Ron Adams, the Mechanicsburg (Pa.) Wastewater Treatment Plant supervisor, wants his customers involved in what he does. He wants them to understand what biosolids are and where they come from. He wants them to recognize the borough’s “better than Class A biosolids” material for what it is — a valuable resource and plant nutrient.

And when it comes to biosolids, the borough council wants to turn its citizens’ ick into OK.

For these reasons, the council — with support from the environmental advisory committee — is sponsoring a name-that-biosolids contest. The prize? Life-long bragging rights and a cubic yard of Class A biosolids delivered by Mayor Jack Ritter.

The contest will begin Jan. 2 and run through March 1. Starting next year, the borough plans to sell the composted material as a fertilizer/soil enhancer to the general public. 

"I am hopeful we will sell about 200 yards to residents," says Adams. 

A history in biosolids
The borough has built a name for itself in the local professional landscaper community as a reliable producer of high-quality fertilizer, so all production typically sells. How this all came about is quite a story.

Mechanicsburg, a borough in southcentral Pennsylvania, operates a 2 mgd wastewater treatment plant that serves more than 7,000 homes and 1,100 commercial customers. Currently, the plant processes about 1 mgd of residential-strength wastewater from its residents and those in four nearby townships.

For its residents and those in adjoining Silver Spring Township, the borough also manages a shared woody waste processing facility — adjacent to the treatment plant — for yard waste, leaves, branches and even large chunks of trees.

According to Adams, the borough land applied its Class B biosolids on agricultural land for many years. When plant operators couldn’t find land app sites, the material was sent to landfills.  

Several years ago, Adams recognized that as farmland was converted to residential areas, the drive time to land app sites was increasing to well over an hour round trip. He also knew that much of the borough’s equipment was nearing the end of its functional life. Adams — faced with a growing supply of Class B material, increased drive times and looming equipment replacement costs — had to think creatively.

“I saw the need and opportunity to look at all of the options,” he says. “That led me to explore further treatment of Class B to Class A material and discover a strong market for the sale of that resource.”

Working with consultant Material Matters and measuring each management decision on whether it would reduce labor demands and operating costs, a new approach to biosolids management emerged. With only a few months of operating history on the books, it appears that careful planning and implementation are delivering expected outcomes.

The hoop barn
The most visible and expensive element of the plan was a new hoop barn where Class B material — after being mixed with woody waste from the yard waste facility — is placed into long windrows for further passive processing. Each windrow is placed over a floor grate system that delivers a slightly pressurized flow of air. The air moves through the windrow, providing oxygen that drives decomposition and kills pathogens. To hold heat in, a covering layer of processed material is spread on each windrow.

After a 30-day cooking cycle, the windrow is broken down and run through a rotating screening machine where the coarse items are returned to form a new starter layer. The fine Class A product is stockpiled for delivery.

Continual temperature monitoring shows windrow temperatures have never fallen below the highest state-mandated minimum, so it’s easy to see how the product has passed every analytical standard. Because the product is sold as a fertilizer, it must also meet minimum analysis standards set by Pennsylvania's Department of Agriculture.

The borough doesn’t plan to bag its yet-to-be-named product, which would drive up labor needs and product costs.

As Adams likes to say, “No matter how much we make, it is all already sold!"