Sewer ventillation

The vital role of sewer ventilation: Understanding the purpose of 10-metre high vents 

Sewer systems are an essential part of urban infrastructure, responsible for carrying away wastewater, ensuring public health and avoiding pollution of our environment. Proper ventilation of these sewer systems is crucial to their functionality and longevity.

The purpose of sewer ventilation

Sewer ventilation serves several important functions, including: 

  • Odour control: Sewers can emit unpleasant odours through sewer manhole lids at ground level. Ventilation systems direct and disperse these odours away from residences and nearby pedestrians. 
  • Managing sewer corrosion: Hydrogen sulfide, a byproduct of sewerage, can cause sewer infrastructure corrosion. Adequate ventilation helps control levels and prolong the life of sewer pipes, thereby reducing disruptions due to the need to reconstruct damaged infrastructure.
  • Preventing health hazards: Sewers can produce hazardous gases like hydrogen sulfide. Proper ventilation helps remove these toxic gases, safeguarding the health of sewer workers and preventing potential explosions.
  • Preventing system blockages: Poor or no ventilation can cause issues inside homes. Ventilation ensures consistent airflow within the sewer system, preventing the formation of stagnant pockets, air locks, pressure build up or vacuums.
  • Improving sewer efficiency: Efficient ventilation systems help maintain proper airflow, allowing wastewater to flow freely, reducing the risk of overflows, preventing water traps from sucking dry and enabling the sewer system to function optimally.

The role of vents (including 10-metre high vents)

All sewerage systems around Australia are ventilated.

Ventilation of sewerage systems occur through a combination of vents located in private homes and vents attached directly to the public sewer pipelines.

Vents installed on homes are privately owned and generally approximately 3 to 4 meters high for a single storey home.  Public vents are either 10-metre high poles or ground-mounted vents containing carbon filters.

There are about 225 10-metre high vents across the Tweed’s gravity sewer network and another dozen ground mounted vents.

Council designs and constructs these vents according to national water industry standards, specifically under the Water Services Association of Australia (WSAA) codes.

Living near vents

Living around 10-metre high sewer vents have both advantages and disadvantages. While these structures provide flood protection, odour control and safety benefits, they can also have visual impacts, although they are less intrusive than say a power pole. 

Residents' experiences can vary depending on their proximity to the vents and their individual tolerance for these factors. Overall, the presence of these vents is essential for the efficient and safe operation of the sewer system, contributing to the well-being of the community as a whole. 

Odour complaints from the sewer network in the Tweed are extremely low and well below industry trends for local water utilities in NSW. Council averages less than one odour complaint per year related to vents.

Pros for residents include:

  • Efficient sewer operation: Vents play a crucial role in maintaining the efficiency of the sewer system. For residents, this means a lower risk of sewer backups and overflows, which could otherwise disrupt daily life and pose sanitation concerns. It also increases the life of the sewer network, reducing the need for maintenance or reconstruction works. In some situations, 10-metre high vents draw air into the sewer system – in much the same way as a second hole on your coffee cup lid allows your coffee to flow freely.
  • Flood protection: Residents living near 10-metre high vents benefit from the flood prevention aspect of these structures. During heavy rain or flood events, the vents provide a path for air in to and out of the system that helps to improve high flows and prevent sewage backups.
  • Reduced odour: Proper ventilation of sewer systems, facilitated by these vents, ensures that uncontrolled unpleasant odours are directed above people and homes and dispersed effectively. This can improve the overall living environment, making it more comfortable for residents.
  • Health and safety: The presence of 10-metre high vents reduces the risk of toxic gases, such as hydrogen sulfide, accumulating in the sewer system. This helps protect the health and safety of residents by mitigating the potential for gas-related health issues and explosions.

Cons for residents include:

  • Visual impact: The size and height of these vents can sometimes be visually obtrusive.
  • Access and maintenance: Sewer maintenance and emergency access may require occasional visits by sewer workers, leading to minor disruptions and noise during these activities. 

Perceived cons include:

  • Noise: In some cases, sewer ventilation systems can produce low-level noise, which might be audible to residents living nearby. While the noise is typically not disruptive, it can be an inconvenience for some. The 10-metre high vents across the Tweed are an open system that do not create noise when drawing in or releasing air.
  • Odours and health risks: Some residents may have concerns or misconceptions about living near sewer vents, associating them with unpleasant odours and health risks, which can impact their perception of the neighbourhood. Vents are an important part of the sewer network, which reduce the risk of unpleasant odours and health problems.