Tampere blocks in-sink food-waste grinders after pilot finds higher contamination, heavy water use

After a year-long pilot at a POAS student residence in Kissanmaa, Tampere's environmental authority has opposed approving in-sink food-waste grinders as an accepted method for collecting household bio-waste, YLE reports. Earlier coverage described how the grinders milled kitchen scraps into slurry and reduced smelly waste during the Kissanmaa pilot.

The pilot connected kitchen grinders to an underground storage tank and had been due to expand to a new student building in Hervanta, but POAS has paused the plan while awaiting permits. Early results showed improved sorting, but later measurements found the share of bio-waste in mixed rubbish rose to over 30 percent, higher than the Tampere average. The grinders also struggled to handle all food waste without extra preparation such as chopping. Officials flagged high water use, about 4.1 litres per resident per day in the pilot, equating to at least 100,000 litres a year in a single building, along with concerns about breakdowns, odours and the need to revert quickly to container collection.

One more sorting study will be carried out before the regional waste authority decides whether such grinders may count as approved bio-waste collection equipment. POAS says it can switch the Kissanmaa building back to ordinary bio-waste bins if required. Ber, the system developer, plans to submit a formal response claiming the city statement contains factual errors, noting the year-long average share of bio-waste in mixed waste was 25 percent and that recent measurements were lower. Tampere's environmental director Kati Skippari said the current negative opinion applies to all similar systems and that a broader pilot would be needed for more reliable conclusions.