Heart of the Valley Sewerage District in Kaukauna, Wisconsin required high-purity water to test plant effluent for biochemical oxygen demand (BOD) and other contaminants. Testing is required to ensure that the effluent meets state and federal guidelines before discharge into the Fox River.
Laboratory manager Chad Giackino tests the facility's effluent daily, using a pure water sample as a benchmark. He used a still to make the pure water; however, it proved unreliable. Many different impurities would often remain in the water that came out of the still, such as organics, inorganics, biological products and microorganisms. Besides yielding unreliable results, the still increased testing time because the tests often had to be repeated.