Feng Zengkun, Environment Correspondent

Manual sorting of waste? Trash that - go high-tech

-- ST ILLUSTRATION: MANNY FRANCISCO
-- ST ILLUSTRATION: MANNY FRANCISCO

Singapore's trash is mounting, and with more waste being recycled, there is a need for better machines and systems to deal with it.

SINGAPORE produces mountains of trash a day but, with this dealt with mostly effectively by the authorities, it has been a case of "out of sight, out of mind".

But with the waste piles set to grow even larger in the next few decades, it is time to sift through the issue and realise that new systems and attitudes are necessary.

At the government level, the National Environment Agency (NEA) has flagged worries that may grow to become problems in future, while on the domestic front, Singaporeans' recycling habits at home are far from ideal.

This is even as the Republic accomplished an environmental goal long in the making last month - more recycling bins in the heartland.

Up until 2011, there used to be just one big blue recycling bin, in which people put paper, plastics and other recyclable items, for every five Housing Board blocks of flats.

But that year, the NEA mandated that every block should have such a bin, under new public waste collection contracts.

Slowly, more and more blue bins began to dot the HDB landscape, culminating last month when the Tanglin-Bukit Merah area was the last off the block to boost its bins.

Even as it ticks that box, the agency also has two more big waste management moves in the offing. In June, it said that it was studying the feasibility of a first-of-its-kind, multi-storey recycling plant.

The facility, expected to be in Lim Chu Kang, is meant to help recycling firms share services and machines such as weighbridges.

The NEA said the final design should also help the firms recycle more trash using less land, and be generic and flexible enough to be replicated across the island.

In July, it announced that a new, mega waste treatment plant will open in Tuas in 2024, which will be able to handle up to half of the country's rubbish, including - in a first - sewage sludge from water treatment plants.

Taken together, the ambitious projects may seem more than enough to tackle whatever additional waste is thrown into the bins and chutes here.

But, in reality, while they are crucial for the country's future, even they may not be sufficient for the country's burgeoning waste treatment needs.

Urgent reasons to recycle

IN JUNE, the NEA put a set of documents on government procurement website Gebiz to ask for help on a new waste management plan for Singapore.

It said the blueprint should include a "clear and realistic" vision for the country up to 2030, and a more "ambitious" plan for the years up to 2050.

By 2030, Singapore's trash is expected to grow to 12.3 million tonnes, up 57 per cent from last year.

But with Singapore's scarce land and "only one offshore landfill available", the NEA is worried about having enough space and capacity to process all that waste.

The Pulau Semakau landfill is expected to meet the country's waste disposal needs up to 2035 or beyond.

Last year, 61 per cent of Singapore's trash was recycled. Of the rest, almost all is incinerated. Ash and non-incinerable waste are deposited in the landfill.

Singapore wants to raise its recycling rate to 70 per cent by 2030. That is environmentally laudable, but there is a more urgent reason to recycle more: to delay the day when the country's landfill is full.

When that day comes, the Republic may have to turn to much more costly options to deal with the ash, such as transporting it to neighbouring countries or using it in construction at a premium.

Sectoral gaps

THE NEA also identified shortcomings and gaps in Singapore's waste management industry and systems. These may become critical issues under the pressure of more trash in future.

Mixed recyclables collected from households, offices and commercial premises are sorted at facilities operated by public and general waste collectors.

"Most of the local (facilities) are small-scale operations where sorting processes are performed manually. (This) is both expensive and time-consuming when handling large volumes of materials," it said in the documents for the waste management blueprint.

Waste collection also faces a manpower productivity problem.

For some landed properties such as bungalows, terraced houses and shophouses, a truck with two collection crew members laboriously goes door to door to collect the trash.

"In view of the constraints in recruiting and retaining manpower, improvements are needed to at least double the manpower productivity to meet waste management demand in 2030," NEA said.

To meet the 2030 recycling target, more also has to be done to get people to segregate their dry waste, such as plastics and paper, and wet waste, including food.

Residents and public waste collectors often complain that recyclables in the bins are contaminated by food, liquids and other wet waste. Entire truckloads of recyclables have been rejected, and the items incinerated instead.

Tech to the rescue

SOME of these issues will be addressed by the NEA's projects, and still others can be solved by technology.

Some of the larger waste collectors here have machines to sort the recyclables. They also employ people to visually inspect the separated waste and manually pick out items that do not belong.

However, the majority of the more than 100 licensed waste companies here are small firms where people have to manually sort all of the recyclables, said Ms Melissa Tan, chairman of the Waste Management and Recycling Association of Singapore.

And yet, advanced machines that sort recyclables automatically and use less manpower are an established technology.

Many plants in the United States and Europe use a combination of, say, magnets to filter ferrous metals like steel, and star-shaped discs called star screens that lift out corrugated cardboard, plus infrared lasers that identify and separate plastics, and a magnetic field that taps electrons in aluminium to sift it.

While such an advanced plant will cost at least millions of dollars to set up, and is perhaps not financially viable for the smaller local firms, the Government can invest in it instead and charge the firms a fee to use it.

In several cities in the US, public waste collectors use trucks fitted with mechanical arms to pick up, empty and return bins to their positions. The driver is the only person needed.

Singapore is moving in the right direction. In January, the HDB said it will put recycling chutes - separate from rubbish chutes - in all new HDB blocks.

A pilot project has found that an estate with such chutes recycles about three times as much recyclable waste as other comparable estates without the chutes.

The NEA's call for a new waste management blueprint - complete with land, manpower and other targets for the various processes - also shows that the agency is aware of, and prepared to tackle, the problems.

Views on trash

BUT hardware aside, one other critical area that needs addressing is people's attitudes and misconceptions towards recycling and waste disposal.

Too many people still use the recycling bins as convenient dumpsters for all manner of waste. Others do not recycle as they suspect their recyclables end up in the same place as other non-recyclable trash and are incinerated anyway.

Some people do not know what can be recycled, or what happens to waste after it goes down the chute or into the recycling bin.

The statistics are sobering. Minister for the Environment and Water Resources Vivian Balakrishnan said in February that the domestic recycling rate is only about 20 per cent, compared with the overall 61 per cent recycling rate.

While nearly all construction debris, used slag and scrap tyres are recycled, the rates for paper/cardboard, glass, food and plastics lag far behind, at 54 per cent, 20 per cent, 13 per cent and 11 per cent respectively last year.

More should be done to remind people of the landfill's limit and the consequences when that disposal option is literally closed off.

Easy-to-understand, pictorial posters showing how to sort waste, what to put in the recycling bins and what happens to the items should be placed at high-traffic areas like lift lobbies.

The recycling rate for plastics is abysmal, and electronic waste is set to be a growing problem.

Both need special attention and more publicity for take-back programmes, like the tie-up between StarHub, DHL Express and home-grown recycling firm TES-AMM to collect electronic waste using bins placed in schools, condominiums and malls.

The Government can take the lead by auditing recycling rates at events it organises, such as Singapore International Energy Week. A national campaign with a catchy slogan will also help. In Sweden, residents are reminded that recycling stations are no more than 300m from any residential area.

But, in the end, there is a limit to the Government's reach. It can install chutes, bins and machines, plaster corridors with posters, and progressively narrow the distance between people and recycling points. But no-one can bridge the final, small stretch except Singaporeans themselves.

zengkun@sph.com.sg