The tunnel system

Syvab - Himmerfjärdsverket
Sweden's fifth largest wastewater treatment plant (WWTP)
The WWTP has been in operation since 1974
The treatment plant is located 40 km south of Stockholm
Our owners are the municipalities Botkyrka, Nykvarn and Salem,
Stockholm Vatten VA AB and Telge i Södertälje AB
350 000 people are connected to the plant
We treat 120 000 000 liters of water every day
(= 1300 liter water per second = 6,5 bathtubs/second)
The tunnel system
• The water flows through a 55 km
long tunnel to the plant
• The water flows through six
(Stockholm, Huddinge, Botkyrka, Salem, Södertälje and
• The water flows by gravity
• The tunnel slope is 1 meter /
kilometer (1 ‰)
• It takes eight hours for the water
to reach the treatment plant
The Himmerfjärden WWTP
3. Filtration
1. Mechanical och chemical
2. Biological
We care about our environment
We produce biogas and biosolids
The biogas is used for:
The biosolids are used for:
• Heat up our offices and digesters
• Gas engine for blowers
• Sludge dryer
• Vehicle fuel
Forest fertilizer
Golf courses
Land restoration
Bio fule