Excursions – technical tours

Technical visits on Wednesday afternoon in 25 September 2019. As a part of the conference we will organize five technical tours.

Registration for technical visits is done via congress online registration. (Nordiwa2019 registration opens 1st April 2019.) After technical visits buses drive first to Helsinki Airport and continue to Clarion Hotel Helsinki.

Technical visits and estimated drop off times at the airport. The journey from Helsinki Airport to Clarion Hotel Helsinki takes about 30 minutes.

  1. Viikinmäki wastewater treatment plant (drop off at the airport at 17.30)
  2. New wastewater treatment plant to Blominmäki (drop off at the airport at 16.30)
  3. Katri Vala Heat Pump Plant (drop off at the Airport at 15.30 and about 30 min later at Clarion Hotel Helsinki)
  4. Three stormwater management sites in Vantaa (drop off at the airport at 15.40)
  5. Mäntymäki wastewater pumping station (drop off at the airport at 15.30)

1. Viikinmäki wastewater treatment plant 

The Viikinmäki wastewater treatment plant located in Helsinki is the largest treatment plant in Finland and the Nordic Countries. The Viikinmäki bedrock treatment plant processes the wastewaters of 800,000 residents in Helsinki and the Metropolitan area as well as the wastewaters of the region’s industry. The annual wastewater flow is around 100 million m3.

The treatment process in Viikinmäki wastewater treatment plant is based on an activated sludge method and it has three phases: mechanic, biological and chemical treatment. The efficiency of nitrogen removal has been increased with denitrifying filters.

In Viikinmäki wastewater treatment plant, 95 percent of solid and oxygen-consuming matter and phosphorus are removed from the wastewater as well as 90 percent of nitrogen.

Viikinmäki treatment plant is self-sufficient in heat and 97 % self-sufficient in energy (year 2018). At the treatment plant,  14,5 milj m3 of biogas is produced yearly and it is used for energy and heat production. The high level of energy efficiency is met with multiple simultaneous means: accurate measurements of the energy consumption, operational optimation, investements, heat recovery optimation, for example.


HSY has invented a nutrient recovery process called RAVITA. In the RAVITA process, the main idea is to recover the phosphorus directly from the effluent water by post-precipitation. The formed chemical sludge is processed to phosphoric acid. A pilot plant (1000 population equivalents) containing the first process units (post-precipitation and dewatering) has been built in Viikinmäki wastewater treatmen plant. The next phase is to build the process units for chemical sludge processing to 1000 PE pilot scale in Spring 2019 and optimize the phosphoric acid production.

The RAVITA project has granted funding from the Finnish Ministry of the Environment’s RAKI Programme and it was one of the Government’s key project on the circular economy in 2017-2018.

More information can be found from our websites: www.hsy.fi/ravita

  • Tour A nutrient recovery process RAVITA pilot
  • Tour B energy efficient solutions

Maximum 80 people can attend excursion to the Viikinmäki WWTP.


2. New wastewater treatment plant to Blominmäki 

A new wastewater treatment plant is built in Espoo’s Blominmäki bedrock. The new treatment plant will replace the current Suomenoja wastewater treatment plant. The capacity of the Suomenoja treatment plant is no longer sufficient to treat the entire area’s wastewater because the population and expectations for intensified wastewater treatment increase. After its completion in 2021, the treatment plant will process the wastewater of 400,000 residents from the western part of the Metropolitan area.

Blominmäki will become an efficient and modern wastewater treatment plant of the 2020s. It treats the wastewater better, the operation is more reliable and safe and it is more energy efficient.

HSY – Helsinki Region Environmental Services Authority Helsinki Region Environmental Services Authority HSY is a municipal body, which produces waste management and water services, as well as provides information on the Helsinki Metropolitan Area and environment. We help inhabitants to act for a better environment. Our principal tasks are supplying high-quality drinking water, organising waste management and treating wastewater generated by the over one million inhabitants throughout the Helsinki Metropolitan Area.

Maximum 60 people can attend excursion to the Blominmäki.


3. Katri Vala Heat Pump Plant

Katri Vala heating and cooling plant is the largest heat pump plant in the world to produce heat and cooling. Its carbon dioxide emissions are 80% smaller than for example in separate heat production with heavy fuel oil. Heat pump plant is using effluent from Viikinmäki wastewater treatment plant as a heat source. The participants get a unique opportunity to visit the plant which is located under the Katri Vala Park in Sörnäinen district.

Helen Ltd. Helen is Finland’s second largest energy company with over 400 000 customers. Services for homes and enterprises: district heat, district cooling, electricity, services for small-scale energy production, electric traffic and energy efficiency. Helen Ltd is owned by the city of Helsinki.

Maximum 30 people can attend excursion to the Katri Vala Heat Pump Plant


4.Three stormwater management sites in Vantaa

A. Natural stormwater management in Illenpuisto Park

Illenpuisto Park, built in 2002, is the oldest and one of the most remarkable stormwater management systems in Vantaa. Stormwater management in the park is natural and multifunctional, mimicking natural water control and purification processes.

An open stream leads runoff water from streets, roads and buildings´ roofs to small ponds, which are natural flooding areas during heavy rains. These retention ponds cut high peak flows, and prevent flooding. At the same time, water quality improves due to the sedimentation process in the ponds. High water flow in the stream is also controlled by stepping stones, small bottom dams and aquatic vegetation. Water plants uptake soluble nutrients, like phosphorus and nitrates. In addition, the open stream with its surroundings makes the district of Pakkala very pleasant.  Read more: Illenpuisto pdf in english

B. Bioretention basins of Meiramitie road

The bioretention structure of Meiramitie road, located in the district of Koivuhaka in Vantaa, was completed in 2013. It contains four separate bioretention basins.

Prior to the filtration process within the bioretention system, stormwater passes through a rock basin, which separates water from solid material, such as sand and litter. Flow then continues into the filtration basin, located between a driving lane and a sidewalk, where the water can build up in the detention area. Eventually, stormwater percolates through vegetation and a filtration media, where physical, chemical and biological treatment takes place, and ends up purified in a drainage.

C. Stormwater management in Koisotie road snow disposal site

Koisotie road snow disposal site, located in the district of Koivuhaka in Vantaa, was revised and taken into use again in 2012. The purpose was to improve the quality of meltwater and control the water flow.

The snow disposal site can hold stormwater up to 600 m3. First, the stormwater is led through the sand separation process, and after that, the water continues to flow through the oil separation process. In the third phase, the water ends up in a bioretention basin. Biological, chemical and mechanical processes in the retention basin reduce the amount of other suspended solids, nutrients and heavy metals in the stormwater. The surface area of the bioretention basin is 1000 m2.

City of Vantaa is located in Southern Finland in the metropolitan area right next to the capital, Helsinki. With a population of 228 000 Vantaa is the fourth most populated city of Finland.



5. Mäntymäki sewage pumping station and Sanitation Safety Plan in HSY

First excursion will head to the Mäntymäki sewage pumping station which situates next to the Helsinki Olympic Stadium. From the pumping station excursion continues to the HSY headquarters  where experiences of the sanitation and safety plan will be presented.

Mäntymäki sewage pumping station

  •  renovated and partly replaced 2016 due to the planning of a sub terrain circular railway in down town Helsinki
  •  30 meters below ground
  • four Flygt N-technology pumps, 180 kW
  • every pump has its own pressure pipe, frequency converter and flow meter
  • max. capacity 7200 m3/h
  • average flow 1730 m3/h
  • peak flow 6000 m3/h
  • combined sewage water area