Sustainability

Sustainability

Sustainability is important to us and our customers. Therefore, we aim for optimal efficiency in the greenhouse when using raw materials, do our utmost to recycle, and have a minimal waste policy.

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Energy

It is vital that we become less dependent on fossil fuels. Using more renewable energy also reduces CO2 emissions. Purple Pride has made great progress in this objective. At our growing locations we use the following energy sources: 

With cogeneration heat, electricity and CO2 is produced at the same time using a heat engine that runs on natural gas. CHP delivers a yield of up to 90%, instead of a maximum of 50% provided by a regular coal-powered plant. The CO2 is purified in the greenhouses. Residual energy is returned to the grid. It allows us to supply almost 15,000 households with power.

The current economy predominantly runs on fossil fuels. CO2 stored in deep layers of the earth for millions of years is released, along with all the damaging effects associated with it. Bio based materials consist of crops and trees that have absorbed CO2 from the air. Unlike fossil fuels this short-lived CO2 cycle does not contribute to the greenhouse effect.

At our Oosterland location we have reduced our fossil fuel use by 70% since the end of 2018 by heating the greenhouses using a wood-burning system. The system uses branches, leaves and unprocessed waste wood from local professional gardeners and forestries. This means no large forests in green areas are involved, and it also saves on transport. The wood burning is organised by the cooperation partnership DES B.V., composed of VOF Prominent Grevelingen, DT van Noord tomaten and Van Duijn aubergines

Geothermal heat is energy in the form of heat stored in the earth. In the six outermost kilometres of the earth’s crust, 50,000 times as much energy is stored in the form of heat than the total supplies of oil and gas. Since the beginning of 2019 the greenhouses are heated using geothermal heat from this source. As a result we need 80% less gas and have increased our sustainability by at least 50%!

In Terneuzen, the chemical industry and greenhouse horticulture coexist a stone’s throw from one another. Tomatoes and bell peppers, as well as aubergines, are grown in the area. Heat pipelines have been installed in two polders, which allow the horticulture industry to use high quality residual heat and pure residual CO2 from the fertiliser producer Yara. CO2 is an important growth substance for plants, which they extract from the air. This allows growers to save 90% on their energy costs. In the greenhouse horticulture area of Zeeuws-Vlaanderen, the amount of heat recycled is equal to the annual consumption of 35,000 households. In terms of scale, this project is unique in the Netherlands!

The development of heat pumps is on the rise in horticulture. In Steenbergen there are two aquifers that store energy in underground water sources. As a result the chimneys at this location do not emit any hot flue gas. During winter the water is pumped up from a depth of 80 metres and upgraded using a heat pump.

Water

A lot of water is needed for food production. Water is becoming increasingly scarce worldwide and the amount of land available for farming is decreasing, while more food is required than ever to feed the growing world population. Our goal? To use water for growing healthy and nutritious aubergines as efficiently and sparingly as possible. 

All growers use rainwater collected in reservoirs to irrigate the plants. They use 30% more water than is needed in order to ensure the soil retains enough moisture. The excess water is purified by a UV decontaminator and subsequently reused. It’s a closed system, which means the water remains bacteria-free. 65% of the irrigation water consists of rainwater and 30% is recycled. We supplement it with a maximum of 5% tap water during periods of drought. Except in Dinteloord. 

Dinteloord has a water reservoir of 3,000 cubic metres (3 million litres) per hectare for storing a total of 17.5 million litres of rainwater. This is sufficient during a season with normal temperatures, but not if it is a particularly hot year. In the horticultural area around Dinteloord, this shortfall is resolved by using water from Suiker Unie’s sugar beet plant. The water content of beets is approximately 70%. This water is released during the sugar production process. In the past the water was simply discharged, but now it is purified and stored underground. A pipeline is used to transport it to the growing location.

Zevenbergen has an ASR (Aquifer Storage and Recovery) for fresh water scarcity. Underground storage helps prevent salinisation and can bridge the gaps in time and storage space between water supply and water demand. Storage capacity can also be created in reservoirs to deal with periods of peak demand. This source acts as an alternative for the traditional water reservoir: it’s filled with the rainwater run-off from the roofs of greenhouses, which can then be used later on for watering plants. Therefore you can continuously fill and draw water.

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An optimal climate for growth ensures strong crops, which are not susceptible to disease and infestation. Naturally we use preventive natural enemies against harmful insects. There are occasions where this is not sufficient and we protect the crop with a crop protection agent. Our aim is to exclusively use organic crop protection.

We cultivate good bacteria in two bioreactors to add to the water used to irrigate the plants. This prevents excessive root growth and increases the amount of oxygen in the water.

The aubergine is a self-pollinator (just like the bell pepper). However, at the beginning of the season (July/August) help is needed with the pollination. For this purpose we use bumblebees. This natural pollination method ensures the optimal setting of the fruit, which results in a higher quality end product.

Aubergine cultivation is quite vulnerable to infestation by, for example, whiteflies, lice, red spider mites and caterpillars. We use natural enemies such as predatory mites and parasitic wasps to prevent or combat these infestations and create a biological balance in the greenhouse. This means the plants are stronger and produce more aubergines.

As a preventive measure we feed organic nutrients to the plant roots to make the plants strong and resilient. After all, healthy plants produce the tastiest aubergines!

100% use

Wasting food is something we are all concerned about. At Purple Pride we try and keep any waste to an absolute minimum. Plant waste is delivered to special companies where it is composted. The rockwool in which the plants grow is recycled to produce stones for paving and new rockwool. Materials such as plastic, film, glass and paper are sorted and recycled. There is no waste from the aubergines; if they aren’t good they are composted.

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