<p><span style="font-family: georgia, 'times new roman', times, serif; font-size: 15px; line-height: 22px;">At the plant that treats most of this city’s sewage, <a href="http://www.nytimes.com/2011/07/24/us/24ttsewage.html?_r=1&amp;ref=water">water</a> sloshes and foams within giant concrete walls. This is cleaned-up sewage, made even purer by processes the plant expanded just a few months ago.</span></p>