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
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.

Conclusion

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 – What goes up must come down.

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.

Conclusion

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) 

 Australia 

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.

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
Cloacina

Ancient Roman Sewer – Cloaca Maxima

Cloaca Maxima

This ancient roman sewer is protected by a goddess!

Tiber river

Tiber River

Strolling along the Tiber River in Rome, you could be forgiven for missing this wastewater wonder of the ancient world. 

While there were many strollers and joggers along the neatly paved banks of the ancient river, my husband and I were bee-lining for our next stop on our Rome itinerary: Cloaca Maxima. 

What is Cloaca Maxima?

Cloaca Maxima is a large diameter drain built in Ancient Roman times in the 6th century BC.  The drainage structure was named after Cloacina, an ancient Roman deity that represented purification. A shrine to this deity was said to be near the original stream, which is said to be the inspiration for the name. The literal translation in Latin is ‘Greatest Sewer’. 

The design and construction

It was initially a stream that was lined with stone, aimed at draining the local marshes and removing waste from the city. By the 3rd century BC, it was enclosed with a stone barrel (semi-circular) vault so that the swampy land around the Roman sewers could be filled in.  

Cloaca Maxima Catchment area in Ancient Augustan Rome

Figure 1 Catchment area map created in 1886 of Cloaca Maxima in Ancient Augustan Rome (source: https://www.wikiwand.com/en/Cloaca_Maxima#Media/File:Roma_Plan.jpg) 

The sewer was said to be dimensions that allowed inspection boats and boats fully laden with hay to pass through. 

This post goes into more detail about the construction and history of the famous sewer for those that are keen to learn more: https://www.wikiwand.com/en/Cloaca_Maxima 

Cloaca Maxima today

Today, the sewer is still in use, though nothing more than a trickle comes out of the once ‘Greatest Sewer’, most likely groundwater, as the city’s sewage has been long diverted to more modern pipe systems.

Cloaca Maxima today

If you are looking to replicate this enviable photo opportunity, you can find Cloaca Maxima still visible where it joins the Tiber River near the Ponte Rotto and Ponte Palatino bridges. 

Lessons from the Ancient Romans

Whilst the sewer is still technically in operation today, its much-diminished role is reportedly due to the misuse of the sewer (people putting all sorts of solid waste down there, even some political execution victims!) and backflow from the Tiber. Over time the once ‘greatest sewer’ has been re-routed to more the modern sewer system that sends sewage to treatment plants for treatment before discharge.

It’s certainly interesting to see and learn about the challenges of legacy wastewater infrastructure. Design challenges such as back flow design can be accounted for with careful planning. Social challenges with sewer misuse can be accounted for with meaningful community awareness campaigns. Either way, engineers today are working to deal with similar challenges today, just manifested with a modern twist. 

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Pipe jetting process

What is Pipe Jetting?

What is Pipe Jetting?

One of the common maintenance activities required to keep sewer and stormwater pipes flowing at full capacity is pipe jetting. Pipe networks are periodically inspected using CCTV cameras to understand the condition of pipes. Operational & Maintenance (or service) defects identified are an indicator that jetting may be required. The most common problems that jetters are used to fix are: 

  • Sediment build-up 
  • Fat, oil, and grease 
  • Tree root removal
  • Object blockages 

There are a wide range of jetting units available that are designed to suit specific tasks or pipe sizes. 

Pipe jetting process

Figure 1 – Pipe jetter in action

Hydro-Jetting Components 

The major components that form a jetting rig are: 

  • Engine 
  • Water tank 
  • Hose & reel 
  • Nozzle 

Depending on the size and power of a jetting unit, it may be: fitted to a truck/van/pick-up, trailer mounted, or be a small portable unit capable of accessing difficult locations. 

Jetting truck

Figure 2 – Jetting Truck

How do jetters work?

Jetters are commonly powered by a diesel engine, although there are also electric and gas-powered options available. The delivery of water to the nozzle is measured in pressure and flow. It is important to understand how these differ and can affect the success of the work at hand. In general, pressure provides the cutting power, and flow will provide the flushing power. The larger the pipe, the more powerful the engine required, and more water required to carry on-board.  

An example range of pressure and flow is listed below; you should contact your local distributor for advice on best options for your typical projects. 

