City of Griffin, GA – Still Branch WTP Conversion to DAF

Raw water for the 8-MGD Still Branch Water Treatment Plant comes from a pumped storage reservoir that has a very small drainage basin. This combination results in raw water with a very low turbidity of less than 1 NTU, which makes conventional treatment challenging due to the difficulty of making a settleable floc that also provides for long filter runs. The floc that is formed in flocculation and sedimentation tends to shear easily and results in short filter runs of the downstream multi-media filters.
ESI worked with the City of Griffin to evaluate the plant in preparation for an expansion needed to meet future demands. The recommendation that resulted from the evaluation was to convert the sedimentation step prior to filtration to Dissolved Air Flotation (DAF). The DAF process requires the formation of only a small pin floc that will float instead of the denser floc required in sedimentation. The conversion to DAF designed by ESI will result in significant savings to the City of Griffin immediately after construction is completed in 2014 and in all future expansions to the facility, which was designed originally to be expanded from the initial capacity of 8 MGD to an ultimate capacity of 48 MGD.

Henry County Water Authority – Water and Sewer Master Plan Update

ESI is updating the 30-year master plans for the Henry County Water Authority’s water and sewer systems. These important updates to the plans will be used by the Authority in preparation of 5-year Capital Improvement Plans through the Year 2045. The updated plans will also be submitted to the Metropolitan North Georgia Water Planning District for the District’s 2016 updates to the Long-Term Wastewater Management Plan and the Water Supply and Water Conservation Management Plan.

Gwinnett County Department of Water Resources – Wastewater Pump Station Condition Assessments

In an effort to better plan the needed improvements within the wastewater pump station system, the Gwinnett County Department of Water Resources (GCDWR) planned a project to conduct condition assessments of the existing pump stations. The project began in 2011 with ESI helping to define the scope of work for the project, plan the assessment procedures, preparing an assessment checklist for each type of pump station, assisting with development of a priority ranking system, and conducting assessments on an initial group of pump stations. After the initial group of stations, the project expanded to cover over two hundred (200) pump stations.
The assessments involved performing site visits to each pump station to evaluate the physical condition of the site assets. This included the driveway, access gates, parking areas, site pad, surrounding perimeter property, fencing, wet wells, valve vaults, storage tanks, pumps, piping and valves, site lighting, generators, electrical panels, and other miscellaneous assets which are present at the pump stations. Additionally, pump drawdown tests were conducted at each site to allow for comparison of the pump operation with the data in the County’s database and pump curves on file. ESI also provided estimates of the remaining useful life of the key assets based on the findings of the site assessments. ESI is now assisting Gwinnett County in implementing the repairs to the pump stations as recommended in the condition assessment reports.

Cobb County Water System – South Cobb Water Reclamation Facility Chemical Systems Upgrade

The Cobb County Water System hired Engineering Strategies, Inc. to provide a design to replace the entire ferrous chloride feed system, to replace existing metering pumps for several chemicals with peristaltic pumps and to evaluate the conversion of the existing hypochlorite system for effluent disinfection from bulk chemical use to an on-site hypochlorite generation system. The ESI team conducted workshops and prepared a Design Development Report that served as the basis of design. The team also prepared construction drawings and technical specifications for the improvements that will be constructed beginning in 2014

Cobb County-Marietta Water Authority and City of Canton, GA – Hickory Log Creek Reservoir and Pump Station SCADA

The Hickory Log Creek Dam, Reservoir and Pump Station were constructed between 2005 and 2008. The dam is 180 feet high that was built using roller-compacted-concrete. Between 2010 and 2014, ESI assisted the project owners in designing and implementing a Supervisory Control and Data Acquisition (SCADA) that allows automated control and remote monitoring of multiple components associated with the dam, reservoir and pump station. The project included addition of electric actuators for sluice gates and valves, temperature and water quality sensors, and a flow meter to measure drainage from the interior dam gallery.