Corrective Action Plan uses HDPE Pipe, Sewer Pumps, Submersible Trash Pumps and Steel Mixer Tanks for Sanitary Sewer Overflow During Wet Weather Events

Baton Rouge received a call from our customer in New Orleans.  The customer was about to start a project in Baton Rouge, Louisiana for the U.S. Corp of Engineers at the South Sewer Treatment Plant. 

The plan was to develop a Sanitary Sewer Overflow Corrective Action Plan consisting of a combination of conveyance, storage, and treatment improvements. The technology must be proven and demonstrate full-scale experience in combined sewer overflow and/or sanitary sewer overflow applications.  The potential technologies must demonstrate rapid startup capabilities and rapid return to steady state treatment conditions due to the rapid increase in flow during wet weather events. There were several obstacles to overcome and they asked for our help. 

The first obstacle:  Get the treated effluent from the west side of the plant back to the east side of the plant by pumping 2,200 gpm without blocking any roadways.  Our solution was to install a DV-150 diesel with 6” suction hose at the effluent sump and run 6” HDPE pipe with Bauer fittings to the road and install an 8” Road Crossing.  We then ran the remaining 1,200 feet of 6” HDPE pipe to the east side of the plant.  Our road crossing saved the customer approximately $2,500.

The second obstacle:  Get the raw sewage from a forty-foot sump to the Ballasted Flocculation Units at a rate of 700 gpm and filter the raw sewage with a 6-millimeter screen.  We set up and installed an 8” electric submersible pump in the bottom of the sump to pump the raw sewage.

The third obstacle:  How to mix the treated effluent and the raw sewage.  Our solution for this problem was to install a mix tank to keep the solids in suspended solution so that it can be fed to the ballasted flocculation units.  A shale shaker unit was installed on the top of the mix tank to filter the raw sewage before it entered the tank.

The fourth obstacle:  How to feed the mixed sewage to the (BFU) at the correct gallons per minute.  Our solution was to install a DV-150 electric pump with a header system equipped with gate valves to regulate the flow to each unit to assure the correct gallons per minute.  Once this was established, we ran the excess flow back to the bottom of the mix tank for additional mixing.

The fifth obstacle:  To maintain a level in the mix tank of 15,000 gallons.  Our solution for this was to incorporate an overflow pipe using the existing man way in the front of the mix tank.  We ran overflow lines (galvanized Bauer pipe along with discharge hose) to the sump to achieve this.

When a similar project for this customer came up in Columbus, Ohio, they did not hesitate to contact our Detroit branch for assistance.