When Mike de Silva, Crossrail’s Sustainability Manager, met Javier Rojo, Quantum Waste’s Director, for the first time back in July 2012, the topic of discussion was applying a new composting technology to the recycling of food waste at Crossrail’s Central offices at 25 Canada Square, Canary Wharf.
The conversation moved quickly into a much more ambitious target: the implementation of a food waste recovery system that could eventually recycle the food waste produced by the thousands of construction and management staff involved in the construction of the Crossrail project.
Mike looked for volunteers among Crossrail contractors with the capability (and, no doubt, with a dose of stamina and ingenuity) to implement a pilot project using Quantum Waste’s technology. Casey Fleming, Morgan Sindall’s Environmental Manager, raised his hand on behalf of his company and that is how the Closed Loop Waste Exemplar project started at the C350 Crossrail construction site (located at Pudding Mill Lane, next door to the Olympic Park).
Crossrail has worked together with Quantum Waste and Morgan Sindall to design a waste management system that maximizes the amounts of materials recovered, that provides a flexible collection system and that adapts to the varying conditions inherent to the life cycle of a construction site.
The system implemented had in consideration Quantum Waste’s premise that it is more efficient to bring technology closer to waste rather than transporting waste large distances to bring it closer to technology and it was designed around Quantum Waste’s container based decentralized composting technology.
Composting is the biological oxidation of organic matter, a procedure equivalent to incineration at a chemical level but without flames. The process is highly exothermic and reaches temperatures of 60 degrees centigrade.
The solution implemented is not only the most sustainable for what it does (transforming food waste into organic fertilizer and recovering several types of recyclable materials) but also for the way it does it (reduced carbon footprint, creating local jobs, lower fuel consumption, etc).
Implementation process. Changing expectations.
After careful consideration the agreed system involves the collection of just two types of bags: “Food waste” (that is converted into organic fertilizer) and “Everything else” (that is separated into cardboard, paper, metals, plastic, etc.. and then baled and re-used).
During the project implementation, the most challenging part was changing the mentality of those working on site and to focus their minds on a new, albeit simpler, recycling system. Susan Harris, Morgan Sindall’s site office manager deserves a lot of credit for the implementation. Susan had to work hard and weather the general uproar that happened on site when people saw their desk bins disappear: From that moment there would be no other option than recycling!
Brand new recycling banks were installed on site across the different working areas.
A significant effort was made to provide people with information using all communication routes available including email, posters, photos and obviously word of mouth!
Inevitably, with only two disposal options, a number of questions appeared regarding the appropriate allocation of “exotic” materials like, for example, tea bags (food waste), sliced bread bags (recyclables), waste from sweeping floors (food waste), a food container stained with some sauce (recyclables), etc…
Performance. Waste recovery and fertilizer quality
The project is currently recovering more than one tonne of waste materials per month of which 50% are compostable materials. Recovery rates improved from low levels before the project to ~65% at the start of the project and evolved into the current ~90% recovery rates. The amount of waste that could not be recovered and that will be incinerated was reduced from ~35% to ~10% of the total. This is a 40% improvement driven by staff involvement and training.
The materials collected are recovered less than 6 miles away from where they are collected. By using small vehicles (50 mpg vs. 12mpg of traditional compactor trucks) over shorter distances the project reduces the consumption of fuel by a factor of 10+. The cooking oil recovered from the project is transformed into biodiesel at a local facility.
The small vehicle strategy and end of the day collections facilitate the adaptation to the natural changes in a construction site and minimizes interference with construction works.
There is a reduced carbon footprint at all stages of the process (smaller vehicles, shorter distances, fewer handling operations and delivery direct to customers)
Every tonne of organic fertilizer produced means the avoidance of close to two tonnes of CO2 emissions. Additionally the production of organic fertilizer reduces the requirement for chemical fertilizers and the amount of energy required to produce them.
The project eliminated the need for a on-site compactor which reduced the amount of flies/vermin problems associated with storing waste on site and provided additional working space.
The project implemented aims to transform the way society manages its waste and proposes a simpler, one step, more sustainable practice, thus reducing the environmental and financial cost of handling waste. Several benefits arise:
Simplicity: Only two types of waste streams are being collected: Food waste & Everything Else. In most professional environments once organic waste (food and garden) has been removed from the waste streams almost all the remaining materials are made of plastic/paper/metal/glass and, as such, can be recycled.
Creating wealth: Organic waste is transformed into valuable components – fertilizer and heat. Recyclable materials are recovered and delivered to end users.
Integration: The technology can be easily integrated into the existing practices of organic waste collection and disposal.
Recycling rates: The segregation of organic waste maximizes recycling rates and landfill diversion. Surveys show that organic waste collection improves the public’s satisfaction levels.
Traceability: Companies’ sustainability commitments and increased regulation require traceability of produced waste and its final destination. Because the project collects individual bags in dedicated vehicles it is in a unique position to report back what is collected, what and how is recycled and what was the final destination.
Social impact: The manufacturing and maintenance of the installed decentralized units will create both qualified and non qualified jobs at a local level.
Environmental impact: Treating organic waste in the presence of oxygen significantly reduces the emission of green house gases associated with the decay of organic matter.
Renewable energy: The composting reaction is highly exothermic. The small scale units are on wheels and can be easily transported to wherever there is a need for low intensity (50 to 60C) heat.
Award recognition and next steps
All the waste recycling work done at Pudding Mill Lane was recognized by the industry when the project was short listed as a finalist on the 2013 Resource Revolution Awards in the Closed Loop category together with companies like Coca Cola and Marks & Spencer. Retail companies, with significant scrutiny from its retail customers, distinguish themselves for their environmental profiles but for a civil works construction operation working with a small start up company to be included in such a selected group is an exceptional achievement.
The project team is now looking at increasing recycling levels among Crossrail operations and is already busy working on a heat recovery application from the food waste collected which would be a first of its kind. Let’s do things the best way we possibly can and watch the progress!