Planning and implementation of a cavern sewage treatment … · 2016-09-14 · HSY Water Services...

21.6.2013

HSY Water Services

Planning and implementation of a cavern sewage treatment

works in Finland

Tommi Fred

21.6.2013HSY Water Services 2

21.6.2013HSY Water Services

100 Years Wastewater Treatment in the Helsinki Metropolitan Area

• Alppila plant 1910–1959

‒ Rock filter and septic tank

• Savila plant 1915–1931

‒ Rock filter and septic tank

• Kyläsaari 1932–1994

‒ The first activated sludge plant in the Nordic countries

• Rajasaari 1936–1978

‒ Activated sludge plant

• Tali 1957–1986

• Herttoniemi 1959–1985

• Kulosaari 1960–1975

• Lauttasaari 1962–1992

• Viikki 1965–1994

• Laajasalo 1966–1988

• Munkkisaari 1967–1991

• Vuosaari 1971–1994

• Viikinmäki 1994–


1980’sDecade of demands and discussions• Pressure to increase treatment efficiency

1970-1980

• Old treatment plant’s efficiency was not adequate

‒ Expansion need or

‒ Centralised treatment plant

• Number of inhabitants increases at the same time

• Demands for centralised wastewater treatment for Central-Uusimaa district as well

• Pressure to control indirect environmental impacts as well

‒ Odours, noise and traffic/logistic

• Employee safety issues and weather impacts came in to the discussion


Helsinki underground planning schema

• Underground plan was updated in the begin of 1980’s

• First area was reserved for centralised treatment plant

• Underground area below Sörnäinen prison area in city centre

‒ Treatment plant would be 60 m under wd• Long logistic tunnel systems• Water treatment lines under sea level

‒ Expensive‒ No reserve for future expansions

• Viikinmäki

‒ Treatment plant would locate optimally for the existing tunnel system

‒ Water treatment area totally above sea level

‒ Area is enough wide and there is reserve for future as well

‒ Above ground buildings won’t cause disturbance to the residential areas

• Other options were also presented

Realistic option turned out to be Viikinmäki


Political decisions for Viikinmäki Project

• Project planning 1985-1986

• Helsinki City council accepted plans to build centralised treatment plant in May 21st 1986

• Financial share of Helsinki 457 Mmk (80 MEur)

• Vantaa and central Uusimaa totally 97 Mmk (17 MEur)


Time for planning 1985-1988

• 1985 Preliminary design by Helsinki Geodeticall Department

• 1986 Terraplan Ltd detailed geodetical design

• 1986 Suunnittelukeskus Ltd ja Soil&Water Ltd shared general planning phase

• 1987 City Council accepted the general plan

• Excursions especially to Stockholm where is two underground treatment plants

‒ Operation manager of the Stockholm Water was part of the design team of Viikinmäki

• 1987-1988 Detailed design

‒ Wastewater treatment process Suunnittelukeskus Ltd.

‒ Sludge treatment and gas handling Soil&Water Ltd.

‒ Rock Engineering; Saanio & Riekkola, Kalliosuunnittelu Ltd. ja Suunnittelukeskus Ltd.

‒ Structure mechanical engineering Pöysälä & Sandberg

‒ Construction design of buildings MV-Konsultit/Soil&Water Ltd.

‒ HVAC Olof Granlund Ky

‒ Electrical and automation design Ekono Ltd.

21.6.2013HSY Water Services 8ITA-AITES World Tunnel Congress 2009 OPEN SESSION

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Courtesy: City of Helsinki

21.6.2013HSY Water Services 9ITA-AITES World Tunnel Congress 2009 OPEN SESSION9Courtesy: City of Helsinki

21.6.2013HSY Water Services 10ITA-AITES World Tunnel Congress 2009 OPEN SESSION

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Courtesy: City of Helsinki


Time for construction 1988-1994 - Excavation period

• 1988 constructions started by the excavations of driving tunnels and process areas

‒ Excavation contract Lemminkäinen Ltd

‒ Crushing contract Teräsbetoni Ltd

• Excavation was divided into 6 phases

• Excavated rock 950 000 m3

• Tolerances ± 15-30 cm

• Excavated rock was crushed on site and sold out

‒ Crushed stone more than 2 000 000 t

‒ 50% Helsinki city purposes

‒ 50% was sold out to open market

• Lemminkäinen utilised new wet spraying method at Viikinmäki site

‒ Automated process

‒ Steel net as a reinforcement (25 mm)

‒ Spraying area more than 110 000 m2

‒ Bolting more than 73 km (20 000 pcs)

• Water treatment line excavations were ready 1990

• Rest of the excavations were ready in the begin of 1992


Time for constructions 1988-1994 - Construction period

• Water treatment line construction started 1990

‒ Contractor Teräsbetoni Ltd.

• Sludge treatment was taken under construction in 1992

‒ Contractor Teräsbetoni Ltd.

• Totally 1 100 000 m3 space in 15 hectare area

• Treatment volume higher than 300 000 m3

• Main part of the construction projects were ready in 1993

• Buildings above the ground was contracted by Puolimatka Ltd

‒ Operation room, offices, catering, storages, social areas for employees and power plant


Time for construction 1988-1994 - Machinery and automation

• Installation of machinery equipments started in 1991

• Main installation wave during 1992

• Contractors: Atmostech Oy, Valmet Oy (Metso), HV-Turbo Oy, YIT-Yhtymä Oy

• Last equipments were accepted in operation 1995


Start-up period

• Two wastewater treatment lines and two digestors were in operation start-up phase in April 1994

• Plant was taken operation in 3.5.1994

• Sludge treatment was taken in operation in July 1994

• Final tunnel systems from city centre and east was ready in August 1994

• During September 1994 plant reached the full capacity


Structure of Viikinmäki in 1994


Expansion phase 2000-2003

• Total nitrogen removal demand increased to 70 %

• Original activated sludge process was not efficient enough for high nitrogen removal

• Biological denitrifying filters and 1+1 extra activated sludge treatment lines were build during the project

• Excavated volume 190 000 m3

• Expansion was ready in the end of 2003

• Actual reduction of nitrogen is 90 %


Structure of Viikinmäki in 2004


Environmental impacts – Phosphorus

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Chemical

phosphorus

removal

Viikinmäki

WWTP Biological

post-denitrification


Environmental impacts - Nitrogen

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DN-process

Biological

post-

denitrification

Viikinmäki

WWTP


Kakolanmäki WWTP

• City of Turku and surrounding municipalities connected

• Locates middle of City Centre

• Operation since 2008

• 400 000 PE

http://www.turunseudunpuhdistamo.fi/images/toiminta-alue/content/toiminta-alue_page_2_large.html

Kakolanmäki WWTP


21.6.2013

Sulkavuori WWTP

• Underground plant for Tampere and it surroundings

• 350 000 PE

• Environmental impact assessment completed

• In operation 2020

Blominmäki WWTP

• Wastewater treatment for City of Espoo and west side Vantaa

• PE 400 000

• Investment cost estimate 280 million euros, including influent and effluent tunnels



Viikinmäki Extension 2030 –preliminary design

Summary

• The biggest cities in Finland are already having cavern wastewater treatment plant or plant is under design

• Environmental impacts have been very small even though plants are located in middle of residential areas

• Cavern treatment plants have proven to safe and reliable solution to large wastewater treatment plants


21.6.2013

HSY Water Services

Thank you!

Planning and implementation of a cavern sewage treatment … · 2016-09-14 · HSY Water Services...

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