Reverse Osmosis (RO) Pre-Treatment
Every system has its own specific design requirements depending on local water conditions. Each system is individually designed to suit those local water conditions. The modular design of the Pre-Treatment guarantees a long life of the RO Plant and maximises patient safety.
Pre-treatment usually consists of the following stages:
20μ Duplex Filter
20 Micron Duplex Filters are fitted to remove TDS (total dissolved solids) from the mains water supply. Each set comprising isolation valves, pressure gauges, housing vent and sample point.
Mains water break tank
The mains water tank is individually sized to suit the individual system requirements. Each tank includes an Aylesbury type float valve and pump protection level controls. All tanks incorporate sloping bottom for drainage purposes and conform to local water regulations.
Duplex mains water booster pumps
Each system has individually sized re-pressure pumps working 'duty-standby'. Each duty pump is controlled via a pressure vessel and pressure switch, working on demand to minimise the use of electricity.
In the event of a duty pump failure the standby pump will automatically come into service.
Each pump will operate for 50% of the dialysis treatment time to avoid water stagnation.
BIRM iron removal plant
Should the incoming mains water have a high level of iron (>2mg/l) then an iron removal plant must be installed to protect the RO membranes. The iron removal media (BIRM) is an insoluble catalyser which converts the bivalent iron oxides into trivalent iron which can then be periodically backwashed to drain.
Each iron removal plant includes pressure gauges, manual by-pass valves and sample point.
All Reverse Osmosis systems in the UK require the removal of calcium and magnesium to protect the life of the RO Membranes.
The softener contains basic exchange resin which converts the calcium and magnesium ions (hardness) into sodium ions. The softeners are regenerated on a capacity basis and operate 'duty-standby' so that there is no interruption of flow to the RO plant.
Usually, the softener includes organic removal resin, which is regenerated simultaneously as the softener resin.
Each softener/scavenger includes pressure gauges, manual by-pass valves and sample point.
Duplex Granular Activated Carbon (GAC) filter
Each GAC filter contains pre-washed activated carbon and is connected in series for the removal of organics, chlorine and chloramines. The GAC filters are sized to give an ECBT (contact time) of 10 minutes. Each GAC filter is programmed to carry out an automatic timed backwash on alternate evenings.
Each GAC filter includes pressure gauges, manual by-pass valves and sample point.