Hardeeville Water Reclamation Facility Expansion
Protecting Public Health and Waterways through Wastewater Treatment Plant Improvements
The residents in and around Hardeeville, South Carolina, place high importance on helping small businesses grow, creating jobs, and conserving natural and historic resources. To support these goals, the Beaufort-Jasper Water and Sewer Authority (BJWSA) asked our team to design the expansion of their Hardeeville Water Reclamation Facility (HWRF) using the Envision® sustainable infrastructure rating system.
Envision provides a framework to help guide the team's decision-making and provides confirmation that environmental, social, and economic goals have been achieved. We are honored to announce that the under-construction HWRF has achieved Envision Bronze verification, making it the first Envision-verified project in the Carolinas!
The main purpose of the project was to expand the facility's permitted capacity to accommodate projected growth in the area. Our design expands the treatment capacity from 1.0 million gallons per day (mgd) to 2.7 mgd, and leaves room for future expansion up to 4.0 mgd. As a result of this project, new businesses will be able to move into the area and existing ones can expand, supporting Hardeeville's goal of creating new jobs, and water quality in the nearby Savannah River will significantly improve, contributing to the goal of natural resource conservation.
In addition to improving water quality, the plant will require less energy to operate (on a per-mgd basis) thanks to multiple smart design features. First, motors associated with most major equipment have Variable Frequency Drives (VFDs), enabling the motor speeds to be increased or decreased to optimize their operation and avoid wasted energy. These VFDs connect to the plant's SCADA (supervisory control and data acquisition) system, which provides real-time energy consumption data for the entire plant and each individual component, allowing plant staff to monitor consumption at a glance and pinpoint any inefficiencies.
We also specified highly energy-efficient equipment, such as a large-bubble compressed air mixing technology that we calculate will reduce energy consumption by 74 percent for flow-equalization tank mixing (compared to the existing submersible mixer) and 63 percent for pre-anoxic zone mixing (compared to a typical mechanical mixer). All of these design features add up to an overall 21 percent anticipated energy savings compared to a conventional wastewater treatment plant.
This energy savings allow a portion of the project to receive a reduced interest rate from the State Revolving Fund; all components demonstrated to achieve a 20 percent energy reduction are eligible for special "Green Funding" loan terms.
The new facility also goes above and beyond by using a robust odor control system that will remove over 99 percent of the hydrogen sulfide (H2S) from air in the headworks and flow equalization basin, which are the two areas where most odor is typically released. This improvement not only benefits the public, but also reduces the rate of corrosion for equipment at or near the headworks, prolonging its useful life.
Indeed, this plant expansion is designed to have a long and sustainable life, and we are very proud of its Envision Bronze award — the first in North or South Carolina!