389075 - The Only Constant is Change: A Better Collection System Model for Capital Savings
Monday, June 4
10:30 AM - 12:00 PM
Location: Mirage Room
Derek Sutton, Indianapolis, IN – Citizens Energy Group; Hazem Gheith, Columbus, OH – Arcadis
Our presentation will summarize the positive change in collection system modeling used by Citizens Energy Group to support its wastewater program as a large wastewater utility under a consent decree with a commitment to efficiently provide sewer service to its ratepayers. The positive change has resulted in capital savings through more consistent and accurate simulation of inflow and infiltration (I/I) in the collection system.
As Citizens was considering a balance of capital projects and rehabilitation for the collection system, progress was being made on a significant expansion of the collection system model to include all 12” pipes and transition the representation of I/I to a groundwater-based process (Gheith, 2014). This new approach of modeling better supports the master planning approach and has paid immediate dividends to Citizens’ wastewater program.
The first priority basin for the expanded model was the Williams Creek interceptor basin, where storage and pumping alternatives were being considered to achieve the level of service, with a potential capital cost of $10 million. The reliability of the simulation of peak I/I flows is due to the representation of I/I as groundwater and a physically-based representation of impervious and pervious surfaces. The overall modeled peak flow in the Williams Creek interceptor was reduced from 9 MGD to 6 MGD as part of the model update and recalibration. This reduction in simulated peak flow eliminated the need for any new capital projects in the interceptor basin, resulting in significant capital savings.