Starting in 2018, greenhouse horticulturalists will be required to treat their discharge water containing plant protection products (PPPs) (for collectives the requirement has to be met by 2021). The greenhouse horticultural sector has also agreed with the government to work towards a (practically) zero emission level of nutrients and PPPs in 2027. Both are needed in order to drastically improve water quality in horticultural areas. Horticultural companies are making an effort to maintain their societal support and licenses to operate, but they come up against a variety of knowledge questions. These relate to (1) the effectiveness of treatment of irregular drain-water streams, and (2) bottlenecks created by the accumulation of sodium and other undesirable substances caused by the long-term recirculation of feed liquids.
The project’s objectives are therefore:
- The development of concepts for the optimal management of water streams, and robust treatment and feedback procedures to strengthen the reliability of PPP treatment technologies in collectives and horticultural companies that have irregular water composition.
- The development of forward osmosis for horticulture to increase the treatment efficiency (by reducing the size of drain-water and other water streams), and to make supplementary sources of irrigation water available by applying a sustainable desalination technique.
- The development of new knowledge about the sodium uptake and sensitivity of greenhouse cultivation, and of innovative cultivation strategies to influence these factors.
- The development of insight into the impact of the use of disinfectants on water quality in recirculation cultivation.
KWR is involved primarily in the first two subjects.
Water stream management and processing
Many horticulturalists do have a clear understanding of their direct (drain) wastewater stream, but their knowledge is incomplete when it comes to the quantity and quality of a number of other streams, such as (CHP) condensate, machine wash water, water mixed with domestic wastewater, etc. The impact of these streams on the treatment technology will be determined with a view to the maximum containment of emissions into surface water.
Forward osmosis for greenhouse horticulture
The research will study whether forward osmosis is a suitable technology to reduce the volumes of drain-water and the water streams to be treated, for both collectives and individual companies. It will also study whether forward osmosis is a cost-effective desalination technology, which can improve the quality of alternative irrigation water sources (e.g., groundwater and surface water), so that the sodium accumulation, and thus crop damage, can be prevented in emission-free cultivation.
Preventing and controlling emissions in greenhouse cultivation
The project will produce different strategies in which the emissions of both PPPs as well as nutrients can be prevented or controlled. They will allow the greenhouse horticultural sector to take a further step towards achieving emission-free cultivation, and to make better use of water sources and plant feed.