Reverse Osmosis Plant


The Reverse Osmosis (R/O) water plant was built in 1981 with a current production capacity of 3.0 MGD. An expansion project has commenced with an anticipated completion of April 2009.

INJECTION WELL – installed in 1985, this 1800 foot deep injection well receives concentrated brine (reject water) from the reverse osmosis plant and deposits it into a saline aquifer. Reject water is pumped at a rate of 750 gpm (gallons per minute). Mechanical integrity tests are performed every 2 years to confirm the continued safety of its use. A second deep injection well serves as a back-up, and is conjunctively used by the reclamation facility.

PROCESS DESCRIPTION– the R/O process utilizes membranes which allow freshwater molecules to pass through them while holding back dissolved inorganic or organic constituents. Feed water supplied by wells is pumped into the plant where a sequestering agent and sulfuric acid are added. The water flows through a pre-filter to the suction inlet of a pressure pump, which sends it to a hydrablock composed of a bank of tubes containing membranes. The water molecules are forced through the membranes and are conducted to a degasifier where carbon dioxide and dissolved hydrogen sulfide gases are removed. The degasified water cascades into a clearwell where it is mixed with lime softened water and chloramines are added for disinfection. The mixed product is transferred to storage tanks before entering the distribution system mains.

STORAGE FACILITIES – four storage tanks with a combined capacity of 7.5 million gallons, plus a 150’ elevated tank of .1 million gallon capacity are maintained. The elevated storage tank is utilized to control pumping and pressure.

PUMPING SYSTEM – the pumping system consists of four (4) pumps rated at 800 gpm (4.5 MGD) each and three (3) pumps rated at 3,000 gpm (12.9 MGD). Computerized controls sense the pressure in the system to activate and control the pumps to maintain constant pressure.