Use 

Pressure 

Flow 

Smaller pipe jetting jobs. 

4000 PSI 

275 Bar 

5 Gallon/min  

20 Litre/min 

Typical all-rounder specification. 

4000 PSI 

275 Bar 

20 Gallon/min  

75 Litre/min 

High pressure output for more powerful cutting. 

5000 PSI 

345 Bar 

9 Gallon/min  

35 Litre/min 

Capable of clearing sediment build-up in larger pipes. 

2000 PSI 

140 Bar 

65 Gallon/min  

250 Litre/min 

Jetting is often completed in the upstream direction so that debris can flow back to the operator’s location, as well as minimising the risk of overflow behind blockages. The jetter nozzle uses the powerful spray of water to move along the pipe and completing the cutting/cleaning/flushing task required. There are hundreds of different nozzle designs on the market with the angle of spray from the nozzle defining if it is better suited to thrust/flushing or cutting/descaling.  

how jet stream works

Figure 3– The angle of jet stream to suit different performance criteria 

Nozzle Types and Accessories

There are standard nozzles designed to cover most circumstances, as well as specific nozzles and jetting accessories available. 

Switching Nozzle: The angle of spray can be adjusted while in the pipe from thrust (flushing) to cutting (descaling). 

Rotating Nozzle: Cleans full pipe surface. You may have seen stripes after cleaning where a fixed nozzle has not hit all parts of the pipe wall 

Sled Nozzles: Designed for heavy duty bottom sediment. Also called bottom cleaners, sledge, or sleigh nozzles. 

Camera Nozzle: Provides the ability to collect imagery from within the pipe while cleaning to collect condition data at the same time 

Debris Basket: Fitted at downstream point to collect debris and avoid secondary blockages after jetting. Also called drain traps, drain catchers.  

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.

Patch repair needed in new pipe

Streamlining CCTV Pipe Acceptance Testing

Streamlining CCTV Pipe Acceptance Testing

What is a pipe acceptance test?

Utilities that manage sewer and stormwater networks increasingly have reticulation pipework extensions constructed by contractors as part of developer works. These pipes are commissioned and adopted by the utility. In many cases, the new pipes are built as part of a larger development that incorporates road, footpath, and lot divisions for sale. It is important for public utilities to have assurance that these new pipe assets have been constructed to their approved design and are defect free prior to them taking ownership.

This inspection, or CCTV acceptance test, is a critical part of the process that confirms the newly constructed pipe meets the requirements set out by the relevant authority. A CCTV inspection for acceptance is intended to focus on a range of areas, including:

  • Surface damage of internal surfaces
  • Cracking, breaking, or holes in the pipe wall
  • Obstructions or deposits within the pipe
  • Constructed grade (fall) of the pipe
  • Deformation
  • Joint defects
  • Ponding of water, or flat sections
  • Connection and junctions
  • Length of constructed pipe

Public utilities usually specify that these inspections be completed to the relevant inspection reporting code and must meet minimum standards to be approved for contributed asset handover.

Patch repair needed in new pipe

Figure 1- Cured-in-place patch to rectify a pipe defect in a new pipe

Who completes and approves an acceptance test?

Civil construction companies are usually required to engage an independent CCTV sub-contractor to complete an acceptance test, with a qualified engineer providing sign-off on the CCTV results and other accompanying reports where required.

When does the acceptance test occur?

Utilities may be descriptive around what stage the acceptance test can occur, with practical completion of various other on-site works a pre-requirement. Where specified, this detail is listed in a specification document or instruction issued directly from the approving authority.

Cause of Delays

Delays in the workflow when submitting acceptance inspections can occur due to:

  • The time it takes to supply the approving authority the specified video and associated report/s; or
  • In instances where a pipe does not pass the acceptance test, there will likely be some form of minor repair/maintenance required and a follow-up CCTV inspection to confirm any identified issues have been rectified. In most cases this will be jetting to remove construction debris/deposits, or patching a location with pipe wall damage

If the follow-up to a failed CCTV acceptance test is delayed due to the workflow that is setup between civil contractor, CCTV contractor, and reviewing engineer; the cost to the overall project can be significant. In some cases, this delay will fall on the critical path of other finalization works and negatively impact other teams working on the development project. VAPAR has specifically designed a workflow that ensures the time between the CCTV inspection and approval is minimized to reduce any unnecessary or costly delays. In instances that repair or maintenance is required, the details of this can be distributed to the required parties quickly.

deposits and debris in pipe

Figure 2- Deposits and debris that requires removal before acceptance

How can VAPAR assist in avoiding costly delays in your review and approval timeline?

