Producing High-Quality Effluent
In January 2004, Enviroquip was selected to provide all equipment, instrumentation and technical support services for a new membrane bioreactor (MBR) wastewater treatment plant in southern Georgia’s Forsyth County. James Creek is a planned community with nature trails, certified wildlife habitats and a tennis center. Built to support the growing community, the MBR process was selected for its superior effluent quality, small footprint, low maintenance, simple operation and flexibility for plant expansion.
Phase I operations began in February 2006, and currently, the plant is treating 170,000 gal per day (gpd). James Creek is the second community in Forsyth County to use an Enviroquip MBR plant. The first, built in a community called the Hamptons in 2003, produces high-quality effluent from its local wastewater flow.
A statewide leader in water reuse, Forsyth County has already reaped benefits from the James Creek facility, particularly during the Georgia drought in 2007. The plant is reusing almost 90% of the influent municipal wastewater. Reuse applications include a variety of public and private land irrigation applications. Concurrently, effluent quality remains stellar. The James Creek plant has never received an effluent fecal lab report with more than zero colonies.
“I’m very impressed,” said Steve Swenson, the plant’s current operator.
As new homes are built and more families move to the area, James Creek developers expect a steady increase in flow to the plant. But the plant is fully prepared. Since the system is designed to be modular, additional equipment is not required before the demand is apparent. Consequently, the developer’s cost burden is eased as the plant optimizes treatment volume with existing equipment.
Using the concept of biohydraulics, the MBR system was designed to exceed biological treatment objectives over the range of expected operating conditions. The James Creek WWTP is comprised of four independent process trains that include one anaerobic zone, one anoxic zone and one MBR zone for maximum flexibility. Currently, only one MBR basin contains installed Kubota submerged membrane units (SMUs). As flows increase, installation of additional units—a relatively simple procedure—will boost production capability.
Quality, Flexibility and Reliability
Another advantage James Creek has over more conventional plants is the ability to operate under very low flow conditions, a condition the community faced during the early stages of low-density development.
Using Kubota SMUs, Enviroquip designed each train in the MBR system to handle average daily flows of 250,000 gpd. All together, they can handle an average total of 1 million gpd. Achieved treatment goals include effluent BOD of less than 3 mg/L, total nitrogen of less than 8 mg/L and total phosphorus levels of less than 0.13 mg/L. The ability to accommodate such tight limits gives operators the time and confidence to manage system upsets.
Additionally, the ability to operate the plant manually, in the event of an emergency, provides another level of reliability that can be invaluable. Unlike many membrane systems that require complex automation and constant adjustments, this plant can be run in a manual mode to protect against power surges, brown outs or a loss of network communications that may temporarily interrupt automation (even with necessary built-in redundancy).
The competitive cost, minimal system footprint and ability to produce reused quality effluent within an outdoor-centric family community demonstrate the ability of MBR systems to be competitive and reliable alternatives to conventional technologies.