FOOD, GLORIOUS FOOD!

Chances are the Credit Crunch – now officially re-titled The Recession – has had an effect on the profitability of your business, and you are coming up with more and more ways of generating income from different sources. Maybe you’ve diversified into setting up recycling programmes in offices and are helping to change the face of waste processing for the future. Maybe not – but one thing’s for sure; to survive the economic downturn you can’t sit back on your laurels eating grapes.
What about those grapes? What about food waste? And I don’t mean the odd half-eaten burger thrown into a skip. What about the food waste generated in every office and public building in the country? There are machines that can deal with this stuff in a sustainable way and are much, much cheaper to implement than large anaerobic digestion sites. If you’ve got the money and want to invest in an AD site that can generate energy from the food waste collected, go ahead. But let’s face it – who’s got a few million knocking around right now?
There are relatively cheap alternatives out there that can effectively treat food waste, reduce its volume by around 65-70% and turn it into a useable product – compost. The boffins in Brussels have just put out a Green Paper about organic waste which recommends that composted organic wastes, especially food wastes, going back to agricultural land is the best use of this waste stream. And who am I to argue?
‘CURRANT’ OPTIONS FOR FOOD WASTE
Landfill – expensive and getting more so. Food and other organic wastes disposed of in landfill sites generate methane – a climate change gas that is 20 times more damaging than CO2. Not the healthy eating option then.
Anaerobic digestion – expensive but can contribute to the energy mix if you want to get into planning applications and the like for the next few years – at least it gives you the time to save up the money!
Incineration – MSW going for incineration can either be considered as energy recovery or disposal; either way the moist food waste can lower the efficiency of incinerators and it’s probably best to remove the food waste from the MSW before incineration. Again costly and difficult to manage efficiency.
Composting – large in-vessel composters are available. They can take up a lot of space and again costs can prohibit the implementation of such a scheme. But on a smaller scale in-vessel composting could be just the thing to open up another sales pipeline that will keep the MD happy.
SMALL-MEDIUM SCALE PROCESSING
One company that is processing food waste from residential and commercial contracts is based in the centre of London. Admittedly, they aren’t a skip company but there are lessons to be learnt here.
Aardvark Recycling was set up as a social enterprise and showing they could cut the costs for the local authority meant they had access to a variety of pots of funding. This helped them to set up a food waste collection service from a densely populated area but also opened up commercial contracts from all over the city.
“Recycling collections in high-density areas are labour intensive and therefore costs are higher for kerbside collections,” explains Joe Tanner, Managing Director of Aardvark Recycling.
When they set up the funding kept them going in the initial stages but it is commercial contracts with offices, retail outlets and such that keep them going.
Joe continues: “We were in the right place at the right time to access pots of funding for the initial capital outlay and education programme. But now that funding has come to an end we are finding that commercial contracts are the way forward.”
At the moment with 30% participation rates by local residents costs per tonne are steep, around £22, but still lower than the £30-£40/tonne that an out of town AD site could cost. As more commercial contracts are won and more residents come on board the only way the costs can go is south. But how do they do it?
Aardvark has thought about every aspect of their service. Lockable caddies, supplied by Peter Ridley Waste Systems, are small enough to be unobtrusive yet large enough to safely contain the 2.5/3kg average of food waste that each family throws away each week. Smaller vans are used to collect the food waste and local tree surgeons supply the woodchip necessary for the composting process to work efficiently in a small scale in-vessel composter. Change that to offices, public buildings and commercial operations and the system could work financially for the skip industry. Woodchip shouldn’t be too much of a problem to get hold of – you probably have masses already. But how would you process the food waste to generate the compost?
There are a couple of systems out there small enough to be economically feasible and big enough to cope with up to 2.5 tonnes per week – that’s a lot of burgers.
The two main players in the UK for these smaller systems are Accelerated Compost and Big Hanna. Aardvark runs eight Rocket® machines supplied by Accelerated Compost, including five of the largest A1200 models that can achieve the 2.5 tonnes per week capacity. That’s around 650 tonnes of food waste processed each year through the A1200’s – small enough to be manageable, large enough to be profitable.
Joe Tanner: “Expanding the commercial contracts to generate finances will give us the money to increase the education programme. This is the key to increasing resident participation rates. We are a fairly new and different type of service and residents find change hard, so right now the commercial contracts are providing the funding for our future – we can’t have one without the other.”
Now I don’t expect that your commercial skip operation would have the high ideals of social enterprise about educating the general public into recycling food waste – but adapting the approach could work for your commercial food waste collection contracts.
HOW IT WORKS AT AARDVARK
Biodegradable caddie liners are supplied to residents and replacement liners can be ordered by telephone or direct from the collection staff as and when they are needed. Full liners are transferred to wheeled bins for easier off-loading at the Aardvark processing site and the empty caddies are left for the resident. All food waste is shredded before entering the Rocket® composting system to increase particle surface area and the composted product is screened before maturation. Any oversize material is put back through the Rocket®.
Huw Crampton, General Manager at ACL, explains how the Rocket® works: “It’s a continual process system, designed to be fed with wastes as frequently as possible – ideally daily. Food and organic waste is simply placed into the hopper on the top of the machine with an equal quantity of “woody” material. The process from then on is automated.
“As the blades of the internal shaft turn they aerate the material, moving it along the body of the machine providing extra loading space at the input end of the machine and pushing finished material from the exit of the machine. The Rocket® is simply a controlled environment in which harmless composting microbes thrive.”
Temperatures inside the Rocket® can reach 70°C+ (158°F), enough to kill off pathogens such as Salmonella and E.Coli. After around 14 days the composted product exits the Rocket®. With a volume reduction of around 65% on the food waste initially put into the Rocket® even if it went to landfill it would cost significantly less than being dumped without too much processing.
But the best use for the compost, and many farmers would be happy to oblige, is spreading
it back to agricultural land to grow more food. Properly composted food waste can cut farmers costs in terms of chemical fertilisers and pesticides. Soils will be more workable due to the increased moisture retaining properties, which also helps to counteract flooding and leaching of nutrients. Soil structure is also improved and the replacement of the organic matter is invaluable – landfeeding rather than landfilling!
COULD IT WORK FOR YOU?
Spending time in a skip yard you get used to the wide variety of smells – composting is no different – but with a closed vessel system the “pong” associated with composting doesn’t exist. It’s more like barley and hops – so odours shouldn’t be too much of a problem.
Setting up a food waste processing area that is compliant with the UK’s Animal By-Products Regulations is not too difficult either, as a number of users of these types of systems have found out, including Salford University who became the first UK University to achieve ABPR compliance status. And if you wanted to go one step further, samples could be sent for analysis with the aim of achieving PAS 100 – then the compost can be sold.
The modular nature of the machinery means that it is adaptable and scalable to keep up with an increase in commercial contracts, and collecting from local offices and commercial operations keep carbon emissions and transport costs low enough to be feasible.
Removing food waste from your own commercial collections would increase the cleanliness of the recyclable waste material brought into your site. Processing food waste through smaller, more manageable in-vessel machines could cut your landfill costs too. And Farmer Giles down the road would find his fields easier to plough and achieve higher yields.
The economies of scale currently prevent local authority collection and recycling of segregated food waste from most high-density population areas or from offices, commercial and retail organisations. But with a little bit of thought you could be helping to solve a problem that is foxing some of the bigger operators. And earn a bit more money too. Bonus!