Darren Inglis

Meet the latest addition to our team: Darren Inglis

Meet the latest addition to our team: Darren Inglis!

Darren Inglis

Meet Darren Inglis, our new Senior Frontend Engineer! With 8 years of experience in the field, Darren has mastered frontend technologies and has a track record of delivering exceptional solutions for clients. Get to know him a little better by reading his Q&A below.

Tell us a bit about your background.

DI: My name is Darren and I’ve come on board VAPAR as a Senior Frontend Engineer to assist in building their exciting new version of VAPAR.

I’ve spent the best part of my career forging new user interfaces and improving tired old designs. I love taking complexity and stripping it away to reveal what’s most pure and rendering that to the user.

How did you come to choose VAPAR?

DI: My career’s been guided by the following: “Work with great people on interesting products”.

So when the opportunity to join VAPAR presented itself I knew I had found home.

What are your interests outside of work?

DI: When I’m not trying to push all the buttons in the right order. I love nothing more than spending time with my young family.

For more information about the latest developments at VAPAR, you can connect with Darren via LinkedIn or our Contact page.

pipe grade target

Targeting the Correct Pipe Slope

Targeting the Correct Pipe Slope

Why is pipe slope important?

Most wastewater networks rely on gravity to function. The term ‘💩 runs downhill’, wasn’t coined by accident. Interconnected gravity sewer pipes collect flow from customers and transport the wastewater downstream to a treatment plant through a series of gravity pipes, pump stations and pumped mains. 

When designing new gravity sewer mains, the ground topography and required grade of the sewer is the driving factor in determining where it will be constructed and how deep it will need to be. A sewer that is too steep will result in fast flow and increased turbulence. A sewer that is flat or has a sag (belly) is problematic and likely to result in ponding water and a build-up of sediments and solids. This gradual build-up of deposits can create blockages and overflows.  

Pipe sag or belly

Figure 1 – Problematic flat spots in a pipe 

Different ways to measure pipe slope and straightness?

Following the construction of a new sewer, a range of tests and checks are carried out to ensure it has been constructed as per design and is fit for purpose. These checks can include an air pressure test, hydrostatic test, ovality test, and pipe grade check. 

Utility organisations, who are the owners of the pipes, may use a variety of methods to be satisfied the new pipe has been constructed to design by housing developers or contractors. These tests check to see if the pipes are straight, free from obstruction and will achieve self-cleansing velocity. Tests can include: 

  • Ball Test 

    A smooth ball is placed at the upstream end of the sewer pipe and should run unobstructed to the downstream end. 

  • Light & Mirror Test 

    A light and mirror are sometimes used to ensure a new sewer main is straight with no unintended horizontal or vertical bends. The projection of a strong light through a straight sewer can be confirmed with a full circle of light visible at the end. 

  • Dynamic Inclination 

    Many CCTV camera crawler systems come with inclinometers that will display the grade of the pipe directly onto the inspection video. Sections of the pipe that are too flat or have a sag/belly can be identified from this displayed value. 

Digital inclination recorded by a CCTV crawler

Figure 2 – Digital inclination recorded by a CCTV crawler 

An out of the box solution!

On a recent trip to the USA, the VAPAR team discovered an out of the box solution from a pilot project in Oregon. The City of Salem have been using an alternate inclination testing approach for decades. It has worked so well for them; they continue to use this unique method to check new pipe meets their requirements. Just prior to the CCTV pipe acceptance inspection, tracing dye is released into the pipe to be tested. If the pipe has a consistent negative slope the dye will not collect and pool in a sag. If there is a pool of dye, then there is a sag present, but the dye will not be able to quantify the magnitude of sagging. 

The method employed by City of Salem is novel in its ability to identify and quantify a sag in a pipe. A target is installed in front of the CCTV camera that clearly identifies if a sag is present. The magnitude of the sag can be observed using a target where the rings correspond to their internal acceptance levels. Any significant sag in the pipe is immediately obvious as the dye level will reach the 4th target ring.  

