2. Definition of biodegradable and sewage sludge
How the Environment Agency defines the terms 'biodegradable' and 'sewage sludge'.
These definitions apply to all processes and operations.
Biodegradable waste is material that can undergo biological anaerobic or aerobic degradation leading to the production of the following, depending on the environmental conditions of the process:
- carbon dioxide (CO2)
- water (H2O)
- methane (CH4)
- compost or digestate
- mineral salts
The biological treatment of waste uses biological processes and agents to bring about a change in that waste. This may be for recovering the waste, remediating a contaminated material, or as a pre-treatment before disposal.
Biological treatment does not include physical treatments like dewatering, mechanical separation or chemical treatments such as lime dosing.
The term 鈥榖iowaste鈥� is often used to describe biodegradable, organic waste. Biowaste is defined in Article 3 of the Waste Framework Directive to mean, 鈥淏iodegradable garden and park waste, food and kitchen waste from households, restaurants, caterers and retail premises and comparable waste from food processing plants鈥�.
Biowaste can also be called 鈥榦rganic matter鈥� which is a collection of complex humic substances and other organic compounds generally of animal or vegetable origin.
Sewage sludge means residual sludge from sewage plants treating domestic or urban waste waters. It also includes sewage sludge from other sewage plants treating waste waters that have a similar composition to domestic and urban waste waters. 鈥