HRG prepared a comprehensive capital improvement plan (CIP) that included the inspection and evaluation of all infrastructure at the wastewater treatment plant. In preparing the plan, HRG evaluated several for anaerobic digestion and various strategies for compliance with the Goose Creek TMDL. The final plan detailed a comprehensive six-year approach to address critical infrastructure and comply with TMDL that included $28 million in collection and conveyance improvements.
Phase 1 of the plan is complete and included:
- new influent mechanical screening and grit removal facilities
- enhanced chemical feed system for pH control and phosphorus precipitation (which help the authority obtain a monthly average concentration of 0.8 mg/L )
- repairs to Primary Clarifier No.3
- replacement of the emergency generator with two generators run in parallel
- removal of all underground fuel storage tanks
- replacement and improvements to the primary and secondary anaerobic digesters to include boiler, mixer, gas conditioning, and safety equipment improvements
Phase 1 also incorporated a phosphorus reduction evaluation and nitrogen reduction optimization study that included bench scale and pilot testing of a ballasted flocculation system for ultra low-level phosphorus removal.
The Phase II improvements are currently under design and include:
- replacement of the existing belt filter presses with new screw presses
- advanced control systems for increased operability of the processes
- a new tertiary treatment system capable of reducing effluent phosphorus concentrations to below 0.1 mg/L
- aeration system improvements to decrease energy loading and operating costs at the wastewater treatment plant
- implementation of a supervisory control and data acquisition system for improved operability and data analysis for the operations staff
