Filamentous Microorganism Evaluation

The Harrisonburg-Rockingham Regional Sewer Authority (HRRSA) owns and operates the 22 MGD North River Wastewater Treatment Facility. The facility was upgraded to Enhanced Nutrient Removal (ENR) treatment standards (5-stage activated sludge process) at the end of 2010 to comply with tributary strategy requirements of the Chesapeake Bay.

Wiley|Wilson’s scope of work includes providing on-going (year-round) wastewater process/control support to plant staff to optimize treatment performance while minimizing operational costs; weekly review of operations data; process/control trouble shooting; conducting operator training workshops; and evaluation of process control sampling/testing and methodology/procedures.

Activated sludge bulking and foaming is a prevalent issue in activated sludge systems and especially in ENR systems during cold weather months.  Specific investigations were performed at the North River WWTF to identify the specific filamentous microorganisms to enable the implementation of process control techniques to increase sludge settleability and thereby reduce the impact of activated sludge bulking and foaming.