20 Waste codes
20 waste codes are municipal wastes (household waste and similar commercial, industrial and institutional wastes) including separately collected fractions. Your permit lists the 20 waste codes you can use. You must follow the guidance given in the Before you start section.
20 02 are garden and park wastes (including cemetery waste).
20 02 01 Plant tissue waste from parks only
You can use these wastes if you hold SR2010 No 4 – see table 2.2B.
It includes:
- waste from shredded source-segregated garden waste
- mulch
In your deployment form use the waste code and description 20 02 01 Plant tissue waste from parks only. State if it is waste from shredded source-segregated garden waste or mulch.
Waste from shredded source-segregated garden waste
This waste stream can include source-segregated household green garden waste collections. Local authorities usually collect the waste and shred and stockpile it before it is available for landspreading. This is often called ‘shred and spread.’
The local authority:
- will have waste acceptance procedures to remove any unsuitable materials
- does not carry out sanitisation or recognised composting activities
Some rotting may occur to stockpiled waste before and after shredding.
The waste types local authorities accept include:
- grass and hedge cuttings
- small plants and shrubs
- small branches, twigs and bark
- leaves and weeds
- flowers
You must not accept waste that contains physical contamination such as:
- kitchen and food waste including vegetable peelings
- plastics including bags and plant pots
- glass, sharps and metal
- rubble, stones and soil
- large branches, logs and stumps
- treated timber – this has potential dangerous or hazardous substances
- pet waste
- batteries
- plasterboard
Benefits and risks
Consider these benefits. It can:
- add green organic material to the soil
- condition the soil
- provide plant nutrients such as nitrogen, phosphorus, potassium, magnesium and sulphur
- encourage biological activity in the soil
Consider these risks. It can cause contamination:
- by pathogens or pests as no thermal destruction has taken place
- of soil or crops with plant diseases, fungal spores, weeds or exotic species
- to grazing and conservation land – exotic species may harm livestock or contaminate silage and hay crops
- from chemical residues such as slug pellets, weed killers or insecticides – this can affect soil biota and growing crops
- by pet faeces – this can affect grassland or land destined for root or vegetable crops
The lack of a recognised composting process means there is potential for transmissible plant diseases to survive. Landspreading these can affect crops and animal health.
Applying to cultivated land may affect how herbicides and other agrochemicals work.
If a local authority shreds waste that contains kitchen vegetable waste and animal faeces, it could introduce:
- escherichia coli
- listeria monocytogenes
- salmonella serotypes
- other animal pathogens and parasites
You must follow the guidance in Landspreading: how to manage soil health for how to manage:
- pests and diseases
- organic manure
- soil organic matter and applied agrochemicals
Operational considerations
Shredded green material contains nutrients in non-readily-available but mineralisable and organic forms. The carbon to nitrogen ratio varies and depends on the wastes you accept. If the waste has a high woody material content it will have a high carbon to nitrogen ratio which may cause nitrogen lock-up in the receiving soil.
You will need to quantify nutrient additions in your benefit statement when you justify your proposed application to land. Your benefit statement must address the:
- potential for pathogen and weed transmission
- risks of spreading this material
- preventative measures you will use during and after the activity
You will need to incorporate this waste into the soil soon after landspreading to allow biological activity to release the nutrients.
Mulch
You can use waste from wood, bark and other plant tissue matter. You can also use 20 02 01 Seaweed as a mulch.
Use mulch to:
- suppress weeds
- reduce water loss from the soil
- provide nutrients or improve the soil structure from the organic matter content
Make sure the mulch you accept is made from suitable materials. These include:
- wood chips from clean untreated timber
- oversize chips from compost screening
- composted source-segregated green waste
It must be:
- free of weed seeds and plant pathogens – composted or pasteurised
- clean and free from physical contamination
- made up of particle sizes of 15mm plus to improve its long term effectiveness, aeration and drainage
- low in salts such as sodium and potassium
The waste must not have a high conductivity result. High levels of sodium and potassium could discourage biological activity in the top layers of the soil.
You must follow the guidance for how to manage salty whey and other high conductivity waste in Landspreading: how to manage soil health.
For waste not treated before mulching, you must show there is no risk to the receiving soil. Do this through your waste analysis.
Do not accept mulch that contains:
- plastics
- seaweed contaminated with flotsam and jetsam and other physical contaminants
- untreated and unsanitised green waste
- treated and painted timber products
- recognisable paper and cardboard
- metals and foils
- plasterboard
- large pieces of masonry or stones
- glass
Benefits and risks
Consider these benefits. Mulch can:
- suppress weeds
- protect against soil erosion
- protect the soil from varying temperatures, for example ground frost
- increase water retention
- reduce soil splashing from rain – beneficial for salad crops and soft fruit
- act as a slow release source of nutrients as it provides organic matter benefit long term
- increase soil organic matter and improve soil bulk density after incorporating
Consider these risks:
- incorporating large amounts of woody mulches may temporarily increase the carbon to nitrogen ratio in the soil causing a net lock up of crop available nitrogen
- there is a higher risk of plant pathogens from untreated plant matter and woody material
- increased risk of pathogens harmful to humans and animals in untreated material
- applications to cultivated land may affect the activity of herbicides and other agrochemicals
You must follow the guidance in Landspreading: how to manage soil health for how to manage:
- pests and diseases
- organic manures
You must also follow the guidance for wood waste under the 03 01 waste codes.
Operational considerations
You must apply mulches as soon as possible after stopping the cultivation and planting operations.
Consider:
- incorporating at a depth of between 50 to 100mm
- that you could refresh shallower depths with more applications if cropping or planting allows
- that a deeper application is generally a one-off application to allow crops to establish
- the application rates – they may vary between 5 and 80t/ha depending on the depth and bulk density of the material
- reapplying mulch to perennial crops such as strawberry and soft fruit production to replace losses through natural oxidation and soil incorporation
- for annual crops, the need to incorporate any remaining mulch with crop residue by the cultivations for the next crop
Mulch is naturally incorporated into the upper layer of the receiving soil. The upper layer gets repeatedly wet and then dry which causes biological action and oxidation. As it settles the mulch layer further reduces on the surface of the soil.
You will need to apply a shallow layer of mulch so that normal agricultural operations can incorporate the material into the agricultural soil profile. For example, you can use deep, shallow and subsoil ploughing. Spreading means any method of applying waste to the surface of the soil or directly within the body of the soil (rooting zone).
If you use the mulch for ecological improvement you may not need to incorporate the mulch. Leaving the mulch on the surface allows it to decay over time as the vegetation it was placed to protect establishes.
Further guidance is provided in:
- BSI PAS 100: Specification for composted materials
- PAS 111: Specification for the requirements and test methods for processing waste wood
20 02 01 Seaweed only
You can use 20 02 01 Seaweed only if you hold SR2010 No 4 – see table 2.2A.
Seaweed can contain physical contaminants like 20 02 01 Plant tissue waste from parks only. You can use it as a mulch. See the guidance given in:
20 02 02 Soils and stones
You can use 20 02 02 Soils and stones if you hold SR2010 No 4 – see table 2.2A.
For this waste you must follow the information for 17 05 04 topsoil, peat, subsoil and stones only other than those mentioned in 17 05 03.