Abstract: Hydro excavation apparatus for excavating earthen material are disclosed. The hydro excavation apparatus includes a first reservoir for holding a base fluid therein, a second reservoir for holding an additive therein, a vacuum system for removing earthen material from an excavation site, and an additive dosing assembly. The additive dosing assembly includes at least one of a pump and a valve fluidly connected to the second reservoir. The additive dosing assembly is selectively controllable to introduce an additive into at least one of the base fluid and the removed earthen material.

Abstract: Systems for reducing or preventing pluggage of spoil material in an excavation vacuum apparatus are disclosed. The pluggage prevention system of the excavation vacuum apparatus may trigger one or more mitigation operations (e.g., addition of water through spray nozzles) to loosen the build-up of spoil material and/or to at least partially shut down the excavation vacuum apparatus to prevent more material being fed to the system.