Hydro excavation vacuum apparatus that process spoil material onboard the apparatus by separating water from the cut earthen material are disclosed.

A hydrovac and method for measuring the current weight of the hydrovac in real-time is provide. The current weight of the hydrovac can be determined by determine a weight of water in the at least one water tank using a pressure sensor, determining a weight of debris in a debris tank using at least one load cell, and using the determined weight of the water in the at least one water tank, the determined weight of the debris in the debris tank, and a predetermined empty weight of the hydrovac to determine a current weight of the hydrovac.

Mixing systems that include a mixer housing and a plurality of roller assemblies for mixing and processing materials is disclosed. Each roller assembly includes a roller that extends between sidewalls in the mixer housing and rotates to mix an additive into the material and to carry agglomerated solids toward a discharge of the mixing system. Each of the rollers may have a protrusion geometry formed in the outer contact surface, where each protrusion geometry is complementary to an adjacent roller.