Glasgow Clyde College Anniesland Campus food residuals project

Early in 2010, while the second phase of the new college campus was still under construction, DRCET, in GCC_Anniesland_Logopartnership with the former Anniesland College, secured funding from the Scottish Climate Challenge Fund for a food waste composting facility on the College site.

The project aimed to use the food waste from the College to produce high quality compost for use by the Landscape Design and Construction course on projects in the College grounds.  The funding allowed for the purchase of an A900 “Rocket” in-vessel composter (IVC) as well as a temporary part time post to develop the initial food collection and composting systems in conjunction with the College.

The project became operational in September 2010, coinciding with the opening of the new College canteen operated by Inspire Catering.  Food waste is collected (usually on a daily basis) from five locations:

  • The Space refectory

    Anniesland_Rocket

    The A900 Rocket In Vessel Composter

  • the G53 training restaurant
  • the coffee shop
  • the special needs kitchen and
  • Treasure Trove Nursery

The food waste is then added to the Rocket IVC along with equal volumes of a bulking agent – wood chip, wood shavings etc. where it is processed in the IVC for 10 to 14 days to produce compost, which is then screened and left in small bays to mature for a further 6-8 weeks.  At the College a significant proportion of the bulking agent consists of wood shavings produced by the joinery workshops (Introduction to Construction Trade Skills course), thus further reducing waste arisings from the College and saving on costs of disposal.

The following photos show the type of materials that go into the Rocket.

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The process works by aerobic bacteria breaking down the organic material and generating heat which in turn contributes to the decomposition process.  As the name indicates these bacteria require oxygen to do this.  They are also known as thermophilic, i.e. heat loving bacteria working most efficiently at a temperature of over 60C.  The food residues are mixed with wood chip for two reasons, firstly to provide a source of carbon which the bacteria require, and secondly to give structure to the mix enabling air to be retained.  Without oxygen the bacteria would soon die off and be replaced with anaerobic bacteria which produce methane and other hydrocarbons – the process which takes place under controlled conditions in an anaerobic digester. The Rocket is also capable of composting grass cuttings and other green waste.

In order to keep the bacteria oxygenated the Rocket has a shaft running up its centre with blades attached which turn the mixture over while gradually pushing it towards the outlet.  This process is automated and can be adjusted so that turning takes place at intervals of from half an hour to three hours.  Each turning involves a backward turn of 30 seconds followed by a forward turn of 3 minutes.  There is also a thermostatically controlled heat blanket near the input end which is required to ensure the perimeter stays at the same temperature as the core. In practice very little heat comes from this source – most of the heat is generated by the bacteria breaking down the organic material.

To date 17.5 tonnes (28 cu. metres) of food waste has been processed to produce compost used by the landscape students.

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In terms of dealing with food waste, the College will therefore be compliant with the Waste (Scotland) Regulations 2012‏ which will start to come into effect from 1 January 2014.  The main requirement of these regulations affecting the College is the requirement to present separated dry recyclables (metals, plastics, paper, card and glass) and food waste of more than 50 kg/week for collection from the end of 2013. There will also be a ban on the use of conventional macerators/waste disposal units connected to the drainage system.

If you would like to find out more about this project or how to volunteer with this project then please contact us.