Trash to Treasure: Blue River Facility Will Turn Solid Waste into Natural Gas and Fertilizer New $140 Million Facility Slated for Commissioning Next Year 

When you flush water and waste down the drain, where does it go?  

It makes its way into the sewer system, which carries it to a wastewater treatment plant. 

In Kansas City, chances are it will end up at the Blue River Wastewater Treatment plant, where 98% of the solid material in the city’s wastewater is processed. The plant, built in the 1960s near Interstate 435 and Front Street, handles 75 million gallons of wastewater a day. 

Once it gets there, the wastewater goes through several rounds of treatment. 

Large debris is removed, and the solid waste is separated from liquid wastewater. The wastewater is then processed by bacteria and disinfected before it is released into the Missouri River.  

But what happens to the solid waste?  

Historically, it would have either been eaten by bacteria or incinerated to be used as fertilizer. But thermal hydrolysis processing offers an alternative to incineration, and KC Water is upgrading the Blue River Wastewater Treatment Plant to support it.  

“Have you ever seen those videos of pressure cookers exploding? It’s basically doing that in a controlled fashion,” said Blake Anderson, project manager for the Blue River Biosolids Facility. 

In other words, the thermal hydrolysis process uses high heat and pressure to prepare solid waste for anaerobic digestion. Anaerobic digestion, a biological process that involves microorganisms breaking down organic material, then converts that waste into products such as biogas and biosolids.  

The $140 million Blue River Biosolids project is a key part of the broader sustainability push in Kansas City. When the project is completed next year, it will improve air quality, reduce odors and create more reusable byproducts. 

“Unlike traditional fossilized natural gas… all the carbon (in) this comes from food, so it’s basically net carbon zero, functionally,” Anderson said. 

Anderson said KC Water already has reached an agreement with utility company Spire to use the extra natural gas that is produced via thermal hydrolysis.  

Additionally, thermal hydrolysis processing turns sludge into Class A biosolids. Class A biosolids are sterilized so that pathogens, including viruses, are killed. These biosolids can then be safely applied as fertilizer to farms or gardens.  

“So, the wastewater is generated at the home, and through our biosolids project, it can end up back at that home in the form of fertilizer that’s bought off the shelf from Home Depot or Lowe’s,” said Andy Shively, deputy director at KC Water. “So, it’s that sustainability, that resiliency of it going back to where it started. So, that’s one of the key components of our program.” 

Anderson said plans call for the facility to start operating in the spring of 2025. In 2021, the Missouri Department of Natural Resources awarded $100 million to Kansas City to upgrade the wastewater facility through the Clean Water State Revolving Fund.  

When construction is complete, the plant will be renamed as the Blue River Biosolids Facility. Notably, the facility will join just a few other plants in the United States that use thermal hydrolysis processing. It would be the first in the Midwest. 

The biosolids facility is seen as a response to the aging infrastructure KC Water has been using to treat wastewater. 

“Our solids handling system hasn’t been upgraded since the ‘90s,” Anderson said. “So, this is basically a major upgrade for its capacity, as well as moving things to more modern standards.” 

The process allows for the plant to double the capacity of its digesters, eliminating the need for more digesters, Anderson said.  

“Basically, it changes our feed material from looking like potting soil to basically milkshake consistency,” Anderson said. “You can mix a milkshake. You can’t really mix right potting soil.” 

When solids are easier to mix, fewer tanks are needed to process them, which frees up space and saves money, Anderson said. 

“We’d have to build two more 3-million-gallon tanks that we don’t have really space on site for,” Anderson said. “So, it allows us to keep everything in its existing location and keep things compact.” 

Anderson noted that continuing to process everything while construction is ongoing is a challenge. 

“Whenever you’re doing work in a wastewater plant, it’s like working on an airplane engine mid-flight,” Anderson said. “…We spend a lot of time on basically the sequence of construction, and making sure that we are managing that risk, and meeting our permit requirements for treating wastewater.” 

Under Construction

Smart Sewer Program

The Blue River Biosolids Facility is just one part of Kansas City’s Smart Sewer Program, which aims to upgrade some of the 2,800 miles of sewer lines below the city’s surface and improve wastewater infrastructure.  

It’s also a response to a 2010 Consent Decree from the Enviornmental Protection Agency that requires the city to address issues related to wet weather sewer overflows. The cost of fulfilling the requirements of the consent decree was estimated at $2.5 billion over 25 years. 

Addressing those issues also means following the water from the treatment plant all the way to its source, and everything it flows through in between.  

“Stop thinking at the bottom of the hill,” Shively said. “Everybody thinks the problem is at the bottom of the hill. … All of our wastewater treatment plants are located literally at the bottom of the hill, just before it goes into a river, right? Let’s go up into the communities. Let’s go up to the middle of the hill. Let’s go up to the top of the hill, and let’s start addressing our infrastructure and our problems out in the community. And let’s see how many dual benefits we can realize from the dollars that we are spending.” 

Kansas City is served by two types of sewer systems: separate and combined. In a combined sewer system, both wastewater and stormwater move through the same pipe. In a separate sewer system, wastewater and stormwater move through separate pipes. When it rains, combined sewer systems can quickly reach capacity and overflow, releasing both stormwater and wastewater into area waterways.  

“One of the progressive responses on the part of the city to this problem has been to try and trap more stormwater at the surface with green infrastructure installations,” said Kristin Riott, executive director of Bridging the Gap. 

Green infrastructure uses natural elements, such as native plants, to capture stormwater, said Riott. 

Bridging the Gap is a Kansas City-based nonprofit that focuses on environmental and social justice issues. The group recently completed six years of maintaining 230 green infrastructure installations for the city, according to Riott. 

“The city has helped to lead the country in the development of green infrastructure and an educational standard and a job certification for people who have green infrastructure maintenance experience,” Riott said.  

Kansas City was the first city with a federal consent decree for reducing sewer overflows to include green infrastructure in their program, Shively said. He said the smart sewer program embraced a more integrated approach to improving an archaic sewer system.  

“Instead of building a whole bunch of new infrastructure, let’s see (if) we can use what we have before building new, and let’s treat it at the source rather than just, hey, let’s collect it, send it all to the bottom of the hill and put it at a treatment plant,” Shively said. 

Julie Freijat is a Kansas City PBS/Flatland reporter and a Report for America corps member working with the Mississippi River Basin Ag & Water Desk. Her work is made possible, in part, through the generous support of the Ewing Marion Kauffman Foundation.