Background

Odor Control in a High-Density Mixed-Use Environment

City Gate is a 30-storey mixed-use complex in Singapore, consisting of 311 residential units plus retail. Waste from homes is collected by a dedicated centralised vacuum pneumatic system, while commercial refuse is handled by conventional wheeled bins

The site is surrounded by high-rise towers, so odor control for the PWCS exhaust air was a critical engineering challenge

  • Exhaust discharge management was critical due to surrounding high-rise buildings that restricted air dispersion.

  • Residential refuse handled by PWCS while commercial waste relies on manual bin collection, requiring seamless integration.

Implementation Approach

The PWCS uses a low-flow, high-pressure vacuum blower that maintains continuous suction. A proprietary air-recirculation loop returns about 86% of the cleaned exhaust air back into the system, greatly diluting odorants before any discharge.

Multi-stage air treatment was added: exhaust is forced through a wet scrubber, fine dust filters, activated carbon adsorbers, and UV sterilisation before being vented.

In effect, the exhaust air is cleaner than the intake air, due to the industrial-grade filtration. These measures eliminate foul smells and allow exhaust outlets to be sited without impacting neighbors

The system was engineered and installed as a turnkey PWCS module. Piping was routed below-grade and through service risers to each inlet. Fans and air-treatment skids were factory-assembled at the waste station, then commissioned on-site.

Once operational, the system’s PLC controls and sensors were fine-tuned to maintain stable vacuum levels and trigger recirculation as needed. Final acceptance tests confirmed the exhaust treatment met stringent odor emission criteria before handover.

“With precise engineering, even the most constrained urban developments can achieve uncompromised waste management. By recirculating up to 86% of exhaust air through a multi-stage treatment process, the system not only met but surpassed stringent odour and air quality requirements.”

In summary

Highlights

Continuous Suction Performance.

  • Single DV servicing all apartments with uninterrupted operation.
  • Ensures immediate conveyance and reduces blockages

Commercial Waste Integration.

  • Manual bin tipping into the compactor operates concurrently with suction.
  • Allows seamless handling of both residential and commercial refuse streams

Advanced Odour Control.

  • 86% of exhaust air is recirculated back into the system.
  • Zero odour complaints since 2018.
  • Multi-stage treatment with scrubbers, filters, activated carbon, and UV sterilisation.
In summary

Highlights

Continuous Suction Performance.

  • Single DV servicing all apartments with uninterrupted operation.
  • Ensures immediate conveyance and reduces blockages

Commercial Waste Integration

  • Manual bin tipping into the compactor operates concurrently with suction.
  • Allows seamless handling of both residential and commercial refuse streams

Advanced Odour Control.

  • 86% of exhaust air is recirculated back into the system.
  • Multi-stage treatment with scrubbers, filters, activated carbon, and UV sterilisation.
  • Zero odour complaints since 2018.

Expertise in complex PWCS Projects

The City Gate project demonstrates how a compact, technically advanced PWCS can effectively manage waste in dense mixed-use developments. The integration of air-recirculation and multi-stage treatment has resolved the critical odour challenge posed by its urban location.

With seamless operation for both residential and commercial strata, the system has delivered reliable and complaint-free performance since commissioning