A picture of biosolids sitting in a storage space, the dark biosolids are spread across a broad concrete space.
Project & Construction Update

Making the Most of Biosolids: Affordable Moves Toward Sustainable Biosolids Use

Based on an interview with Giovanna Forti Portiolli, Charlotte Water’s Resource Recovery Manager

Charlotte Water manages the largest public water and wastewater utility system in the Carolinas, serving more than one million people across Mecklenburg County. With five water resource recovery facilities (WRRFs) treating a combined average of 86 million gallons per day, the system also produces a significant amount of biosolids, about 120,000 wet tons per year. Traditionally, most of this material has been sent for beneficial reuse through land application, but rapid regional growth, tight storage capacity, and operational challenges have made that increasingly difficult.

I sat down with Giovanna Forti Portiolli, Charlotte Water’s Resource Recovery Manager, to discuss how Charlotte Water has navigated these hurdles without relying on significant immediate capital investments. Instead of waiting years for large-scale upgrades, her team found creative, collaborative, and cost-effective solutions that keep biosolids moving toward beneficial reuse rather than landfills.

Below are the key strategies and outcomes her team has piloted across our facilities.

Tackling Foreign Debris with a Sludge Screen Pilot at Irwin Creek WRRF

For almost two years, all of Irwin Creek’s biosolids were being landfilled out of precaution when the team started observing foreign debris finding its way to the final biosolids product. Landfilling biosolids is expensive, not sustainable, and wasteful of important nutrients and organic matter.

The operations team piloted a rental sludge screen to fine screen foreign debris out before dewatering the sludge. The impact was immediate. The utility was able to go back to beneficially reusing and recycling nutrients and organic matter from the biosolids, while also saving on landfill tipping fees. Renting the equipment also gave Charlotte Water time to test, refine, and validate the technology before purchasing and installing a permanent unit. This is a key example of how improperly disposing trash at home can have a direct negative impact in the community (e.g., higher costs and wasting important resources).

The image shows three columns of debris found in Biosolids. The columns are Nurdles/Pellets, Labels/Stickers, and Hair, from left to right.
Examples of debris causing this specific issue
Finding Storage Space

Biosolids storage is a valuable and often expensive resource to expand. Instead of launching a multimillion-dollar capital project, Charlotte Water took a more resourceful approach by looking inward at what already existed.

At Charlotte Water’s largest wastewater facility, McAlpine Creek Water Resource Recovery Facility, staff identified old, unused, or obsolete equipment inside the Residuals Management Facility that could be safely demolished to free up staging areas for future use. This newly reclaimed space eased bottlenecks and reduced the strain on limited storage. The effort generated savings of at least $135,000 every year.

A cleared-out space in the Biosolids storage. A large concrete space with barriers on the sides give potential room for biosolids. A truck has its lights on in the distant background of the facility.
Cleared out room for Biosolids storage
Strengthening Contractor Partnerships and Diversifying Outputs

Biosolids management is a shared effort. Charlotte Water works closely with its biosolids contractor to haul and land apply material, and Giovanna emphasized how important that relationship became during this transition.

Together, the team is exploring new outlets for beneficial reuse, including adding the ability to send a portion of biosolids to a composting facility. Furthermore, team is currently studying additional beneficial use outlet alternatives (e.g., alternative landfill daily cover, stormwater research). Additional reuse pathways reduce dependency on a single outlet when weather or operational conditions limits traditional land application. This adds more flexibility during challenging periods

To the right in the image a machine used to apply Biosolids onto land is spraying and distributing biosolids throughout a field. The sky is blue and there is a line of trees in the background.
Land application of Biosolids
Shifting to Seven-Day Dewatering at McAlpine Creek

For years, McAlpine operated on a five-day, twenty-four-hour dewatering schedule. This schedule created added operational pressure and challenges. The operations team transitioned to continuous seven-day operations, which streamlined biosolids flow and optimized every part of the process.

The change improved equipment efficiency, translated into a slight increase in cake solids, which help utilize storage more effectively. Even a small improvement in cake solids can reduce haul volumes and strengthen land application operations.

A Bigger Picture: Innovation Without a Giant Price Tag

All of these efforts share a commonality. Instead of waiting for long-term capital funding, staff, contractors, and consultants collaborated to identify practical, low-cost improvements that delivered benefits immediately.

Each strategy followed the same pattern:

• Start small

• Pilot first

• Measure everything

• Scale what works

And above all, stay open to ideas that come from every level of the organization.

These low-cost wins demonstrate how Charlotte Water is continuing to guide biosolids management toward higher efficiency, sustainable environmental outcomes, and reduced landfill dependency, while serving one of the country’s fastest-growing regions.

For questions, you can email Giovanna.FortiPortiolli@CharlotteNC.gov