Dublin City Council is urging people to continue separating their household waste before bringing it to recycling centres even though some of it is "mixed" back together by council workers.
Certain plastic products and Tetra Pak containers separated out into different bins by consumers at the council's "bring centres" are transferred back into the one large bin before they are taken for processing, a council official said.
The practice applies to plastic wrapping and light packaging, Tetra Pak containers and plastic bottles at the Grangegorman "bring centre" and plastic wrapping and Tetra Paks at the city's eight other full recycling facilities.
Paper waste, also handled by the council, is not included in the re-mix, Ms Margaret Foynes, the council's environment awareness officer, said.
The products, segregated out by the public, were put back together, "for ease of transport", to the Oxigen recycling plant at Clonshaugh in north Dublin, where workers separated them again. Extra products were included in the mix at Grangegorman because it was "a smaller facility, very restricted for space", she said.
Users of the centres who witnessed the practice were concerned that the waste they had segregated was being dumped in landfills.
This was not the case, Ms Foynes said. "The materials are taken from the separate bins and consolidated for transport to the Oxigen sorting facility at Clonshaugh. They are mixed for transport, but they are definitely not going to landfill."
She urged people using the facilities to continue putting the materials in their individual bins to stop "contamination".
"The mixing only happens in transit. The materials only come back together briefly. It doesn't mean people are wasting their time separating them out, because they're keeping the products in good condition."
If left together in the one bin for too long, liquids left in the end of containers could damage other products, she said.
The council is in discussions with residents in the Grangegorman area to develop a larger recycling centre at Prussia Street, she added.
A spokesman for Oxigen said waste that was mixed when it arrived at Clonshaugh was initially sorted mechanically and then "handpicked" to maintain "levels of purity".
