SARS-CoV-2 at wastewater treatment plants



Unit at THL:

Expert Microbiology Unit TEAM

Wastewater-based monitoring of SARS-CoV-2 is a part of national koronavirus surveillance and can produce an early-warning of local COVID19 occurrence.


The aim of wastewater monitoring is to provide timely information on SARS-CoV-2 virus numbers in comparison to COVID19 infection incidence in a representative manner among the population. In particular, the focus of work is to prepare for the probable new waves of COVID-19. Changes in the number of virus in wastewater compared to baseline may help predict the onset and progression of a new epidemic.


The wastewater sampling is conducted to analyze a representative fraction of wastewaters in Finland to determine the temporal and local variation in the occurrence of coronavirus.

At the moment, samples of incoming wastewater will be collected weekly from the following wastewater treatment plants: Helsinki, Espoo, Turku, Tampere, Jyväskylä and Oulu. In addition, samples are collected every other week from Lappeenranta and Rovaniemi and once a month from Kuopio, Pietarsaari, Seinäjoki and Tornio. If the epidemic situation so requires, monitoring can be extended to other locations. Monitoring represents about 40% of the wastewater of the Finnish population.

The samples are collected as 24-hour composite samples using automatic collection equipment's at the wastewater treatment plants and delivered as soon as possible after sampling as refrigerated transport to the water microbiology laboratory in Kuopio. For some facilities, treated wastewater and sewage sludge are also collected.


  • University of Helsinki
  • Tampere university


  • THL
  • Ministry of Agriculture and Forestry
  • Finnish Water Utilities Development Fund
  • Ministry of Environment
  • National Emergency Supply Agency

Contact information

Tarja Pitkänen
Chief specialist
Phone +358 29 524 6315
Email: [email protected]