Life Cycle Cost Integration for the Rehabilitation of Wastewater Infrastructure

In 2000, the American Society of Civil Engineers (ASCE) ranked America's wastewater infrastructure a grade of "D" and stated that the U.S. needs to invest roughly $140 billion over the next 20 years in its wastewater treatment systems. Of that total, roughly $10 billion is needed for upgrading existing wastewater collection system, $22 billion for construction of new sewer system, and $45 billion for controlling Combined Sewer Overflows (CSOs). With the increasing need for wastewater infrastructure rehabilitation, the need for effective infrastructure management system under budgetary constraints is crucial. The use of Life Cycle Cost Analysis (LCCA) for infrastructure management can contribute to the goals of reducing construction, operation, and maintenance costs. One mathematical tool that is viable for LCCA is probabilistic dynamic programming, which recommends optimal Maintenance & Rehabilitation (M&R) methods for each segment in the network. In many cases, the aggregate cost of applying the suggested M&R techniques to all segments within a network is often higher than available budgets. This paper describes a procedure to prioritize M&R programs to acquire a network-optimal solution. Efficient use of limited funds in construction, maintenance and operation of sewer systems will result in better quality of infrastructure and improved economic well-being of communities.