A system for cleaning gas turbine engines is described. More specifically, methods and apparatuses for cleaning stationary gas turbines and on-wing turbofan engines found on aircraft are disclosed that includes a trailer-mounted, automated low-pressure water delivery system, additive and detergent injection system, nozzle and manifold technology, and active waste water effluent collector system. The system will deliver the liquid cleaning medium at a specific pressure, temperature, and flow rate to optimize the atomization that occurs at the nozzles.