To design and supply a means of making water sourced from a reservoir safe for irrigating leafy salads.

System Application:

To facilitate this requirement, the source water had to be tested to determine size of particles in suspension, which is the main criteria for effectively sizing a filter.  The source water was also tested for turbidity, which is the prerequisite for determining the number and intensity of bulbs (lamps) required in the UV disinfection unit.   

The application at hand required 3 x Amiad SAF3000 automatic filters units, which were placed in parallel on a manifold.  Each filter was fitted with a 25 micron screen element, so that particles exceeding this size were trapped and removed from the system at filtration stage. For comparison, 25 micron is equivalent to a quarter of the thickness of a human hair.  The elimination of particles in excess of 25 micron prevents any shadowing of pathogens from the UV light that they would have created as they passed through the UV disinfection system.

Tests over the years has confirmed that most of the microbiological contamination is colonised on the physical debris, and so in removing debris, you also remove a large portion of the biology itself.  Nevertheless, it is vital to treat the filtered water with UV disinfection to complete the process.


The system has now been in continual use for 10 seasons, with its effectiveness continually tested and monitored during that time.  This has proved to be a long term reliable solution.