Source: https://ayuntamiento.alhamademurcia.es/noticia.asp?cat=8818 (Google translation)
As this City Council announced last July , the Department of Infrastructures and Public Services has been carrying out weekly analyzes of the municipality's wastewater since August in order to detect remains of the Covid-19 virus, through PCR tests (Reaction in Polymerase chain), at the entrance to the treatment plants of the entire municipality.
The objective of this measure is the creation of an early warning system where signs of the presence of the virus would be detected in wastewater, in population groups, being able to advance the preventive measures to be taken on the area / s with the highest incidence.
The method is based on the detection of the concentration of genes collected in the wastewater; the coronavirus leaves a genetic trace (RNA) that remains in the body of those infected for 20 days. Later they expel it through feces and other secretion methods, all of this collected through the sewage network and transported to the Wastewater Treatment Plants (WWTP).
One of the difficulties that the current coronavirus health crisis presents is the detection of all infected people, since it would be necessary to carry out a PCR test on the entire population. Faced with this impossibility, the City Council decided to take this measure as a tool to control the virus in the population. With this method, the equivalence between detected genetic load and number of people cannot be established, due to its complexity, but it is possible to see the trend of the presence of Covid-19 in the municipality.
Since August, weekly analyzes have been carried out in the different treatment plants of the municipality to detect the influence of the virus in Alhama. The municipality's WWTPs are distributed in the following nuclei:
- WWTP ALHAMA: Alhama and Industrial Park.
- EDAR COUNTY
- EDAR EL BERRO
- WWTP GEBAS
- EDAR EL CAÑARICO
At the Alhama, El Berro, Gebas and El Cañarico WWTPs, automatic sampling equipment has been installed for 24 samples / day (full day). The periodicity of the sampling is weekly, taking the results of the measurements the following week. In the Condado WWTP, due to its characteristics, a non-automatic daily sample is carried out.
The analyzes of the basic parameters, necessary to refine the results, are carried out in the SOCAMEX laboratory, and the specific tests of genome copies are carried out in a laboratory certified by the Ministry of Health for this work. The results obtained in Alhama are periodically sent to the ministry. Alhama is part of the group of municipalities that participate in this experience to better understand the behavior of Covid-19 and its influence on the population.
The Department of Infrastructures and Public Services has held meetings with those responsible for ESAMUR, which currently carries out controls in several municipalities in the Region, and which collaborates with working groups with different countries that are conducting similar analyzes. To date, the contrast of the data from Alhama with respect to the data handled by the Entity of Sanitation and Wastewater Treatment of the Region of Murcia from other localities, determines that our municipality has lower levels of presence of the virus in sewage.
With the data obtained to date, the quantification of the genetic load detected follows a moderate trend, in the shape of a sawtooth. The data for the last week indicate a small rebound.
In the Gebas and Cañarico WWTPs, after six weeks of sampling, and since no significant genome units were found, it was decided to carry out specific controls based on the data obtained in the other WWTPs. In this way, controls are concentrated in the WWTPs of Alhama, Condado and El Berro. In the other two WWTPs, sporadic controls will continue and two new points have been enabled within the sewerage network and collectors, in which automatic sampling has been installed, dividing the urban center into two areas to obtain more precise data in those not influenced by industrial waters.
"Of these last two samples we only have three analyzes, which so far does not allow us to obtain conclusive data. Weekly we will make the data obtained public, to know how the presence of the virus is evolving in our sewage network", explains the Councilor Antonio García.
The data obtained have been taken into account by CECOPAL when adopting the prevention and information measures that are in force by the Alhama City Council.