City of Salisbury Maryland – Waste Water Treatment Facility

Grout Injection Injection in Clarifier Floor to Control / Stop I & I – Salisbury, Maryland

The City of Salisbury, Waste Water Treatment Department, encountered an ongoing problem regarding I & I, Infiltration & Inflow, with their # 2 clarifier. Ground water infiltration from this tank alone amounted to hundreds of thousands of gallons of water. The excess water entering the treatment system (via I & I) costs tens of thousands of dollars, since they were effectively treating a “non-waste” water stream. Likewise, there were environmental concerns. If the concrete tank allows water to enter, then there is no assurance that the reverse does not occur; that is water could be flowing into the ground water supply.

George, Miles & Buhr Engineering Firm (GMB) was called in to manage the repair project. GMB recommended and specified a grout injection process in order to halt the I & I.

Pro Coat first identified which cracks were the targets & allowing water infiltration to occur. A pattern was marked for injection sites, every six feet and alternating sides of the cracks.

5/8 inch holes were drilled thru the entire depth of the concrete and punching thru into the “void” beneath the concrete slab. Ports were installed into each hole. Each port has a ball valve control in order to provide shut off of grout flow. A concrete patch material is applied over the top of the cracks, between all ports. The patch closes off the top side of the concrete crack and insures that the grout injection material will be contained below the concrete surface and that the material will flow lengthwise down the length of the interior crack area.

Pro Coat used Fox Systems (Simpson Strong Tie) Jet Set III Grout Injection System. This material is pumped into each and every port. Pump pressure is carefully monitored & when pressure rises to a given threshold it indicates that the void is filled and the port can be shut off. When the grout material comes in contact with moisture it expands many times its original / liquid form size thereby filling the void and the crack which prohibits future water intrusion.

By proceeding from one port to the next & pumping until the voids are full, the entire crack is fully sealed off from the bottom side of the concrete slab. This ultimately eliminates, or greatly minimizes any significant water intrusion. The final step is removal of all ports & installing a concrete patch in each port hole. Then all excess concrete patching applied between ports is ground to flush with the original surface.

The entire process only took a matter of days for Salisbury WWT, Clarifier # 2 Project. One could see the tank literally dry up before their eyes, leaks disappeared and the tanks were completely dry in a very short amount of time. The City of Salisbury has saved / eliminated tens of thousands of cost since that time by eliminating this additional “non-waste” stream into their treatment system.