Biosolids compost facility is ready to roll

The construction of a new biosolids compost facility in Sedalia was completed earlier this month, and the center is set to begin composting organic material from the city’s wastewater treatment plants along with wood from the yard waste drop-off site to produce fertilizer in the coming weeks.

The city contracted Septagon Construction last November to construct the compost facility at 27882 state Route U for $1.57 million.

Public Works Director Bill Beck said the idea to construct the composting site arose about four years ago, when Sedalia’s Water Pollution Control Department started experiencing difficulties in maintaining a Class B biosolid rating at two of the city’s three wastewater treatment plants.

Environmental Protection Agency regulations categorize biosolids as Class A or B, depending on the level of bacteria remaining in the material after being treated at a wastewater plant. Class A biosolids can be applied as a fertilizer without any pathogen-related restrictions, but there are buffer requirements, public access and crop harvesting restrictions for most Class B biosolids.

Correcting the issues with biosolids coming from the treatment plants would have required digester improvements for at least two of the facilities, Beck said, and would have cost the city upward of $4 million to ensure it was meeting the Class B rating.

“If we don’t hit that Class B number, our choices are to find another process to do that or put it in the landfill,” Beck said. “It’s not economical to (send it to the landfill), and it’s just wrong anyway.”

City officials devised an alternative strategy that entailed the development of a $1.5 million facility that would compost the wastewater biosolids along with the materials collected at the yard waste drop-off site to produce a Class A biosolid that the city could market as a fertilizer.

“It’s a less expensive deal, and we’re attacking two things at the same time,” Beck said.
The recently constructed facility includes a covered sorting area, where the biosolid and wood will be separated before composting. The materials are then blended and treated, while computers monitor the temperature and blow more air into the hoses when it drops below a certain level.

“After a while, the temperature will stay pretty static, and that’s when the compost time is completed,” Beck said.

The pile of material is then run through a screener, separating fine particles from larger wood pieces that have not been degraded, and those larger chunks are replaced in the sorting area to go through the process again.

The compost is then subjected to a series of tests to ensure its levels of nutrients, metals and organic materials comply with the Class A categorization standards. Once it checks out with the testing, the material can be bagged and marketed for application to fields, lawns and gardens.

Beck said officials expect to have enough of the product to put a marketing plan in place by the start of 2011.

“We’ve got all sorts of ideas on how to market it,” Beck said. “It’s a great soil amendment, and it has a good fertilizer value to it. If you’ve got clay soil it really loosens it up, and if you’re in a sandy area it helps bind it.”

The Water Pollution Control Department will oversee the operation of the facility. But with a computer monitoring the process and sending updates wirelessly, Beck said officials anticipate the site will only need to be staffed about once a week, when the materials are mixed, put in a row, separated and bagged.

Beck said the material sorting areas are covered to prevent the site from causing a stink with surrounding property owners. Its location is at a fair distance from any densely residential areas, while remaining a short trip from the city’s wood disposal site and nearby water treatment facility.

“It shouldn’t be too odorous. We really wanted to be a good neighbor, and we don’t want any complaints,” he said. “It’s still located pretty close to our wood drop-site and it’s not very far from the southeast wastewater plant, ... they’re one of our biggest biosolid producers.”