Toys that have arrived over the years at the Viikinmäki wastewater treatment plant with the wastewater. Photo: HSY


Helsinki Region Environmental Services Authority (HSY) has reported a concerning issue: last year, approximately 800 tons of garbage, which should not have been there, ended up at its wastewater treatment plants. This waste, including toys, cell phones, and even dentures, gets caught in the early stage sieves, or 'välppä', of the treatment process.

The most common types of trash found in the sewage system are hand towels, biodegradable waste, and hygiene products like cotton swabs and tampons.

Occasionally, more unusual items are flushed down the toilet, either intentionally or accidentally, causing significant issues in the sewage network and treatment facilities.

These foreign objects not only cause blockages in residential properties, leading to costly repairs charged to residents, but they also clog pumps at HSY's sewage pumping stations, disrupting the flow of wastewater. Petteri Jokinen, head of the remote control unit, explained that clearing pump blockages costs about €300,000 annually and diverts staff from other essential maintenance tasks. The number of blockages has increased in recent years, partly due to the inappropriate disposal of hygiene products like rubber gloves, cleaning wipes, and face masks, especially during the COVID-19 pandemic.

At the treatment plants, waste larger than one centimeter is removed using the 'välppä' process. This trash then undergoes a drying process before being transported for incineration, amounting to about 150 truckloads annually. The handling and transportation of this waste also incur costs, which are ultimately borne by residents through sewage fees.

HSY emphasizes that only human waste, toilet paper, and washing water should go down the drains. Other types of paper, such as kitchen and hand towels, do not disintegrate properly in the sewer system. With the holiday season approaching, Elina Tanner, an environmental expert, reminds residents that fats, including those from cooking like ham fat, should not be poured down the drain. They can solidify in pipes and cause blockages. Instead, solidified fats should be disposed of in biodegradable waste or compost, while liquid fats can be collected in a sealed container and disposed of in mixed waste or taken to designated fat collection points. Improper disposal of fats and biowaste can also contribute to rodent problems in the sewer system.

HSY recommends installing trash bins in bathrooms and toilets to facilitate proper disposal of waste, thereby preventing the sewer system from becoming clogged and reducing unnecessary expenses for both residents and the sewage treatment facilities.