Reverse osmosis methods

A method of reverse osmosis comprising:

• selecting a forward flow mode of a reverse osmosis system, via a valved circulation apparatus of the system, wherein a circulation pump outlet of a circulation pump of the system is connected to a first port of a pressure vessel of the system and a circulation pump inlet of the circulation pump is connected to a second port of the pressure vessel;
• pressurizing concentrate, via a high pressure pump of the system, to flow through the pressure vessel in a forward flow direction from the first port to the second port;
• permeating water from the concentrate via reverse osmosis through one or more membranes of one or more membrane modules disposed in the pressure vessel, as the concentrate flows in the forward flow direction;
• flowing the water as a permeate out of a permeate outlet of the pressure vessel;
• blocking permeation of dissolved solids from the concentrate through the membranes, as the concentrate flows in the forward flow direction;
• circulating, via the circulation pump, the concentrate back from the second port to the first port in the forward flow direction;
• selecting a forward discharge mode of the system, via the valved circulation apparatus,
• wherein the circulation pump inlet is connected to a high pressure pump inlet of the high pressure pump and the circulation pump outlet is connected to the first port;
• discharging the concentrate from the system through a first discharge line connected to the second port when the system is in the forward discharge mode;
• pressurizing the concentrate, via the high pressure pump, to a pressure that is greater than a predetermined threshold osmotic pressure of the system;
• and
• preventing production of permeate by closing a permeate discharge valve connected to the permeate outlet.