From April 2009 all products containing gypsum products can no longer be disposed of at landfill. Although gypsum by itself is not considered a hazardous material, when mixed with other biodegradable waste it has the potential to cause harm and it is then classified as a hazardous material.
The Environment Agency has issued a guide which is intended for producers and waste managers of gypsum wastes or other waste streams with a high sulphate content.
Sulphates in gypsum can break down in a landfill to produce toxic and odorous hydrogen sulphide gas. The landfilling of gypsum and other high sulphate-bearing wastes with biodegradable waste has been prohibited in England and Wales since July 2005. However, we have been taking a pragmatic view that separate disposal of these substances is not necessary where a waste contains less than 10 per cent of gypsum or other high sulphate bearing waste. This was a working guideline that we always planned to review in response to scientific research.
The relationship between sulphate in waste and the production of hydrogen sulphide gas is complex, but there is no minimum quantity of gypsum below which no hydrogen sulphide gas will be produced in a landfill. The Environment Agency have therefore revised their guidance to remove the 10 per cent guideline value.
The intention is to encourage the reuse and recycling of more gypsum while reducing the potential production of hydrogen sulphide gas at landfill.
How to deal with waste gypsum
-
All waste must be treated before it is sent to landfill.
-
Loads containing any identifiable gypsum should not be taken to landfill but should be treated to remove the gypsum.
-
Where a load of gypsum must go to landfill, it must be deposited in a separate cell where no biodegradable waste has been accepted.
-
The simplest method of treating gypsum is to separate it from other waste at the point of production.
-
It could also be sent it to a contractor to sort it at a waste transfer facility.
-
Separated gypsum can be recycled or reused, for example in the manufacture of plasterboard or for agricultural soil treatment.
Enforcement
After 1 April 2009, if gypsum is accepted for disposal in the same cell as biodegradable waste, the Environment Agency will take action in accordance with their enforcement and prosecution policy which can be found at http://www.environment-agency.gov.uk/static/documents/Business/mwrp007_2163539.pdf