Disinfection in every WWTP independently of the treated water destiny

By project AQUARES

Published on 06 May 2020

Spain

About this good practice

Segura river has a very low flow rate. It means that any Waste Water Treatment Plant (from now on WWTP) discharge in bad conditions can produce a huge problem for the environment and many uses in the river. On the river, the water is taken for many uses, mainly for agricultural irrigation. This practice doesn´t require any control by the authorities. If we discharge treated water without disinfection, the low dilution will make that the amount of pathogens in the river is very high, jeopardizing the safety of the agricultural products irrigated with river water. Therefore, in Murcia Region, all the plants have disinfection treatment to be sure there won´t be any risk for this practice.
Moreover, according with the principle “who pollutes, pays “this cost is paid by the citizens by the sanitation levy, because they have polluted this water.
Really the main interested in this practice are the environment and the citizens, because river water can be used safely for any application or it Is not harmful for the environment.

Expert opinion

The good practice is an example of high level of disinfection of water treated at WWTP in order to avoid pollution of local rivers receiving the treated water. The good practice could be of interest to municipalities in regions suffering from water scarcity. They could further explore the additional level of desinfection and associated costs.

Ruslan Zhechkov

Resources needed

The average operational cost of the usual tertiary treatment in our region is 0,07 €/m3. Really around 55 % treated water (54 Hm3/year) is reused directly for agricultural irrigation and it is mandatory due to Spanish Laws 41 % treated water (40 Hm3/year) is used after the discharge to the river.

Evidence of success

It is not easy to know how many problems of food safety or bathing have been avoided by this practice. But the evidence is that thousands of agricultural products have been irrigated with water from Segura River, and the number of outbreaks happened in consumers is negligible, according to the information of RASFF (Food and Feed Safety Alerts) of the European Commission. Therefore, it is a good practice, especially where the treated water discharges are a high ercentage of river flow rate.

Potential for learning or transfer

Water scarcity is a situation more and more common in the most of the European countries. To preserve any source of water is crucial and it means go further in the intensity of the treatments, including disinfection ones, not mandatory for discharges, so far.
Many European, North-African or South-American countries, visit the Murcia Region to know the treatments and the management model we have in the region related to water reuse.