All rainwater falling on the roof of the greenhouse and commercial buildings is collected in a water basin. This water is used to water the plants. This is fully computer controlled. This way, the plants can get the water they need which is already provided with the optimal amount of fertilizers. So there is little waste. The water that is not absorbed by the plants is collected in a water silo. 85% of this water is reused after disinfection. The fertilizers (nutrients) are also reused. The remaining 15% drain water is discharged into the sewerage system, where the water purification company can treat it. No waste water is being discharged into the surface water.
To produce the plants, we mainly use a lot of organic crop protection agents. Only if there is no other way, we will use some non-natural pesticides. Over the past 5 years, the use of organic resources has increased significantly and the use of non-natural resources has decreased dramatically. We have invested a lot of time in research into ways to deal with diseases and pests in a organic way. Unfortunately, it is currently not yet possible to do everything organically.
Green plants are produced all over the world. Kwekerij Duijn-Hove tries to teach its foreign suppliers which crop protection products they are allowed to use under European/Dutch legislation and which they are not allowed to use. Many plants imported by Duijn-Hove are over 15 years old. It could therefore happen that in the past, agents have been used which are no longer permitted. Efforts are being made to rule out this practice for the longer term.
Concerning energy consumption and emission of gases regarding air pollution
The location in Maasland is 100% connected to residual heat from the neighbour’s nursery. This heat comes from his cogeneration plant. The neighbour uses the heat only partly for his own greenhouse, but he has a surplus of heat. Normally he would destroy this surplus heat but instead he now delivers it to Duijn-Hove. This is a sustainable cooperation.
Several sources of energy are used at the location in Maasdijk. Here we use our own cogeneration plant. Electricity is produced for the required lighting and the residual heat is used to heat the greenhouse. In addition to the cogeneration plant, we also use a heat pump to cool the plant cultivation areas, in combination with underground hot and cold sources. Through these sources and heat pumps it is possible to collect and store the cold in the winter, that can be used for cooling in the summer. In the summer, heat is collected and stored to be used in the winter to heat the greenhouses.
This sustainable way of using energy will greatly reduce the use of fossil fuels. To cope with some extreme peaks, there is the possibility to use the gas boiler. Use of this boiler is kept to a minimum.
In order for the plants to grow well, they need CO2. At both locations there is an OCAP connection (organic CO2 for assimilation by plants) for the supply of CO2. This connection ensures that the CO2 from another industry that normally would end up in the atmosphere, is now supplied via a piping system to Duijn-Hove. Duijn-Hove uses this CO2 to grow the plants. This approach makes a significant contribution to reducing the climate problem.
And of course all waste is separated. Carton, plastic, soil residues, green waste and residual waste are all separated from each other. Here too, Duijn-Hove contributes to the environment.