FOGO in MUDs – how to make it work
By: Maya Deacock, James Cosgrove and Mike Ritchie, MRA Consulting Group
MRA is regularly asked to explain whether FOGO (Food Organic and Garden Organic waste collected in a dedicated green lidded bin, from households) works in MUDs.
Although FOGO has multiple benefits and is being adopted around the country, Councils with high MUD density are naturally cautious about FOGO[1] and want to know if it is worth the effort in terms of benefits ($, greenhouse gas emissions, compost value etc). FOGO is usually 55% by weight of all waste produced by a household.
Our planning team regularly advises Councils and developers on the preferred mechanisms for FOGO, recyclables and garbage from MUDs. We also recently completed an international review of organics recovery in MUDs including Europe and North America.
There is a real mix of methods for collecting FOGO (and recyclables) in Australian MUDs.
Let’s look at each.
Chutes
Developers are providing fewer chutes in MUDs today. They take up valuable real estate, are expensive to operate and often gum up with waste. Residents like the convenience when they work, but maintenance can be a killer. Mostly developers are now opting for bin options (see below) but if they do provide a chute they generally only provide 1 chute (with an e-diverter to allow both recycling and waste to go down the same chute) or 2 chutes (one each for recycling and waste). Chutes for FOGO are very rare.
In our view chutes are almost always unnecessary. Cardboard clogs them up, E-diverters break or are misused. The taller the building the more likely that the chute system will fail or clog up due to the many additional mechanisms with height. Broken chutes leave residents frustrated and often leads to improper disposal (dumping on the floor etc).
Many State guidelines still require chutes for buildings above 7 storeys. But it takes no more time to go down in a lift from the 9th floor than the 7th, or 20th for that matter. Thankfully most State documents are guidelines only (and not statutory requirements). So, for many reasons, chutes and FOGO are not a good mix.
Bins in the basement
This is the best option in terms of costs and contamination. Walking or taking the lift to the waste room is almost always preferrable. It reduces the likelihood of dumping on each floor, it reduces contamination of streams and allows for more and different recycling options in the basement (e.g. FOGO, textiles, batteries, fluoro tubes etc).
However, it requires the resident to bring the FOGO bag down to common FOGO bins in the basement or bin bay.
In general, 1 x 240 litre FOGO bin per 3-4 units collected weekly adequately substitutes the weekly volume of food being taken out of the red bin.
There are many MUDs providing successful FOGO services with good recovery rates and low contamination, via the bins in the basement method. It is simple and provides the flexibility to accommodate changing services.
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Bins on each floor
A smaller number of MUDs provide a FOGO bin on each floor. Usually in a bin room. Of course that takes up more space on each floor but is very convenient for residents. Littering, contamination and improper disposal are also minimised. It does require an agreement with the cleaners or corporate body to remove the bins to the ground level for bin night.
Bins placed on each floor can work for low-medium rise buildings but it becomes increasingly labour intensive for taller buildings.
There are many MUDs providing successful FOGO services with good recovery rates and low contamination rates via this method.
Pneumatic Systems
Pneumatic systems use vacuums to suck waste along a tube to a central waste hub, from which it is removed by a truck.
These are very expensive and are generally only cost effective across a CBD or a large greenfield development.
You still need to drive a truck to the Hub so doing it for a single building doesn’t add any value. To permit recycling you need colour coded bags and optical sorting at the Hub.
MRA research did not find a single example of FOGO collection using pneumatic systems in Australia.
There are pneumatic systems operating for FOGO (mainly FO) in Europe but usually as part of a district wide scheme.
Suburban or street corner hubs
Some European cities provide organics (and recyclable) collection via a bulk bin located centrally to a suburb or located on prominent street corners.
This works well in terms of quality and contamination because only the most committed households use the system. On the other hand recovery rates of organics are usually significantly lower than a system operating in each MUD.
In-sink macerator
In-sink macerators are shredding units installed in kitchen sinks. Food waste is shredded to small pieces which are then flushed with water into the sewerage system. This is a space-efficient way of managing certain types of food waste. Bones and fruit stones still need to be disposed of separately.
50% of Auckland MUDs have insink macerators. They work well to capture food waste from MUDs. However, the water/sewage authorities in Australia have generally taken a dim view of them because of the additional load they place on the waste water treatment system. While the FO adds to BOD (biological oxygen demand), the bigger challenge is the additional volume of liquid going down existing (and often constrained) sewer lines.
On the positive side FO is a brilliant source of energy for anaerobic digestion at the sewage treatment plant. But unless the water authorities have a change of heart, this is not a serious contender for FO collections.
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Onsite food processing units
This technology is not really a FOGO collection method but works well for high density FO sources such as mixed use developments with MUDs and food courts or restaurants on ground level.
There are a range of onsite food processing types – including macerators, digestors with disposal to sewer, and dehydrators.
However, they are a relatively high cost option compared to universal FOGO collections (i.e. a 240 bin service rolled out to all households in a Council area), due to the lower economies of scale.
Having said that, on-site processors are becoming much more common for large commercial food generators, mixed use developments, universities, hospitals etc. They have had a fairly limited application in MUDs only.
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In summary:
- Councils should definitely include MUD FOGO in their waste strategy evaluations. MUDs will generate a preponderance of FO.
- Most Councils collect MUD FO as part of a universal FOGO roll-out to all SUDs and MUDs.
- Irrespective of the collection method, a FOGO service will improve recycling rates, reduce greenhouse gas emissions and most often reduce costs (especially where landfill levies are rising).
- Contamination rates are best managed via a comprehensive and ongoing education program, whichever collection system is adopted. (Kitchen caddies and liners are also highly beneficial in terms of recovery rates and lowering contamination).
- The most effective systems for collecting FOGO in MUDs are “Bins in the Basement” and “Bins on each Floor”.
[1] We should also clarify that by FOGO we really mean FO (or predominantly food) since many MUDs do not have gardens or the gardening contractor removes the garden organics (GO). So while Councils may offer a FOGO service, the MUDs will generate a preponderance of FO.
If you would like further information, please contact us at info@mraconsulting.com.au
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