DUNCAN, OK (KSWO)-Heavy rainfall from 2015 and 2016 caused problems at Duncan's waste water treatment plant. The City recently hired a engineering company named Tetra Tech to study the inflow and the infiltration in the system. The company will survey manholes and test thousands of feet of sewer line.
Tetra Tech Field Service Administrator and Technician Manager Bryan Ballard said the purpose of this project is to allow engineers to evaluate each manhole and measure the defects in the system.
"During the evaluation they will log the condition of all the components of the manhole cover, all the way down through the wall and the bottom of the manhole, evaluate it for structure integrity as well as inflow and infiltration that might get into the system," said Ballard.
Tetra Tech is a company that specializes in sewer studies and they have a nearly $400,000 contract with the City of Duncan. Over the next 4 years engineers will work in different phases to survey manholes and 200,000 feet of sewer line.
Ballard said heavy rainfall from over the years can seep through the walls of the manhole causing problems.
"In some cases during a rain event if enough water gets into the system, the system surcharges up it can cause a backup into a home in a low basement area. It doesn't allow the sewage to get out and down the treatment plant in the quickest way as it should," said Ballard.
Public Works Director for the City of Duncan Alex Henry said the waste water treatment plant is designed to handle 6.25 million gallons of waste water per day and they are seeing 13 million gallons come through. Henry adds this project will help save the city money in the long run.
"We have to treat any water that goes through the waste water plant if it is sewage even though it may be storm water so obviously the chemical cost go up, the electrical cost go up, it's more wear and tear on the pumps," said Henry.
The project is split up in different phases. In this first phase engineers will evaluate over 800 manholes. In the next few years they will evaluate over 3,000 manholes within the city.
City officials said if the company has to perform any work close to neighborhoods, engineers will notify homeowners about what they will be doing first.