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, Wastewater Treatment Department, encountered ongoing problems regarding I & I, Infiltration & Inflow, with their # 2 clarifier. Groundwater infiltration from this tank alone amounted to hundreds of thousands of gallons of water per year. 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 groundwater supply.
George, Miles & Buhr Engineering Firm (GMB) was contracted to manage the repair project. GMB specified utilizing a hydrophilic grout injection process in order to halt the I & I.
Pro Coat first identified specific cracks that were targeted by GMB & allowing water infiltration to occur. A pattern was marked showing injection sites, every six feet, and alternating sides of the cracks.
5/8 inch holes were drilled through the entire depth of the concrete and punched through into the “void” beneath the concrete slab. Ports were installed into each hole. Each port has a ball valve in order to control the flow and shut off the material 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 ensures that the grout injection material will be contained below the concrete surface, directing the flow lengthwise down the interior crack area and filling the void below.
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, 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/“blind side” of the concrete slab. This ultimately eliminates or greatly minimizes any significant water intrusion.
The final step is the removal of all ports & installing a concrete patch in each porthole. 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 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 tens of thousands of dollars per year since that time by eliminating this additional “non-waste” stream into their treatment system.