Numerous changes have taken place in the Pittsburgh region over the last 50 years. Pittsburgh, once known as the "smoky city," has established itself as a center for advanced technology. Another remarkable change is the transformation of area rivers and streams from open sewers to waterways safe for recreation and commerce.
Prior to the completion of the ALCOSAN interceptor sewer system and primary treatment plant in 1959, however, raw sewage and industrial wastes flowed directly into district waterways. Aquatic life and dissolved oxygen concentration in the Ohio, Monongahela and Allegheny rivers were severely impacted.
ALCOSAN was formed in 1946 to design, construct and operate the interceptor system and a treatment plant for residential, commercial and industrial wastewater. As national environmental awareness grew, it became clear that primary treatment was insufficient in meeting increasing river quality standards. The design of secondary, or biological, treatment processes began in the late 1960’s and operation of the secondary treatment plant commenced in 1973.
By 1992, ALCOSAN began addressing the growing concern over sewer overflows and wet weather pollution control and, in 1994, started planning for permit requirements as required by the Clean Water Act and the US EPA’s CSO Control Policy. Enacted in 1977, the Clean Water Act prohibits the discharge of pollution into waterways unless a permit has been secured and requires the elimination of all SSOs and a significant reduction in CSOs.
From 1995 to 1999, ALCOSAN worked with federal and state environmental regulatory agencies, which led to a Consent Decree that would satisfy ALCOSAN’s obligations under environmental law to comply with the Clean Water Act and US EPA CSO Control Policy. The Consent Decree received final approval in January, 2008. ALCOSAN now has 20 years to repair broken sewer lines, reduce inflow and infiltration, reduce the frequency and amount of CSOs and eliminate SSOs as mandated in this Consent Decree.
As ALCOSAN embarks on this new era of environmental responsibility, we invite you to take a fascinating look back at the early history of the Authority and the land that it has occupied for more than fifty years.