Shallow aquifers used for water supply. Many municipal wastewater network operators Collaboration on research. High water tables

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1 No Dig Roadshow Leeds October 2017 Underground infrastructure Comparative performance of sewer rehabilitation methods The German Approach Iain Naismith IKT Institute for Underground Infrastructure Gelsenkirchen (D)/Arnhem (NL) Source: Source: Heidelberger Versorgungs- und Verkehrsbetriebe GmbH Source: DWA Situation affecting German network operators Shallow aquifers used for water supply Strong legislation to prevent contamination Emphasis on sewer network not leaking High water tables Infiltration affects performance of STWs Ageing infrastructure Requirement for regular sewer flushing Requirement for sewer inspection Blockages Tree roots much research Situation affecting German network operators Many municipal wastewater network operators Collaboration on research North Rhine Westphalia Lander Environment Ministry funds research Very active on standards - D, EN and ISO Quality Assurance very important Striving for level playing field on quality Disposable wipes first workshops this year North Rhine Westphalia Research NRW Environment Ministry funds major projects Must address needs of wastewater network operators and they provide some funding Usually two years Projects managed and undertaken by IKT Projects overseen by Steering Group Approves all elements of the project May meet a dozen times Involved in assessment of performance 1

2 Research Systems Life cycles Quality factors LinerReport Annual comparison Quality assurance Performance Approvals/Acceptance Testing for Approvals Acceptance of Works Operational Tests Networking Experience Strategies Joint Projects Education Technical Requirements Innovative Developments Comparative Tests Quality Assessment Market Overview Past research on sewer rehabilitation Past research on sewer rehab Past research on sewer rehab Three examples of comparative testing Lateral connection rehab Manhole rehabilitation Rising mains inspection 2

3 Lateral connection repair Lateral connection damage is most common damage found by German network operators Aims Comparatively evaluate contractor performance Generate market pressure for performance improvement Two different test situations Lateral re-connection to a lined sewer Repair of lateral connection from un-lined sewer Lateral connection repair Market survey 10 manufacturers of rehab robots 52 rehab contractors All invited One manufacturer agreed One manufacturer recommended their trusted contractor. 11 other contractors submitted quotation 4 selected. Contractors in the test Steering Group discuss damage scenarios Case 1: Case 2: Contractors in the test Lateral connection Lateral reconnection repair to a liner-refurbished main sewer in a non-refurbished main sewer IBG HydroTech GmbH KATEC Kanaltechnik Müller & Wahl GmbH Kuchem GmbH PLITT-ROHRSANIERUNGSGESELLSCHAFT mbh Swietelsky-Faber GmbH Kanalsanierung Onyx Rohr- und Kanal-Service GmbH Geiger Kanaltechnik GmbH & Co. KG Deciding on damage Damage scenarios reconnection/repair Case 1: Lateral reconnection Damage scenarios in a liner-refurbished main sewer (in GRP and NF sections in each case) Scenario I Scenario II Scenario III Case 2: Lateral connection repair Damage scenarios in a non-refurbished main sewer (in concrete and vitrified-clay pipes in each case) Scenario I Scenario II Scenario III 3

4 Lateral reconnection Two lines of concrete pipe DN300 with concrete manholes DN1000 for access. One lined with GRP the other with needle felt liner. Lateral connections of vitrified clay pipe DN 150. Each pipe divided into 6 sections (of three lateral connections) one for each contractor. Lateral repair Two scenarios Lateral connections of vitrified clay pipe DN 150 into concrete pipe DN 300. Lateral connections of vitrified clay pipe DN 150 into clay pipe DN 300. Concrete manholes DN1000 for access. Buried under sand Access only from manhole Up to contractor how the work was done No time limit Testing Application of external water pressure to 2m above the pipe crown Short term - <72 hrs Long term 4 months for reconnection 2 months for lateral repair Sewer cleaning Standard HP operational load: 80 bar at nozzle for 15 cycles. Additional tests not used for evaluation Groundwater at 4.5m above crown, HP at 100 bar and internal pressure tests. Assessment Water tightness No abnormalities Visible discolouration and/or moisture Visible infiltration Functionality Visual assessment of serviceability Visual assessment following jetting QA Process manual, operator training, test certificates for materials, supervision Observation in the field Lateral reconnection results Reconnection results 59% exhibited no abnormalities If initially watertight under short term test unlikely to develop problems later. Some deterioration of those with problems as testing progressed. At end of testing (incl. 4.5 m head) 8 of 34 laterals had visible infiltration. Tight in GRP Tight in NF Discoloration Moisture Jet Gushing 4