Figure 3 – Crawler camera with dye target mounted out  front 

When the pipe doesn’t meet the required slope

If there are a number of these instances of this occurring, it may trigger a complete pipe relay. A single instance where the dye reaches the 5th target ring will generally require a dig-up to address the sag and remove the risk of settling deposits and blockages. In-service pipes with sags/ponding often require regular jetting to minimise this risk. 

Figure 4 – The City of Salem target 

Evolution of ideas

The team at the City of Salem are an excellent example of not limiting the approach to a problem or task with a narrow and set method, but rather to think about the job at hand and include innovative ideas to achieve a desired outcome. Testing alternate equipment, technology, and methodologies is an important part in process evolution throughout the world.  

We would love to hear from others who have a unique solution to complete a part of their job! 

About the Author


Mark Lee is the Business Development Manager (Aus/Nz) at VAPAR and a former Senior Asset Engineer who has spent more than a decade managing the asset lifecycle of infrastructure. He has extensive experience managing pipeline networks, including design, construction, condition assessment and decommissioning.

Mark lee posing for a photo

Learn more about Sewer Network

VAPAR automates sewer and stormwater pipe condition assessment for councils, utilities and CCTV contractors.  Learn how we help improve the monitoring and maintenance of the underground pipes using AI.

manhole step iron

To step or not to step – that is the question: Sewer manhole step iron debate. 

To step or not to step – that is the question: Sewer manhole step iron debate

Regardless of where you are in the world, there is likely a healthy debate on the need for manhole step irons. There are many opinions from design engineers, construction teams and maintenance teams about the usefulness of manhole step irons. 

What are manhole step irons?

Step irons are installed in manholes to facilitate access to maintenance workers and/or aid self-rescue in the case of accidental entry into the sewer network. They are usually made of metal or plastic and are installed in manholes in a vertical alignment (think of a ladder) to allow people to move from the bottom of the manhole to the top of the manhole.  

manhole iron steps

Manhole step irons

What is the debate about?

Originally, step irons were installed in manholes almost without exception. But with the ever-increasing focus on safety in the civil infrastructure industry, there are questions being posed about the need for manhole steps irons. The anti-step iron argument comes from the drive to use confined spaces equipment for entry into the sewer network, primarily a harness and tripod set up over the manhole that negates the use of step irons, in fact, they can sometimes get in the way of ease of entry/egress.

In regions that enforce confine space entry practices, entry to the sewer network is prohibited without the necessary training or equipment. So removing the need for manhole step irons has a case, especially when you consider the likelihood of associated ragging, corrosion and maintenance. To this extent, some authorities have gone to the lengths of cutting out manhole step irons form existing infrastructure. 

confined space entry manhole

 Confined space entry manhole

The argument for keeping manhole step irons can be strongest in regions where manhole step irons don’t pose a significant maintenance burden, confined spaces practice is not as enforced, and/or illegal access to the sewer network is possible. The argument of self-rescue is a common reason for continuing to install the step irons. Similar to the ladders that you see installed on the edges of non-swimming water bodies, asset owners are obliged (sometimes legally) to provide a way for people to self-rescue in the event of an accident. 


In summary, there is no set way to do things. The decision on whether to step iron or not should take into consideration a number of factors, not least of which a rigorous risk assessment to understand your options. 

Have I missed anything? Leave your comment below

Has your organisation taken a position on new manhole designs, or feel free to share your personal thoughts – I would love to hear your feedback. 

For more content like this or to suggest a topic follow VAPAR on social media. 

About the author

sewer blowback

Sewer Blowbacks –Releasing the pressure!

Sewer Blowbacks – Releasing the pressure!

What is a Sewer Blowback?

A sewer blowback is when a combination of air/water/wastewater is ejected from a household wastewater fixture, such as a basin, floor drain, gully trap, and, most commonly a toilet.

