Waste characterisation
Encyclopedia
Waste characterisation is the process by which the composition of different waste streams is analysed. Waste characterisation plays an important part in any treatment of waste which may occur. Developers of new waste technologies must take into account what exactly waste streams consist of in order to fully treat the waste. The biodegradable element
of the waste stream is vitally important in the use of systems such as composting or anaerobic digestion
.
Municipal waste streams are commonly broken down into the following constituents:
Biodegradable fraction
Absolute hazardous entries are hazardous not due to the composition of the waste but by virtue of the process that produced it, the same is true for non-hazardous absolute entries. Mirror entries can either be hazardous or non-hazardous depending on the composition of the waste.
Deciding whether a mirror entry is hazardous or non-hazardous by composition involves reference to the Approved Supply List (ASL) initially. If a substance is not listed in the ASL then the regulations permit the use of other sources such as Manufacturer's Safety Data Sheets (MSDS) to classify the waste. These documents contain Risk Phrases, which describe the hazards that the substance or substances present. Risk phrases have threshold values attached to them that indicate what concentration of a substance must be present in order for the waste to be classified as hazardous by the Hazard Code attached to the Risk Phrase.
Biodegradable waste
Biodegradable waste is a type of waste, typically originating from plant or animal sources, which may be degraded by other living organisms. Waste that cannot be broken down by other living organisms are called non-biodegradable....
of the waste stream is vitally important in the use of systems such as composting or anaerobic digestion
Anaerobic digestion
Anaerobic digestion is a series of processes in which microorganisms break down biodegradable material in the absence of oxygen. It is used for industrial or domestic purposes to manage waste and/or to release energy....
.
Municipal waste streams are commonly broken down into the following constituents:
- Film plastic-LDPE
- Dense plastic-HDPE, PETPolyethylene terephthalatePolyethylene terephthalate , commonly abbreviated PET, PETE, or the obsolete PETP or PET-P, is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination...
- FerrousFerrousFerrous , in chemistry, indicates a divalent iron compound , as opposed to ferric, which indicates a trivalent iron compound ....
metal - Non-ferrous metals
- GlassGlassGlass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
- Textiles
- "Other" any remaining items which do not fit
Biodegradable fraction
- GlassGlassGlass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
- PaperPaperPaper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....
& cardboard - Garden waste or green wasteGreen wasteGreen waste is biodegradable waste that can be composed of garden or park waste, such as grass or flower cuttings and hedge trimmings, as well as domestic and commercial food waste...
- Fines (items below a certain screen size)
The European Waste Catalogue
The first step in characterising waste is to decide on the appropriate EWC code. The list of these codes is available from the Environment Agency's website in the guidance document WM2. These codes carry three categories - absolute non-hazardous, mirror entries and absolute hazardous.Absolute hazardous entries are hazardous not due to the composition of the waste but by virtue of the process that produced it, the same is true for non-hazardous absolute entries. Mirror entries can either be hazardous or non-hazardous depending on the composition of the waste.
Deciding whether a mirror entry is hazardous or non-hazardous by composition involves reference to the Approved Supply List (ASL) initially. If a substance is not listed in the ASL then the regulations permit the use of other sources such as Manufacturer's Safety Data Sheets (MSDS) to classify the waste. These documents contain Risk Phrases, which describe the hazards that the substance or substances present. Risk phrases have threshold values attached to them that indicate what concentration of a substance must be present in order for the waste to be classified as hazardous by the Hazard Code attached to the Risk Phrase.
See also
- List of waste treatment technologies