Project Appreciation and Objectives
Reducing infiltration is a key issue for many UK sewerage undertakes and AMP4 programmes include extensive cured-in-place pipe (CIPP) lining. Infiltration reduction is important to sewerage undertakers for a number of reasons:
- Infiltrating water reduces the hydraulic capacity of the sewerage system which may in turn result in increased flooding incidents and less 'headroom' for future flow increase;
- surcharging sewage treatment works risk breaching discharge consents, and;
- treating groundwater has an operational cost.
Until recently it was generally believed that CIPP renovation greatly reduced infiltration. However, an infiltration test developed by Don Ridgers (Thames Water) has shown that only 1 of 10 CIPP systems tested to date met the test criteria for minimising infiltration. Experience of using this test procedure has raised a number of issues that require further investigation.
At Don Ridgers invitation WRc will take on 'management' of the infiltration test and examine the issues and update the test procedure in light of experience of its application to date. WRc will witness subsequent tests undertaken by manufacturers and contractors, or audit witnessing by other independent organisations, and will maintain a register of test results within the public domain. An additional objective is to promote this methodology as a basis for a UK/European standard.
Benefits to Clients
- Establishment of a common test methodology which will provide end user confidence that CIPP lining systems perform satisfactorily with respect to infiltration.
- Justification that the extensive capital expenditure renovation programme planned by the WaSC's throughout AMP4 will result in the expected/required infiltration reduction.
- Desk based review of Worldwide infiltration research and testing, including end seal systems;
- Review of the current infiltration test procedure with manufacturers, contractors and sewerage undertakers;
- Examine the issues raised and where appropriate revise the test procedure in light of feedback;
- Witness infiltration testing on a range of CIPP systems, or audit independent witnessing, and;
- Maintain a register of test results within the public domain.
- Project report
- Revised infiltration test procedure
- A register of test results within the public domain
- CP278 "Infiltration Control Via 'Top-Hat' and Grouting Repair Systems", 2006.
- CP167 "Long term hydrostatic testing of sewer repair and sealing techniques", 2005.
- Suite of six (Club and Portfolio) research projects in the area of Localised Sewer Repairs, 1995 to 2003.
Duration: 12 months