This can occur when routine or reactive maintenance is being carried out on the utility’s sewer network with high-pressure water
jetting equipment. Water jetters are used to clear roots, debris and blockages in the sewer system and ensure flow occurs uninhibited. 

Blowbacks occur due to difference in pressure in both the main sewer line and the attached house plumbing. When jetting equipment is in use, water is forced into the sewer main under high pressure, this requires the displacement of a similar volume of air. The space behind the jetter is an area of high pressure, while there can be a negative pressure zone in front of the jetter nozzle. In most cases this air is forced along the sewer main or out private property vents. However, if there is insufficient ventilation, or a blockage in a house vent, this pressure will move to take the path of least resistance. This can result in pipe odors rising through floor drains, and if there is enough positive pressure the water seal in the toilet bed can be blown with force out of the fixture. 

The inverse of a ‘blowback’ can occur where negative pressure occurs in property plumbing, and the water seal in fitting bends can be sucked out, resulting in an atmospheric opening to the sewer causing the odour from the sewer to flow through the fixture into the room that it is located. In these cases, it can be rectified by adding additional water to the water seal 

sewer blowback process

Why do sewer blowbacks occur?

There are two factors that can be attributed to a sewer blowback within the property drain itself. 

A drainage vent can become blocked or restricted over time which can increase the likelihood of a sewer blowback. 

Blockages within the sewer main can also cause water to build up on the upstream side of them; when the jetter nozzle goes past the property connection the water can be forced up the connection pressurizing the property drain unless it has somewhere to go. 

sewer blowback

How can we prevent or minimise sewer blowbacks happening?

 There are several factors that contribute to sewer blowbacks that happen during the cleaning of the sewer main, some can be minimised/mitigated, and others cannot. 

  1.  Communicating to property owners that sewer main cleaning is scheduled, and it is recommended that they keep toilet lids closed. 
  2. Opening the upstream manhole to allow additional flow into the main being cleaned. 
  3. Using lower pressure and/or flow from the jetting truck.

    Most blowbacks consist of only the contents of the water volume within the trap/water seal and is usually clean water that is replaced on a regular basis by flushing the toilet and running a tap. Some utilities will keep a blowback register of historical occurrences. It is recommended to contact them if this happens to help inform future maintenance programs and minimise the potential of it happening again.  


About the author Anthony Woodhouse
Declan Smit posing for picture

Meet the latest addition to our team: Declan Smit

Meet the latest addition to our team: Declan Smit!

Declan Smit has joined VAPAR as your Customer Success Analyst; with strong data analysis background, he will be creating interactive Power BI dashboards and gathering user insights from the platform to improve the customer experience.

To share a little more about Declan, we asked him to answer some questions about his background, interests and more.

Tell us a bit about your background.

DS: When I was younger, I travelled around the world in places like South America and later to the UK. I wasn’t sure what I wanted to do as a career, so I did a Business and Management degree at the University of Portsmouth. I really enjoyed my time there; I studied a variety of subjects but was drawn to process improvement and reducing inefficiencies. Once I completed university, I started my role at South West Water, analysing the data and applying what I learnt from my studies. In a short period, I grew in that role to become one of the main data analysts in my area of specialisation, developing processes and learning new ways of presenting data to a high level.

What made you choose VAPAR?

DS: At South West Water I started to develop my analytical skills however felt limited in the access I was given. The opportunity to join VAPAR was very enticing as they have given me the freedom to be creative with displaying data and further my skills in a supportive environment.

What are your interests outside of work?

DS: I enjoy watching all sports, but I’m obsessed with everything about football. I play for 2 teams at the weekend and run the Instagram page for the Sunday team. We are currently fighting for 1st place in the league after a good start

For more information about the latest developments at VAPAR, you can connect with Declan via LinkedIn or our Contact page.

lateral sewer pipes

Thinking laterally – Can lateral inspections supplement your inspection program?

