North London boroughs told of composting concerns

The message comes from LondonWaste Ltd which has highlighted concerns over plastic contamination in green waste at its Edmonton composting site. LondonWaste Ltd is the waste management company in which North London Waste Authority boroughs and SITA UK have an equal share.

” Residents need to understand what green waste means if they partake in a green waste system and to know the difference between compostable and biodegradable bags “
– Wendy Lord, LondonWaste Ltd
At the same time, discussions have been instigated with equipment supplier Agrivert over the level of effectiveness of the screening process at the site.

Agrivert was commissioned to build the 30,000 tonne in-vessel kitchen and green waste plant in Edmonton which opened in March this year. The NLWA has now agreed with contractor SITA arrangements for taking the composted material from the Edmonton site for agricultural, soil blending and landscaping purposes.

Quality
LondonWaste board members have been told that the quality of composted material from the plant is “pleasing”, but that there is a concern regarding plastic contamination from plastic bags.

Speaking to letsrecycle.com, Wendy Lord, spokeswoman for LondonWaste denied that plastic contamination was a problem, although she did accept there was a need for councils to increase public awareness about best practice for composting.

Bags
Ms Lord said: “Residents need to understand what green waste means if they partake in a green waste system and to know the difference between compostable and biodegradable bags.”

LondonWaste recommended that the public always use DIN-certified bags for their green waste – bags which achieve complete biodegradation and disintegration under compost conditions (see letsrecycle.com story).

Screening
Harry Waters, sales and marketing director for Agrivert defended the screening system used for material at the Edmonton facility. The company has provided a “wind sifter” machine to separate particles towards the end of the composting process into lighter particles such plastic and heavier, woodier particles of compost.

Mr Waters said: “There is less than 1% plastic contamination in the site because of our use of the wind sifter, which enables us to produce a high quality end-product even when dealing with contaminated waste.”

The Agrivert sales and marketing director did, however, agree that councils generally could do more to inform the public concerning the use of plastic bags in green waste collections.

He said: “We need to start the project on the right footing and get the plastic out at the first stage.”