Problem
The water that dialysis machines use during blood purification must be free of bacteria, pH-adjusted and of low conductivity. The hardness and dissolved minerals in the feed water threatened both these values and the life of the membranes.
Solution
- Removal of suspended solids and chlorine with a sand filter and an activated carbon filter
- Protection against scaling with duplex softening and an antiscalant unit
- Double-pass reverse osmosis: RO1500 and RO1000 units
- pH-controlled dosing and an intermediate transfer tank between the passes
- Lowering conductivity with a demineralisation system
- Redox-controlled dosing, treated water tank and booster set
- UV disinfection and 0.22 micron endotoxin filtration after the treated water tank
Result
The dialysis line is supplied with water that has passed through double-pass reverse osmosis and demineralisation; because each stage is arranged to protect the next, the membranes are safe from scale and chlorine and the product water is kept at low conductivity. After the treated water tank, the UV system inactivates bacteria and germs that may enter from the air; because the dead bacteria inactivated by UV remain in the water, they are removed with a 0.22 micron endotoxin filter.
Technical specifications
Double-pass reverse osmosis line
| System type | Double-pass reverse osmosis |
|---|---|
| 1st pass | RO1500 reverse osmosis unit, 36,000 L/day |
| 2nd pass | RO1000 reverse osmosis unit, 24,000 L/day |
| Pretreatment | Sand filter, activated carbon filter, duplex softening |
| Dosing | Chlorine, antiscalant, pH-controlled and redox-controlled |
| Final stage | Demineralisation |
| Storage | Raw water, intermediate transfer and treated water tanks |
| Pressurisation | Raw water and treated water booster sets |
| RO unit dimensions | 2400 × 900 × 1240 mm (W × D × H) |
| Disinfection | UV system after the treated water tank |
| Endotoxin filter | 0.22 micron, removal of dead bacteria |
