Hanovia UV technology has been selected by NZ Hothouse, a leading New Zealand provider of fresh produce, to disinfect the water used for soil-less plant cultivation in its glasshouses.
Located near Auckland, NZ Hothouse has almost 20 hectares of glasshouses on two sites growing tomatoes, capsicums and cucumbers for distribution both nationally and internationally.
The source of the water is a combination of rain water and borehole water, which is stored in large outside holding ponds. The main microbial challenge organisms in the water include fungi such as Pythium, Phytophthora and Fusarium; bacteria such as Clavibacter and viruses such as tomato bronze (wilt) virus and tomato mosaic virus.
No conventional microbiological checks are carried out, but NZ Hothouse uses what it calls ‘bait tests’ with very young plants to see if they fall victim to any of these water-borne pathogens.
Two Hanovia PMD200 medium pressure systems are installed – one for each site – treating up to 68 m3 water per hour. UV treatment is ideal for this application as it is a completely clean technology that introduces no chemicals or unwanted disinfection by-products into the water and does not alter its pH.
The UV systems feature an automatic wiper which prevents the build-up of deposits on the quartz tube, ensuring optimum UV dose at all times. Photon control panels provide the operators with data on flow rate, UV dose and intensity and can log up to one year’s performance data, which is downloadable to a PC via an RS323 port. The control panel can also be operated remotely, allowing the system to run 24 hours a day. Maintenance of the unit is restricted to the replacement of a lamp every six months, a simple operation that can be carried out by on-site staff.
All Hanovia UV disinfection systems are easy to install, with minimum disruption to the plant. They need very little maintenance, the only requirement being replacement of the UV lamps and servicing of the wiper systems every 12 months, depending on use. For more information please visit the company’s website at www.hanovia.com.