(679f) Economic Evaluation of Wastewater Treatment Plant Construction in Small Communities

Wastewater collection and treatment systems are an integral part of communities. In the life of a town, its investment in wastewater collection and treatment systems is hugely important for attracting industry, protecting the environment, and conforming to state law. Through this work we seek to understand the optimal size of a town for construction of a wastewater collection and treatment system.

We utilize data covering wastewater treatment plants in small towns across Oregon to estimate parameters utilized in a series of costing models. Using several capital cost estimating techniques, we identify the optimal size of town for capital investment in wastewater collection and plant systems.

We then compare early, late, and optimal construction timing with status quo (septic) setups to gain a better understanding of the consequences of ill-timed investment. Through the cost models, we analyze a number of different configurations for wastewater treatment plants including utilizing different machinery and perform sensitivity analysis on major parameters to gain an understanding of the uncertainties in our model.

Lastly, we utilize our model setup to observe several real cities amid wastewater collection and plant investment controversy to see the consequences in practice of regulatory and investment decisions. We quantify some of the projected costs associated with those communities and compare those to costs under ideal timeliness of investment.