PHASED DESIGN-BUILD CONVERTS 0.5 MGD SBR TO 2.5 MGD MBR

Prior to 2003, the City of Woodstock operated a 0.5 million gallons per day (MGD) Sequencing Batch Reactor (SBR) facility at the Rubes Creek Water Pollution Control Plant (WPCP). The facility would be unable to treat future increasing wastewater flows resulting from rapid growth in areas north of Atlanta and infiltration into the collection system following three years of drought. The City's plan to transfer new wastewater flow to a neighboring wastewater treatment plant was not possible due to delays in expanding that plant. In addition, strict new effluent phosphorus limits were anticipated based on a new waste load allocation (WLA) issued by the Georgia Environmental Protection Division (GEPD). The City of Woodstock was forced to place a moratorium on new sewer connections until the plant's capacity could be increased and was under threat of lawsuits by local developers if the moratorium was not lifted by January 1, 2004.CH2M HILL was contracted in February, 2003 to design and build improvements to the plant. Facilities for treatment of up to 1 MGD had to be in place and operational by January 1, 2004. Completion of a second part of the Phase 1 contract, to treat up to 1.5 MGD, would then need to be complete by May 2004. The project had to be designed to accommodate a Phase 2 upgrade, which would further increase the treatment capacity to 2.5 MGD. A phased facility plan and design-build (DB) program was developed to achieve these goals while maintaining treatment capability.