Pressure sewer pipes like gravity sewers that are getting on in years need to be renovated. But, which methods are suitable? What are their strengths and weaknesses? The recent IKT comparative product test on pressure sewer liners provides answers.

Pressure sewers are critical and sensitive elements of urban wastewater infrastructure. Many are ageing so sewer network owners are increasingly having to deal with their rehabilitation and there are different methods available on the market for this.

Consequently, the neutral, independent and not for profit IKT Institute for Underground Infrastructure, in Germany, has been examining rehabilitation solutions in an extensive comparative product test. Over a three-year period an evaluation project was undertaken on behalf of six municipal network operators from Bottrop, Bremen, Burscheid, Iserlohn, Cologne and Voerde and two regional water associations, the Emschergenossenschaft and the Wupperverband.

The project was supported by the district government of Münster and the State Office for Nature, Environment and Consumer Protection of North Rhine-Westphalia (LANUV). It was financed jointly by the NRW Ministry of the Environment and the eight network operators.

These organisations formed a steering group that determined the pressure sewer damage scenarios to be remedied, the testing programme and the evaluation of the results. IKT developed the test concept, set up the test rigs in its large 1:1 scale test pit and carried out the testing.

Six liners in the comparative product test

The steering committee selected the following lining technologies for the comparative product test:

Close-fit linier method:

• Compact Pipe (Wavin GmbH)
• egeLiner (egeplast international GmbH)

Cured in Place Pipe (CIPP) liner process:

• Esders HPS Liner (Esders Pipeline Service GmbH)
• Nordiflow WPE (NordiTube Technologies SE)
• SaniPipe (AMEX Sanivar AG)
• Starliner Structure-S (Karl Weiss Technologies GmbH)

Remediation task

For each liner system, the test setup consisted of a DN200 steel pipe with damage patterns such as holes, leaky connections, point loads, transverse and longitudinal cracks, ovalisation and incrustations. This realistically depicted the damage that network operators find in their pipes.

Class A liner systems

The central issue was whether the liners are suitable as Class A products. A Class A liner must be able to withstand internal and external stresses on its own, regardless of the condition of the host pipe. The stress testing programme conducted as part of the IKT comparative product test went well beyond the regular warranty period of five years in order to consider the entire useful life.

Test program and evaluation scheme

The test programme consists of three phases: The first phase depicted the regular, normal operation of a rehabilitated pressure pipe. Internal water pressures of between 2 and 6 bar were applied at different flow speeds.

In the second phase, the degeneration of the host pipe was simulated over a prolonged period of time. For this purpose, some of the damage scenarios in the host old pipe were worsened in order to simulate progressive damage development and the resulting changes in external influences on the liner. Test pressures and flow rates remained the same as in the first phase.

Finally, the third phase served to simulate additional, non-every day and extraordinary loads on the liner that may occur over the course of its useful life. These included high-pressure cleaning at 80 bar, abrasive substances, the rapid switching on and off of the pump or elevated groundwater levels, such as those that occur when pipes pass under rivers.

Evaluation criteria

The overall grades for the liner systems are made up of the four main criteria of tightness, stability, operational safety and quality assurance. These are divided into nine sub-criteria. The range of grades lies between VERY GOOD (1.0) and INADEQUATE (6.0).

Watertightness criterion (weighting 45%)

The main weak points found in the four CIPP liner processes were the end connections to the host pipe, there were leaks. In contrast, the PE flange and electrofusion sleeve connections of the close-fit liners were reliably watertight.

The close-fit systems Compact Pipe and egeLiner proved to be watertight after renovation. In contrast, the picture for the CIPP liner end connections was very different: Nordiflow and SaniPipe each had to be reworked once to make them all watertight, whilst the Starline end connections had to be reworked twice in order to get them tight. The Esders HPS liner remained leaky even after the connections had been repaired twice and thus it failed on this criterion.

