The Clean Water Act of 1972 was to intended to upgrade the US’s sewer systems.  In the 1970s and 1980s, Congress distributed more than $60 billion to cities to upgrade sewer systems.  In 1994 the Environmental Protection Agency (EPA) issued a
national framework to control overflows, to ensure
that pipes are designed so they are not easily become plugged by debris
and warning the public when overflows occur. In 2000, Congress amended
the Clean Water Act to further limit overflows.

According to the New York Times, in the last three years more than 9,400 of the US’s 25,000 sewage systems have violated the law by dumping untreated or partly treated human waste, chemicals and other hazardous materials into rivers and lakes and elsewhere, according to data from state environmental agencies and the EPA.  More than a third of all sewer systems including San Diego, Houston, Phoenix, San Antonio, Philadelphia, San Jose and San Francisco have violated environmental laws since 2006, according to a New York Times analysis of EPA data.  In New York the sewer system overflows just about every other time it rains.  Similar problems occur in other municipalities such as Newport, Rhode Island.

In Ottawa it was reported that the equivalent of about 265 Olympic swimming pools full of overflow sewage entered the Ottawa and Rideau rivers from the City of Ottawa during the 2007 rainy season.  Rainfall between April and November 2007 was slightly above average in volume and intensity.  An estimated 730,000 cubic metres of sewage mixed with stormwater overflowed from 18 pipes between April 15 and Nov. 15, 2007. That represents two per cent of all sewage in the part of downtown served by combined sewers.  As a rule of thumb municipalities east of the Mississippi have combined sewers, one sewer system for sanitary and storm sewers.  West of the Mississippi, most municipalities have separate sanitary and storm sewers.

According to the EPA and the Government Accountability Office (GAO), $400 billion in extra spending is needed over the next
decade to fix the US’s sewer infrastructure.  The ARRA stimulus bill has set aside $6 billion to improve sewers and other water systems.

At Autodesk University next week Asa Reese of Parsons is going to talk about a DeKalb County, GA project to double water treatment capacity using innovative bioreactor membrane (MBR) technology.

Thanks to Chris Maeder for pointing to the New York Times article and the Newport, RI video.