Wastewater Operations – 30-Inch Force Main Replacement
The City of Fort Lauderdale is in the midst of a major infrastructure improvement project to replace a 30-inch wastewater force main that runs through the Durrs, Dorsey Riverbend, Sailboat Bend, and Tarpon River neighborhoods. This critically important project for the future of the City is currently impacting several neighborhoods in terms of construction and increased use of tanker trucks to vacuum and transport wastewater. We share neighbors’ concerns and apologize for the inconvenience as we move forward with major improvements in our community. (You can also download a PDF version of this FAQ .)
- How does sewage (also known as wastewater) get from my house to the Wastewater Treatment Plant?
After you flush your toilet, wastewater (sewage) travels down a pipe on your property, called a lateral, and merges into a larger city-owned pipe called a gravity sewer main. From there, wastewater flows downhill to a lift station which pumps the wastewater into another pipe called a Force Main. These pressurized pipes are the main highways through which wastewater flows. They can be as small as 4 inches in diameter and as large as 4.5 feet in diameter. A series of additional smaller pump stations or large repump stations push the wastewater toward the City’s George T. Lohmeyer Wastewater Treatment Plant (GTL) located near the Broward County Convention Center just north of Port Everglades.
- What is involved in the project to replace the 30-inch wastewater force main?
Replacing the 30-inch force main, which connects A-Repump station (located at Sistrunk Blvd and I-95) to the George T. Lohmeyer Wastewater Treatment Plant (GTL), is one of the City’s highest priorities. The infrastructure project, which is moving forward at an unprecedented pace, involves one of the City’s four primary force mains. This one pipe conveys more than 30% of all wastewater in the City to GTL. After several repeated breaks and repairs in this pressurized pipe, the City Commission approved an emergency declaration on June 1, 2017 to allow for its replacement. The City quickly developed a design criteria package and awarded a contract to Murphy Pipeline, Inc, on August 22nd, 2017 for $14,560,456. Work includes not only replacement of 11,500 linear feet of existing 30 inch pipe, but also the installation of 8,000 linear feet of new pipe for additional redundancy in the system. Almost all work is being done using construction techniques that avoid large road cuts and minimize traffic impacts.
- When will the 30-inch wastewater force main project be completed?
The project is divided into four phases which are being simultaneously constructed.
Phase I, replacing the southern portion of the existing force main from SW 2 Street to SW 7 Street, including a pipe that runs under the New River, which is scheduled to be complete by December 1, 2017
Phase II, constructing 1500 feet of new force main along SW 2 Street from SW 8 Avenue to SW 4 Avenue, which is scheduled to be complete by November 17, 2017.
Phase III, constructing 6,400 feet of new force main along Sistrunk Blvd from NW 19 Avenue to NW 4 Avenue, which is scheduled to be complete by January 3, 2018.
Phase IV, replacing 8,300 feet of the northern portion of existing force main from NW 6 Street (Sistrunk Blvd) to SW 2 Street, which is scheduled to be complete by May 1, 2018.
- Why are tanker trucks being used while this project is under construction?
During the construction of this critical force main, the community continues to generate wastewater. Without the force main to push large volumes of wastewater toward the plant, the gravity sewer mains tend to fill up, a condition called surcharging. Surcharged systems can overflow through manholes and cause back-ups into individual properties. The use of tanker trucks helps prevent wastewater overflows and is an absolute necessity until the major components of the 30-inch force main project are complete. While the force main is out of service, we must move wastewater through other parts of the system to deliver it to the treatment plant. In some cases, however, there is no pathway and the City must manually pump wastewater from upstream lift stations to those further downstream and bypass the pipe under repair. The volume of wastewater that must be moved varies from day to day. Several factors influence the demands of the system including day of the week, time of day, rainfall, king tides, and even the elevation of the groundwater table.
- Do rain or king tides affect the wastewater system?
The wastewater collection system including private laterals, gravity sewer mains, and force mains are not perfectly water tight. Broken or cracked pipes can allow inflow and infiltration (I&I) of groundwater, rainfall, and king tides into the wastewater collection system. When the groundwater table is lower or there are fewer rain events, less volume enters the wastewater system. As the wet season begins, it rains more, the groundwater table increases and many of the pipes become submerged allowing greater I&I to occur. The City is proceeding forward with an aggressive program to reduce I&I and the impacts of rain and king tides.
- How did Hurricane Irma contribute to the problem?
