The irrigation water that horticulture greenhouse farmers recirculate contains crop protection agents, nutrients and other substances that do not occur naturally in the environment. When concentrations are too high, the water has to be discharged or cleaned.
TNO is now aiming to recover the salts and fertilizers from the water with a technology developed for preventing limescale. Advantages are a less frequent need to discharge water, and nutrient reuse. Because horticulture greenhouse farmers overwater their crops to maximize growth, plants do not absorb all the irrigation water. The excess is recirculated. However, through contact with the crops recirculation water contains crop protection agents, nutrients and other substances that do not occur naturally in the environment. It also contains salts. The more the irrigation water is recirculated, the higher the concentrations of these substances. Substances such as sodium are even harmful to plants. If the concentration is too high, greenhouse farmers have to discharge or clean the water.
TNO has already developed various water cleaning techniques, such as Memstill. But TNO is now going one step further. We are investigating the application of FACT, Filtration Assisted Crystallization Technology, in greenhouse horticulture. This technology, which was developed to prevent limescale, facilitates the recovery of nutrients from water. It works like this: we allow salts or other substances to crystallize in a controlled way on small seed crystals before separating from the water in simple filters. The result is sustainable: clean water fit for re-use, fewer discharges and the reuse of valuable nutrients.