M5 East tunnel filtration trial

An 18 month trial of air filtration technology in the M5 East westbound tunnel commenced on 9 March 2010.

The objectives of the trial include:

  • Evaluating the ability of the plant to reduce levels of nitrogen dioxide and particulates in the tunnel
  • Evaluating the ability of the plant to reduce haze levels (particularly at the western end of the westbound tunnel)
  • Assessing the amount of electricity used to run the fans and equipment, and the resulting generation of greenhouse emissions
  • Understanding the operating performance including factors such as reliability, shutdowns and maintenance requirements and the limits of the technology.

The plant does not run 24 hours a day. Roads and Maritime Services is testing the equipment at different times of day and in different environmental and traffic conditions, which provides information about the best times to operate the filtration plant to achieve best results.

The information gained throughout the trial is being used to evaluate the requirements for similar equipment in existing and future road tunnels.Read more about the filtration plant and its equipment.

Key points

  • Filtration technology is being used in road tunnels in Norway, Japan and Spain however, there is little published data on the effectiveness of air filters for road tunnels
  • The filtration plant has been retrofitted, or added onto, the M5 East tunnel which was completed in December 2001
  • Much of the way this system has been set up during construction and commissioning is unique to this plant
  • The monitoring equipment used to take various readings of the air quality before and after it goes through the filtration process, is the best technology commercially available. However, it has not been designed specifically for these filters or for this operating environment
  • Roads and Maritime Services has engaged the CSIRO to undertake a six month monitoring and analysis program of the electrostatic precipitator to review the filtration plant's performance. CSIRO consultants will also examine the performance and reliability of the recently installed Tapered Element Oscillating Microbalance monitors to determine their effectiveness in a road tunnel environment.

Filtration plant and equipment

The M5 East Tunnel filtration plant is located on the eastern side of Bexley Road at Wolli Avenue, Earlwood. Most of the filtration plant is located underground and its design is sympathetic to the surroundings, with landscaping over much of the site. This means that nearby residents do not have adverse visual impacts.

The building above ground incorporates a landscaped 'green' roof of native trees and a grassed terrace.

The filtration plant has been designed to have minimal impact on the Wolli Creek Regional Park vegetation communities.

The filtration equipment was installed in December 2009. Preliminary testing and fine tuning was undertaken during February 2010. This is a normal part of commissioning infrastructure like this. Initial testing showed refinements were needed to the air tunnel to ensure the smooth flow of air to the plant. These refinements were completed in early March 2010 and an18 month trial of the M5 East air filtration equipment commenced on 9 March 2010.

Filtration equipment goals

The filtration equipment is designed to filter and clean approximately:

  • 200 cubic metres of air per second to remove at least 80% of particulates less than 10 microns in diameter from the westbound tunnel
  • 50 cubic metres of air per second to remove at least 90% of nitrogen dioxide.

Filtration plant operating hours

The filtration plant has been operating on weekdays, generally between midday and 6pm.

Filtration process animation

Share this page: