🔍 Key Concepts

• Reverse osmosis (RO) systems need high pressure on the feed side to push water through the membrane. • The pressure regulator is used to create and control backpressure so the pump can build enough pressure without overloading the membrane modules. • Think about which line (feed, product/fresh water, or brine/concentrate) is normally used to control system pressure in an RO unit.

💭 Think About

• If you want to increase or decrease the pressure across the membrane, which stream would you throttle or regulate without starving the pump or restricting the clean product water? • What happens to the flow and pressure on the membrane if you place the regulator on the suction side of the pump versus on a line leaving the membranes? • Which outlet (fresh water vs. brine) is typically used to control how long water stays in contact with the membrane and at what pressure?

✅ Before You Answer

• Verify which line in an RO system is commonly fitted with a backpressure valve/pressure regulator to maintain operating pressure. • Check which location would best protect the membrane by allowing pressure to be relieved safely while still letting the high‑pressure pump operate correctly. • Eliminate options where a regulator would starve the pump or unnecessarily restrict the low‑pressure product (fresh water) line.