Wastewater Maintenance

The wastewater collection system is designed to eliminate and carry the wastewater through the City’s sewer lines. A vast system of underground sewers, force mains and pumping stations collect the wastewater from the homes of the city's residents and deliver it to North Texas Municipal Water District’s (NTMWD) main sewer lines, then to their waste water treatment plant located near Lucas. The operation and maintenance of over 300 miles of pipes and six lift stations are performed by 14 employees of the sewer division in the community services department. Their responsibilities include maintaining all the lift stations, and managing the City’s preventive maintenance program for all items related to the sewer collection system.

Wastewater Collection System

Wastewater discharged from a home or business enters the sewer system through service lines eight inches or smaller. These service lines carry the flow of wastewater to the City’s trunk lines consisting of pipes eight inches or larger. Based on the topography of the city, if the flow is not by gravity, there are lift stations to pump the wastewater from the trunk sewers into the main NTMWD interceptor sewers. The wastewater flows by gravity through these large interceptor sewers, which are up to 60 inches diameter,to the NTMWD treatment plants.

Sewer Lift Stations

Lift stations are an integral part of the collection and conveyance system.Collection systems are built to utilize the natural flow of gravity when possible.When wastewater cannot travel through the lines by gravity, pumps are used to force the wastewater through the force mains until it can again be transported by gravity flow. The City of Allen has six lift stations strategically located based on the topography of the area.

Sewer Line Maintenance

The Wastewater Division has a very proactive preventative maintenance program to keep our wastewater system functioning properly and to accomplish the City’s goal to protect the environment. A comprehensive program of on-going investigation and preventative maintenance maximizes system performance to prevent emergency repairs.

Despite proactive efforts to maintain the system, operational complications may sometimes occur. Some of the common causes of system problems include:

In order to maintain our wastewater system and to keep it functioning properly, our sewer division utilizes the following preventative maintenance procedures:

Visual Inspection

Maintenance crews regularly check manholes, frames and covers to look out for cracks, breaks or missing parts, which may prevent them from maintaining airtight integrity.Replacement and maintenance is scheduled as necessary.

TV Inspections of Lines

As a preventive maintenance tool, TV inspections are performed on sewers lines as a result of line blockages and other sewer related problems. The TV inspection process is critical in the detection and location of needed repairs. With the TV camera, that is lowered into a manhole and pulled through the line, the crew can find the exact location of a lateral connection and type of problem. Testing and repair equipment used in conjunction with the camera will determine if there are areas of weakness in the joints and pipes and look for leakage. This information is valuable in the digging and repair process as it eliminates "guess work" in isolating a problem.

Jet/Vacuum Cleaning

Sewer lines are often rodded to remove roots or other material then cleaned with high-pressure water by using a combination jet vacuum system. This year, the City of Allen will purchase a second Vactor Truck, to assist our maintenance staff in restoring pipe line and manhole stoppages and conducting regular preventative maintenance. This equipment is used to jet clean the line with high pressure water hose. The debris is then vacuumed from the manhole with the high powered vacuum hose.

 

Smoke Testing

By blowing smoke into a sewer line, crews can determine areas of breaks, improper connections and other system problems which than can be scheduled for repair or replacement.This procedure sometimes identifies problems on the property owner’s side of the system.In these cases, the property owners are notified and advised to make the appropriate repairs.

Chemical Root Treatment

In some areas, workers may find it helpful to use a foaming chemical root treatment.This foam is pumped into selected sewer mains to kill existing roots and to inhibit their regrowth.

Inflow and Infiltration

An aging sewer system is in constant need of inspection and repair. Cracked and broken sewer lines and manholes allow ground water to enter the sewers system. In additional to groundwater, illegal sump pump connections and roof downspouts add rainwater to the sewer system. This additional water volume is called inflow and infiltration. During a rain event this additional water can overburden the sewer system and cause overflows. These types of connections are reported to code enforcement for action.

Sewer Clean-Outs

All properties built in Allen after 1997 have been built with a sewer clean-out, which is a pipe placed into a sewer line to provide an opening at ground level to connect the private property’s service line with the City’s sewer line. Cleanouts are typically installed at the edge of the easement or property line, or in close proximity of the house foundation.

The property owner is responsible for maintaining the service line (private sewer) from the property line, including the cleanout, to the home. The City is responsible for maintaining the sewer line from the property line to the main sewer line. This type of pipe allows for easy access to the City of Allen’s main line and access to the property owner’s line for the private service connection.

It is standard practice to install cleanouts at the edge of easements or property lines. This prevents the necessity of going into private homes to correct stoppages.

If your property does not have a sewer clean-out, the City of Allen will install one at the front of the property line for $100. Contact Community Services at 214.509.4500.

Read more...