Sewage hailed as latest green fuel

Meet the Bio-Bug, a VW Beetle which runs on the methane gas generated during the sewage treatment process. Waste flushed down the toilets of just 70 homes is enough to power the car for a yearEngineers have come up with a way of running vehicles on the methane gas generated from human waste.
      
Waste flushed down the toilets of just 70 homes is enough to power the Bio-Bug, a VW Beetle, for a year, based on an annual mileage of 10,000 miles.
    
With support from the South West Regional Development Agency, GENeco, a Wessex Water-owned company, imported specialist equipment to treat gas generated at its Bristol sewage treatment works in Avonmouth to power the VW Beetle in a way that doesn’t affect its performance. The company says the trials prove that ‘people-power’ could be used as an alternative fuel for their company vehicles.
     
GENeco’s Mohammed Saddiq said: “Previously the gas hasn’t been ‘clean’ enough to fuel motor vehicles without it affecting performance. However, through using the latest technology our Bio-Bug drives like any conventional car and what’s more it uses sustainable fuel.
     
“The choice of car was inspired by students who took part in a workshop. They thought it would be appropriate that the poo-powered car should be the classic VW Beetle Bug because bugs naturally breakdown waste at sewage works to start the treatment process which goes on to produce the energy.

“At the moment we are using waste flushed down the toilets in homes in Bristol to power the Bio-Bug, but it won’t be long before the energy will also be generated through the treatment of food waste when we start recycling it at our sewage works.”

POWER FROM NATURAL GAS
Countries including India and China use compressed natural gas (CNG) to power vehicles and a number of companies in the UK are now using CNG mainly to fuel buses and commercial vehicles. In Sweden, more than 11,500 vehicles already run on biomethane produced from sewage plants.
     
But using biogas from sewage sludge is yet to take off despite a significant amount being produced everyday at sewage plants around the country and it is sustainable.
    
GENeco said it would produce significantly more gas at its Bristol sewage treatment works in Avonmouth through recycling food waste from homes and businesses in the south west.
    
It will mean both human waste and food waste could be used to power vehicles in the future.
     
Around 18 million cubic metres of biogas is produced at Bristol sewage treatment works a year. It is generated through anaerobic digestion – a process in which bugs in the absence of oxygen break down biodegradable material to produce methane.

If all of the biogas produced at GENeco’s plant at Avonmouth was used to fuel vehicles it would avoid 19,000 tonnes of CO2 being put into the atmosphere.

GREEN FUEL, HIGH PERFORMANCE
Bath-based Greenfuel Company converted the Beetle so it could run on biogas while bosses from GENeco ran a workshop at a University of Bath event for teenagers from schools in Bath and North East Somerset to come up with ideas for the car’s design.
     
Mr Saddiq added: “If you were to drive the car you wouldn’t know it was powered by biogas as it performs just like any conventional car. It is probably the most sustainable car around.”
     
By generating renewable electricity from biogas GENeco is already contributing to the UK’s target of a 34 per cent reduction in greenhouse gas emissions by 2020 and an 80 per cent reduction by 2050.
     
If the company was to further convert biogas to compressed biomethane for use as a vehicle fuel a further contribution would be made to reducing greenhouse gas emissions.

AN ALTERNATIVE
The Anaerobic Digestion and Biogas Association (ADBA) said the launch of the Bio-Bug proved that biomethane from sewage sludge could be used as an alternative fuel for vehicles.
     
ADBA chairman Lord Rupert Redesdale said: “This is a very exciting and forward-thinking project demonstrating the myriad benefits of anaerobic digestion (AD). 

“Biomethane cars could be just as important as electric cars, and the water regulator Ofwat should promote the generation of as much biogas as possible through sewage works in the fight against climate change.”
    
ADBA chief executive Charlotte Morton added: “We are delighted to see such ingenuity and commitment to maximising the potential of AD from the water industry.”

GENeco said if the trial involving the Bio-Bug proved successful it would look to convert some of the company’s fleet of vehicles to run on biogas.

Interesting Facts
•    Enough Biogas is produced at Avonmouth to send a car to the moon and back 119 times or around the world 2,287 times
•    The Bio-Bug does 5.3 miles per m3 of biogas
•    Waste flushed down the toilet of just 70 homes is enough to power the Bio-Bug for year based on an annual mileage of 10,000 miles
•    In Sweden more than 11,500 vehicles run on methane produced from sewage plants
•    To use biogas as vehicle fuel the gas needs to be treated – a process called biogas upgrading. It involves carbon dioxide being separated from the biogas
•    In the past methane hasn’t been “clean” enough which has meant it has affected the car performance
•    Bristol treatment works treats waste from around 1 million people living in Bristol, South Gloucestershire and North Somerset.

Anaerobic Digestion
Anaerobic digestion is a process in which microorganisms in the absence of oxygen break down biodegradable material to produce biomethane. The environmental benefits of anaerobic digestion include:
• Collection of methane providing a source of renewable energy that is carbon neutral, ie, providing energy with no net increase in atmospheric CO2.
• The production of biosolids, which offer farmers a safe, sustainable source of nutrients that supply crop nutrients and enrich land with organic matter.
• Reduction in the sludge volumes that have to leave the site.
• Significantly lowers carbon footprint of the operating site.
• Less smell than more conventional processes.