A pressure keeping mechanism is provided downstream of a discharge port of a compressor. Embodiments of the floor treating system include a floor treating device with a power source having a rotatable drive shaft with an axis of rotation, a flywheel with an aperture for receiving the drive shaft, a counterbalance connected to the flywheel, and a floor treating attachment located at a distance of at least 0. The hydrothermal reaction is carried out while maintaining the initial dilution for a preselected reaction time at a preselected reaction temperature.