The importance of knowing how mutual aid tankers offload their water cannot be overstated. At small incidents, you generally find that the companies that respond are also companies that work together on a regular basis. However, on the big incidents, we can often have a couple dozen departments forced to work together who rarely ever see each other. Ideally, every mutual aid tanker should offload its water the same...but seldom is that the case. Therefore, it normally takes one or two passes through the dump site to figure out what rigs offload fast and what rigs slow down the process. A tanker that can only pump off its water often proves problematic at a large-scale dump tank operation.
During our 2012 seminar in Sumter County, Alabama we had one 2500-gallon tanker that could only pump off its water and the rig only had one, 3-inch tank-to-pump line. The folks working the dump site quickly recognized the problem after the first pass at the dump site and created a set-up where the tanker could still contribute its 2500 gallons of water while not blocking out tankers trying to dump water. In a non-hydranted area, 2500 gallons is 2500 gallons and folks need to work out how best to use that water in a time efficient matter.
No worries in Sumter County, the folks set up dual, 2-1/2-inch hose lines feeding directly into a dump tank. When the tanker in question arrived at the dump site, the operator simply connected the two hose lines and pumped of the water....while all along the other tankers dumped their water. This seems like a simple concept...but sometimes simple gets overlooked.