Flow rate 0.04 -— 0.35 m3/hr The E1 Reverse Osmosis System is an economical water treatment solution, which reduces operating and post treatment costs. The E1 Reverse Osmosis system helps you reduce maintenance costs by reducing contaminants from your water that affect taste and can clog equipment. Control your installation costs by using a system configured for your unique needs. Keep your operating costs low with an easy-to-use electronic controller.