Biosolids Management Program

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p1010004cThe Town of Cary’s water reclamation facilities (WRFs) utilize advanced treatment processes to achieve high quality effluent. Biosolids are the nutrient rich organic byproduct of the enhanced nutrient removal treatment processes. The Town has a progressive biosolids management program to further treat and stabilize these byproducts to produce pathogen free, nutrient rich biosolids that can be distributed and beneficially reused in agricultural applications. This program allows the nutrients captured in the WRF treatment process to be used as a beneficial resource.


Cary RBMP Flow Chart

South CaryThe Town’s biosolids program uses a regional approach in which nutrient rich organic byproducts generated from multiple water reclamation facilities are treated together at regional biosolids management facilities. The regional biosolids program uses heat dryer systems to produce dry, nutrient rich pellets, which can in turn be used as a fertilizer in agricultural applications. The heat dryer systems used are approved by the US Environmental Protection Agency (USEPA) and the North Carolina Department of Environment and Natural Resources (NC DENR) as systems that meet Class A Exceptional Quality (EQ) biosolids. The Town markets its fertilizer pellets under the name Enviro Gems and they are currently sold to a wholesaler who distributes the final product for use as a fertilizer for agricultural applications.

In summary, the WRF advanced treatment process removes most of the wastewater nutrients treated and the biosolids management process allows these nutrients to be beneficially recycled.

Regional Biosolids Program

The Town currently has one heat dryer system in operation at its South Cary Water Reclamation Facility (SCWRF). The Town of Cary began operating the South Cary regional dryer system in 2005 to provide a cost effective and sustainable reuse program serving the communities of Cary, Morrisville, and the Wake County portion of Research Triangle Park. The Town of Apex has been a part of the program since 2010. The South Cary regional dryer system currently treats solids generated at the North Cary Water Reclamation Facility (NCWRF), the South Cary Water Reclamation Facility (SCWRF), and Town of Apex’s wastewater treatment facility.

West Plant PhotoIn 2014, a second regional drying system began operating at the new Western Wake Regional Water Reclamation Facility (WWRWRF). The Town of Apex transports its solids to Western Wake Regional WRF for biosolids treatment. The South Cary regional dryer system will continue to treat all of the solids from North Cary and South Cary Water Reclamation Facilities. The two regional dryer systems will provide the Town with numerous back-up options and flexible contingency plans to effectively manage all of the solids generated in the service area, even in the case of a temporary interruption in routine management strategies.

Read more about our biosolids handling systems

NCWRF Biosolids Management Facilities Diagram
SCWRF Biosolids Management Facilities Diagram
WWRWRF Biosolids Management Facilities Diagram

Biosolids FAQs

Class A Exceptional Quality Biosolids:

Class A Exceptional Quality is the highest quality State and Federally regulated classification for biosolids. Class A biosolids are free of pathogens, can be distributed to the public, and can be beneficially reused without site restrictions.


Jamie Revels. P. E. 
Utilities Director
(919) 469-4303

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