The reuse of graywaters means that humanity has finally become aware that the amount of water available on earth does not change, that we drink the same water that the dinosaurs drank and that water is not, after all, a good acquired at birth. But what are graywaters after all? And how can graywaters help to ensure the balance of water ecosystems?

We live on a planet covered in water. However, more than 97% of this water is salty and about 2% is retained in the form of ice and snow. Ultimately, humanity has less than 1% to irrigate crops, to supply industry and for domestic consumption. If the percentage of available water is already small, things tend to get worse if we consider that the world’s population continues to grow.

As Man abandons the myth of the infinite generosity of the earth, measures emerge to obtain a more efficient use of water. Water conservation is one of our civilization’s greatest challenges. Reducing consumption and reducing losses are among the most used measures. However, the reuse of graywaters is also assuming its importance to ensure that, in the future, the water will continue to flow in the taps of our children and grandchildren.

Graywaters has a low content of organic matter, nitrates and phosphates, as well as a reduced bacteriological component. This is why water from sinks and dishwashers is normally excluded from the classification of graywater. With higher levels of organic matter, as well as fats, oils and detergents, their reuse requires a more complex and costly treatment.

Graywater and its characteristics

Graywater has a low content of organic matter, nitrates and phosphates, as well as a reduced bacteriological component. This is why water from sinks and dishwashers is normally excluded from the classification of graywater. With higher levels of organic matter, as well as fats, oils and detergents, their reuse requires a more complex and costly treatment.

How graywaters can make a difference in human water efficiency?

In the domestic system, the reuse of graywater makes it possible to reduce the need for drinking water by about 50%. Surprised? If we think that these graywaters can replace drinking water from toilets, pre-washing clothes and dishes, watering and washing patios and vehicles, everything starts to make sense. What if we told you that, by its nature, graywater treatment and reuse can be installed in residential and service office areas?

If we consider that a washing machine weighing 7 kg uses, on average, 57 liters of water per wash. And that a 5-minute quick shower sends about 25 liters of gray water down the drain, so you just have to do the math.