Better air quality in Stockholm thanks to sewage sludge

Under information facts the swedish epa presents facts aboUt different issUes

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may 2009

photo: stockholm vatten

better air quality in stockholm

thanks to sewage sludge

the sewage treatment plants of the city of stockholm, the capital of sweden, produce biogas from the sludge. the gas can be used both for heating and as a vehicle gas and produces no net co₂ emissions. the plants have reduced their emissions and become energy suppliers. the sewage sludge and the sewage treatment by-product biogas are now an important resource rather than an environmental problem.

Stockholm Vatten’s project Biogas from Sewage Sludge shows that two differ-ent environmdiffer-ental problems can be solved: waste managemdiffer-ent and emissions from fossil fuels. With support from the Local Investment Programme (LIP), two biogas plants were built, at the Bromma and Henriksdal sewage treatment plants,

with total annual production capacity of 6 million Nm3_{. One aim was to increase}

the production of treated biogas for vehicle fuel. Another was to reduce the

en-ergy use of the plants and their emissions of CO₂, particulates and carcinogenic

substances by replacing fossil fuels with biogas.

Positive environmental and economic imPacts

Reduced energy use (5 GWh/year) •

Increased gas production due to input of organic material (5 GWh/year) •

Reduced use of petrol and diesel (6 million litres/year) •

Reduced CO

• ₂ emissions (14,000 tonnes CO₂ /year)

Lower emissions of particulates and nitrogen oxides •

Low operating costs and development of new technology •

for fUrther information contact person: lars rahm, +46 (0)8-522 131 28, lars.rahm@stockholmvatten.se lars-gunnar reinius, +46 (0)8-522 124 90, lars-gunnar.reinius@stockholmvatten.se contractor:

läckeby water, martin hagbyhn, +46 (0)46-19 19 70, martin.hagbyhn@lackebywater.se

malmbergs water, rune simonsson,

+46 (0)44-23 18 00,rune.simonsson@malmberg.se

the project on the internet:

www.stockholmvatten.se/vattnets väg/restprodukter/ biogas

for further information on best practice: www.swedishepa.se/bestpractice www.naturvardsverket.se/mir facts

lip stockholm 1998 action no 3

environmental investment: mseK 88 grant: mseK 23

swedish ePa se-106 48 stockholm. visiting address: stockholm - valhallavägen 195, Östersund - forskarens väg 5 hus Ub, Kiruna - Kaserngatan 14.

tel: +46 8-698 10 00, fax: +46 8-20 29 25, e-mail: registrator@naturvardsverket.se internet: www.swedishepa.se orders ordertel: +46 8-505 933 40,

orderfax: +46 8-505 933 99, e-mail: natur@cm.se address: cm-gruppen, box 110 93, se-161 11 bromma. internet: www.naturvardsverket.se/bokhandeln

imPlementation

The Stockholm Vatten biogas initiative developed from the local investment pro-gramme (LIP). The project has led to technological development, reduced energy use and lower emissions, and the sewage treatment plants have become suppliers of renewable energy. Another important customer is SL, which has invested in biogas buses for city-centre transport. Cooperation with AGA, which buys and distributes the gas in the Strockholm area, has also speeded up development. Stockholm Vatten cooperates with biogas producers in Biogas Öst. The project has attracted considerable interest, as biogas allows several environmental prob-lems to be solved at once. Many articles and reports have been published.

Potential and future benefit

When biogas is used for heating as a vehicle fuel there is no net increase in CO₂

in the air and no environmentally hazardous particulates are emitted. The sewage sludge becomes a resource for biogas production. Stockholm Vatten has recently set up a vehicle gas production company. Developing new technology allows the energy efficiency of biogas to be increased by 10–20% over petrol. New engines and more biogas filling stations will be needed in the future.

why best practice

biogas is an important factor in the switch from fossil to renewable fuels. biogas produced from waste products eliminates a waste problem with possible adverse environmental impact. at the same time production does not lead to any conflicts over land use e.g. for food production.

the sewage treatment plants have become net suppliers of energy, and emissions from the plants and vehicles have fallen. water supply, waste, landfills and biogas are closely related areas, and biogas allows several environme-ntal problems to be solved.

information facts best practice examples biogas lip – local investment programme, sweden

may 2009 isbn: 978-91-620-8403-5