Treated effluent as alternative water resource for greenhouses
4 June, 2050
Delft Water Blue
Waste water source
WWTP of Harnaschpolder in Delfland.
Two distribution systems were tested. One is to provide the water with pressurized pipes. The other solution is to transport the effluent from the WWTP over canals to the region with a lot of horticulture, where it is disinfected and provided to the glasshouse itselve.
The reclaimed water is used to irrigate hydroponically grown vegetables, flowers...
Waste water treatment description
Nutrient removal :
Treatment 1: reverse osmosis
Treatment 2: Static bed bioreactor, BiopROtector fluidized bed reactor
Pesticide removal : none
Treatment 1: ultrafiltration and reverse osmosis
Treatment 2: vertical reverse osmosis
Suspended solids removal :
Treatment 1: sand filtration and multimediafiltration
Treatment 2: static bed bioreactor, flexible fiber filter
Treatment ones goal is to transport the water with existing canals to the tertiary treatment plant, treatment twos goal is to provide water to the greenhouses that has already underwent tertiary treatment.
A demonstration hall was constructed next to the Harnaschpolder wastewater treatment plant that treats around 10,000 m³/h. The demonstration hall harbours the different treatment lines. This way, different treatment can be compared simultaneously in the framework of the research project. It has a capacity to treat a maximum of 50 m3 effluent per hour.
Extent of the agricultural beneficiaries
The demonstration took place in a greenhouse with tomato production of 180 m2. Half of the greenhouse was irrigated with rainwater, while the other half was supplied with treated wastewater of the Delft Blue Water project. Both water systems were totally separated.
Type of agreement
Measurements have been made in the areas of (I) food safety, (II) plant health and (III) crop growth and crop production. These extensive measurements indicate that there is no significant difference between the two types of irrigation water sources – rainwater and the treated wastewater. The only exception to this is the sodium content measured during leaf and fruit analyses. The tomatoes grown on DBW irrigation water contain on average 25% less sodium than the tomatoes irrigated with rainwater. The demonstration research has shown that the DBW irrigation water is of high quality and is suitable for growing crops. This makes Delft Blue Water a potential alternative irrigation water source for the Delfland region.