Water is a critical part of power production. For example, it is boiled to create the high-pressure steam that turns a turbine so that power can be made. Water is also circulated to condense the steam for re-use, and at the end of the process it is combined with lime to create a slurry that extracts sulfur from flue gases. Conesville treats 20 million gallons of water a day with large “clarifier” tanks that remove solids and purify the water. This image focuses on the drain, and the transition from clean to dirty to clean.