Where sewage sludge is serious business

The topic of solid waste treatment rarely makes for an engaging presentation, but Ben Nydegger, the biosolids program manager for the city of Boise’s Public Works department, actually has a pretty interesting story to tell about what happens to what’s flushed in the city of Boise.

Nydegger dispenses with the most unsavory realities first: that the city takes the biosolids, mostly human waste, from the city’s two main “water renewal facilities” (once known as wastewater treatment plants), treats it to remove the pathogens, and then trucks it out of town to a property the city owns in unincorporated Ada County. There, the treated solids, which look like dirt, are used to fertilize 4,200 acres of alfalfa, corn and wheat at a farm called the 20 Mile South Biosolids Application Site.

In a good year, the farm’s crops make $3 million to $4 million, which helps pay for some of the costs of the city’s wastewater treatment.

“That’s why we’re in the farming business,” said Nydegger of the city. With farm commodity prices down this year, Nydegger experts the crops to make $2.8 million this year.

The Boise biosolids farm program, which treats 30 million gallons of wastewater per day, is unusual because it’s tied to a city-owned farming operation that itself is a model of environmental sustainability. Many cities, such as Denver and Calgary, treat biosolids for farm field application, but no other city had the foresight to purchase a farm in 1994 as the city of Boise did, says Maile Lono-Batura, executive director of the Northwest Biosolids, the industry interest group in Seattle.

“Most utilities don’t buy huge tracts of land,” said Lono-Batura. “Buying a farm is something people at many utilities wish they had thought of when land prices weren’t what they are now.”

Not only is the city farming with biosolids, but its small administration building is the state’s first energy-neutral commercial building. Completed in July 2016, it uses triple-paned windows, solar panels and geothermal energy for heating and cooling. Farm irrigation is provided by 12 wells.

There’s just not a whole lot outside of farming that you can do with biosolids. Most cities treat them somehow so they can be used as fertilizer or compost; incinerate them; or – as in the case of Nampa and Caldwell, Nydegger said – send them to the landfill.

The 20 Mile South farm, which employs 14 people, is also the place where the city of Boise stores the compost it has received  since it started its composting program in June 2017. After it has been sorted and left to heat up, killing the weed seeds and pathogens, the composted organic matter is trucked back to Boise to be given out to local gardeners who take part in the composting program.

In May, Nydegger led a tour of the Boise farm to a group of Treasure Valley residents who had signed up for the city’s Livability Ambassador program, a new venture that’s the work of the city’s office of community engagement. The Livability Ambassador program was created to address the fact that the city is running a handful of innovative sustainability projects that nobody in the area seems to know about. For reasons unknown, the city generally eschews the more common public awareness tactic of talking to the media in favor of creating a program over which it feels more control. Sustainability Coordinator Jami Goldman said the purpose of the program is to create messengers who will spend the occasional Saturday morning learning about these projects, one at a time, and then spread the information about the projects organically, through their own community, family and friend networks.

Indeed, when I told colleagues, friends and family about my eye-opening trip to the biosolids farm, the first reaction was inevitably, “why haven’t I ever heard about this?”

The 18 or so Livability Ambassadors are all professionals from around the Treasure Valley, and many have a background in sustainability or science or both. The program is inexpensive; for our trip to the farm, the driver of our small bus was Public Works Director Steve Burgos, who gave up his Saturday morning to tour the farm with the ambassadors. Among other things, the program also includes excursions to the city’s innovative Dixie Drain phosphorus removal project in Parma; the Foothills Learning Center; the Ada County Landfill and Hazardous Waste Facility; the Boise WaterShed and River Campus; and a tour of the geothermal energy facilities in Boise’s Central Addition.

Nydegger’s been in his position since December 2010. He’s become very good at explaining what he does for a living, and where.

“When I talk to people on a personal basis, I have to get into the details, because I get a lot of blank stares when I tell them the city is involved in a farming operation,” Nydegger said. “The fact that we’re using waste to sustainably grow crops that can be sold and offset the cost of wastewater treatment for our rate-payers is a pretty cool thing.”

Anne Wallace Allen is the editor of the Idaho Business Review.