Leading New Zealand Greenhouse Operator Chooses Hanovia UV To Disinfect Cultivation Water

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.

Hanovia UV system for greenhouses

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.

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‘Vegetable Garden Of Europe’ Irrigated With UV-Treated Effluent

In one of the first schemes of its kind in Europe, Hanovia ultraviolet (UV) technology is being used to treat municipal effluent for irrigating crops in the arid Murcia region of Spain.

UV system for effluent re-use

Murcia has a unique microclimate which allows fruit and vegetables to be grown all year round, giving the area its popular name ‘the vegetable garden of Europe’. Because of its unusual geography, however, the region has very low rainfall, meaning that irrigation water is extremely scarce. For this reason effluent is now being used for watering crops.

“The effluent supply is gravity-fed, so the disinfection system is very susceptible to pressure loss,” explained Hanovia’s Spanish distributor. “Hanovia’s medium pressure UV technology was therefore a deciding factor in the choice of treatment system, as the low number of UV lamps in each chamber offers less resistance to fluid flow, resulting in lower overall head loss. Medium pressure technology also results in energy and component savings for the system operators and is more reliable at permanently destroying microorganisms,” he added.

The installation consists of three Hanovia medium pressure UV treatment chambers installed in series. They treat a combined effluent volume of 500m3/hour and are normally running 16 hours per day, although they can operate 24 hours a day if required.

Commenting on the project, Craig Howarth, Hanovia’s Managing Director, said, “The Murcia project once again demonstrates Hanovia’s ability to provide custom-designed solutions for specific disinfection problems.”

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