Sewer Collection System Annual Performance Report
City of Eden, North Carolina
July 1, 2017 to June 30, 2018
I. General Information
Facility/System Name: City of Eden, Sewer Collection and Treatment System
Responsible Entity: City of Eden, Brad Corcoran, City Manager
Person in Charge/ Contact: Collection System and Pump Stations, Mark T. Bullins, Operator-in-Responsible Charge, 336-397-4385
Mebane Bridge Wastewater Treatment Plant, Melinda S. Ward, Operator-in-Responsible Charge, 336-627-1009
Applicable Permits: Sewer Collection System – WQC200018
Mebane Bridge Wastewater Treatment Plant – NPDES Permit NC0025071
Land Application of Wastewater Residuals – NC Permit WQ0003035
Description of Collection and Treatment Process:
The collection system consists of 161+ miles of gravity and 19.4 miles force main sewer pipelines. The pipelines are composed of a mixture of clay, PVC, RCP, steel and ductile iron pipe, ranging in size from 6 to 36 inches. Age of the sewer pipelines range from new to more than 50 years old. Collection is accomplished by gravity from homes and businesses until it is necessary to pump from low elevations in force main sewer lines that transport the sewage to the treatment plant. There are 20 pump stations in the collection system. These range in size from pumping a few thousand gallons per day to more than five million gallons a day (MGD). The City has one primary collection drainage area. All of the city sewer drains, collects, or is pumped to the Mebane Bridge Wastewater Treatment Plant (MBWWTP), which can treat 13.5 MGD.
The MBWWTP has treated on average about 3.150 MGD this past year. This means that currently the Mebane Bridge plant operates at less than one quarter of its capacity. The plant has mechanical barscreens to remove larger inert material, a grit removal system following the bar screens, and a fine screen after the grit removal system to further remove any material that is missed by prior treatment systems. Extended aeration using activated sludge is the next process to reduce and remove biochemical oxygen demand and ammonia. The sludge is separated from treated water by circular clarifiers. Collected sludge or biosolids are wasted to the aerobic digester or returned to the aeration system. The biosolids from the digester are then dewatered and land applied on permitted sites. Treated water to the effluent leaves the clarifiers and is disinfected with chlorine and then dechlorinated. The treated effluent is then returned to the Dan River meeting all State Permit Discharge requirements.
The City of Eden is presently under an administrative order on consent reissued by the Environmental Protection Agency to eliminate sanitary sewer overflows that continue to occur from its sewer collection system. We have until February 28, 2022 to complete all improvements.
The City has Collection & Distribution field personnel to respond to emergencies in order to maintain the sewer collection system. Their job is to repair broken lines, installation of new sewer line, mow and maintain sewer outfall lines, and respond to, rectify and mitigate sewer bypasses. Personnel are on call nights and weekends year round to respond to emergency problems in the collection system. The City’s 20 pump stations are monitored by (2) Collection & Distribution Operators 24 hours per day, 7 days per week, by remote telemetry (Mission Communications) and physically checked on normal workdays by Collection & Distribution personnel for proper operation. Maintenance crews along with C&D personnel perform scheduled preventative maintenance on each of these pump stations to protect the equipment and insure long life. An extensive warehouse of supplies and parts are maintained to address emergency breakdowns and failures in the pump stations and the sewer lines.
The following was accomplished during fiscal year 2017-2018:
A total of 42 Inflow & Infiltration problems were responded to and repaired.
A total of 99 laterals and 30 sewer mains were responded to and unstopped.
A total of 16.29 miles (86,048.5 linear ft.) of sewer mains throughout the City of Eden were cleaned by sewer jet or rodder
A total of 7.73 miles (40,834.8 linear ft.) of sewer mains throughout the City of Eden were inspected by CCTV throughout the City of Eden.
Treatment Plant Operators are on duty 24 hours per day, 7 days per week, to ensure proper treatment of all incoming wastewater. They monitor plant equipment and do inspections during each shift to insure process control and the mechanical operation of the equipment. Maintenance personnel are available each day to service equipment and are on call nights and weekends for emergency repairs in case the treatment equipment suffers failure. A large parts inventory is maintained of the items that have historically been prone to failure.
Collection System Operations
There were 4 events in the past 12 months during which 5 incidents occurred where raw sewage overflowed or bypassed from the gravity collection system to surface waters. The overflows from these gravity flow pipelines in the collection system, most of which were immediately upstream of pump stations, totaled 34,500 gallons, with 33,500 reaching surface waters. The majority of these overflows were caused by Inflow & infiltration of storm water into the gravity sewer mains. For one of the other overflows a blockage of excessive paper in the sewer line was the cause releasing 7,000 gallons of the total volume. Two of the overflows were the result of pipe failure contributing 8,100 gallons to the total overflow volume.
Of our 20 pump stations; (2) pump stations had sanitary sewer overflows during the last 12 months in a single event. These were as follows: Covenant Branch Pump Station releasing 14,900 gallons and Railroad Pump Station releasing 4,500 gallons of untreated sewage all of which entered surface waters. The cause for these overflows was inflow and infiltration of storm water.
When overflows or bypasses occurred, the affected sites were evaluated, cordoned off from or otherwise isolated from the public and/or receiving streams and monitored for environmental impacts as conditions dictated.
*Numerous sources of inflow & infiltration continue to be identified and repaired.
Treatment Plants Operations
Compliance with North Carolina NPDES (National Pollution Discharge Elimination System) Permit is based on meeting discharge parameters set forth in the NPDES Permit. This information is reported monthly to the North Carolina Department of Environment and Natural Resources through self-monitoring reports. The following is a summary of our plant permit compliance for the last 12 months: Reporting Month Mebane Bridge Plant
July 2017 Compliant
August 2017 Compliant
September 2017 Compliant
October 2017 Compliant
November 2017 Compliant
December 2017 Compliant
January 2018 Compliant
February 2018 Compliant
March 2018 Compliant
April 2018 Compliant
May 2018 Compliant
June 2018 Compliant
This report will be submitted to the State Division of Water Quality and be released to the local news media and posted on the City’s internet web site at www.edennc.us.
“I certify, under penalty of law, that this document and all attachments were prepared under my direction of supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fines and imprisonment for knowing violation.”