Evaluating the Effects of Climate Change on the Operation, Design and Cost of Water Treatment

摘要

It is anticipated that global climate change will adversely impact source water quality in many areas of the United States and will therefore impact the design and operation of current and future water treatment systems. The USEPA has initiated an effort called the Water Resources Adaptation Program (WRAP) which is intended to develop tools and techniques that can assess the impact of global climate change on urban drinking water and wastewater infrastructure. As an illustration of the research conducted under this project a three step approach to assessing climate change impacts on water treatment operation and design is presented. The first step is the stochastic characterization of source water, the second step is the use of the EPA Water Treatment Plant model and the third step is the application of cost algorithms to provide a metric that can be used to assess the impact of climate change. The model was validated using data collected from the Greater Cincinnati Water Works' Richard Miller water treatment plant for the USEPA Information Collection Rule (ICR) database. An analysis of the water treatment processes in response to assumed perturbations in raw water quality identified TOC, pH, and bromide as the three most important parameters affecting performance of the Miller WTP. The Miller plant was simulated using the EPA WTP model to examine the impact of these parameters on selected regulated water quality parameters. Uncertainty in existing and future WTP flow rates and influent water quality was analyzed to estimate the risk of violating drinking water Maximum Contaminant Levels (MCLs). Water quality changes in the Ohio River were projected for 2100 using Monte Carlo simulation. The WTP simulation model was then used to evaluate the effects of water quality changes on WTP design and operation. Results indicate that the existing Miller WTP operation can accommodate most changes in inflow and water quality but might not meet Safe Drinking Water Act MCL requirements for certain extreme future conditions. However, it was found that the risk of MCL violations under future conditions could be controlled by enhancing existing WTP design and operation or by process retrofitting and modification. Algorithms were applied to estimate the costs associated with these WTP adaptations.