Improvements secure capabilities of treatment plant
WASTEWATER PLANT
The Environmental Protection Agency (EPA) says that wastewater treatment is one of the most common forms of pollution control in the United States.
It is also one of the most critical, yet often overlooked, aspects of a city's ability to function properly on a day-to-day basis.
“There's a saying: flush it and forget it,” said Tim Halfhide, the plant manager for Concordia's wastewater treatment program. “But if things go wrong, you've got a lot of problems on your hands.”
On average, Concordia's treatment plant handles about 400,000 gallons of sewage a day, depending on the weather and how active the town is.
“In 2003, the plant handled between 500,000-600,000 gallons a day,” said Halfhide. “Some of the difference can be attributed to population decline, but a lot of that is just more efficient water systems: washing machines, dishwashers, sinks and toilets.”
There are more efficient water systems in homes, but by 2015, the treatment plant in Concordia that serviced those homes was aged and outdated by just about any standard. And new regulations from the EPA and the Kansas Department of Health & Environment (KDHE) were requiring changes.
“Here's the thing: that water is always running,” Halfhide said. “This plant runs around the clock, 365 days a year. If something quits or breaks, you've got to have a Plan B, because that water (400,000 gallons a day) is always coming in. We were basically down to one influent pump that was running all the time. And I think it had been put in in the late-80s. It had become difficult to actually find parts for it. When you're down to one pump, there's no back-up. If it goes out, then you're doing something in an emergency, because that water is going to keep coming in. It was just not a good situation.”
A study and survey were completed in 2015 that addressed the problems with Concordia's treatment plant system.
“It was a two-phase solution,” said Sarah Unruh, the team leader of the water/wastewater group at Professional Engineering Consultants (PEC), the engineering firm that Concordia contracted with on the wastewater treatment plant program. “Phase 1, which was completed in 2018, atddressed the aging equipment at the plant. Phase 2 was how best to deal with the sludge.”
Phase 1, including the rehabilitation and upgrades of the clarifiers, grit chamber, the return sludge facility, and the installation of a screw press, was completed at a cost of $2,749,140.53.
Phase 2 updated old voltage electrical boxes and panels, installed a generator that will run the entire plant in emergencies, upgraded the influent pumps, switched from producing Class B biosolids to Class A, and replaced an ultraviolet disinfection system. The work was completed in 2023 at a cost of $3,744,507.95, including change order and design and construction inspection.
The new generator was mandated by the federal government. “One of the things we're now called upon to do by the federal government is be self-sufficient in an emergency for up to seventy-two hours before we can count on help from outside agencies,” said city manager Amy Lange. “We had a generator before, but it only operated a portion of the plant. This new generator will operate the entire plant in the case of an emergency.”
The addition of new machinery and technology did not come cheap, but the improvements should secure Concordia's wastewater treatment capabilities for decades to come.
In a very basic sense, wastewater goes through a multi-step process when it reaches the treatment plant. It first passes through a series of screens to remove solids and debris. And the word 'debris' is all-inclusive. “We've had everything from McDonald's toys to dollar bills come through,” said Concordia's utilities director Jeremy Arnold.
“We catch a lot of things in the screen,” agreed Halfhide. “Here's one thing that's not true: 'flushable' wipes. They're not. They stick together and clog up pumps.”
The next step in the process is the grit chamber that removes sand and other types of grit. “The less of that stuff that goes through our pumps the better,” said Arnold.
The wastewater is then sent to a large tank where bacteria is introduced and processed in a swirling manner as if it were going around a racetrack. The tank holds thousands of gallons and the process can take days.
That wastewater is then sent to the clarifier, where the sludge and water are separated. The water moves on to another tank where it is zapped with ultraviolet light that kills all the leftover bacteria in the water, such as E. coli. After undergoing a rigid series of tests, the clean water is then sent to the river.
Based on EPA guidelines, monitored by KDHE, the plant must test the Biological Oxygen Demand (BOD), which is a five-day test; the Total Suspended Solids; Total Phosphorous; and the Total Kjeldahl Nitrogen, which is the sum of nitrogen bound in organic substances, nitrogen in ammonia, and in ammonium in the chemical analysis of soil, water, or wastewater.