Stability criterion (weighting 25%)

The stability (load-bearing capacity of the structure) was classified by the steering committee as a central “KO” (failure) criterion. It was gratifying that five of the six liner systems tested passed this criterion with GOOD or SATISFACTORY grades. They show no or only minor abnormalities such as local wrinkling.

The SaniPipe liner failed this criterion as it collapsed under external pressure. The reason for this was insufficient fabrication of the liner, which took place without static proof. It was therefore not a Class A liner and consequently received the overall rating INADEQUATE, regardless of performance against all other criteria.

Operational performance criterion (weighting 15%)

This examined to what extent the liners can withstand normal operating conditions such as pressure fluctuations, abrasion, static pressures and high-pressure cleaning.

Here, Compact Pipe and egeLiner scored a GOOD grade. Also, they did not form folds and obstacles along their length. However, their installation leads to a hydraulic loss of 6% compared to unlined pipe this was in the middle range. The Nordiflow and Starline liners both had folds larger than 6 mm in the installed liners sheets and thus achieved a SATISFACTORY score. However, the hydraulic power loss of the Nordiflow was particularly high at 8%, whilst the Starline was the lowest at 3%.

With high-pressure cleaning, the Compact Pipe and egeLiner close-fit products achieved a VERY GOOD rating. Nordiflow and Starline withstood this operational stress SATISFACTORILY. On the other hand, Esders and SaniPipe failed this criterion because holes and delaminations occurred. Chemical loads did not have a negative effect on any liner system.

Quality assurance criterion (weighting 15%)

Although all the manufacturers provided an installation procedure manual, some of them have significant deficits in training, test certificates and external and internal monitoring. In addition, the installed Esders and SaniPipe liners each had a continuous longitudinal fold along the length and SaniPipe had design defects, which led to a devaluation of the grade.

Overall result and conclusion

The IKT comparative product test “Renovation process for sewage pressure pipes – Class A liner” confirmed that it is possible to achieve good renovation results. However, there are major differences in the performance of the six rehabilitation technologies examined, which are reflected in the test results awarded. One of the six liners could not qualify as a Class A liner.

Passed:

• Compact Pipe (Wavin) GOOD (1.8)
• egeLiner (egeplast international) GOOD (1.8)
• Nordiflow W PE (NordiTube Technologies) SATISFACTORY (2.6)
• Starline Structure-S (Karl Weiss Technologies) SATISFACTORY (2.6)

Failed:

• Esders HPS Liner (Esders Pipeline Service) DEFICIENT (5.3)
• SaniPipe (Amex Sanivar) INADEQUATE (6.0)

Results at a glance and complete report (English)

The further deterioration of the condition of the host pipe over time was found to have no effect on the success of the rehabilitation. This applied in particular to signs of corrosion such as simulated pitting and point loads. Only in one case did the complete loss of the supporting host pipe lead to liner failure under external water pressure.

All six of the liner systems could be installed through the four 15° bends included in the rig. Three of the liners were even able to install through a further 30° bend.

The systems were able to withstand normal operating conditions such as pressure fluctuations, abrasion and static pressure without any problems. However, there are clear limits to high-pressure cleaning and holes and delamination can occur here. Chemical stresses did not affect the tightness of the liner.

All liner systems lead to hydraulic performance losses in the pressure sewer the highest up to 8% at the top. The internal diameter was reduced by more than 20% in some places in some liners. Wrinkles >6 mm could be seen on all the CIPP liners. In contrast, the close-fit liners showed no creasing whatsoever, but there was clear ovalisation in the bends.

We have evaluated with sewer network owners the suitability of “Flowable Backfill” for use sewer trench backfilling in an IKT-Compare evaluation of this technology. Five products were compared and all were found to flow well into 1:1 scale excavation pits in our large-scale test facility – around pipes and manholes shafts and into every corner of the simulated trenches. However, during the subsequent performance tests it became increasingly clear that only three suppliers had actually installed “Flowable Backfill”. One product more or less concreted over the test pit, another material took far too long to set and posed a risk to working safety. The results have now been made publicly available.

