Churchill Fellowship winner Lisa Brown last provided Inside Waste an update from Oslo, Norway at the start of her two and a half month adventure studying international food waste management systems. She has now investigated different approaches in England, Norway and Canada - and found some interesting trends.

The Churchill Trust sends approximately 100 Australians each year, from all backgrounds, ages and industries, overseas to research activities being undertaken in other parts of the world that are not being done in Australia.

One of the most interesting things I have seen on this trip is the wide use of Anaerobic Digestion (AD) to simultaneously deal with a ‘waste’ and generate a much needed commodity - renewable energy.

One of the more impressive AD facilities was located at a sewage treatment plant in Norway where the biogas was used both to generate electricity and as a replacement for natural gas in powering 25 local vehicles.

Whilst use of biogas to generate electricity is reasonably common, upgrading biogas to increase the percentage of methane from approximately 60-65% to 98% for use as a replacement for natural gas is less widely done - but gaining increasing attention.

Interestingly, commercial food waste was only recently introduced as a feedstock in Oslo. By adding only a small amount of food waste (10% of the feedstock by weight), the operator was able to almost triple the quantity of biogas produced.

Upgrading biogas for use in vehicles is at the centre of the city’s proposed organics management program. It aims to power its public buses on upgraded biogas generated from a new residential source separated food waste collection service. I assume they will carry advertising that reads This Bus is Powered by Your Banana Skin, or something similar!

The other interesting aspect of Oslo’s new organics management system is the way in which they propose to collect the food waste.

To avoid giving residents a second (or third) bin, the city will instruct residents to place three streams (garbage, recyclable plastics and food organics) into the one bin, using three different coloured plastic bags. The city will then use optical sorting technology to sort the three streams.

After Norway I visited the Canadian City of Toronto and four of its neighbouring municipalities. In this part of the province of Ontario source separated organics collection and processing is very widespread, with approximately 1.9 million single dwellings having access to a food organics collection service.

But while there are some similarities, each region approaches the system a little differently. Toronto, for example, collects a very wide range of organics including soiled nappies, cat litter and hair, in addition to all cooked and uncooked fruit, vegetables, meat, bones and dairy.

Toronto allows residents to use plastic bags for the food/organic material and relies upon AD to process its material. The city has a very impressive participation rate of over 90% (for single dwellings) and does appear to be able to separate the plastic bags out of the organics at the processing facilities.

I visited one of the composting plants that accepts the digestate from the AD facility and was surprised to learn the contamination in the digestate was manageable and the final compost made the highest grading.

In contrast to Toronto, the neighbouring regions of Peel, Durham, Halton, York and Niagara rely on composting for processing. They accept the normal range of food organics (cooked and uncooked fruit and vegetables, meat and bones and diary etc) and do not allow plastic bags.

I am now in San Fransisco learning all about the systems in Alameda County, which introduced the first residential food waste collection service in the US.

I will visit Portland attending the US composting conference in Houston, Texas.

Lisa Brown is manager of contracts and projects with Impact Environmental Consulting. Inside Waste has been providing regular updates on her Churchill Fellowship travels – read her first postcard here.

Click here to read the rest of today's news stories.