Thinking laterally – Can lateral inspections supplement your inspection program?

The majority of any pipe network is made up of the smaller diameter lateral connecting pipe lengths (relative to mainline lengths), so it’s no surprise that lateral inspections are becoming more and more popular.

Let’s take a look at what you need to know about lateral inspections.

lateral sewer pipes

What are lateral inspections?

Lateral inspections are inspections that survey the connecting pipe to the main line. The inspection can either be done from an access point upstream of the connection back down to the mainline or from the mainline up through the lateral connection to a connection point or boundary point upstream.

Depending on where in the world you are, these connecting pipes to the main line are sometimes called house branch connections, junctions or taps. Similarly, there are also varying ways to undertake a lateral inspection or coding defects associated with the lateral. Some countries include lateral condition coding with mainline condition coding, whilst others treat the lateral condition coding separately.

Why are lateral inspections required?

Water authorities will do lateral inspections for several reasons. Most organisations undertake lateral inspections in their network because they own the lateral and are therefore required to maintain all or part of the lateral length. There are some organisations that proactively undertake lateral inspections to investigate unknown connectivity of the network.

When should I do a lateral inspection?

Funding an inspection program can be challenging sometimes. So, adding lateral inspections to your inspection program might sound like an extra burden. Let’s look at some of the reasons water authorities choose lateral inspections for their inspection program that make the investment worth it:

  1. Investigating reported customer issues – if a customer reports an issue and no problem can be identified with the mainline pipe.
  2. Investigating network connectivity – if there are suspected illegal connections in the lateral network, or if th
  3. As a workaround for upstream access restrictions

All of the above challenges cost the water authority’s money if left unresolved, which makes the business case for lateral inspections much easier. The magnitude to which this impacts your organisation will drive a cost-benefit ratio that makes sense for your organisation’s circumstances.

lateral inspection launch

Minicam lateral launch

How can I get a lateral inspections done?

Depending on the reason for the inspection, and that site access conditions, lateral inspections are usually undertaken in one of two ways.

  1. Starting from the mainline – The first, is from the mainline using specialist inspection camera technology. This involves a type of camera that has ‘lateral launch’ functionality, which basically means a camera can be ‘launched’ up the lateral up to a length of 150 ft or 45.72 meters.  There are restrictions on the use of these types of cameras, such as lateral and camera angles. This type of inspection can help with access issues, and investigations of network connectivity.
  2. Starting from an upstream point in the lateral – The second way to do an inspection of the lateral starting from an upstream point in the lateral down towards the mainline. Its possible to do this type of inspection with a standard CCTV inspection camera (either crawler or pushrod). This type of inspection can help with investigations of customer issues.


The increased demand for lateral inspections can be attributed to a number of things, not least of which the availability of the technology, and increased customer reporting capability and more. Either way, these inspection methods are a great way to supplement your upcoming inspection programs where the needs arise.

About the author
pipe inclination in roman aqueducts

Pipe inclination

Pipe inclination - What goes up must come down?

What is pipe inclination?

Most of the world’s sewers and storm pipes operated as gravity pipe network. What that means is that the water in the pipes drain to the outlet point under gravity. For this to happen, the entire pipe network needs to be laid on a slight incline in the direction of the downstream outlet.

This is the most efficient method of transporting water from one point to another and has been a method used since ancient times. The Roman aqueducts brought water from the various springs in the Anio valley and its uplands to Rome, over 92000 metres or 301837.27 ft away, entirely using this method; slowly declining the aqueduct over the length of it so that water would fall in the direction of Rome.

roman aqueduct

Roman aqueducts crossing a valley

That is why when aqueducts needed to cross valleys, the Romans made every effort to keep the level of the structure constant, as dropping the level to match the valley would eventually require some sort of pumping action.

Why is inclination in pipes so important?