While repairs are ongoing, the wastewater system is more susceptible to surcharging issues and impacts during periods of heavy rainfall and king tides. When this occurs, the use of manual wastewater servicing with tanker trucks is required on a more frequent basis. The historic rainfall event of June 7 caused significant surcharging impacts throughout the system over several weeks that required additional resources to move wastewater through the system. During Hurricane Irma, the City lost power to almost 50 of its 186 pump stations. In spite of this, the City used a combination of generators and tanker trucks to continue operating the system without major service disruption to our neighbors. As heavy rains and king tides continue to impact our area, we continue to experience surcharging issues in portions of the wastewater system, particularly in the downtown area.
- How many trucks are involved and when are they operating?
The number of trucks being used varies by the capacity of the truck and the current flow into the system. In the late October timeframe, the City had 25 trucks performing tankering services. Once the rainy season ends, the wastewater collection system will recover capacity and fewer trucks will be required to prevent surcharging. Staff adjusts the number of trucks scheduled for each shift as needed based on demand.
- Why am I seeing more trucks now than in the spring?
During the spring, the groundwater table is lower and we have fewer rain events resulting in less I&I impacts. As stated above, when the wet season begins, it rains more frequently and the groundwater table gradually increases. When this occurs, many of the pipes become submerged which results in greater I&I. The City closely monitors wastewater flows and makes operational changes to keep the system operating smoothly and to reduce surcharging. This operation in the wet season has required a greater number of tanker trucks than in the spring. With the end of the rainy season, the system will recover capacity and fewer trucks will be required to prevent surcharging.
- How long will the city be using tanker trucks?
As stated above, the number of tanker trucks used varies by the capacity of the truck as well as current flow into the system. With the end of the rainy season, the system will recover capacity, requiring fewer trucks to prevent surcharging. It is anticipated that when several phases of this project are completed in December, the system can be operated without the need for tanker trucks.
- How much does this cost the City?
Numerous factors impact the cost of tanker trucks, including the size of the truck, availability from different vendors, and time of operation. Staff adjusts the number based on the volume of wastewater in the system to ensure that the minimum number of trucks needed each day is utilized. The City has negotiated with several vendors to provide services at the lowest possible cost.
- Is it safe to be moving wastewater by tanker truck?
There are many environmental regulations involved with wastewater management. Vendors must be licensed, insured and have the required permits to operate. City staff closely monitors all tanker truck operators to ensure they provide services in a way that keeps our community safe. Wastewater can only be discharged into the sanitary sewer system, so it does not impact our waterways. Any spills, regardless of size, must be immediately reported and response teams are available to assist with cleanup if necessary.
- What should I do if I believe a truck operator isn’t operating in accordance with the rules?
If a neighbor observes, or suspects, a tanker operator is not operating in a safe manner, they should immediately report their concerns to our Neighbor Service Center at (954) 828-8000 and the appropriate City staff will respond.
- How do I report if sewage is overflowing or backing up in my neighborhood or into my property?
When gravity pipes are surcharged, they are more susceptible to blockages or backups. Neighbors should report any issues to our Neighbor Service Center at (954) 828-8000 and the appropriate City staff to address.
- Why are trucks constantly on my street?
Wastewater flows downhill through gravity sewer main into a large underground storage tank at each of the neighborhood lift stations. When the system is surcharged, the tanks cannot empty into the pressurized force mains and the gravity pipes back up. Trucks must manually remove wastewater from these storage locations with tanker trucks. When deciding where to unload trucks, staff evaluates which pipes and lift stations have additional capacity to move the wastewater. Discharges are made into the gravity sewer mains near the lift station. Trucks are rotated through several neighborhoods to minimize impact on any one neighborhood; however, there are only a limited number of downstream lift stations with the capacity to accept additional flows.
- Where can I get additional information about my questions?
Please refer any questions to our Neighbor Service Center at (954) 828-8000.
GLOSSARY OF TERMS
Force Mains - Force mains are pressurized pipelines that move wastewater to the sewage treatment plant.
Gravity Sewer Main - A gravity sewer main is a pipeline that uses the difference in elevation, or height above sea level, to move sewage to a lower elevation. Because of Fort Lauderdale’s low elevation, the City must use a combination of gravity and force mains to move sewage to the treatment plant.
Inflow & Infiltration (I&I) Reduction - Inflow and Infiltration refers to stormwater and groundwater that enters the sanitary sewer system through a variety of defects, including cracks and bad joints in pipes, causing large volumes of water to enter the wastewater system.
Lift Stations - Lift stations (also known as pump stations) move wastewater from lower to higher elevations which are necessary at locations where gravity flow is not sufficient for moving sewage to the treatment plant.
Sewer Surcharge - Sewer surcharge refers to the overloading of the sewer beyond its design capacity as Inflow and Infiltration from rainfall, king tides, and several other factors impact volume. A surcharging sewer may result in a sewer overflow at a manhole.
Wastewater - Wastewater is the same as sewage.