A vehicle-mounted conveyor system including an infeed conveyor assembly mounted for powered rotation relative to the vehicle. Inside channels are formed to supply a combustion gas and discharge the exhaust gas. The washing solution includes a polyelectrolyte. The device has an assembled configuration in which the first member and second member are interlocked with one another with the second trunk portion coaxially contained within the first trunk portion, the second leg portion protruding through the first opening, and the second opening facing the first leg portion.