Central Otago District Council environmental engineering manager Peter Greenwood said the public did not "appreciate the gravity of this issue", and a public education campaign was being prepared.
Until February last year, all Central Otago's glass recycling was sent to an external crushing plant, at Parkburn Quarry, near Cromwell.
However, since then the contractor could no longer accept the glass because of the "high contamination levels", Mr Greenwood said.
In the past 12 months, 990 tonnes of glass from blue recycling bins had gone into landfill, he said.
The contamination came from things residents were putting into the bins, such as bottle caps, cigarette butts, alcohol packaging and other general rubbish and recycling.
"The levels of contamination were unacceptably high and this made it unfeasible for them [the contractor] to keep crushing our glass ... it [the glass] still had food or other general waste present so could not be mixed with clean glass for crushing."
Mr Greenwood said the frequency of bin collection was consulted on as part of council's 2018-28 long-term plan, and there had been an improvement since increasing the frequency of kerbside collection of yellow bins, which are for plastic and paper/cardboard recycling.
There had also been a bin survey of residents in April 2018, and feedback to residents rating their "household recycling efforts".
"It was hoped that this feedback would motivate people to improve, but sadly this was not the case."
Mr Greenwood said over the next few months council would be rolling out some educational videos, social media prompts and hard-copy brochures encouraging correct recycling.
"We need everyone to commit to playing their part to ensure that they clean their glass thoroughly and place their items in the correct bins. When this is not done, it simply undermines the efforts of everyone else who does care about glass recycling."
Advice for glass recycling included to recycle only bottles and jars, and take the lids off them.
Glass that cannot be recycled and should not be put into kerbside bins includes light bulbs and fluorescent tubes, cookware and drinking glasses, and window and mirror glass.
Source: Otago Daily Times
The original article can be found on odt.co.nz