What we don’t see we don’t often think about. Just below your feet, the United States has an estimated 1.2 million miles of underground sanitary and combined sewer systems.
Underground Sewer System Types
When combined sewer systems were introduced in 1855, they were celebrated as a huge improvement over urban cesspool ditches that ran along city streets and flooded when it rained. Combined sewer systems were—and still are—a wonderful thing, except for one occurrence. When too much stormwater is added to the flow of raw sewage, the typical result is usually an overflow. As our population continues to grow, the current sewer system infrastructure is being pushed to its’ limit. With such growing pressures on the aging infrastructure systems, they are failing and can’t handle the increased demand.
Difference between CSO and SSO
Today a simple rain event can threaten our clean water by causing sanitary sewer overflows (SSO) and combined sewer overflows (CSO). The SSOs and CSOs are caused by unmaintained and underdeveloped underground infrastructure. During wet events water enters the sewer system via infiltration and inflow (I/I) as a result the systems exceeds capacity and the overflow occurs.
CSOs annually result in an estimated 850 billion gallons of untreated wastewater and stormwater being discharged into U.S. waterways, according to an EPA report. Each year 23,000 to 75,000 SSOs occur, resulting in 3 to 10 billion gallons of untreated waste water being released. The sewage release is a direct threat to America’s watershed and raises public health concerns. The EPA also reports “microbial pathogens and toxics can be present in CSOs and SSOs at levels that pose risks to human health.” Human health impacts occur when people become ill due to contact with water or ingestion of water or shellfish that have been contaminated by CSO or SSO discharges.
Sewer System Maintenance and Inspection Programs
Many stoppages in sewer systems are caused by a buildup that can include grease, sand, sludge or other types of debris. Root intrusion and other structural defects such as pipe joint offsets, cracks, and protruding taps can also cause slow flows resulting in debris build-up in mains and private lateral connections. Once the blockage has begun, it traps more and more debris which will cause a back-up and, if not discovered in time, a sewer overflow
A vital part of stopping these SSOs and CSOs are Sewer System Maintenance and Inspection Programs.
It is recommended that 100% of a sewer system be hydro flushed on a 3 to 5 year cycle. Problematic pipelines should be visually inspected with robotic cameras that can identify additional unforeseen problems during this cycle as well. American Underground, Inc. is proud to be on the front lines in the battle to keep our environment clean and safe not only now, but for future generations as well.
The success that the nation has achieved in improving water quality since passage of the Clean Water Act is due to the collective efforts of federal and state agencies, municipalities, industry, non-governmental organizations, and citizens. Continued cooperation among these groups is essential to meet the challenges to clean water that lie ahead. As described in this Report to Congress, numerous pollutant sources threaten the environment and human health, but establishing direct cause-and effect relationships is often difficult. The information necessary to manage water quality problems comes from many sources. EPA recognizes the value of working with stakeholders and has pursued a strategy of extensive stakeholder participation in its policymaking on CSO and SSO issues. Likewise, as communities continue to implement CSO and SSO controls, further cooperation with municipal, industry, and environmental organizations is essential to ensure successful development and implementation of environmental programs. – 2004 EPA Report to Congress on the Impacts and Control of CSOs and SSOs