©2013 Elizabethtown Regional Sewer Authority
Did you know…
Regional Sewer system? FOG can lead to overflows and sewer backups. Instead
of dumping FOG down your drain, pour or scrape grease from pots and pans
into an old coffee can. Allow the grease to cool and solidify (refrigerate if
necessary) then throw away in the trash.
While current building codes require traps and vents on drain lines associated with
the interior plumbing, there are portions of the Authority’s system that pre-
The traps utilize a water seal to maintain a gas barrier between the sewer mains and the buildings. If your home or business will remain unoccupied for extended durations of several weeks or longer, it’s a good practice to occasionally run a faucet or flush a toilet to keep the trap filled with water and in working order.
ELIZABETHTOWN REGIONAL SEWER AUTHORITY
I/I Identification and Removal Program
What is I/I?
Infiltration/Inflow: Causes dilution in sanitary sewers. Dilution of sewage decreases the efficiency of treatment, and may cause sewage volumes to exceed design capacity. Although inflow is technically different from infiltration, it may be difficult to determine which is causing dilution problems in inaccessible sewers.
Background: Early combined sewers used surface runoff to dilute waste from toilets and carry it away from urban areas into natural waterways. Sewage treatment can remove some pollutants from toilet waste, but treatment of diluted flow from combined sewers produces higher volumes of treated sewage with similar pollutant concentrations. Modern sanitary sewers are designed to transport domestic and industrial wastewater directly to treatment facilities with dilution.
Infiltration: Groundwater entering sanitary sewers through defective pipe joints and broken pipes is called infiltration. Pipes may leak because of careless installation; or they may be damaged after installation by differential ground movement, heavy vehicle traffic on roadways above the sewer, careless construction practices in nearby trenches, or degradation of the sewer pipe materials. In general, volume of leakage will increase over time.
Infiltration will occur where local groundwater elevation is higher than the sewer pipe. Gravel bedding materials in sewer pipe trenches act as a French drain. Groundwater flows parallel to the sewer until it reaches the area of damaged pipe. In areas of low groundwater, sewage may exfiltrate into groundwater from a leaking sewer.
Inflow: Water entering sanitary sewers from inappropriate connections is called inflow. Typical sources include sump pumps, roof drains, cellar drains, and yard drains where urban features prevent surface runoff, and storm drains are not conveniently accessible or identifiable. Inflow tends to peak during precipitation events, and causes greater flow variation than infiltration.
Impact: High rates of infiltration/inflow may make the sanitary sewer incapable of carrying sewage from the design service area. Sewage may back up into the lowest homes during wet weather, or street manholes may overflow. ERSA pays to treat every gallon of wastewater delivered to the Borough’s sewage treatment plant. Removal of clear or I/I water reduces the amount ERSA pays for treatment.
What has the Elizabethtown Regional Sewer Authority done about I/I removal?
Manhole Inspections and Repairs: The Authority has installed manhole inserts at
key locations that were witnessed to have substantial inflow during rain events.
The Authority’s long-
The Authority performed a post-
The Authority monitored I/I in the Bossler Road No. 1 drainage basin during 2009 by visually inspecting the manholes. The Authority intends to continue to inspect manholes for defects and incorporate repairs into future rehabilitation projects.
House Inflow Inspections: Authority personnel plan to perform house inspections to confirm that illegal connections have been disconnected. In order to enforce sump pump removal, the Authority adopted a resolution that prohibits discharge of any source other than permitted sanitary sewer to the Authority conveyance system and imposes financial penalties that increase with each quarter that illegal discharge is not properly terminated. It is the Authority’s intention to focus house inflow inspections in the Nolt Road drainage area during 2013.
Sewer Televising and Repair: The Authority has a sewer televising program in which they annually televise a section of the sewer system so that every 5 to 10 years, the entire sewer system is televised. As a result of this televising, the Authority identifies areas where sewer line remedial activities are required. The Authority performed some of the critical repairs during 2001, including three leaking sewer laterals in the Bossler No. 1 basin, a leaking joint in the Turnpike No. 2 basin, and the installation of a watertight manhole riser in the Turnpike No. 2 basin.
The Authority completed additional remedial activities during 2002 in conjunction with the manhole raising described above, including approximately 140 linear feet of sewer repairs in the Bossler Road No. 1 and Miller Road drainage basins.
The Authority purchased a mini camera in 2000 for the purpose of investigating leaking laterals and suspected problematic laterals. Inspection personnel have been trained on the proper use of the camera, and the Authority has begun a lateral televising plan. The Authority has televised all of the laterals in the Bossler Road No. 1, Wilkens Street drainage basins, and a portion of the laterals in the Miller Road and Turnpike Road No. 2 drainage basins.
As stated previously, the Authority performed additional wet weather manhole inspections
during 2003 and 2004 following post-
The Authority televised the entire Nolt Road drainage basin during 2004. In 2005,
the Authority televised the Bossler Road No. 1, Turnpike Road No. 1, Turnpike Road
No. 2, and Wilkens drainage basins. In 2006 the Authority televised the Nolt Road
and Colebrook Road drainage basins, and part of Miller Road drainage basin. As a
result of this work, the Authority identified sewers in need of rehabilitation and
replaced 700 feet of 12-
In 2007, the Authority televised approximately 18,000 feet of the Cameron Street
and approximately 9,000 of the Miller Road drainage basins. In 2008, the Authority
televised sections of sewer located within roads identified for re-
In 2010, the Authority televised approximately 4,700 linear feet of truss pipe in
the Bossler No. 1 drainage basin. Based upon the results of the televising, the
Authority rehabilitated approximately 4,350 linear feet of pipe with cured-
In 2011, the Authority purchased a portable flow monitoring devise, a “flow poke,” to monitor I/I in the entire Turnpike Road No. 2 drainage basin. Based on this I/I investigation the Authority rehabilitated approximately 6,642 LF of truss pipe and 85 laterals utilizing CIPP technology which has shown reduction in I/I throughout the basin.
In 2013, the Authority intends to investigate the flow in the sewers along Mount Gretna Road and within the Nolt Road Pumping Station drainage basin to develop a sense of the I/I present in the area and make repair decisions based on the finding of the investigation.