A compactor system for compressing a mass including liquid and solids includes: a pressure vessel defining a pressure chamber to hold the mass; a compaction mechanism to compress the mass in the pressure chamber to remove the liquid from the solids; a drain port communicating with the pressure chamber and through which the removed liquid drains out of the pressure chamber; drain piping fluidly connected to the drain port to direct the removed liquid to a collection site; and an influent system configured to inject an influent fluid into the pressure chamber through the drain port.