Pipes have inclination for the same reason as the Roman aqueducts do, water transport efficiency. The degree of inclination in pipes is a subject of much debate and is an ongoing engineering design and maintenance challenge. The more inclined the pipe, the faster the water will flow, the slighter the incline, the slower the water will flow. An interesting thing happens when water moves fast; it starts to pick up debris in the flow. Conversely, when the same flow starts to slow down, the debris that was once swept up in the flow begins to settle out.

For this reason, design engineers try to maximise inclination of the pipe network to encourage ‘self-cleaning’ velocities in the pipe network as a low-cost way to prevent blockages in the network. Anecdotally, a reasonable self-cleaning inclination would be between 1-2% grade depending on the diameter. A grade of 2.00% is the same as a ratio of 1 in 50. This means over a distance of 50 m the trench or pipe will slope down or fall 1 m from the horizontal.
However, in a flat catchment, there may not be a big enough difference in height between the top of the catchment and the bottom. When this happens, there is an increased risk of blockages and flooding because the water is not able to move itself (or debris) to the outlet as efficiently.

How can I test for inclination?

Testing for inclination can be done a couple of ways, but the most common are:

  1. Using pipe lengths and elevations between access points – Measuring the reduced level of the pipe from an upstream node and subtracting it from the reduced level of the downstream node would give you the elevation drop. Dividing that elevation drop by the length of the pipe would give you the indicative inclination of that pipe. The reason this method is only indicative is that there may be other dips and changes in direction of the pipe between the two access points that would affect the exact calculation.
  2. Using dynamic inclination measurements during CCTV inspections – Most standard CCTV camera crawler systems come with inclinometers as part of the equipment and the inclination is logged as part of the camera telemetry data. For water authorities to access this information, they will need to request and have the ability to decode this telemetry data. Or asking your CCTV contractor to display inclination on the on-screen display (OSD) as part of the inspection will also provide you with the information you need.


For gravity pipe networks, the inclination is very important for the efficiency of the network performance. Introducing additional debris, such as wet wipes or any other items that should not be flushed, into the sewer or storm pipe network only adds to the challenges that gravity networks have, which has the unfortunate impact of increases operational and maintenance costs for water authorities.

Effective public awareness campaigns to reduce sewer misuse such as #binthewipe and #weirdthingsinpipes can help to raise awareness about sewer misuse in the community to ensure we keep our pipes running as efficiently as possible.

About the author
sewer inspection software featured image

Sewer Inspection Software 

Sewer Inspection Software

Why is asset condition important?

One of the fundamental tasks of an asset manager is knowledge of asset condition. Whether this is buildings, bridges, plant, or pipes; collecting accurate information on the condition of the asset base is essential in understanding risk, developing budgets, and preparing asset maintenance and repair programs. 

 For those that manage wastewater and stormwater pipe networks, there is an additional challenge with the assets requiring inspection usually being located underground.  

What is the role of inspection software for sewer and stormwater pipes?

With cities and utilities managing vast pipe networks, there is a necessity for an efficient way to collect data and make decisions based on this information. The typical requirements of sewer inspection software are: 

  • Record defects and pipe features to inform pipe condition and details 
  • Apply consistent scoring of defects based on regional coding systems 
  • Provide a method to grade pipes to determine priority for maintenance and repair work that is required 
  • Generate informative reports to share inspection details with relevant stakeholders 
  • Deliver a structure for further data analysis, and information transfer to asset management software and geographical information systems 
VAPAR sewer inspection software

Figure 1 – Current generation of pipe inspection software

Regional differences between inspection codes

Different countries and regions around the globe have developed pipeline inspection codes in slightly different ways. The goal of each of these codes is typically the same; to provide a uniform standard for a region to apply a consistent approach to the inspection of pipes. 

Below is a list of some of the most common regions and codes that are used around the world. 

