Have you ever dug your toes into the fine, white, soft sand of a Florida beach and thought, “This stuff must really wreak havoc on the lateral pipes in this town?” Probably not, but that is nonetheless a fact of life in areas like Pensacola, Florida.
Thankfully, the sewer provider for Pensacola is the Emerald Coast Utilities Authority (ECUA) and since 2014 it has taken a long-term, proactive approach to dealing with the issues of inflow and infiltration in both main lines and service laterals. ECUA has a collection system of 1,225 miles of sewer lines that service more than 70,000 customers. Some of these sewer lines are 100-plus years old, which makes it one of the oldest sewage collection systems in the state of Florida. With aging pipes, there is an increased need to address cracks, root intrusion, and joint issues that compromise the integrity of both main lines and service laterals and the area above and around that piping.
In addition to the age of the sewage collection system, the environment of Pensacola contributes to the issue of I/I. The powdery sand that draws thousands of tourists to their beaches also finds its way into the pipes, causing joint failures and faulty connections. Because some areas of Pensacola are influenced by the tides, ground conditions fluctuate. High tide brings with it sand and other debris that can then end up compromising the sewage collection system.
A further environmental challenge is precipitation levels. Florida gets more than its fair share of rain annually (ranking fifth in the United States in annual rainfall). Pensacola can experience significant precipitation in short timeframes because of heavy storm activity on the coast. For example, the city experienced more than 20 in. of rain in a 24-hour period in 2014. These types of conditions are one reason ECUA takes a comprehensive approach in addressing the maintenance and repair of their service laterals.
Municipalities often only focus on mainlines for infiltration reduction, but service laterals are also a major source of I/I. In fact, ECUA conducted flow monitoring prior to cured-in-place pipe (CIPP) mainline rehabilitation in the downtown Pensacola area. Flow monitoring conducted by ECUA proved that while flows were reduced after mainline CIPP rehabilitation, there was still a significant opportunity to further reduce extraneous flows by addressing the service laterals.
ECUA has contracted with BLD Services, LLC from Kenner, Louisiana, since 2014 to clean, inspect and rehabilitate service laterals through CIPP lining. BLD is the largest lateral contractor in the United States with 30-plus crews in 14 locations across the Eastern portion of the United States. BLD relies on vacuum trucks and trailer jets for cleaning the pipes and Aries Industries CCTV lateral inspection vehicles equipped with LETS 6.0 system to capture detailed video of the pipe condition. From the mainline, the crew is able to launch the Aries LETS6.0 lateral camera (with or against the flow) to identify and report issues within the laterals that need to be remedied.
The BLD “Service Connection Seal + Lateral” is used to complete the CIPP lining work necessary to restore the integrity of the pipes. Once cured, the Aries LETS 6.0 system is deployed again to inspect the lining and ensure the integrity of all the joints. BLD has one fulltime crew dedicated to the lateral work in Pensacola, with an additional 2-3 crews brought in as needed. To date, BLD has inspected more than 5,000 laterals and of those has rehabilitated more than 4,000. In some areas of ECUA’s collection system, the BLD lateral lining system has now been in service for more than 10 years.
“ECUA deserves a lot of credit for being proactive and not waiting for something catastrophic before rehabilitating their system. They take a very comprehensive approach. Due to funding constraints, many municipalities will only address the worst laterals. Out of 300 service laterals they may only inspect 100 and rehab fewer than that. ECUA is committed to being thorough by inspecting every single lateral neighborhood-by-neighborhood. It pays off for them in unexpected savings,” says vice president of BLD Services Jacob Trapani.
ECUA’s approach has reaped long term financial benefits. Reduction in energy costs for pump stations, which are a critical component of a complex system in a flat coastal terrain like Pensacola, plus savings in sewer treatment have all been outcomes of the ongoing effort to reduce the I/I in service laterals. An added benefit is the reduction in complaints from residents regarding sewer overflow or drainage issues.
BLD Services was recently awarded another four-year contract from ECUA. In the years to come, they expect to inspect an estimated 800 to 1,200 service laterals per year. The ECUA program is a success story of the value being proactive and comprehensive in addressing I/I in main lines and service laterals. The proof is in the data.
In two sewer basins, the data from average daily flow after rehabilitation was reduced by 58 percent. More impressive, the base infiltration, the infiltration that is already present year-round in the system on dry days prior to a rain event was reduced by 81 percent.
Looking ahead to the future of preserving the integrity of the sewage collection system, ECUA is considering how to extend the inspection/rehabilitation to the residential side of the laterals. As one might expect this will require a nuanced approach in working with residents and is still in the planning stages. Taking this aspect of the system into consideration is just another example of the proactive nature ECUA takes in maintaining the underground infrastructure that exists beneath the sunny skies and sandy landscape of Pensacola.