“We are at the point now where we have a detectable amount that is extremely small and well below EPA standards,” said Halfhide. “And in some cases the amount is non-detectable.”
Halfhide said that, in many aspects, the water that the plant sends to the river is cleaner than the water in the river. “I look at it as this: we're making a product,” Halfhide said. “The product is the water that goes to the river. We're taking sewer water from the town, putting it through the wastewater plant, and sending water to the river that's not going to hurt the environment.”
Once the treatment plant processes sewage into safe water that is sent to the Republican River, there still remains the byproduct of that entire process: the sludge. The plant had always produced highly-restricted Class B soil.
“Class B soil is only for agricultural land that is not used for human consumption,” said Sarah Unruh of PEC. “For instance, it can be used on an alfalfa field, but not a corn or wheat field. The soil must be hauled to a location for use or disposal. So there was a real desire in Concordia to create Class A soil, which anybody can use.”
“There were changing regulations for the end use product,” Lange said. “Our changing point came a couple years ago. We held a study session with the city commission and said there were two ways we could handle the sludge now. We could add a reactor on the back side of the screw press and cook the cake, bake the cake, for a certain amount of time at a certain temperature and create Class A soil. Or we could do what we've always done: Class B soil. But now the EPA was saying that we have to dry out that Class B soil. We would have to put it on a concrete bed with three sides and a drain that would go back to the influent pump. There would also have to be a pole shed over the bed to protect it from rainwater. And because the bed would be in the floodplain we would have to elevate the entire thing four feet off the ground. Then there would have to be a giant rototiller on a tractor to till it up before it could be disposed of at approved sites. The cost would be around $1 million. But, for about the same price, we could install a reactor, bake the cake and have Class A soil which provides us more flexibility for disposal and less EPA regulation. This is a byproduct that we can apply on crop ground, or even on someone's garden and yard.”
Concordia became the first wastewater treatment with this kind of technology in the state of Kansas.
The sludge that was removed during the treatment process is now sent to a screw press and turned from a one-percent solid into a 22% solid. That solid material then goes to a reactor where lime and sulfamic acid are introduced. The chemical reaction creates an extreme heat that bakes the solid and kills all the pathogens, creating a nutrient-rich Class A soil.
“We are the first site in Kansas that does this,” Lange said, “but before we ever presented this to the city commission, we went and visited a site in Columbus, Nebraska, that has this technology and was using it for several years. We toured their plant, and they were very pleased with the way things were working for them. “
The upgrades to Concordia's water treatment plant have been a conversation point for Lange at conferences. “I had the opportunity to present with PEC (the engineering firm) at the Kansas Rural Water Conference last fall in Wichita. We haven't really been online long enough to provide substantial data or feedback yet, but there were communities interested in what we had done and wanted to hear reports six months to a year down the road.”
Is it correct to say that the city of Concordia now has a state-of-the-art wastewater treatment system? “Yes, absolutely,” said Lange. “Our biosolids processing and creation of Class A soil is very unique.”
“Now that we've got all these upgrades, I sleep better at night,” Halfhide said. “There's still things that could break down. When you've got equipment that basically runs twenty-four hours a day, every day of the year, something's going to happen. You always have to have a plan. A one-week plan, a six-month plan, a plan for three-to-five years down the road. But now everything is manageable.”
Lange sees the new technology at Concordia's treatment plant as a stepping stone to further education and employment opportunities, not only in Concordia, but state-wide. “What I would like to see in the near future is to find a way to work with the Kansas Rural Water Association and Cloud County Community College on a certificate program that would help train wastewater operators. There is a severe shortage of wastewater treatment operators across the state. If we're not building a pipeline to the workforce right now, we're going to hit a cliff where there's going to be a lot of plants in Kansas that are in a non-compliant situation with KDHE. We now have the ability to showcase the technology that can help out with that situation.”
The Class A soil is available to anyone. It is an excellent fertilizer and is free to the general public for use on their garden or lawn. “The Class A soil is not bagged, so you would need to bring the vehicle to haul the material in, something to place the Class A soil in, and a shovel,” Lange said. “We will work with farmers for larger loads.”
If anyone is interested in using the Class A soil, contact City Hall and ask for Jeremy Arnold. He'll make arrangements to provide anything from a bucket-full for your garden to a dump truck-sized load.