IKT-Compare evaluation of Flowable Backfill in Sewer Construction
Results table in English (PDF)
Product test report in German (PDF)

Flowable backfill is also known as „Controlled Low-Strength Material“ (CLSM) or „Temporarily Flowable, Self-compacting Backfill Material“ (TFSB, or ZFSV in Germany). These products can be used to fill a pipe trench quickly, without the need for compaction equipment. They have the potential to flow into every corner of the trench, to bed the pipes optimally and to then harden to such an extent that you can build a pavement or road on top. And, if you need to access the pipe again later, the material can be dug out again – in the ideal case.

Advantages and risks of using Flowable Backfill

The demands on the material are high. What if the supplier does not quite meet the optimum performance? What if after some time the road surface sinks, or in 20 years’ time you can no longer get to the pipe because the once-liquid soil is as hard as concrete?

It is not surprising that Flowable Backfills are popular. But, the enthusiasm of clients for their benefits often obscures awareness of the risks. IKT, as a neutral and independent institute, has considered these, working with with eleven committed wastewater network operators, to undertake a major comparative product test of the technology. So, in future wastewater network operators will know what to look out for when they order a Flowable Backfill.

Can a product deliver all the desired properties?

Five systems from five suppliers were tested under realistic, reproducible conditions in a large-scale test facility. After long and intensive preparation, the product test team spent a year testing, measuring, observing, evaluating and reporting. Now the results of this new IKT-Compare product test “Flowable Backfill in Sewer Construction”, funded by the NRW Environment Ministry, are available. The testing has basically confirmed the performance advantages of Flowable Backfill that network operators appreciate, but only if the formula and installation is correct.

It was found that all five materials were able to fill the trenches completely without voids – even when shoring removal was simulated after backfilling. The testers rated the pipe bedding provided by the products very positively, and a contribution to protection of pipes from tree roots can be expected from all the products. However, two Flowable Backfills failed to meet all criteria set by the steering committee (made up of wastewater network owners), as being essential for their use in sewer construction. One material hardened to such an extent that the required re-excavation capability was not achieved, another took far too long to achieve the strength required for building over, and also exhibited risks for re-excavating of the material and an unacceptable ammonia load during excavation.

Five participants at the start

The five systems tested achieved grades varying from GOOD (1.9) to INADEQUATE (6.0) (on a scale from 1 to 6) – see link to results table below. In terms of quality, there are significant differences between the individual materials:

• Carbofill from Thomas Zement GmbH & Co KG – GOOD (score 1.9)
• RSS Flüssigboden from FiFB Research Institute for Flowable Backfill GmbH – GOOD (score 1.9)
• TerraFlow from Heidelberger Beton GmbH – SATISFACTORY (score 3.4)
• Terrapact by Holcim Beton und Betonwaren GmbH – INADEQUATE – cannot be used in sewer construction due to very poor re-excavation properties
• WBM-Flüssigboden by WBM-Flüssigboden GmbH – INADEQUATE – cannot be used in sewer construction due to slow hardening, poor recyclability and high ammonia values

Three reached the finish line, two fell by the wayside

The winner with the grade GOOD (1.9) was Carbofill from the manufacturer Thomas Zement, which only has a weakness worth mentioning in the test of walkability after filling. In second place, very close behind, comes the RSS liquid floor from the FiFB (Forschungsinstitut für Flüssigboden) research institute, also with a GOOD (1.9) rating. The material only had difficulties with the filling of the shoring removal simulation. TerraFlow from Heidelberger Beton received a low score for “re-excavation capability”, a devaluation of 1.0 grade points, but is otherwise on a par with the best performers. Overall, TerraFlow achieved a SATISFACTORY (3.4) and thus third place.

The Terrapact material from Holcim Beton und Betonwaren could only be removed from the test trench with great effort and heavy equipment. The result was an INADEQUATE in the criterion of re-excavation capability, and thus was found to be not suitable for use in sewer construction. The WBM-Flüssigboden material, on the other hand, had a problem with the criterion of hardening. It could only have been built over after considerably more than 28 days. In addition, the MAK value for ammonia was exceeded for this product (MAK = maximum allowable workplace concentration) and the recyclability was also inadequate. The verdict of the testers: INADEQUATE, not applicable in sewer construction.

