Wastewater : conquering blue gold… recycled!

A few months ago, we were zooming in on the “REUSE“, a new European regulation governing the use and treatment of wastewater in order to recycle and “reuse” it.
But the REUSE is more than a regulatory directive: it is a trend that is developing more and more throughout the world.

In order to delve deeper into the subject, here is a longer article about this new practice with vast potential!

Protection of the environment : Towards sustainable management of the water cycle

Water, a vital resource but also in the midst of a crisis, is the pillar of this.

“Water is not necessary for life, it is life”. Antoine de Saint-Exupéry

Antoine de Saint-Exupéry summed up the essence of water in one sentence. This is why, in order to protect nature, it is necessary to preserve the primordial element from which it is made.

As a natural resource essential to life, water is in short supply on our planet. While 70% of the Earth’s water is water, only 2.5% of it is fresh water for consumption, of which only 0.7% is accessible on the surface. But access to this resource is so unequal that it is a source of many conflicts. Faced with this environmental degradation, the societal expectation to avoid wastingwater is increasing. “We have to find a way out of the droughts, stop wasting water. Recycling and reuse of water is now strongly encouraged”. (Source : Futura-Sciences)

The trend towards recycling is winning over water

In a context of global expansion of water recycling, treated wastewater represents millions of m³ of water, which is little used. The increased reuse of water should therefore alleviate the pressure on freshwater supplies. Wastewater reuse, known as REUSE, is thus seen as a way forward for the circular economy and a promising solution to climate change.

What are the benefits of REUSE?

The reuse of treated wastewater is of great environmental and economic interest:

Environmental benefits	Economic benefits
Reduction of pollutant discharges into the natural environment Limiting the overexploitation of natural resources	Creation of a reliable water resource, independent of climatic hazards Creation of a cheaper water resource for uses other than human consumption (agriculture, industry, leisure areas, etc.)

What recyclable wastewater are we talking about?

These are essentially:

Grey water from treatment plants
Industrial wastewater
Urban rainwater

The regulations governing the use of “Re-use” differ from one country to another. Several countries around the world have already taken measures for the environment, and more specifically the protection of our water reserves. Some of them have also drawn up a decree on the use of water from urban wastewater treatment for the irrigation of crops or green spaces.

In Europe, falling groundwater levels – due in particular to agricultural irrigation but also to industrial use and urban development – are one of the main threats to the aquatic environment. (Source : European Parliament)

Global drought: governments mobilise

Some developed countries subject to intense drought have turned to wastewater reuse in recent decades, such as Australia, Singapore, Israel and the countries of the Persian Gulf, or the southern United States (California, Florida, Texas, Arizona). In fact, the State of California, a pioneer in wastewater reuse, introduced the first regulations in this area at the beginning of the 20th century.

Since then, these regulations have evolved with ever more advanced treatments to guarantee very high quality water, which many countries have drawn inspiration from.

Europe adopts REUSE in its Environmental Plan 2025

Europe is lagging behind when it comes to wastewater reuse. Over the last ten years or so, the volume of wastewater reused has grown by 10 to 30% in Europe. The European champions of the REUSE river are Italy and Spain, with 8 and 14% use of their treated wastewater. But this is still very little compared to countries such as Namibia or Singapore, which reach 100%!

In this context and in order to homogenise the reuse of waste water, the European Parliament adopted last May a new regulation on the hygienisation of water in four levels (A, B, C and D). Although this regulation is stricter, Europe foresees a wastewater reuse potential of 6.6 billion m³ by 2025 (compared to 1.1 billion each year currently).

Wastewater reuse: a resource with great potential for all sectors

But how can this recycled wastewater become a complementary water resource for agriculture, industry or even cities and communities?

Agriculture

Agricultural irrigation has always been the largest consumer of recycled water and water consumer (70% of global demand). This makes it a key player in the reuse of wastewater and the maintenance of natural resources. As an example, on a farm, wastewater (or agricultural effluents – with the exception of black water) can be recycled thanks to a micro-purification plant.

Industry

Industry, which is a large water consumer, is also a source of waste water: industrial effluents. In the context of the circular economy, these effluents – commonly loaded with micropollutants – can go from being waste to being a resource.
Thus, water from industries and treatment plants can be used in closed circuits for liquid processes, cleaning, energy production (biomethanisation) or heating.

City & Community

At urban and peri-urban level, once treated, wastewater is used to water green spaces (watering gardens, golf courses, stadiums, etc.). In addition to the irrigation of crops and green spaces, REUSE can also have environmental uses such as fire-fighting or the maintenance of water bodies, rivers and wetlands.

Depending on the country and the progress of a law governing REUSE, professionals will have to adapt their structures – more or less quickly – in order to be able to use their wastewater according to the established standards. Certificates, such as those currently in use, will be used to control, among other things, the level of water quality.

What are the solutions for these new measures?

In addition to appropriate treatment solutions, industrialists, farmers and also local authorities must ensure that the storage and reuse of wastewater complies with regulations. Storage in particular, must take into account several aspects:

Treated water must not be contaminated by external pollution, which would require new treatment before it can be used for irrigation.
Treated water should generally be kept away from the public to control human exposure.
Wastewater has suspended solids that create the risk of deposits in the storage solution or clogging of localized irrigation systems.

The container (storage solution) must also limit the transfer of substances.

REUSE is a controversial issue. In particular, the question of health risks, potential soil pollution, and the cost of treating this “grey water” is hindering its use. However, all the different alternative uses mentioned above are certainly identified as sustainable solutions to the problems of global water shortage that some countries should start to face in the next twenty years… or even in the next decade.

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