Same day turn-around can be achieved with upload from site that only requires the video file and an internet connection to your internet browser. VAPAR’s AI processing time is measured in minutes, not days. Your reviewed inspection results can be shared in real time with clients you have invited into the VAPAR.Solutions platform in a structured library of current and past inspection projects.

Alternatively, you can choose to send your package of inspection results for the day, or week, as a pdf report set or spreadsheet summary. What does this mean in practical terms? Data and results (including access to the selected inspection video files) can be shared without the requirement for downloaded software or file sharing programs. The CCTV inspection videos, and associated results are available directly to your client in the method most convenient for your situation.

Keeping all your inspections organised and accessible

VAPAR’s cloud storage solution for inspections means cataloguing, finding, and viewing your past CCTV results is both user friendly, and eliminates the requirement for on-premises storage. No more lost files spread across different servers and cluttered folder structures. For utilities that would like to compare original acceptance inspections with end of defect-liability inspection, or condition assessment years down the line, this can be done directly from your internet browser by searching asset ID, or node, to bring up your matching results.

Image of VAPAR.Solutions

Figure 3- Searching past inspections of the same pipe asset

About the Author Mark Lee
waste water monitoring

Increasing the value of wastewater network monitoring

Increasing the value of wastewater network monitoring

Innovation is the key to delivering ever-increasing performance

Asset owners around the world are looking for innovative ways to deliver on the challenge of increasing wastewater network performance targets. With improved technology and the ability to handle large amounts of data, it’s become significantly easier to monitor flow and depth patterns, and highlight issues within a network that trigger a maintenance response prior to a flooding or pollution incident occuring.

waste water monitoring

Radar level and IoT telemetry device from Metasphere (Sense Level, ART Sewer)
Wastewater monitoring can generate a return on investment when they prevent flooding and pollution incidents.

Of course, there is no point in installing monitors for the sake of it, they should be positioned so that they have the greatest value. Having monitors in areas that don’t generate a return on investment is not prudent, therefore knowledge of current system performance and planning is required to determine the optimal locations that will provide a positive return when installed in locations that are most likely to prevent flooding or pollution incidents. 

The most important part of the puzzle in locating monitors is to understand the characteristics of the most common failures within the network; blockages. A previous UKWIR project  identified the following: 

  • 20% of blockages reported over a year are repeats at property level and this increases to between 40% and 60% when analysed at the postcode level. 
  • The proportion of repeats increases to 30% and 70% at a property and postcode resolution respectively when there are 5 years of data available. 
  • Approximately 50% of postcodes and 4% of properties have suffered 1 or more blockages over a 9-year period, this reduces to 23% of postcodes and 1.2% of properties suffering repeat blockages over the same period. 
Picture of sewer blockage

Analysis of historic blockage data indicates blockages repeat at the same location over time.

This analysis shows repeat blockages happen at the same location and that if monitors are located correctly, they can be effective in preventing major incidents. 

 The report also identified the most common causes of blockages: high density of interceptors, high densities of FOG (fats. oils & grease) generating properties, older properties, terraced / high rise properties, small diameter sewers and lower affluence. 

 This suggests that taking remedial action such as removing interceptors, root cutting, repairing structural defects and educating customers about the use of FOGs and wet wipes would mitigate the probability of repeat blockages. Fixing the root cause will prevent having to constantly reattend to carry out blockage clearance maintenance, which causes inconvenience for the customers and increases operational costs. 

 In a perfect world asset owners would repair and replace all the defects in a wastewater network. The reality of course is there is no bottomless pit of money for this activity and funding will continue to be challenged given the current focus on the affordability of utility bills.  

Person calculating his expenses

The affordability challenge associated with utility bills means there will never be sufficient funding to repair all defects on the network.

Repairs are not always practical or cost effective

This is where asset management comes in and provides us with the capability to effectively balance the cost, risk and performance triangle depending on the objectives of the asset owner. For example, In the case of complicated wastewater networks that may run beneath buildings with a flat gradient that increases the blockage probability, then the implementation of a proactive cleansing programme is likely the best approach to balance cost, risk and performance.  The use of monitoring in these situations allows the proactive maintenance costs to be optimised and ensure cleansing is only completed when it is required. 

