When Punggol resident Eloise Huang sent her husband to the blue recycling bin at the foot of their block with a big bag of recyclables, she had assumed that all of it - paper, plastic, glass and metal - would escape the landfill.
Yet, according to a recent Facebook post by Ms Huang, the collector who came to pick it up removed all paper and cardboard from the bag before dumping the rest of the contents into the green bins meant for trash.
"Save your plastics, metals elsewhere for recycling, since they will end up in the normal bin," she wrote.
SembWaste, which collects recyclables in the area, and the National Environment Agency (NEA) say they are looking into the case.
"At no point would we condone staff wilfully discarding materials meant to be recycled," said SembWaste.
NEA said its officers conduct random site inspections of collection from the blue bins and sorting activities at the materials recovery facilities.
"In this case, if the allegation is substantiated after our investigations, a financial penalty will be imposed on the public waste collector and demerit points awarded... which is taken into consideration during evaluation of future public waste collection tenders," said an NEA spokesman.
The incident of the picky collector is not the only case of recycling efforts mishandled by public waste collectors and has raised questions from environmental groups about the effectiveness of recent programmes meant to encourage recycling.
In 2015, waste company Veolia was found to have mixed items to be recycled with rubbish for incineration during collection, even though NEA requires recyclables and waste to be collected separately and in separate trucks.
Recyclables from households and premises such as schools, army camps, petrol kiosks, places of worship and shophouses are collected by public waste collectors under the National Recycling Programme, as well as the informal recycling sector, such as rag-and-bone men.
In 2016, only 21 per cent of waste produced by households was recycled. The aim is to bump this up to 30 per cent by 2030.
Singapore's domestic recycling sector has remained lacklustre despite national efforts to encourage people to recycle more.
For example, since 2014, every HDB block has been provided with a blue recycling bin - up from one bin for every five blocks.
In 2014, the Government announced that all new public housing projects will be fitted with recycling chutes with throw points on each floor.
But it is not clear if these efforts have borne fruit.
Asked to give the tonnage of recyclables collected under the National Recycling Programme in 2016, NEA would say only that it "does not have a breakdown of the quantity of recyclables". Instead, it uses surveys to track the proportion of residents who recycle and how they do so.
For example, in a 2015/2016 survey involving face-to-face interviews with 5,700 residents, the proportion of residents who recycle was more than 70 per cent, up from 15 per cent in 2001, said NEA. "Out of those who recycle, more than 80 per cent indicated that they made use of the blue bins to recycle," its spokesman said.
Ms Pamela Low from environmental group Singapore Youth for Climate Action noted that both Taiwan and Hong Kong measure their recycling rate by tracking the tonnage of recyclables collected.
"We should measure our recycling rate using international standards of measurement," said Ms Low.
"Also, if NEA surveys show that we have a 70 per cent recycling participation rate... why then are we only targeting a 30 per cent household recycling rate by 2030? We can be more ambitious in our target household recycling rate."