The rising cost of waste material disposal and a growing consciousness for the environment also contribute to the increasing importance of waste wood recycling. The term “waste wood” includes all woods and wood-based materials that have come to the end of their product lifespan and are thus considered waste.
Collection and Sorting of Wood Waste
Wood waste can be collected via a number of routes depending on its source, amount and grade. Household wood waste is usually collected at household waste recycling centres (HWRC) or via the council’s bulky waste collection (in the case of furniture), where this is available. Wood waste from C&D and C&I sources can be collected either by waste management companies in skips or can be taken to reprocessors directly by the producer.
There are also a number of informal wood waste disposal routes such as burning in small scale boilers either by the producing company or its employees.
The price of wood waste depends on its quality and thus the sorting and grading operations required to meet the expected wood quality. Wood sorting is 'designed in' to the collection system by pricing incoming wood waste.
This gives waste producers and intermediaries price incentives to keep lower grade wood waste separate. The wood waste is then subject to a range of sorting and grading processes.
More investment and overheads in processing are required to produce high value feedstocks whereas high throughput and low handling costs are necessary to produce a lower value, higher volume product. Larger processors may choose some balance between the two.
Wood waste is often sorted according to its grade. Grade A material goes to higher value markets such as animal bedding and panel products as well as in any incinerator. Grade B can be used in panel products and WID compliant incineration3 . Grades C and D must be used in a WID compliant incinerator (Grade D is hazardous wood waste and only suitable for specialist landfill or WID compliant incineration).
Sorting wood waste into the various grades is not always straight forward and is not always done consistently by all producers. The PAS111:2012 ‘Specification for the requirements and test methods for processing waste wood’ provides guidance on the quality requirements for a number of end-uses and also sets out 'Grades' for wood waste.
There is a separate PAS, PAS104:2004 ‘Wood recycling in the panelboard manufacturing industry’ testing for chemical contamination which is still being developed, reports from www.defra.gov.uk.
