Mansura hears info on ‘Sewer Sentry’ system

May seek grant to reduce water infiltration into sewer lines

Several municipalities around the parish have complained about the problem they have with rainwater entering the sanitary sewer line, forcing pumps to work harder and costing the towns money in chemicals to treat the excess water. At its meeting on July 10, the Mansura Town Council listened to a proposal from a company that believes it has an effective and economical answer to that problem.

While council members said they were impressed by Lynn Lofton’s presentation on the Sewer Sentry System, Mayor Kenneth Pickett said the town’s budget will not allow it to make that kind of investment at this time. However, Pickett said Mansura would consider that option should it obtain a grant to address its water infiltration problem.

Lofton, of Effie, is a sales representative for the Monroe-based company. The Sewer Sentry “is simply a raised hole,” Lofton said. The system “fixes” the manhole covers, which are a source of significant infiltration, by sealing the cover with a gasket, drilling a hole through the cover and installing a plastic plug with a hole to vent gas. The plug is 5/8 of an inch high.

‘SUPER TOUGH' POLYMER

The plug is constructed of a “super tough” nylon polymer resin that is resistant to impact, chemicals, UV light, heat and cold temperatures. It is approved for this type of use by DOTD, Lofton said.

Lofton said Sewer Sentry not only addresses direct issues of infiltration and odor problems, but a town’s “secondary problems” of unhappy customers and the possibility of environmental damage that could result in costly fines from state or federal agencies.

Reducing the amount of water going through the sewer system will reduce costs by reducing the amount of electricity used to run the pumps and the amount of chemicals used to treat the water.

Lofton said a one-inch rain produces about 27,154 gallons of water per acre. A national study found that a 24-inch manhole cover that is flush to the ground allows 12 gallons per minute to enter the system. That study found that a raised manhole allows four gallons per minute into the sewer system.

Lofton said Sewer Sentry conducted a test and found that less than 1 gallon per minute entered manholes equipped with the Sewer Sentry system.

OTHER SOLUTIONS

Municipalities have considered solutions such as sealing the manhole covers or installing a pan to catch the rain entering the manhole, he said.

Sealing the manholes “stops up the system so it can’t breathe, which causes potential deadly and costly gas problems,” Lofton continued. The pans can be effective, but “they can fall into the system and have to be removed.”

Lofton said Sewer Sentry will keep 90 percent of inflow from entering the sewer system while allowing the sewer lines to breathe and reducing electricity usage by 25-45 percent and the cost on treatment chemicals.

Lofton said the cost of a Sewer Sentry kit is $175 per manhole. If a Sewer Sentry technician installs it, the cost would be an additional $150 for a total cost of $325 per manhole.

Mansura has less than 200 manholes in its system, which would make the cost to purchase and install the system about $65,000.

Lofton said the company recommends a municipality have a thorough inspection prior to installing the Sewer Sentry. The company also offers an inspection service, with all necessary documentation, at a cost of $180 per hour. Approximately 30-50 manholes can be inspected per day. The number depends on the terrain and location of the manholes, he said.

Lofton said some municipalities have opted to install the kits with their own employees. He said Sewer Sentry can train town employees how to install the kit.

He said Sewer Sentry takes pride in its product. However, the company only looks good if the product is successful, and it cannot be as successful as it should be if it is not properly installed and the sewer system has not been inspected to detect any other problems that might affect outcomes.

As the company has spread outside of Louisiana and the South, it has had to make adjustments.

The polymer resin plugs in an Ohio town had to be replaced with metal ones “because the plastic ones don’t hold up too well to snow plows,” Lofton said. “I don’t think snow plows would be a problem in Mansura.”

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