5 Reconnection - functionality No significant differences between repairs to GRP and needle felt lined pipes. Significant differences between contractors with grades from 1.7 to 5.1. Four GOOD One SATISFACTORY One DEFICIENT Jetting resulted in only minimal changes in grades Damage scenario 1 with pipe at 45 degrees was most problematic for contractors Best graded after jetting in GRP (L) and NF (R) Worst graded after jetting GRP (L) NF (R) Grading for lateral reconnection Lateral repair results Contractors Testing 85% QA 15% Overall Kuchem GmbH Good (1.6) Very Good (1.0) VERY GOOD (1.5) KATEC Kanaltechnik Müller & Wahl GmbH Good (1.8) Very Good (1.0) GOOD (1.6) Swietelsky-Faber GmbH Kanalsanierung Good (2.0) Good (2.0) GOOD (2.0) PLITT-ROHRSANIERUNGSGESELLSCHAFT mbh Good (2.5) Very Good (1.0) GOOD (2.3) Onyx Rohr- und Kanal-Service GmbH Adequate (4.0) Satisfactory (3.0) ADEQUATE (3.9) IBG HydroTech GmbH Inadequate (5.6) Good (2.0) DEFICIENT (5.0) Water tightness 67% exhibited no abnormalities Where repair was initially watertight it generally remained so 7 of 36 lateral had visible infiltration and five had moisture. Functionality No differences between clay and concrete pipe 4 GOOD, 1 SATISFACTORY, 1 ADEQUATE Minimal change following jetting 45 degree connection again most difficult Tight connection in concrete pipe Tight connection in vitrified-clay pipe Leaking in concrete pipe Leaking in vitrified-clay pipe Moisture, with no infiltration 5

6 Grading for lateral repair Contractors Test 85% QA 15% Overall KATEC Kanaltechnik Müller & Wahl GmbH Good (1.7) Very Good (1.0) GOOD (1.6) The best-graded lateral connection for "Functionality" after jetting concrete pipe (left); vitrified-clay pipe (right) Kuchem GmbH PLITT- ROHRSANIERUNGSGESELLSCHAFT mbh Swietelsky-Faber GmbH Kanalsanierung Good (1.7) Very Good (1.0) GOOD (1.6) Good (2.4) Very Good (1.0) GOOD (2.2) Satisfactory (2.8) Good (2.0) SATISFACTORY (2.7) Geiger Kanaltechnik GmbH & Co. KG Satisfactory (3.2) Very Good (1.0) SATISFACTORY (3.2) Poorest-graded lateral connection for functionality after jetting concrete pipe (left); vitrified-clay pipe (right) IBG HydroTech GmbH Deficient (4.7) Satisfactory (3.0) ADEQUATE (4.5) Manhole rehabilitation Manhole rehabilitation Task set for manhole rehab contractors Rehabilitate 5m high, DN 1000 concrete manhole. With defects Against rising groundwater Assessment of: System performance Quality assurance provisions Damage scenarios selected Damage scenarios selected 8 isolated damage 10mm drill hole 5 leaking ring joints Each 4 6 mm drill hole 2 area damage mm drill holes in cm mould release agent on small (L) and large area (R) 6

7 Task set Test programme Rehabilitation target Restore water-tightness Restore load bearing capability Up to contractor how it was achieved Planning Conception Rehabilitation No time limit Short-term exposure to groundwater Increments up to 5m Holding time 17.5 days 3.5 days per load level Long-term exposure to groundwater Constant 5m Holding time 67 days Inspection After each increment Once per week for long term Leaks, cavities, cracks, etc. recorded Additional tests Extra tests Tensile adhesion strengths measured MAC system used to measure stability Acceptability Steering group inspection of each repair Quality Assurance Contractors QA assessed method statements, training records, test certificates, supervision. Onsite evaluation Comparison of installation in lab with realities in the field Systems compared Table 1: Methods tested in the IKT "Manhole refurbishing" product test Supplier a) Mortar coatings System Hermes Technologie GmbH & Co. KG Ergelit KS 1 MC-Bauchemie Müller GmbH & Co. KG Ombran MHP PCI Augsburg GmbH Nanocret R4 Remmers Baustofftechnik GmbH Betofix R4 SR Remmers Baustofftechnik GmbH Silicate R Sika Deutschland GmbH Sewer profiling mortar b) Plastic coatings FSB Bautechnik GmbH Spectrashield PSL Handels GmbH Olodur WS 56 Source One Environmental UK (S1E) c) Linings Aarsleff Rohrsanierung GmbH Hobas Rohre GmbH SEKISUI SPR Germany GmbH Ultracoat GRP, back-anchored GRP inner shaft GRP, adhesive Schacht + Trumme Sielregulierungen W. Schwarz GmbH HDPE segmental lining Installation Completed rehabilitations 7

