Sterile Irrigation Water by Enerdes®

Sterile Irrigation water is a high cost in the greenhouse industry and the price of water will increase over the years. Therefore it would be a waste of water to drain the return irrigation water. A sterilizer is the perfect solution to prevent water wastage. 


The Enerdes expertise

Sterilizer for irrigation water

A sterilizer operates on a heat source, with this heat source the drain water is heated to a minimum of 85  °C. By heating the water to this temperature, 99.9% of the viruses and bacteria are killed. To increase the efficiency of the sterilizer, the heated return irrigation water is being used to heat up cold supply water and at the same time, cooling down the sterile irrigation water, this increases the overall system efficiency. The sterile water can then be used for irrigation, saving you a fast amount of water per year. Please contact us if you would like to know more about our water sterilizers.

Enerdes is related to Reinders Corporation, which has been developing and producing climate control systems since 1910. For over a 100 years we have been on the frontline of innovation for the agriculture and horticulture industry.  

Greenhouse irrigation system

Water is one of the most important raw materials in the horticulture industry. However, water is a precious commodity that will be even scarcer in the future. One of the challenges of modern greenhouses is the efficient use of water. Re-use of drain water is a benefit for the environment, but also has financial benefits. By recycling drain water, you save water and fertilizers. Nutrients that have not been absorbed by plants, are still present in the collected water. They are preserved during the sterilization process and presented to the plants again during the next irrigation round.

For modern greenhouses, the greenhouse irrigation system is an intricate system with a complex infrastructure. Especially for greenhouses with a hydroponic system, irrigation water treatment is quite essential. After the irrigation system lay out has been designed and installed in the greenhouse, Enerdes takes care of the sterilization. With the growing desire to recycle water and reuse irrigation water, sterilization or disinfection of the irrigation water has become important for modern greenhouses.

The importance of sterile irrigation water

With recirculation of drain water, the risk of spread of bacteria, fungi and viruses arises. A drain water sterilizer can limit this spread. A sterilizer kills the bacteria, fungi and viruses that are harmful to your plants. At the same time, the sterilizer preserves the oxygen and the fertilizer (the nutrients) in the water.

The working principles of a water sterilizer

There are many ways to disinfect drain water. The most commonly applied from of drain water disinfection is the disinfection by means of heat. Sometimes called water heat treatment, or heat pasteurization. A sterilizer kills germs by means of heat. The water is heated to a certain temperature for a certain amount of time. The advantage of a sterilizer which makes use of heating is that it very efficiently kills all germs. In addition, the temperature and residence time are easily controllable. An example of effective parameters for disinfecting irrigation water is to heat the water up to least 85°C for at least 3 minutes.

Responsible drain water sterilizer

In order to reduce the energy consumption to a minimum, the heat which is released during the cooling of the sterilized water will be used again to heat the contaminated water. Enerdes sterilizers use heat to kill the micro-organisms. The drain water is heated quickly, then kept for some time at that temperature and cooled back in the counter-current. The heat that is released during this process is re-used to heat polluted water.

Enerdes water sterilizer

An Enerdes sterilizer disinfects 99.9% of your drain water, while ensuring that all the oxygen and fertilizers remain in the water. In addition, the sterilizer is very energy efficient and has a long lifespan. Water must be acidified before it is heated otherwise the heat exchanger would quickly be filled with calcium deposits. So, beforehand, the water is acidified to a pH of approximately 4.5. After this, the water is heated up until all pathogens and microbes are killed. Before the water can be used as sterile irrigation water, it must be cooled down sufficiently and it must be neutralized to a pH of approximately 7 again. After this, the water is perfectly safe to use. Additional nutrients and fertilizer can be added for the plants, and the sterile irrigation water is distributed over the greenhouse.

The advantages of a sterilizer based on heat treatment are for example:

  • All pathogens and microbes are killed
  • Algae are killed
  • It is not a chemical treatment
  • Organic substances nitric acid and lye are dosed to achieve the desired pH value for your crops.
  • Robust water treatment process
  • Perfect for disinfection of irrigation water for plants

Compared to other water disinfection processes like UV sterilization or ozone sterilization, water heat treatment is a much more reliable process. The components used in our sterilizers are very robust and reliable. The process kills more than 99.9 % of all pathogens present in the water. With an Enerdes heat sterilizer, you will always have clean, safe and sterile irrigation water available for your plants. Enerdes can build a water sterilizer in any size. When talking about a sterilizer size, the amount of water that can be sterilized per hour is mostly indicated. Some standard water sterilizer sizes (water volume that is disinfected per hour) are:

  • 10 m3/h
  • 25 m3/h
  • 40 m3/h
  • 50 m3/h

UV water sterilizer short for Ultraviolet sterilizer

Some greenhouse companies prefer to use a UV sterilizer. Heat treatment sterilizers are especially suitable for large volumes of irrigation water that need to be disinfected. For smaller volumes, an ultraviolet water sterilizer may be convenient. UV water sterilizer contain lamps that emit UV-C light. Microbes and pathogens are killed by UV-C light if the radiation power is strong enough and the exposure time sufficiently long. When ordering a UV sterilizer, a few factor are important to consider:

  • The UV-C lamp must have sufficient power to kill all microbes in the water flow that is to be disinfected
  • The lamps must be long enough or the water velocity low enough such that the exposure time is sufficiently long for eradication of all contaminants
  • UV-C lamp product life time is a year to maximally 2 years. After this, the irradiation power degrades and they are no longer suitable for water sterilization.
  • UV-C light is hazardous for humans! Handle UV sterilizerd and UV-C lamps with care. UV-C irradiation may cause harm to eyes and skin.

Enerdes UV sterilizers are built with very strict safety precautions. The power and exposure time are sufficient for water disinfection. After UV sterilization the water is perfectly safe to use for plant irrigation. The water is not chemically altered.

Greenhouse Water filtration

Apart from microbes, pathogens and algae, other debris like sand or soil may need to be filtered from the irrigation water.

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