Written by Tom Welch
The Big Creek Water Reclamation Facility is located in North Fulton County, on the north side of Atlanta within the Big Creek Basin.
Big Creek WRF is the largest Water Reclamation Facility in regards to both flow and service area in North Fulton County. The service area is approximately 70 square miles and includes Roswell, Alpharetta, portions of Milton, and areas of Cobb and Forsyth Counties. The facility was originally constructed in 1969 with a treatment capacity of 0.75 MGD (million gallons per day). Several upgrades and expansions have been completed on the facility to its current permitted treatment capacity of 32 MGD.
Due to the Metropolitan North Georgia Water Planning District forecast, which takes the continued population growth and economic development of the service area into account, the facility requires additional capacity to meet the growing wastewater treatment demands. The project will include a phased expansion from the 32 MGD to 38 MGD (Maximum Month) while implementing new membrane bioreactor (MBR) technology to achieve more stringent discharge levels required by the new permit. New biological nutrient removal (BNR) basins and membrane trains (together comprising the MBR system), and new aerobic digesters will be constructed for the full capacity.
The multi-phase construction started in 2020 and is expected to be completed in mid-2024. A new dewatering building, featuring some of the largest screw presses in North America, was built in phase two and commissioned in May of 2022. This new dewatering building showcases two of Schwing Bioset’s model FSP 1203 screw presses. Each Press has a 1200 mm screw diameter and is capable of a throughput of 2600 dry pounds per hour of aerobically digested sludge. These two new presses were designed to replace the existing five smaller screw presses, the largest available from that manufacturer, with 800 mm diameter screws. For comparison, the older presses were typically run at a maximum throughput of 550 dry pounds per hour, dewatering WAS sludge.
Veolia operates the Fulton County Big Creek facility, including the dewatering facility. The FSP 1203 screw presses are dewatering WAS sludge currently, and each machine is running as high as 250 gpm of 1% feed solids. The equipment is operated about 18 hours a day, 5 to 6 days a week, and a total of five, 25-ton trailers, are hauled to the local landfills each day. Each FSP 1203 screw press is only operating at 50% of the design capacity. The facility is designed to accommodate a total of five FSP 1203 machines in the future. Schwing Bioset’s high-performance design produces the highest throughput, most efficient screw presses in the dewatering market, and these two FSP 1203 machines are examples of that.
The new Schwing Bioset FSP 1203 presses are currently processing WAS. Once the new MBR trains and digesters are completed, and the volatile solids are lowered to the new design levels, consistent dewatered solids will be able to be maintained in the low 20% range. Final acceptance testing will be performed after the completion of the new digesters in mid-2024.
Tipping fees at the local landfills have increased dramatically over the last several years, with an average tipping fee being $80/ wet ton. Hauling less water to the landfill provides significant savings in disposal costs of dewatered solids. The new Schwing Bioset FSP 1203 screw presses are expected to save approximately 20% from the current landfilling costs once the project is complete. Additional savings afforded by the 1203 presses include:
- Electrical consumption is reduced as the two screw presses have roughly 50% less connected horsepower than the equivalent number of 800mm machines for the same processing capacity.
- Maintenance requirements are reduced with fewer machines to manage, freeing maintenance staff for other activities within the plant.
- Building size to house equipment is reduced saving construction costs.
The overall project has been a success and is another prime example that illustrates the clear differences in capabilities between Schwing Bioset’s screw presses and legacy equipment in the market. Contact us today to learn how a high-performance screw press built by Schwing Bioset can help you save costs on your next large dewatering project.
Contact us today to learn how a high-performance screw press built by Schwing Bioset can help you save costs on your next large dewatering project or visit our website to read more about our products and solutions.