Greenhouses and Hydroponics

Incoming Water Processing

Incoming water treatment can be an important step for assured quality, especially for well or surface-water sources. It is safe for roots and plants and adds oxygen to the water.

Ozone is classified as organic and can be used “on demand” to produce premium quality water that is fully disinfected and is rich in oxygen, which optimizes plant growth without phytotoxicity. Ozone can treat and filter with ozone removed or in some facilities a residual amount can be left in the water to protect against bacteria, biofilm and other contaminants.

In fact, studies show that ozone can control a number of common pathogens with little potential for phytotoxic effects at lower levels. (Zheng et al., 2007).

Ohashi-Kaneko et al. (2009) investigated the effect of using a nutrient solution mixed with ozonated water at a concentration of 1.5 mg L-1 (ppm) on hydroponically grown tomatoes.

Their study tested the phytotoxicity of the residual ozone and determined no detrimental effects to the plant growth or the water quality while noting increased dissolved oxygen levels during the first 30 minutes after application to the roots.

A similar study done by Graham et al. (2011) was conducted in which cucumber and tomato plants grown in rockwool were subjected to single high doses of ozone (0-20 mg L-1 O3) and then repeated low doses (0-6 mg L-1 O3) to assess the phytotoxicity on the plant growth. The results showed that there was no negative effect on the shoot dry weight or leaf area.

Ozone is compliant with Health Canada, the CFIA and the US FDA for both food and surface sanitization when applied correctly. Aclarus Ozone offers NSF-61 compliant systems for assured food grade quality.

Clean-In-Place (CIP) Sanitation

Ozone is gentler than many common chemicals currently used for sanitation when using a properly designed system. Aqueous ozone can be safely used for cleaning surfaces – such as equipment, walls, floors and tables – reducing costs for soap, acid and cleaners. Ozone is made on-site instantly and for CIP the ozone dose is set to meet government regulations either manually or with in-line monitoring.

Surfaces are cleaned using industry standard practices and ozone is applied as a final rinse to sanitize the surface, destroying bacteria, viruses, fungi, and spores. Only cold water is required, and no subsequent rinse is needed, as ozone leaves no residue. This saves water and power costs.

Replacing or supplementing chemicals with ozone for CIP, is more efficient and effective and also improves wastewater quality. Chemical residuals can have negative impacts on wastewater which can lead to regulatory overage charges and impacts with septic systems; ozone improves wastewater quality and then breaks back to oxygen and water.

Ozone tests at a fruit and vegetable pilot plant at California Polytechnic State University showed ozone’s ability in reducing microbiological loading with a 2.0 ppm level that was sprayed on the surfaces to be sanitized. No other cleaning was used to ensure all reductions in bacteria were attributed to the aqueous ozone.

Fujiwara at al. (2011) found that intensive spraying of plants of ozonated water at levels as high as 8.0 ppm of ozone for airborne disease control does not cause any visible injury to the fruit-vegetable seedlings.