From “single-use” Water to Water Reuse

Nikoletta Tsiarta (ESR14)



Take a moment to recall all the small things you do when your daily routine begins.

When we open the water tap to wash our face, brush our teeth, or even drink, flush the toilet, take a shower or put a laundry, water is readily available for our use. We don’t have to fetch it from a well or carry it for miles beforehand, which is still the case in some countries.

We use this drinking quality water for all purposes, even those that would not normally require water of such high-quality standards. We don’t overthink where it comes from, nor about where it goes after disappearing through our drain. Therefore, most of our water is so-called “single-use” water. After using it, the water turns into wastewater and is drained through the sewerage system into the wastewater treatment plant (WWTP). WWTPs are equipped with adequate technology in order to treat wastewater to a quality that is not harmful to the environment. After that, treated water is discharged into a stream, following which it will sooner or later end up in the ocean, and it is, therefore, lost for further human use.

Recently, the stress on the naturally available water resources increased drastically due to climate change and growing demand in different sectors. For example, poor rainfall stresses natural water resources, especially in the Mediterranean region. Consequently, some regions face severe water stress and cannot cover their demand with the naturally available water resources. According to researchers, 17 countries worldwide, including Cyprus and Spain, face “extremely high-water stress”, which means consuming more than 80 percent of their available surface and groundwater resources in a year.

This is where water reuse comes into the picture. The reclamation and reuse of single-use wastewater describe the effort to intensify the state-of-the-art wastewater treatment to a level that can be reused for purposes that do not require quality drinking water. The agricultural sector, for example, has a very high water demand. Still, the required water does not necessarily need drinking water quality, as long as it does not contain compounds harmful to the environment or human health. On the contrary, reclaimed water even includes nutrients that can be beneficial for plant growth. This is why extensive research has determined the agricultural sector’s highest potential for water reuse application (Alcalde-Sanz & Gawlik, 2017; EC, 2016).

The identified main barrier, keeping water reuse application in the EU well below its potential, was the lack of an EU-level harmonized quality requirements for water reuse. This lack was sought to be mitigated by introducing EU-level minimum requirements for agricultural, industrial, and energy water reuse purposes in the new water reuse regulation (EU 2020/741). But the implementation is strongly dependent on public acceptance and the available capacity of treated wastewater in each country.

For example, my home country Cyprus is the European country facing the most severe water stress. Still, according to the Water Reuse Europe Review of 2018, Cyprus already reuses 97% of all water that enters the centralized sewerage system. However, only villages of more than 2000 inhabitants are being connected to the centralized sewerage system.

In this case, it is important to consider the implementation of decentralized water treatment systems. These systems include a small-scale water treatment unit and a direct reuse application on-site, directly where the wastewater is produced. One of the key advantages is that they can be tailored to the specific demands of each community, taking into account the financial capacity for investment, (waste)water quality and quantity, as well as soil and land properties.

Cyprus is a country whose economy is mainly supported by tourism. And providing a decent environment for vacations is of high priority. Water shortcut events will undoubtedly negatively impact the island´s economy. So, if we don’t act fast and smart, water shortcuts might be our new normality. Therefore, hotels can be equipped with those systems to tackle the high-water pressure caused by the tourism sector’s demand during the summer months and use recycled water for garden irrigation.

Single-use water should no longer be an option!


Alcalde-Sanz, L. & Gawlik, B. M. (2017). Minimum quality requirements for water reuse in agricultural irrigation and aquifer recharge – Towards a legal instrument on water reuse at EU level. European Commission, Joint Research Centre (JRC) Science and Policy Reports, EUR 28962 EN, published by Publications Office of the European Union, Luxembourg, ISBN 978-92-79-77175-0, JRC109291.
EC (2016). EU-level instruments on water reuse: Final report to support the Commission´s Impact Assessment. Prepared by Amec Foster Wheeler Environment & Infrastructure UK Ltd, IEEP, ACTeon, IMDEA and NTUA, October 2016; ISBN 978-92-79-62616-6
Water Resources Management in Cyprus. (2016). Audit Office of the Republic, Republic of Cyprus  (link)
Picture source: Freepik