Composting breaks down organic material to produce safe, stable compost. The temperatures achieved during composting destroy any harmful pathogens present. You can compost most organic waste, but the method depends on the nature and amount of the waste and the level of regulation that applies.
Materials such as garden waste - so-called 'green waste' including grass cuttings, prunings and leaves - from your grounds can be composted easily outdoors. Material liable to cause smells may need to be put in a box or tank to minimise odour and prevent leaks of any liquids that may be produced.
The most appropriate composting method is likely to depend on how much waste you produce.
Composting small amounts of organic waste
Relatively small amounts of waste - eg leftover food from a small restaurant - can be treated in a 'back-door' composter similar to home compost bins. Such composting is lightly regulated providing any product is used only on site, eg for mulching flower beds around a hotel or kitchen. You should:
- ensure the composter is vermin-proof
- blend material likely to cause smells with garden wastes and other materials (eg cardboard) to reduce the risk
- aerate simple compost boxes by turning the contents (eg using a garden fork) regularly
You can also use this kind of composting at larger sites. You should establish a contained system to make it easier for staff to use and to keep the process clean.
Composting large amounts of organic waste
For larger quantities of green waste, you can generally carry out composting outdoors using relatively simple equipment such as tractors/loaders or tractor-drawn compost turners to aerate windrows. You may require additional equipment such as shredders.
These relatively simple operations tend to be labour-intensive and have a high energy cost per tonne. They may also result in poor product quality. Larger operations using specialist equipment are more likely to be successful but require investment in dedicated machinery. When deciding which machinery to use, capital cost may be less important than long-term operating and servicing costs.
Although large-scale composting is not appropriate for most businesses, there may be opportunities to form a partnership with neighbours. For example, a farm may be willing to compost rejects from a local vegetable processing plant.
The compost that you produce is likely to still be waste until it has been spread on land for beneficial purposes.
If you choose not to go down the quality protocol route the compost must be spread under either a waste exemption or a land-spreading permit. Most businesses will qualify for a waste exemption. In the unlikely event that you don't you will need to obtain a permit.
Wastes covered by the Animal By-products Regulations
Various requirements apply if material to be composted is covered under the Animal By-Products Regulations. Complying with the regulations is a requirement for any commercial waste food processing.