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Landfill

Portsmouth is one of the best authorities in the country for landfill diversion, the bulk of our waste goes to the Energy From Waste plant (EFW).

What is a Landfill?

A landfill site is an area of land used to dispose of waste either by digging a hole for the waste to go into (landfilling) or by putting it directly onto the ground and mounding it up (landraising).

Originally landfill sites were just holes in the ground where any rubbish was dumped.  Then people realised that this caused contamination into the surrounding area.  To prevent contamination, holes were then lined with clay to help contain leachate, the liquid produced from the waste breaking down.  Now, any new landfill site is lined with a thick plastic lining to contain the leachate so that it can be easily removed for treatment.

Landfill sites are used to dispose of both household and commercial waste which includes:

Organic matter

• Food
• Wood
• Cardboard
• Paper
• Garden waste
• Textiles

General household waste

• Plastic
• Tin cans
• Nappies
• Glass

Construction waste

• Soil
• Brick
• Rubble

With the rise in awareness of recycling and reusing most of the waste put into landfill sites is construction and commercial waste. These materials are generally inert and do not react with each other, unlike the organic matter.

How safe are landfills?

Providing the sites are regularly monitored and any gases and leachate are removed the sites are relatively safe.  There is a small risk from escaped gas, but this is more likely to be a problem to plants and trees than cause an explosion. Most sites that are full are converted into open spaces so that if gas did escape it would go straight into the atmosphere.

The Landfill site at Port Solent

Before the Energy Recycling Facility was built in Portsmouth, most household waste was disposed of in the landfill site at Port Solent, which was first used in the 1960s.  Growing awareness of environmental issues meant that in the 1990s simply throwing rubbish in a hole was no longer acceptable.  After the 1990s,  the landfill hole was clayed lined before any waste was added, to ensure that leachate was contained within the site.

Gradually the site filled up and areas were covered over forming the pyramids you can see today.  The site closed completely in 2004 and the area is currently being capped and covered with soil to create an open space for the public to use in the future.  This will provide spectacular views over Portsmouth Harbour and the surrounding area.

Is the site monitored?

The site is monitored regularly for gas emissions and leachate production and monitoring will continue for many years. 

The degrading waste produces 400-500 cubic metres of gas per one tonne of rubbish. As the area is covered over, gases form in the waste decaying below.  The gases contain methane, carbon dioxide and small amounts of other gases. These are fed to the nearby energy recovery station which in turn feeds into the national grid. Enough electricity is produced to supply 2,400 homes. 

Leachate becomes toxic as it reacts with other waste.  To prevent contamination of nearby water, Portsmouth Harbour for example, the leachate is fed into sewage systems and treated at Budds Farm in Havant by Southern Water.