Bio methane production in Växjö

Content

• History

• Present situation

• Future

Bio-methane history

Old sewage

plant

1 digester / gas-

boiler

1994 - Sundet

2 digesters / gas-

boiler, gas-engine

2003 Agropti-gas

closed

Co-digestion of

biowaste, manure

and grass crop

2006 New reception

lines

Liquid organic waste

2007 New gas

upgrading and filling

station (SESAC-

project)

2008 New gas-engine2008 Decision source

separation in

households of

biowaste

Totalt mottogs 14 839 m3 externslam under 2007 vilket motsvarar ungefär 21,5% av totala slammängden som

pumpats in i rötkammaren (resten är Sundets interna slam)

Present situation

Feedstock for digestion 2011

Internal sludges sewage water treatment 65 000 ton

Sludge small sewage treatment plants 3 000 ton

Sludge septic tanks 11 000 ton

Sludge grease traps 900 ton

Food waste 300 ton

Food waste collection system, waste disposer –

tank store

...transport to sewage plant for co-digestion with sewage

sludge

The result – bio methane for vehicle

fuel and .el and heat production

Present situation

Food waste large scale kitchen

The present system

Energy utilization from crude gas

6%

1%

84%

9%

Flare

Burner

Engines

Fuel-prod

Internal goal 60% el selfsuffiency

El selfsufficiency

0%10%20%30%40%50%60%70%

Janu

ary 2

008

Febru

ary

Mar

chA

pril

May

June

July

Aug

ust

Sep

tem

ber

Oct

ober

Nove

mbe

rD

ecem

ber

Sustainable waste handling

Future bio-methane production

Today household waste

to incineration plant in Ljungby for el and

heat production

Reloading at landfill area and transport

250 kg/inhabitant 18 % package products

48 % food waste

0,2 % env dangerous waste

Present situation

National goals waste handling

• Waste to deposit shall decrease at least 50% from 1994 to 2005

• 2010 shall at least 50 % all waste from household be used for material

recovery included biological treatment.

• 2010 shall at least 35% of the foodwaste from households, restaurants and

institutional kitchens be treated by biological methods for recovery

• 2015 shall 60% of the content of phoforus in the sewer system be recycled

for agricultural purposes

General: The total amount of waste shall decrease

Collection system

· Paper bag system

· Separate 140 lit dust bin with

ventilation,

Pre treatment plant

Increased digestion capacity

New Gas-Cleaning

The CApureTM process tecn.

Biogas pipeline Sundet - Hammerdalsgatan

• 4 300 m

• Dy 125 mm

• Pressure <4 bar

Slow fuel filling for buses

Future bio methane production

• Existing crude gas production

Sundet 720 000 Nm3 vehicle

fuel

• Future crude gas production

with foodwaste 1 300 000 Nm3

vehicle fuel

El (MWh) Värme (MWh) Fordonsbränsle(MWh)

Totalenergi (MWh)

Changed production

- 2 410 - 3 550 + 12 500 + 6 540

Changed consumphtion

+ 1 120 + 510 - 40 + 1 590

Changed energy balance

- 3 530 - 4060 + 12 540 + 4950

Ton CO2/år Ton CO2/år Ton CO2/år Summa ton CO2/år

Changed CO2

emission+ 113 Ingen - 3 360 - 3247

Effects - energy utilization and green house gases

•Lower exhaust emissions from bio methane compared to diesel

•Renewable fuelled buses is a good argument to choice bus

•Less fuel prize fluctuation

•The city obtains the national environmental goals

•Better material recovery of other materials (experience from other municipalities)

•Recycling of nutrients

Other advantages with source separation of biological waste and bio methane fuel production for buses

Energy supply to Växjö 2010

13%

14%

1%

9%

2%

38%

10%

7%

1%

1%

1%

3%

Total 2711 GWhGasoline

Diesel

Aviation fuel

Oil

Peat

Wood fuels

Renewable imported electricity

Non-renewable importedelectricityLocal windpower

Local hydropower

Biogas

Solar energy

Ethanol

FAME

Heatpumps

Straw

LPG

Ecopar

Thanks !

Steve Karlsson

tekniska förvaltningen

steve.karlsson@vaxjo.se