Waste disposal in high-rise homes in Singapore: Then and now

A few weeks ago, the residents of Canberra Crescent had a shock when they were greeted with a foul odour in their common corridor due to a choke in their waste disposal system.

The affected blocks were 131B and 131C, and it was reported that the common rubbish chutes were crammed with garbage up to the third floor. Residents were concerned that it would be a breeding ground for pests or viruses after cockroaches and used face masks were spotted among the waste.

The problem persisted from Jan 3, 2022 until Jan 6, 2022, when the refuse was collected. According to a spokesperson from Sembawang Town Council, the waste pileup was due to a refuse collection problem faced by the newly appointed public waste collector for Sembawang GRC.

Incidents like what happened at Canberra Crescent remind us not to take the waste disposal systems in our high-rise homes for granted. This article looks at how waste disposal systems in high-rise residences in Singapore (HDBs and condos) have been improved over the years to increase efficiency and cleanliness.

These systems may be one of the more underappreciated functions in an apartment, but they are undeniably one of the most important.

Waste Disposal before 1989: Individual Refuse Collection System (IRCS)

HDB flats constructed before 1989 use the Individual Refuse Collection System (IRCS) for waste disposal. Each unit has a refuse chute hopper in the kitchen, allowing residents to throw their rubbish down the individual refuse chutes into the collection bin on the ground floor. The trash is manually collected daily and openly transported to the bin centre to be removed by the National Environmental Agency’s (NEA) public waste collectors.

However, this is a labour-intensive process with an open nature that carries a risk of waste spillage, which can cause odour, sanitary, and pest problems. Regular washing is required to maintain the cleanliness of these HDB estates.

Waste Disposal after 1989: Central Refuse Chute (CRC) System

To improve efficiency, the Central Refuse Chute (CRC) system was launched in 1989. Instead of individual refuse chutes with each unit having its refuse chute hopper, HDB flats constructed after 1989 have central refuse chutes with common refuse chute hoppers located at the lift landing of each floor.

This allows for fewer refuse chutes to be installed in each flat, which reduces the number of refuse collection points that rubbish needs to be manually collected and transported from, streamlining the waste disposal process.

The Central Refuse Chute (CRC) system is the waste disposal system most new HDBs still use today. For condos, on the other hand, it is up to the property developer to decide if they want to design the condo with individual refuse chute hoppers in each unit or shared refuse chute hoppers for each floor.

Waste Disposal Now and in the Future?

Pneumatic Waste Conveyance System (PWCS)

In 2015, the Housing and Development Board (HDB) introduced a new waste disposal system called the Pneumatic Waste Conveyance System (PWCS). This automated system eliminates the need for workers to manually collect and transport waste from refuse chutes to bin centres.

The rubbish is thrown down the refuse chutes and falls into a refuse chamber on the ground floor. When the refuse chamber is full, a sensor is triggered, which causes the waste to be transported through underground pipes. The waste travels at a speed of 50 to 80 kilometres per hour to a centralised bin, where it is stored in sealed containers. For comparison, the MRT speed is also around 80 kilometres per hour.

When these containers are full, they are brought to incineration plants by truck. Meanwhile, the exhaust air used to convey the waste to the centralised bin is passed through odour and dust filters before being released into the atmosphere as clean air. Because of its automated process, the PWCS is expected to reduce manpower needs by 70 per cent. The enclosed nature of the PWCS also increases cleanliness by reducing waste spillage and pest issues.

The PWCS was first implemented in 38 blocks at the Yuhua Estate. HDB has since installed it in several new HDB developments, such as Tampines North, Punggol, Bidadari, Toa Payoh, and Sengkang.

Private properties have also adopted this new waste disposal system. In 2017, there were over 100 private residential developments with the PWCS, and since 1 April 2018, it has been required for all new non-landed private residential developments, with 500 or more dwelling units, to implement it.

Dual Waste Chutes – for Recyclables and Trash

HDB first piloted the dual waste chutes in a Choa Chu Kang block in 2006. By installing a separate recycling chute, also termed the Centralised Chute for Recyclables, at the common area of every floor, residents were granted the convenience of depositing their recyclables down the chute at any time. Later, these dual chutes were installed in Fernvale Vista in Sengkang and [email protected] .

Following the successful pilot, all new public housing developments since 2014 have dual chutes for residents to deposit their recyclables as conveniently as their trash. This feature has also been required for all new non-landed private residential developments with more than four storeys, since April 1, 2018.

It is understood that CDL’s Parc Emily, which was completed in 2008, was the first private development in Singapore to install a twin-chute pneumatic waste disposal system. At the condo’s Open House, homebuyers received a goodie bag containing a Personal Green Living Guide with helpful green tips for home, recipes for healthy living, a recyclable bag and a plant.

Anyway, by implementing dual waste chutes, the government hopes to raise the recycling rates in Singapore. This measure is part of initiatives to increase the national recycling rate to 70 per cent by 2030, as outlined in Singapore’s Zero Waste Masterplan.

Food Waste Lockers

A more recent innovation for waste disposal in high-rise homes is the launch of 10 smart lockers in the Ang Mo Kio-Toa Payoh sector to collect food waste from residents. These food waste lockers are part of a one-year trial conducted by public waste collector 800 Super Waste Management in November 2021.

According to NEA, the smart lockers are installed with an Internet of Things remote access smart system, a QR code scanner and a load cell weighing scale. Participating households are issued a unique QR code and air-tight reusable plastic containers for storing their food waste.

The smart lockers allow participating residents to exchange food waste-filled containers with empty containers. Participants are rewarded with points in their 800 Super mobile app, based on the amount of food waste they deposit as an incentive to use the smart lockers. They can then exchange these points for grocery vouchers.

NEA has announced that 800 Super Waste Management will implement another 83 smart lockers in the sector if the one-year trial is successful.

This article was first published in 99.co.