Poo bus goes on the road

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The Scania gas bus is expected to operate on Bath Bus Company’s airport service for six months
The Scania gas bus is expected to operate on Bath Bus Company’s airport service for six months

UK first attracts national media coverage in both newspapers and on TV

The UK’s first bus running on human sewage and food waste was expected to enter service with Bath Bus Company (BBC) on Monday morning.

The 40-seat ADL Enviro300SG-bodied Scania K270UB former demonstrator is being hired to BBC for a six-month period so it can operate it on the A4 route from Bath to Bristol Airport, via South Bristol.

Bristol has been named European Green Capital for 2015 so the bus is expected to continue to operate in the area after that trial is completed. It’s entry into service is an industry first that has attracted national media attention both in newspapers and on TV because of the nature of the fuel source which is entirely sustainable and renewable.

The Scania can travel up to 300km on a full tank of gas, which takes the annual waste of around five people to produce. Using the annual waste generated from one bus load of passengers would provide enough power for it to travel a return journey from Land’s End to John O’Groats.

A temporary refuelling station designed to satisfy the needs of this one vehicle has been installed by Roadgas at the Bristol Sewage Treatment Works, Avonmouth run by GENeco, a subsidiary of Wessex Water. The onsite anaerobic digestion plant supplies it directly as well as injecting into the national grid. Compression of the fuel enables fast fill to take place in around five minutes. A permanent refuelling facility is a possibility for the future.

GENeco was launched in 2010 so Wessex Water could increase the amount of renewable energy it can produce. In 2012 it opened the country’s first co-located food waste plant at a sewage works. The Avonmouth gas to grid plant was built this year.

While there are other anaerobic digestion plants already connected to the national grid, Wessex Water says that its is the first to inject bio-methane produced from this type of waste. While UK operators of gas buses purchase bio-methane through green gas certificates, the vehicles actually run on Compressed Natural Gas (CNG) as, more than likely, that’s what actually comes out of the gas main.

The Bristol treatment works deals with around 75 million cubic metres of sewage waste and 35,000 tonnes of food waste, collected from households, supermarkets and food manufacturers, every year. The anaerobic digestion plant can produce 17 million cubic metres of bio-methane. Impurities are removed by a bioscrubber and activated carbon filters to produce virtually odour free emissions to air. Propane is added to the bio-methane, enriching it to natural gas quality and calorific value. It’s analysed and monitored to ensure it is of the correct standard before being fed into the local gas distribution network.

GENeco General Manager Mohammed Saddiq said: “Through treating sewage and food that’s unfit for human consumption we’re able to produce enough bio-methane to provide a significant supply of gas to the national gas network that’s capable of powering almost 8,500 homes as well as fuelling the ‘Bio-Bus’.

“Gas powered vehicles have an important role to play in improving air quality in UK cities, but the Bio-Bus goes further than that and is actually powered by people living in the local area, including quite possibly those on the bus itself.

“Using bio-methane in this way not only provides a sustainable fuel, but also reduces our reliance on traditional fossil fuels.”

BBC’s Engineering Director Collin Field said: “Up to 10,000 passengers are expected to travel on the A4 service in a month, which is available not only for airport travel, but also local journeys along the route through Saltford, Keynsham, Brislington, Knowle and Hengrove.

“As part of the RATP Dev UK group, this (project) represents RATP Dev’s involvement in the latest of a number of initiatives to gain experience of alternative fuels, with sister companies also experimenting with different alternatives. The information we gain will be shared with other group companies across the UK and Europe.

“The timing of the initiative could not be more appropriate as we approach 2015 when the City of Bristol itself becomes European Green Capital. With so much attention being directed towards improving air quality generally, the public reaction to the appearance of this bus on a service between a World Heritage city and an airport will further focus on the potential for this particular fuel.”

Charlotte Morton, Chief Executive of the Anaerobic Digestion & Bioresources Association (ADBA) added: “GENeco’s Bio-Bus is an excellent demonstration of bio-methane’s unique benefits; decarbonising areas other renewables can’t reach. A home generated green gas, bio-methane is capable of replacing around 10% of the UK’s domestic gas needs and is currently the only renewable fuel available to commercial vehicles.

“The bus also clearly shows that human poo and our waste food are valuable resources. Food which is unsuitable for human consumption should be separately collected and recycled through anaerobic digestion into green gas and bio-fertilisers, not wasted in landfill sites or incinerators. The Bio-Bus will also help to demonstrate the true value of separate food waste collections, which are now obligatory in all other regions, to the English government.”

Businesses backing the project include Scania, Roadgas, CNG Services, Dampney’s Agri Environmental, Trant, Grontmij and AIR Decker.