Food and green waste comes from both the household and commercial sectors and, while the majority of green waste is generated at home, more food waste comes from the commercial sector. Material being diverted from landfill is generally treated using either composting or anaerobic digestion.
Organic waste makes up a significant section of the household waste stream in the UK – around 20% is green waste and 17% kitchen waste.
There are a number of treatment routes, other than landfill or MBT, for organic waste:
The end product from open windrow and IVC treatment – compost – can be used in horticulture, agriculture, land remediation and on brownfield sites. The output from anaerobic digestion (AD), which is known as digestate, can also be used in several of these applications.
Composters who treat food waste which includes animal-derived products, must comply with Animal By-Product Regulations (ABPR) to ensure the safety of the compost they make. The ABPR sets out a number of rules which composters must follow in order to kill any animal pathogens which could remain in the compost and potentially spread disease.
In Scotland, AD operators have reported a significant increase in the amount of food waste treatment taking place since the end of 2013, which could see an impact on the food waste price market in Scotland. This coincides with the Zero Waste Regulations coming to force from January 2014, which require Scottish businesses in urban areas producing more than 50kg of food waste to present it separately for collection.
letsrecycle.com provides four prices to indicate trends in the cost of UK composting and anaerobic digestion.
Prior to August 2012 three gate fee prices were shown: green waste disposal; food waste disposal; and, a selling price for compost.
Due to the growth of the anaerobic digestion market, the first two prices were replaced with prices for sending green waste for open windrow composting; sending food and/or green waste to in vessel composting; and, sending food waste to anaerobic digestion.
A selling price is still given for graded, clean and contaminant-free compost and mulch sales prices. This gives an indication of the amount good quality composts and mulches produced are being sold for. Compost is typically available in at least three grades: 0-10mm, 0-25mm and 0-40mm.