One city’s waste is Karcher Creek’s treasure

Walking along the edge of his field at the Hood Canal Nursery transplant site, past 1.8 million different fir saplings, Robert Weatherill, Jr., points out the subtle difference of growth in each row.

On one side of the field of seemingly endless rows of trees poking up less than a foot off of the ground, Weatherill notes the wide space between each row. Walking to the other side, he shows trees that have grown so fully, spreading small branches out farther and fuller, that the rows are nearly indistinguishable, crossing into each other.

What’s the difference between these saplings that were planted at the same time? Biosolids, Weatherill said.

"I can’t believe how healthy they are," he said, noting that he saw the different growth patterns immediately after planting.

Biosolids are just one of several byproducts produced by the Karcher Creek Sewer District that Plant Manager John Poppe believes can be put to real use. Along with the biosolids, Poppe said the district also produces usable water and methane gas.

The district is looking to gain approval to reuse these byproducts it generates in bulk. Every day, Karcher Creek dumps 1.5 million gallons of clean water into the Puget Sound, and produces three cubic yards of biosolids.

Biosolids are the solid remains of wastewater after significant digesting and pasteurizing. Washington State University Extension Soil Scientist Craig Cogger said the material is mostly “dead bug bodies” — the solid remains from the digestion process.

Up until March, Weatherill collected biosolids produced by Karcher Creek Sewer District in Port Orchard, but a glitch in wastewater processing halted production of the material while the district complied with orders from the state Department of Ecology.

Karcher Creek was hit with a fine of $10,500 and ordered to haul off the remaining piles of biosolids to an approved site in Centralia.

Weatherill had not finished distributing the biosolids across his field in Hansville, creating one experimental advantage. Weatherill can compare the growth patterns between those saplings growing in soil supplemented with biosolids and those without.

The difference is huge, he said.

Beyond the growth observed on the field, a side-by-side examination of the saplings shows a two- to three-inch difference in height, an expanded root system and stems up to one millimeter wider at the base.

Across the board, saplings planted with biosolids grew taller and fuller.

Weatherill credits the material for more than its rich supply of nutrients — like nitrogen, phosphorus, calcium and potassium. The main advantage, he said, is water retention.

“It’s like a sponge,” Weatherill said. “It holds the chemicals right there for the trees.”

Cogger confirmed what Weatherill said. Biosolids hold water, and allow slow release of nutrients.

“You’re going to get nutrients released over the course of the growing season,” Cogger said.

This is the type of material reuse Poppe champions — taking what once would merely be dumped into Puget Sound and finding a use elsewhere for it.

Human waste is heavily regulated, and must be cleaned of pathogens like e. Coli and salmonella.

A glitch in the system prevented Karcher Creek technicians from knowing positively that the biosolids were considered Class A — with no detectable pathogens — or Class B — with at least 90 percent of all pathogens destroyed.

A formula in the computers that determine how long to heat the biosolids contained a small calculation error. Poppe said the material could, in fact, be Class A, but he could not prove that it was Class A.

After hiring a consulting company, CH2M Hill, to assess the plant and determine any needed changes, Poppe wants to dive back into the reuse game, finding agencies to use the biosolids.

The solution should be simple, Poppe said, hopefully just a minor formula fix.

“This is not rocket science,” Poppe said. “This is a procedural error.”

Marietta Sharp, biosolids coordinator for the Department of Ecology, said once Karcher Creek gets its process in order and its paperwork completed, the biosolids program offers a good product.

But regulations are strict.

Sharp admitted the regulations are in part due to what she called the “yuck” factor. People think of human waste, and don’t want to go anywhere near it, even though gardeners put raw, unprocessed livestock manure on their plants.

But Cogger said many people are eager to step in and reuse an otherwise wasted resource.

“Some people look at biosolids, they say, ‘yuck.’ Other people look at it and say, ‘I don’t mind where it’s coming from and I’m closing the recycling loop,’” Cogger said.

Reusing products like biosolids not only helps the environment, Poppe said, but it could potentially save the district money.

Currently, the district hauls its biosolids to Centralia, generating significant expenditures for fuel. That cost is why Karcher Creek is considering hauling the solids to a nearby landfill rather than down to Centralia, where it could eventually be used again. Ideally, Poppe wants to use it locally.

“Why would we want to haul it to Centralia when we can use it here?” Poppe asked.

And he’s using the same thinking for the other two products that leave the processing plant — water and methane gas.

The water, he said, could be used to irrigate local parks, and Karcher Creek is already in talks with the Department of Veterans Affairs to supply the Veterans Home at Retsil with methane to heat the building.

The plant already burns the methane gas to heat its own building and the equipment that processes the wastewater. But the plant still produces excess gas that could be used by the Veterans Home.

“If they’re burning it off and we can use it to, say, heat some water, rather than heating cold water off the street, it could conceivably save us some money,” said Randy Graham, facilities planner for Veterans Affairs.

Karcher Creek Manager Larry Curles credits the district’s board of commissioners for the environmental thinking. He said the plans came from on high, and the district is gladly following the commissioners’ desire.

“Our board is very progressive. We can do a great deal, and they want use to do more than our traditional role,” Curles said. “It’d be so easy to just be a sewer collection site, treat the waste and not worry about the rest of the world. Our goal is to make this place better than we left it.”

Poppe enthusiastically agrees, explaining that the county is full of people who want to reuse the material. He said that if everyone that wanted biosolids could take them, “we can’t make it fast enough.”

“We want people to reuse properly treated biosolids in Kitsap County,” Poppe said. “It’s the right thing to do.”


Karcher Creek collects raw sewage and immediately processes it in a membrane system. The water is pulled through a collection of semi-permeable tubes, leaving the solid material behind. The water is cleaned and released into the Puget Sound.

The solids are held in a digester at 98 degrees fahrenheit — the same temperature as the human body — where bacteria consumes and destroys most of the pathogens.

En route to a second digester, the biosolids are heated to at least 150 degrees, essentially pasteurizing the product. They sit in the second digester at a about 125 degrees to fully digest.

At this point, the biosolids contain no detectable pathogens and can be used in gardens safely.

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