Abstract: Provided is a coiled manhole cover cushion having at least one flat edge on a first side of the manhole cover cushion. Also provided is a system for sealing a manhole. The system includes a manhole having an access hole; a seating receptacle positioned adjacent to the access hole of the manhole. The seating receptacle includes an outer flange, a vertical wall extending downward at a substantially right angle from the outer flange, and a seat positioned at a substantially right angle adjacent to the vertical wall. The system also includes a coiled manhole cover cushion comprising at least one flat edge on a first side of the manhole cover cushion which may be positioned at the edge of the substantially right angle between the vertical wall and the seat of the seating receptacle. A method of installing a coiled manhole cover cushion is also provided herein.

Abstract: A tracing agent for use in a water system having starch; water; water soluble dye; wherein the starch, water and water soluble dye are blended to form a dyed starch paste and wherein the dyed starch paste is extruded from an extruder to create a dyed starched foam.