After a considerable delay due to storm damage in January, the horticultural water purification plant De Vlot in Monster has entered the start-up and research phase.
The equipment is now connected and the necessary permits are in place. The biological filters and the active carbon filters are being fine-tuned, and the process for governmental approval has also been started.
With this water purification plant, the 'dirty' CAD water from 65 horticulture companies in Monster and 's-Gravenzande will be filtered in several steps and across three watercourses, something that is required by Dutch law.
It concerns open field growers, potted plant growers, ornamental plant growers and hydroponic greenhouse growers. The growers are expected to deliver 300,000 to 500,000m3 of water annually. Pesticide and nutrients residues will be removed from this water. The costs of purifying amounts to 1100 euro per hectare.
The system has been developed by Aqua-Terra Nova, which previously also developed Aqua ReUse.
Fine-tuning the purification process
Aqua-Terra Nova will fine-tune Tuinbouw WaterZuivering De Vlot, carry out measurements on purification and take care of the BZG approval process. The inlet facility of 100 m3 per hour captures the large and heavy particles. Sedimentation takes place in the buffer silos. By adding the coagulant of iron chloride, floating particles clump together, which then settle in the silos.
The biological process in the slow sand filters needs to start. This is done by dosing nutrients for bacteria in the silos. The various water flows are measured in real-time and the pre-filtration process is optimized. The control parameters can be optimized on the basis of the measurement results of sensors in the measuring line along with (laboratory) tests.
Active carbon filtration
The biological filters removes fertilizer from the water by extracting the nitrogen and phosphate. Organic material is also removed as it's not desirable to have it pass through the active carbon filters. The nine active carbon filters then remove the crop protection agents from the water. "The active carbon filtration is not yet operational, because we first have to start the biological filtration. This is expected to take a few months at most, after which we can start working with active carbon," says Aad Wubben of Aqua-Terra Nova.
BZG approval procedure
When the slow sand filtration is stable, the procedure for BZG approval is set in motion from December. Wubben: "Because there is no specific measurement protocol for shared waste water treatment plants, we made separate agreements for this." The application process has been mapped out in consultation with the Beoordelingscommissie Zuiveringsinstallaties Glastuinbouw. The treatment plant will be tested by adding crop protection agents to the water to see how it's processed by the filters. If test results are good, the BZG can issue approval.
Once the treatment plant has been set up properly, management will be transferred to the two operators representing the 65 horticulture companies. The operators are provided with the necessary information about the facilities and the periodic inspections.
Once everything is up and running, it's the intention that the purified water will be reused by the horticultural companies in the area.
You can view the video item on the WOS site here.
Source: Glastuinbouw Waterproof