Cost, risk and performance triangle

Asset Management provides the capability to balance the cost, risk and performance triangle to deliver the asset owner’s objectives.

Alternatively, the installation of a monitor where roots have been identified or where a partial collapse has occurred is unlikely to balance the triangle correctly. It will likely be more efficient to mitigate the root cause (e.g. cut out the roots or repair the collapse) compared to monitoring the location.  

Data is key to making informed decisions

The ability to adapt the correct balance of cost, risk and performance for each scenario is based on having the right data available to understand the root cause of a flooding or pollution location.  Using CCTV pipe inspection data provides the ability to understand the root cause and enables monitors to be installed at locations where they can generate the greatest Return on Investment (ROI).  The historic challenges with CCTV pipe inspection data have been its cost (e.g. it is not cost-effective to survey the entire network) and the ability to provide the outputs in a format that allows good investment decisions. 

 VAPAR uniquely combines Artificial Intelligence, the latest software capability and human input, reducing the cost of CCTV pipe inspections and making the outputs more accessible to decision-makers. Reducing the cost of CCTV pipe inspections makes it more economical to either complete CCTV pipe inspections prior to installing a monitor or use existing inspection data as part of the monitoring decision-making process. A great example of making the CCTV pipe inspection data more accessible is the visualisation of the survey results via a GIS, where the defect locations can be understood relative to the proposed monitor location on the pipe network. 

Pipe network and defects seen on GIS using VAPAR

VAPAR’s capability to visualise CCTV pipe inspection data allows monitoring locations to be identified that will deliver the greatest ROI.

Conclusion

It is fundamental for Asset Managers to look at alternate and innovative ways of managing pipe networks if they are to deliver the increasingly challenging financial and performance targets. The use of network monitoring provides one of these innovative ways, however, it will not provide a ‘Silver Bullet’ in isolation.  The use of VAPAR alongside monitoring will allow CCTV pipe inspection data to inform the decision-making process on where to install monitors. Ultimately this will balance cost, risk and performance and ensure the return on investment from monitoring is realised. 

Nathan Muggeridge - Author
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Too many engineers, not enough data analysts?

Too many engineers, not enough data analysts?

“Data is not information, information is not knowledge, knowledge is not understanding, understanding is not wisdom”

Clifford Stoll

One of the significant changes for utility providers in the 21st century is the massive increase in data that is now available and streaming into organisations. It wasn’t so long ago that engineers were hand drawing pipe long sections and calculating maximum flows without the aid of hydraulic models, or even a computer. Those days are gone, long gone; the new breed of engineer now has access to a wide array of software programs, intelligent devices, and predictive tools that are all generating gigabytes of data for consumption:

  • Hydraulic models
  • Digital twins
  • Artificial intelligence processors
  • 3D LiDAR mapping
  • Telemetry and remote SCADA Systems
  • Digital flow meters
  • Leak detection loggers
  • Overflow and pressure transient sensors
  • Multi-camera inspection robots

The result is the availability of more data than organisations have ever had in their history, and it continues to accumulate at a faster and faster pace each year. What hasn’t changed so quickly is the traditional skills that engineers are taught during studies and the types of roles that organisations create to look after their assets.

Turning data into information, and then using that information to make smart decisions and gain improved understanding of assets requires a different skill set than traditional engineers may be used to. Not only is more data coming in, but it needs storage, user access, and interaction among different software programs. Organisations that can successfully accept the substantial amounts of data and efficiently cleanse, analyse, and integrate it throughout their processes have a distinct advantage in providing services that return value for money and meet the objectives for their community or customers.

Taking advantage of Application Programming Interfaces (APIs) and integration options that are often market supplied and understanding the methods of detecting trends, risks and insights is a smoother process when organisations have data analysts on board who can be the key player to ensure engineers are working with information and knowledge and not just data.

Has there been enough discussion in the industry about the creation of these targeted positions and then attracting and keeping data analysts? Opening a dialogue with sector leaders and obtaining human resources buy-in that positions like this are essential, may be a different challenge, but one that is going to be worth taking on.

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