Background

Beginning in 2007, the North Carolina General Assembly implemented the Renewable Energy and Energy Efficiency Portfolio Standard (REPS), which mandates that electric utilities meet 12.5 percent of their electric needs through renewable sources. This act has furthered the development of private infrastructure for the purposes of generating renewable energy for sale to the Utilities.

Following this legislative action, Cary investigated the possibility of installing renewable energy generation equipment, specifically a photovoltaic system. The South Cary Water Reclamation Facility (SCWRF) was selected based on available space, suitability for the efficient collection of solar energy with no impact on operations, and future expansion plans.

FLS Energy was selected as its solar energy partner. FLS Energy had considerable local experience developing solar projects in North Carolina, including installations at SAS and a number of rooftop projects in the Triangle area. In 2016, FLS Energy was purchased by Cypress Creek Renewables, who subsequently took over operation of the solar installation at South Cary Water Reclamation Facility. In 2022, Cary acquired the solar array at SCWRF from CCR.

Mission

The mission of the SCWRF is to treat wastewater from the community to a level that meets or exceeds permit compliance limits issued by regulatory authorities while maintaining 100 percent compliance with all of the facility’s regulatory program standards. It is the goal of this facility to accomplish this mission in a cost-effective manner while promoting a safe, team–oriented environment in which quality workmanship, high professional standards and continuous improvement are emphasized and maintained. The SCWRF staff is committed to serving the community by achieving high standards for wastewater treatment and being a good neighbor to the communities located adjacent to the plant.

South Cary Solar Array

The South Cary Water Reclamation Solar Array was placed in service in December 2012 and has the capacity to generate 2,150 MWh annually of electricity. This system consists of nearly 6,000 solar panels that generate enough energy to offset roughly 1,500 tons of greenhouse gas emissions annually. Power generated is returned to the distribution grid as a renewable source of energy.

During the initial phase, Cary leased approximately eight acres to Cypress Creek Renewables (previously FLS Energy) with no upfront costs or maintenance costs during the life of the lease. As part of the 2022 acquisition agreement between Cary and CCR, CCR will continue to support solar-related maintenance needs at the SCWRF while Cary citizens will now directly benefit from the energy savings.

Wastewater Operations

The SCWRF is rated as a 12 million gallon per day (MGD), wastewater treatment facility and is designed to remove Biochemical Oxygen Demand, Total Suspended Solids, Total Nitrogen compounds, Total Phosphorus compounds, turbidity agents, and other undesirable constituents from Plant influent before releasing highly treated and clean wastewater back to the natural environment. The SCWRF laboratory staff ensures compliance with the Town and EPA/NCDEQ’s standards for wastewater treatment by performing laboratory analysis in an on-site laboratory, which is well equipped with the latest technology for providing precise and accurate data. The data generated by the laboratory is utilized by operations staff when making process control decisions for proper operation of the plant and determining permit compliance. Laboratory staff at the SCWRF work with other Town of Cary departments, NCDEQ, and other municipalities to provide and support long-term improvements throughout the river basin. The SCWRF laboratory is audited and certified by the NCDEQ Laboratory Certification Branch annually.

Wastewater treatment begins on-site with preliminary treatment, which consists of mechanical screening and aerated grit removal of influent wastewater. Secondary treatment is provided through a five-stage biological nutrient reduction (BNR) process. At present, the SCWRF has three trains of operation for advanced secondary treatment. Clarification immediately follows the BNR process. This is where treated wastewater effluent is separated from the microorganisms, in the form of solids, which drive the BNR process. These microorganisms (or biosolids) are either recirculated back through the BNR process or wasted to gravity belt thickeners. Tertiary treatment of the effluent is provided through deep bed sand filtration (SCWRF has seven filters) and then ultraviolet disinfection for final pathogen destruction. The UV system is designed for a peak flow capacity of 32 MGD. Additional aeration of the final effluent is provided through a cascade aeration structure before final release to Middle Creek.

A portion of the final effluent is conveyed to the SCWRF reclaimed water facility for chlorine disinfection before further use in on-site plant processes, bulk water applications, and the offsite reclaimed water distribution system. The SCWRF added a 500,000-gallon storage tank for reclaimed water in 2012. The SCWRF has been operating its reclaimed water distribution system since 2001, making the SCWRF one of the first facilities in North Carolina to utilize reclaimed water.

Solids removal occurs when waste biosolids are thickened with gravity belt thickeners and then pumped into aerated holding tanks for further storage and stabilization. In 2005, the SCWRF began operation of an on-site Thermal Biosolids Management Facility. The SCWRF now processes biosolids from the North and South Cary Water Reclamation Facilities. In 2010, the Town amended its Biosolids Permit to accept and process waste biosolids from the Town of Apex Middle Creek WRF. The thermal biosolids dryer produces dried pellets, which are currently hauled off site by an outside vendor for agricultural usage. The SCWRF Thermal Biosolids Management Facility produces Class A-EQ (Exceptional Quality) biosolids in compliance with EPA 503 regulations.

The SCWRF has a staff of 20 employees and is staffed 24 hours per day/7 days per week. These positions include a Facility Manager, Laboratory Supervisor, Facility Operations Supervisor,  Maintenance Supervisor, and a Business Specialist. The SCWRF work team also consists of Facility Operations staff, Biosolids Dryer Operations staff, Facility Maintenance staff, and Laboratory staff.

Related Links

Sustainability

Energy Production

The table below shows the kWh produced by month.

Administrative Contact

Hours: 8 a.m. to 5 p.m. Monday through Friday

Jarrod Buchanan, Facility Manager
Jarrod.Buchanan@carync.gov

Jennifer Exum, Laboratory Supervisor
Jennifer.Exum@carync.gov

Larry James, Maintenance Supervisor
Larry.James@carync.gov

Phone: (919) 779-0697
Fax: (919) 662-8118

4900 West Lake Road
Apex, NC 27539
P.O. Box 8005
Cary, NC 27512-8005