North America 

Code: Pipeline Assessment & Certification Program (PACP) Reference Manual 

Issuer: National Association of Sewer Service Companies (NASSCO) 

 United Kingdom 

Code: Manual of Sewer Condition Classification (MSCC)  

Issuer: Water Research Centre (WRc) 


Code: WSA 05 – 2020 Conduit Inspection Reporting Code of Australia 

Issuer: Water Services Association of Australia (WSAA) 

 New Zealand 

Code: New Zealand Gravity Pipe Inspection Manual 

Issuer: Water New Zealand (with ProjectMax) 

 European Union 

Code: DIN EN 13508-2 Investigation and assessment of drain and sewer systems outside buildings – Part 2: Visual inspection coding system 

Issuer: European Committee for Standardization (CEN) 


pipe inspection manual picture

Figure 2– There is a variety of regional coding standards around the world 

How recording inspections has changed over the decades

Clay sewer pipes were first constructed by the Mesopotamians over 6,000 years ago, with modern city sewer construction beginning in the 19th century. Before inspection crawler cameras and computers, these underground pipe networks still required periodic inspection. This was initially a visual inspection that was carried out either by walking or floating through the underground infrastructure. 

Old sewer inspection by canoe

Figure 3 – Pipe inspection by canoe (1908) 

Inspections gradually moved to photography and hand-written logs of defects. The 1950s saw the first development of remote camera deployment into underground pipes. As videography become an option in the 1970s/80s, the opportunity to capture condition information in a video format became accessible to utilities.  

Sewer inspection software evolved as computers became commonplace in businesses. Software provided numerous advantages over written/typed records. Errors reduced, consistency improved and access to information became easier. 

VHS capture of pipe inspection


Figure 4 – VHS capture of pipe condition information 

Video capture then evolved from VHS to digital media storage, and as data capture and storage advanced, inspection file size also grew. This presented fresh challenges for organisations as the transfer and storage of substantial amounts of data required careful management to ensure the condition information remained accessible to those who needed access to it.  

The current generation of sewer inspection software is using artificial intelligence to automatically identify defects and automate many of the tasks that are logic based and ideal for computer-assisted decisions. Data storage is increasingly moving into the cloud to provide fast and organised access to the growing amounts of collected data with ease. 

Pipe inspections still require operator controlled (or staged) capture of data in the field, and results processed through artificial intelligence models are combined with human quality assurance. There is excitement in the industry as the next generation of software is being advanced to further improve the tools available to asset managers.  

Watch this space!  

About the Author Mark Lee

Learn more about Sewer Network

VAPAR automates sewer and stormwater pipe condition assessment for councils, utilities and CCTV contractors.  Learn how we help improve the monitoring and maintenance of the underground pipes using AI.

Paul Cooper introduction

Meet the latest addition to our team: Paul Cooper

Meet the latest addition to our team: Paul Cooper!

Paul Cooper photo

As a Software Engineer, Paul Cooper is focused on delivering high-quality, reliable and performant code for the VAPAR platform.

To share a little more about Paul, we asked him to answer some questions about his background, interests and more.

Tell us a bit about your background.

PC: I was born in the South West of England in a town called Plymouth. I came to Australia when I was two and grew up on a naval base in Darwin and then South East Queensland. Since leaving school, I’ve lived in Sydney, Paris and Berlin. I’ve always been interested in technology, especially software development. There is beauty in solving problems digitally because (almost) all variables can be controlled. You can remove almost all randomness and subjectivity and create a solution that will work every time.

Then there is the ability to scale the solutions almost infinitely. When a product is built in 1s and 0s rather than bricks and mortar, it can be copied and shared endlessly. This allows technology to solve global problems via what is essentially just the communication of ideas and information. I’ve always felt this way, and so I first taught myself to code, then built video games, and then built software that optimised digital ad campaigns. This introduced me to the magic of machine learning. Now I’m here.

How did you come to join VAPAR?

