What should we consider to monitoring water quality?
For the World Water Monitoring Day we tell you the most important things you need to know in order to reuse water with excellent properties.
Firstly, we should be aware that an agreement was reached this year to update the Urban Wastewater Treatment Directive with the aim of improving collection, treatment and discharge of urban waste water. The new legislation will require stricter controls on various public health parameters, such as emerging pathogens, permanent chemical pollutants, microplastics and antimicrobial resistance. In other words, water treatment plants will have to improve their technologies to make water safer and of higher quality before it is discharged into the environment.
The agreement also provides for national authorities to promote the reuse of treated wastewater in wastewater treatment plants, especially in areas with high water stress. This market for water reuse is becoming more and more important and larger, but in order to obtain high-quality water we must take into account the current laws in this respect.
Water reuse regulations
At the European level, it is Regulation (EU) 2020/741 that establishes the minimum water quality and monitoring requirements for the reuse of treated water for agricultural irrigation. According to this law, the quality of reuse water can be classified as follows:
- Class A: This is the label with the most restrictions, as it implies that the water obtained is the purest. It can be reused in food crops that are consumed raw and in those where the edible part is in contact with reclaimed water.
- Class B: Water can be reused on food crops that are consumed raw when the edible part is produced above ground level and is not in direct contact with reclaimed water, as well as on processed food crops and non-food crops (including crops used to feed dairy and meat producing animals). Under this label, all irrigation methods are covered.
- Class C: Has the same application as the previous label, except that the irrigation system would now be drip irrigation.
- Class D: Corresponds to the least restrictive label, as water reuse is allowed for crops for industry, energy and seed production.
Currently, in Spain, Royal Decree 1620/2007 regulates the reuse of water for agricultural irrigation, urban uses, industrial uses, recreational and environmental uses. Therefore, if we compare both regulatory frameworks, we will see that, although the Spanish law includes more uses, the European regulation is more restrictive, since, for example, it sets lower concentration values for microorganisms than the national standard.
However, Real Decreto-ley 4/2023, of 11th May, has amended the water law by introducing, among other aspects, the new legal framework for water reuse, which allows the Spanish legal regime for water reuse to be adapted to the European regulation, thus promoting the use of reclaimed water. Specifically, the law refers to “the recovery of the cost of investments related to urban discharges, their collection and treatment, in addition to the integration of European regulations on the reuse of reclaimed wastewater, as well as its promotion”.
How do we at CETIM apply the regulations to obtain high-quality reusable water?
In CETIM we face the challenges and opportunities that arise in the sector, developing successful cases such as LIFE PHOENIX or LIFE GREEN SEWER. Both projects aim to obtain high-quality treated water according to the European legal framework.
In the case of LIFE PHOENIX, we are developing different technological solutions applicable to tertiary water treatment to reduce the current cost of the process and increase the degree of disinfection required in Regulation (EU) 2020/741, as well as to recover nutrients and create a decision support system and a sustainability tool. Similarly, this research will minimise negative environmental and health effects by reducing ecotoxicity, emerging pollutants, antibiotic resistant bacteria, microplastics and carbon footprint.
The main objective of LIFE PHOENIX is to obtain class A water according to European regulatory standards and, to achieve this, we are implementing a disinfection process at the WWTP del Toyo (Almeria), where we are validating the technologies developed. Currently, we have already achieved to reduce between 60% and 80% of nitrogen and phosphorus present in the secondary effluent.
Pilot plant indoors developed at LIFE PHOENIX.
In LIFE GREEN SEWER, a project that we have led from CETIM and that has recently finished, we have managed to obtain class B reuse water, recover energy and nutrients through the creation of a pilot plant with membrane technologies that we have validated in the WWTP of Ferrol (Galicia) and in Almendralejo (Extremadura). By carrying out the research in both areas, we have been able to test the effectiveness of the technologies in different climatic conditions.
These two projects are just an example of how adjusting to the demands of water quality control is a challenge, but that CETIM can help you overcome thanks to R&D&I.