Hi All,
I have had limited success on other forums, so I am hoping to receive some out-of-the-box thoughts on how my council can deal with a complex sewer pressure main asset management issue. There is a lot of detail, but I will try to keep it succinct.
Context:
The Eastern and Western Force Main (EWFM) network delivers sewerage from a repump station in the centre of the council boundary to a sewerage treatment plant in the north of the of the council boundary. The force mains collect a number of large injecting along the way and is hydraulically assisted by 3 booster pump stations along the way (2 on the eastern force main (EFM) and 1 on the western force main (WFM)). A few key details of the network are listed below, however do not consider this an exhaustive list:
[ul]
[li]The total network is approximately 37km long.[/li]
[li]The Eastern Force Main (EFM) is majority comprised of late 1970s asbestos cement located predominantly in low lying areas adjacent to a significant waterway. The WFM then turns inland and transitions to mild steel cement lined of approx. the same vintage before entering the sewerage treatment plant. The EFM is almost entirely DN600 with a portion of DN800. There are 2 booster stations located approx. 50% along the alignment and then 75% along the alignment.[/li]
[li]The Western Force Main (WFM) is majority ductile iron cement lined and mild steel cement lined pipe of late 1980s vintage that traverses the council boundary further inland, where it is subjected to more intermediate high and low points. The WFM varies from DN600 to DN1200 along its length and features 1 booster station approx. 50% along its alignment.[/li]
[li]The EFM and WFM have two cross connections. The first is located approximately 10% along the subject alignments and the second is approximately 25% along the subject alignments. These cross connections serve to balance flows within the network and as contingency in reactive and planned maintenance situations.[/li]
[li]The system as a whole has a disproportionally high failure rate and the resulting failures have a high impact (location profile, high spill volumes, community and environmentally significant areas, significant resource drain to manage and repair, cases of media exposure, etc.).[/li]
[li]There have been approx. 26 failures throughout the mains life (varying levels of data certainty).[/li]
[li]This network is operationally complex and not very receptive to operational change (given the number of injecting sewer pump stations and booster stations along its alignment).[/li]
[li]This network poses major risks to our council (reputation, financial, environmental, etc.)[/li]
[/ul]
Current Works:
Our council is currently completing the following works to better understand the network, proactively plan renewals, and plan replacement or alternate servicing strategies. This is all done with the intention to reduce the risk of the network:
[ul]
[li]Desktop Condition Assessment – study to identify likely locations of pipeline issues. Review of (Built characteristics, Internal and external corrosion mechanisms, Operation and maintenance, Historical failure records).[/li]
[li]Holistic Screening – PCAT is the currently chosen technology here, it is a transient inducing and sensing procedure that yields a sectional based wall thickness result across the tested sections. At present the first stage of these works is in progress with additional sections to follow successively pending the value of the initial sections results.[/li]
[li]Local Detailed Investigation – Detailed investigations will be undertaken to validate and calibrate the results of the desktop condition assessment and holistic screening. It is envisioned that these detailed investigations will be either pipe scanning or sampling/laboratory testing pending the locations pipe material.[/li]
[li]Operational Contingency – additional large valves are being procured with the intention to install them in key locations (i.e. injection points). This will allow additional portions of the network to be protected from extensive spills during planned or reactive scenarios.[/li]
[li]MHL Dosing – An MHL dosing setup is due for construction and ongoing maintenance at the inlet to the repump station (i.e. just prior to the EWFM Network). The intention of this process is to reduce the overall corrosivity of the sewerage that is transported through the network.[/li]
[li]General Works - GRV's and Odour Control Units – The council has ongoing maintenance programs for the GRVs and Odour control units attached to this network (and across the whole council). this program involves a significant emphasis on improving the infrastructure and increasing or decreasing frequency where required.[/li]
[/ul]
Future works:
[ul]
[li]Optimisation of network flows – The operational teams in the field have been and will continue to run select tests on how the network can be operated to better induce scouring and slime stripping within the mains.[/li]
[li]Renewals – At the completion of the condition assessments listed above an overarching the council will have a better idea of the remaining useful life left for the underlying assets. Renewals will be proactively planned based off this information.[/li]
[li]Planning/modelling review of network – where a significant portion of the network requires renewal or a significant inefficiency in the network is identified the planning team will focus on the possibility of alternatives. As a general idea of what this could be, insertion of sewer pump stations, conversion of the booster stations to sewer pump stations, independent rising mains for large injection stations, gravity tunnel, new sewerage treatment plant… some of these items are significantly more likely than others.[/li]
[li]Additional maintenance plans – If the condition assessments demonstrate that a new maintenance plan should be created (i.e. pigging) this will be considered.[/li]
[/ul]
My Questions:
[ol 1]
[li]Is there anything that is clearly missing in our approach to reducing the risk of this asset?[/li]
[li]Are there any alternative condition assessment technologies that are worth researching?[/li]
[li]Are there any viable spray lining or slip lining technologies that can navigate a complex alignment?[/li]
[li]Are there any additional maintenance techniques that might provide additional useful life to the sewer pressure assets?[/li]
[li]Any other value you can add feel free.[/li]
[/ol]
Thanks for taking the time to read/respond.
