years,” Boling says. “Safety is a mindset, and it comes back to housekeeping and a well-maintained plant where everything is clean, there are no trip hazards and the walkways are free and clear.

“We have tailgate sessions in the morning where we talk about ladders, hand-tool safety, electrical safety and other topics. Our Fire Department provides annual training on bloodborne pathogens, fire extinguishers, first aid and CPR. We have training to make sure our people wear the personal protective equipment that’s required.”

To keep everything running smoothly, Boling strives to create a positive work environment. “Good communication is the big thing,” he says. “It’s a top priority of mine to make sure there is up and down communication so that everyone knows what’s going on. There are no hidden agendas.

“I don’t want to be the only one who knows how to do things. Everybody needs to know a little bit about everything.” In morning meetings, team members discuss what is in store for the day so each person knows what the others are doing. In addition, Boling gives the staff a bigger picture by communicating what is happening in the Public Works Department.

Industry connections

Boling came to his role in Norfolk with a farm background and two years of experience as a master plumber. He started with the city in the water department, and seven years later, in 1988, he switched to wastewater side. He became wastewater superintendent in 1995.

Last year he received a WEF Service Award. Besides being active in the Nebraska Water Environment Association, he has represented Nebraska as a WEF delegate and served for six years as a WEF delegate at large. He has chaired the House of Delegates Nominating Committee and has served on the WEF National Nominating Committee.

“You network with a lot of people who have similar concerns about how to manage people, operate your plant and take care of equipment,” Boling says. “You also meet people who may have experience with the same issues you’re dealing with. That is of great value.”

It has certainly helped Boling and his team keep the Norfolk plant in the topmost tier of clean-water facilities in Nebraska.

Tested under pressure

The true measure of a plant team comes in an emergency. For the team in Norfolk, Nebraska, that was the 2010 flood of the Elkhorn River, the plant’s receiving stream and a Missouri River tributary.

Heavy rains fell in early June in an area 50 to 100 miles upstream, and that gradually but significantly raised the river’s level at Norfolk. “We knew the flood was coming, so we prepared to have staff on board,” says Todd Boling, wastewater superintendent.

“As the river came up, we found out that the flows were increasing on the influent side of the plant. Two of our three clay sewer lines had collapsed, so river water was entering the influent stream. That forced us to run the plant manually 24/7 from June 10 to July 3 while we put the Band-Aids on. We were pumping 15 mgd through the plant and still meeting our permit limits.

“We couldn’t pump the water out to the river because it was so high that the water would basically come around back to us.” The floodwater didn’t enter any buildings or any clarifiers or other tankage, but high levels persisted for several days.

“We hired a local company that does lagoon cleaning,” Boling says. “Once we got things situated, they were able to take that 15 million gallons and with large pumps and long, thick hoses send it downstream to get it away from the plant.”

During the flood, the plant team members rotated shifts to ensure staffing around the clock. Equipment maintenance was critical as river sand entered through the broken pipes and caused issues with pumps and other equipment.

“The grit collectors were filling up so they had to hand-scoop them out into a dump truck and get that evacuated,” Boling says. “Then our influent screen and wet press got plugged with sand as well. We had to take that equipment apart, get the sand out and start it up again.

“The team did an excellent job of keeping the equipment running and the plant in compliance. I was expecting to submit a noncompliance because of the way things were going, but when we did all the testing, we were putting out clean water within the permit limits.”


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