PC: Infrastructure is really fascinating part of our society because it is both essential and often invisible. Until it isn’t working. The number of moving parts and variables to consider, the complexity of the issues involved and the massive benefits to everyone if we can get it right are all reasons that drew me to VAPAR. Start-ups are places where you will get to work with the most cutting-edge technology, solving the most important problems – and often with the most interesting people. That’s definitely the case here!

What are your interests outside of work?

PC: Although a lot of my life revolves around technology, I also love reading/watching/listening to podcasts and books surrounding philosophy, history and culture. Economics and psychology too. I think all these areas of interest stem from a desire to understand how everything works, why we do the things we do and what the common threads are across cultures and times. I also enjoy hanging out with my black and white border-collie Maverick.

For more information about the latest developments at VAPAR, you can connect with Paul via our Contact page.

Sewer vent

What are sewer vents for and how do they work?

What are sewer vents for and how do they work?

Sewer vent

Inspecting sewer vent

Transporting more than wastewater

The process of transporting wastewater from houses to treatment facility is a journey through pipes and pumps of various type and size. When designing and optimising the transport of this fluid, there is another key factor that must be considered by engineers – ventilation of the sewer network. 

As wastewater is pumped up and flows down through the different pipes in the system, there is also a movement of air. Due to the atmospheric pressure differentials at pump stations and within the headspace in the top half of gravity pipes, the network itself needs to breathe. The system must move air, as well as fluid.  

Why do we need sewer vents?

Venting of the wastewater network is important for several reasons, this includes: 

  • Providing airflow and pressure equalisation between the home and the pipe network 
  • Reducing and controlling odour issues above ground.
  • Avoid creating corrosive environments below ground that reduce asset life 

The ins and outs of vents

House vent – Otherwise known as a drainage waste vent (DWV) consisting of a 50mm (2”) PVC for a single dwelling and up to 200mm (8”) PVC for multiple dwellings, which extends above a roof of a building. This is usually installed at the head (furthest point from the main drain) of your property’s drainage system to allow enough air movement for you to flush your toilets and use all fixtures within your house and still maintain the water seals within each fixture 

Pump Station Vents (induct & educt) and Discharge manhole ventAt the pump station, a vent stack will also be present. This usually extends above the tree line, or nearby property roof level.  Vents are often constructed at the discharge points of the rising/forced mains. With wastewater being forced into the gravity system between two points, both locations need to have an open flow of air as from one end it draws in and the other it exhausts as the wastewater is displaced from one to the other.  

sewer vent

Image: Sewer Ventilation Clearance Requirements 

Forced ventilation (e.g., tunnels)Mechanical ventilation using a powered fan generates airflow at a controlled rate to ensure a sufficient volume of fresh air is circulated to ensure critical structures do not experience accelerated material corrosion. . 

Odour control units

In instances within sewer networks where odour is problematic, activated carbon filters can be used as a replacement for vent stacks. Vent stacks can become an occupational health and safety risk due to their deteriorating condition over their lifetime. Activated carbon neutralises gasses before they exit the vent pipe. In some cases, they are reducing odours up to 99%.  

There is a move to replace vent stacks due to ageing infrastructure and the risk they can pose to the public if they fail/collapse. An example of this is here, where a vent stack located near Muswellbrook High School (Australia) was replaced following ongoing odour complaints and the risk that it posed to the surrounding neighbourhood. 

Installing vent stack

Vent stack replacement. Muswellbrook High School, Australia (before and after)

There are several different options available to suit the needs of the situation. However, the principle is the same. Air flows in or out of the sewer through the replaceable filter media removing unpleasant odours without restricting the air requirements for the sewer to operate as intended.

Examples of types of vent replacement options.

These units ensure that harmful gasses within our sewer networks are ventilated and treated, helping keep us safe and extend the life of the underground assets for the utilities of your local area. 

About the author Anthony Woodhouse