Untreated sewage leak sends 4.3 million litres into Porvoo bay

About 4.3 million litres of untreated sewage leaked into Kodderviken, a sea bay near Porvoo, over roughly a week, Yle reports. The damaged pipe has been repaired, but people are advised not to swim in the bay until tests confirm the water is safe.

The leak came from a pipeline built in 1976. The roughly one-kilometre pressure sewer carries about two per cent of Porvoo’s wastewater to the central treatment plant. Porvoo Water chief executive Elina Antila said the pipe had gradually been damaged by resting on a rock.

The wastewater seeped through a crack, and the utility said it was liquid, with no toilet paper or similar material reaching the environment. While repairs were under way, vacuum trucks transported wastewater to the treatment plant to limit further discharge.

Porvoo Water detected the problem through its automated monitoring system. Workers found the leak near the shoreline on Thursday while surveying the area between the Kodderviken pumping station and the central treatment plant.

The utility has commissioned outside experts to analyse water samples and is monitoring water quality with environmental authorities. The checks will continue as long as necessary.

Porvoo Water manages 1,300 kilometres of pipe network and spends about 5.5 million euros a year on repairs. Antila said the damaged pipeline was already included in the utility’s repair plans, while replacing the entire line would cost millions of euros.