Water management

From waste to raw material – re-using water

Stefanie Wienhoven
Stefanie Wienhoven
16 October 2019

According to the United Nations (UN), water is the primary medium through which we will experience the effects of climate change1. Water availability is becoming less predictable in many places, and increased incidences of flooding threaten to destroy or contaminate sources of water, and water sanitation facilities. In some regions, droughts are exacerbating water scarcity and thereby impacting people’s health and productivity negatively. Thus, ensuring that everyone has access to sustainable water and sanitation services is a critical climate change mitigation strategy for the years ahead.

Taking it to the next level

To truly make a difference, we need to look at the issue at a societal level. Seventy percent of the global fresh water is used in agriculture. A sustainable food production sector is the only way we can provide adequate food and water for the world’s population of an expected nine billion people by 2050. One answer is circular agriculture that enables us to produce enough food for a growing world population, within the boundaries set by our planet2. It is the system in which the least resources are lost. This vision is as necessary as it is ambitious. In the future, we must consider how agriculture can reduce, or recycle waste, save water and reduce carbon emissions.

Waste, no more …

Within agriculture, the greenhouse hydroponic cultivation sector already uses water more efficiently than soil-based production systems. Within both circular agriculture and hydroponic cultivation, you have the opportunity to collect rainwater for irrigation. In the open field, however, you cannot re-apply and re-collect as easily as is possible with indoor growing systems.

For the horticulture world to make a difference there are many things to consider – from the production of sustainable growing media to wastewater management technology, and from high-tech sensors in greenhouses to collecting evaporated water from plants.

Let’s take waste water management. Dedicated wastewater management in greenhouses, is crucial if we want to grow crops sustainably. By using filtered excess drain water and reapplying it to the crop you can significantly improve water use efficiency. If you carefully manage water and nutrients in combination with recycling this will help to save costs, optimise the growth of the crops, and protect the environment.

Hydroponic greenhouse cultivation is on the rise all around the world, in rich as well as poor countries. Soilless growing can be done anywhere, even in urban areas that would otherwise be completely unsuitable for traditional soil-based production. Alongside the rise of horticulture, the demand for non-soil growing media alternatives (e.g. stone wool) is increasing. Growing media suppliers are important to the modern horticultural industry and are important contributors to its sustainability3. Also, the sector is known for its innovative character, constantly investigating new ways to optimise the controlled growing of crops. That’s good news for water management practices and an opportunity to be increasingly ambitious about water efficiency.

Consumers expect a more sustainable food production, and growing media play a distinctive role in this. Thus, we need to start thinking of used water as a raw material rather than a waste product. If we combine this with a few changes to our daily water consumption habits, we can all help e.g. communities and cities become more sustainable and ensure clean drinking water for future generations.

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