Cheers, BWills
I have had limited success on other forums, so I am hoping to receive some out-of-the-box thoughts on how my council can deal with a complex sewer pressure main asset management issue. There is a lot of detail, but I will try to keep it succinct.
Context:
The Eastern and Western Force Main (EWFM) network delivers sewerage from a repump station in the centre of the council boundary to a sewerage treatment plant in the north of the of the council boundary. The force mains collect a number of large injecting along the way and is hydraulically assisted by 3 booster pump stations along the way (2 on the eastern force main (EFM) and 1 on the western force main (WFM)). A few key details of the network are listed below, however do not consider this an exhaustive list:
[ul]
[li]The total network is approximately 37km long.[/li]
[li]The Eastern Force Main (EFM) is majority comprised of late 1970s asbestos cement located predominantly in low lying areas adjacent to a significant waterway. The WFM then turns inland and transitions to mild steel cement lined of approx. the same vintage before entering the sewerage treatment plant. The EFM is almost entirely DN600 with a portion of DN800. There are 2 booster stations located approx. 50% along the alignment and then 75% along the alignment.[/li]
[li]The Western Force Main (WFM) is majority ductile iron cement lined and mild steel cement lined pipe of late 1980s vintage that traverses the council boundary further inland, where it is subjected to more intermediate high and low points. The WFM varies from DN600 to DN1200 along its length and features 1 booster station approx. 50% along its alignment.[/li]
[li]The EFM and WFM have two cross connections. The first is located approximately 10% along the subject alignments and the second is approximately 25% along the subject alignments. These cross connections serve to balance flows within the network and as contingency in reactive and planned maintenance situations.[/li]
[li]The system as a whole has a disproportionally high failure rate and the resulting failures have a high impact (location profile, high spill volumes, community and environmentally significant areas, significant resource drain to manage and repair, cases of media exposure, etc.).[/li]
[li]There have been approx. 26 failures throughout the mains life (varying levels of data certainty).[/li]
[li]This network is operationally complex and not very receptive to operational change (given the number of injecting sewer pump stations and booster stations along its alignment).[/li]
[li]This network poses major risks to our council (reputation, financial, environmental, etc.)[/li]
[/ul]
Current Works:
Our council is currently completing the following works to better understand the network, proactively plan renewals, and plan replacement or alternate servicing strategies. This is all done with the intention to reduce the risk of the network:
[ul]
[li]Desktop Condition Assessment – study to identify likely locations of pipeline issues. Review of (Built characteristics, Internal and external corrosion mechanisms, Operation and maintenance, Historical failure records).[/li]
[li]Holistic Screening – PCAT is the currently chosen technology here, it is a transient inducing and sensing procedure that yields a sectional based wall thickness result across the tested sections. At present the first stage of these works is in progress with additional sections to follow successively pending the value of the initial sections results.[/li]
[li]Local Detailed Investigation – Detailed investigations will be undertaken to validate and calibrate the results of the desktop condition assessment and holistic screening. It is envisioned that these detailed investigations will be either pipe scanning or sampling/laboratory testing pending the locations pipe material.[/li]
[li]Operational Contingency – additional large valves are being procured with the intention to install them in key locations (i.e. injection points). This will allow additional portions of the network to be protected from extensive spills during planned or reactive scenarios.[/li]
[li]MHL Dosing – An MHL dosing setup is due for construction and ongoing maintenance at the inlet to the repump station (i.e. just prior to the EWFM Network). The intention of this process is to reduce the overall corrosivity of the sewerage that is transported through the network.[/li]
[li]General Works - GRV's and Odour Control Units – The council has ongoing maintenance programs for the GRVs and Odour control units attached to this network (and across the whole council). this program involves a significant emphasis on improving the infrastructure and increasing or decreasing frequency where required.[/li]
[/ul]
Future works:
[ul]
[li]Optimisation of network flows – The operational teams in the field have been and will continue to run select tests on how the network can be operated to better induce scouring and slime stripping within the mains.[/li]
[li]Renewals – At the completion of the condition assessments listed above an overarching the council will have a better idea of the remaining useful life left for the underlying assets. Renewals will be proactively planned based off this information.[/li]
[li]Planning/modelling review of network – where a significant portion of the network requires renewal or a significant inefficiency in the network is identified the planning team will focus on the possibility of alternatives. As a general idea of what this could be, insertion of sewer pump stations, conversion of the booster stations to sewer pump stations, independent rising mains for large injection stations, gravity tunnel, new sewerage treatment plant… some of these items are significantly more likely than others.[/li]
[li]Additional maintenance plans – If the condition assessments demonstrate that a new maintenance plan should be created (i.e. pigging) this will be considered.[/li]
[/ul]
My Questions:
[ol 1]
[li]Is there anything that is clearly missing in our approach to reducing the risk of this asset?[/li]
[li]Are there any alternative condition assessment technologies that are worth researching?[/li]
[li]Are there any viable spray lining or slip lining technologies that can navigate a complex alignment?[/li]
[li]Are there any additional maintenance techniques that might provide additional useful life to the sewer pressure assets?[/li]
[li]Any other value you can add feel free.[/li]
[/ol]
Thanks for taking the time to read/respond.
Cheers, BWills