8 Steering group inspection System failure Water tightness assessment Damp patch < 25cm Damp patch > 25cm Spreading plume >40cm Infiltration Results Manhole conclusions Supplier & System Testing 85% QA 15% Overall Hobas Rohre GmbH, GRP inner shaft Very Good (1.3) Satisfactory (3.5) GOOD (1.6) PCI Augsburg GmbH, Nanocret R4 Very Good (1.3) Adequate (4.0) GOOD (1.7) Schacht + Trumme Sielregulierungen W. Good (2.0) Good (2.5) GOOD (2.1) Schwarz GmbH, HDPE segmental lining Sika Deutschland GmbH, Sewer reprofiling Very Good (1.5) Defficient (5.5) GOOD (2.1) mortar Aarsleff Rohrsanierung GmbH, GRP, backanchored Good (2.1) Satisfactory (3.0) GOOD (2.2) PSL Handels GmbH, Olodur WS 56 Good (2.3) Adequate (4.5) SATISFACTORY (2.6) Hermes Technologie GmbH & Co. KG, Ergelit Good (2.5) Adequate (4.0) SATISFACTORY (2.7) KS 1 Source One Environmental UK (S1E), Good (2.5) Adequate (4.5) SATISFACTORY (2.8) Ultracoat Remmers Baustofftechnik GmbH, Betofix R4 Satisfactory (2.8) Satisfactory (3.5) SATISFACTORY (2.9) SR SEKISUI SPR Germany GmbH, GRP, Satisfactory (3.0) Inadequate (6.0) SATISFACTORY (3.5) adhesive Remmers Baustofftechnik GmbH, Silicate R Satisfactory (3.6) Satisfactory (3.0) SATISFACTORY (3.5) MC-Bauchemie Müller GmbH & Co. KG, Adequate (4.0) Very Good (1.0) SUFFICIENT (3.6) Ombran MHP FSB Bautechnik GmbH, Spectrashield System failure Good (2.5) Not Evaluable Reliable manhole rehab possible but wide range of scores Substrate preparation very important One failed, others cracked, blistered, leaked If watertight immediately after ground water applied no further deterioration Acceptance inspection recommended QA very patchy Majority unable to cite training certificates, approvals 8

9 Rising Mains Inspection Federal Regulations require inspection and monitoring of rising mains Different materials - Steel, cast iron, asbestos cement & plastic High points and low points with no valves for draining/venting Better understanding needed of Inspection technology Performing water tightness tests Selection of rehab techniques Risk modelling Rising Mains Inspection Workshop with inspection technology manufacturers wastewater, oil, gas and water. Identified specific requirements for technologies to address water tightness Leak detection Weak points Inspection equipment examined Findings Steel sewer radar, eddy-current method (magnetic) Cast Iron eddy-current method Asbestos Cement sewer radar Evaluated on pipe samples and in-situ deployments Sewer radar worked well in asbestos cement Eddy-current worked well for steel and cast iron on sudden changes in wall thickness and simulated areas of corrosion. Not suitable in principle for plastic pipes Water tightness test for plastic pipes Rising main inspection test rig For plastic pipes hydraulic water pressure testing may be more appropriate. Included in standard on-site acceptance tests for new gravity and pressure sewers (EN 1610). But no dedicated inspection procedure in available standards for buried rising mains. So test pipe set up at IKT. 27m, PE 100, 150 diam. bends slopes, high/low points, valves 9

10 Aims Testing Aims Effects of different pressure Effect of duration of test Effect of air remaining in the pipe Can water tightness be reliably determined Four contractors selected to undertake test IKT also undertook the test with its own equipment Contractors test focused on: Were they aware of the requirements for leak tightness testing. Whether they could apply correctly. Test 1 8% air pocket in first bend Test 2 30% air pocket Test 3 No air pocket Testing scenarios Example of testing equipment Results IKT performed extensive additional experimental tests: Magnitude of number of leaks Varying the test time 192 mins, 48 mins, 30 mins total. Different pressures 8 bar, 6 bar, 5 bar, 4 bar. Air inclusions Test time most important consideration for sewer operators standard test can be three hours. Three of the contractors had inadequate knowledge on performing tests and interpreting results. It was possible to undertake satisfactory testing in 30 minutes. Can identify leaks quickly if results correctly interpreted. Conclusions could be drawn even at low pressures. 10

11 Risk Model Results Risk index Probability of occurrence Extent of damage 1 Impossible Very low 2 Unlikely Low 3 Possible Moderate 4 Probable High 5 Very probable Very high Risk factors Weighting Geometry/diameter of the pressure pipeline 2.57 Age of pressure pipeline 4.14 Location/depth of pressure pipeline 2.57 Installation/bedding errors 3.00 Technical pump aspects 3.29 Conveyed fluid 3.86 Materials properties 3.86 Soil properties 2.00 Damage-extent factors Weighting 2.0 Costs Lack of knowledge among some network operators training needed Serious deficiencies apparent in performance of water tightness tests by some contractors hydraulics, codes of practice, measurement, safety training needed Number/importance of connected households 1.0 Environmental effects 1.0 Summary Lateral repair from sewer Current project Completed next year Ongoing liner QA The LinerReport New Projects being planned Since 2003 Minimum of 25 samples >5 sites Contractors and systems Liquid soils Image from WBM-Flüssigboden GmbH website Rising mains repair techniques Lining systems for rising mains repair 11

12 New Projects being planned Decentralised treatment in surface drains Further information Reports on the three projects described are available in English from Iain Naismith Tel: