Recycling benefits the climate by reducing greenhouse gas emissions, and it conserves natural resources such as timber, water and minerals. Yet in 2014, only 44.9% of household waste was recycled, and fell to 44.3% in 2015. Traditional waste handling systems are inefficient, relying on households to sort waste into different bins that are transported to separate locations. The waste cannot be completely separated either.
For instance, paper containers are typically made of a paper exterior, a foil interior, a plastic screw cap, and remnants of whatever substance was inside the containers. At best, households can screw off the plastic cap for recycling and empty the container as much as possible. They cannot separate the paper from the foil.
But with DONG Energy's REnescience technology, enzymes separate waste so that the materials can be recycled. Leftovers and paper are turn into biogas, plastic is re-purposed for new plastic goods, and foil is burned in a waste incinerator to generate energy.
When unsorted waste enters a bio plant, it is given a treatment that can be likened to a washing machine. The waste slowly spins for hours in a mixture of water and enzymes. It is then separated into a biological faction (including substances such as food waste) and a non-biological faction (including substances such as plastic and foil). From there, the substances are used in various ways: metal and plastic are recycled, non-degradable plastic is used as fuel at the incineration plant and bioliquid (fluid made from dissolved organic parts of waste) is turned into biogas, which is used for green power, green gas and transport fuel.
REnescience produces four to five times the amount of biogas from biodegradable parts and recycles more waste than traditional waste handling systems. By being able to separate out all the parts, it can release more value from the waste. It also centralises the sorting of waste to one location, making the collection system simpler.
The new bio plant will be built in Norwich near Manchester. It has an annual capacity of 120,000 tonnes, which corresponds to the waste from almost 110,000 households. The waste will be supplied by FCC Environment, a waste management company which already collects household waste in the region. Construction is currently underway and the plant is to be commissioned in early 2017.