Much effort was expended in order to provide users with valuable insights

For this IKT-Compare product test “Flowable Backfill in Sewer Construction”, the test hall team divided the Institute’s 15-metre long, six-metre wide and six-metre deep large-scale test stand using 25 millimetre thick steel plates to create five test chambers. Exactly the same construction of concrete manhole shafts, plastic manholes shafts and shoring boxes, as well as main, transverse and longitudinal pipes were installed in each chamber. The man-hours for installation alone added up to many weeks. Added to this is the time spent by IKT structural engineer Dr Mark Klameth on the calculations for the installations. A total of 30 tonnes of steel were used. Then the suppliers came and pumped their Flowable Backfills into the compartments and the evaluations could begin.

Testing confirmed that Flowable Backfill has many advantages

All five materials flowed well into the trenches – a pleasure to watch as, like liquid lava (only not so hot), they glided elegantly into every corner, enclosed the pipes and manhole shafts, and filled the test stand up to the top. Satisfied faces were also to be seen on the construction sites that the evaluation team visited to gather in-situ impressions and experiences.

Extensive test programme

The extensive testing programme began during the installation of the Flowable Backfills: the product test team determined the consistency of the backfill, among other things, by means of a spreader gauge, checked the shear strength with a visco-balance, measured the pH value, filled the containers for a 3-segment cylinder test – which shows whether the suspension separates over time – and took samples for cube pressure testing, which determines the modulus of elasticity after seven days. This was followed by walkability tests, load plate compression tests and the cube compression tests mentioned above. In further testing during the use and disposal phases, the product testers examined the pipe bedding and the backfilling of the shoring removal simulation. The results of eluate tests allowed the scientists to assess the environmental compatibility of the materials. And the steering committee members evaluated the ability of the soil to be removed using a spade by picking up the spade themselves and comparing the materials directly.

With exceptions, Flowable Backfill can be built over within 7 days

A minimum value of 45 MN/mm² achieved in the load plate compression test is decisive for determining if hardened Flowable Backfill can be built over. The measured EV2 values (modulus of elasticity) reached this value within the first week for four of the five products tested. However, extremely high EV2 values can also indicate that the final strength of the flooring may be too high for re-excavation.

In addition to the laboratory tests at IKT, the Flowable Backfills were also installed in trenches at a test site in Burscheid. Here and during further construction site investigations, the basic handling of the materials under practical conditions was recorded and any differences with the installations witnessed in the IKT large test facility was also checked. These observations were considered as part of the scoring for quality assurance.

Quite OK: Quality assurance by contractors

In addition to the system tests of the Flowable Backfills in the test set-ups, the testers also examined the quality assurance provisions by the manufacturers. With few exceptions, the scores in this area show that the suppliers are making great efforts to ensure quality. But there is still a bit of room for improvement.

Special attention to meeting key performance criteria

The steering committee of the network operators defined early on the performance characteristics which must be met at all costs in order to ensure that a Flowable Backfill can be used in sewer construction. These concerned: the flowability in the installation phase, the build over capability in the utilisation phase and the re-excavation capability and potential for recycling in the disposal phase. Two out of five products proved to be defect-free in tests against all these criteria: Carbofill and RSS Flüssigboden. The remaining products, on the other hand, revealed visible or even serious defects, which in two cases led to the IKT-Compare test verdict “Inadequate”.

Quality assurance in the mixing plant is extremely important

In the test, the suppliers were asked to offer the products in such a way that their composition was clearly defined and that it was also possible to re-order them for future installations. Accordingly, the suppliers were free to choose the soil material to be used. In at least one case, however, an unsuitable soil material (organic matter, ammonia release, poor build over capability) was used in the performance tests. The network operators represented in the steering committee see the suppliers/manufacturers as responsible here for reliably determining the quality of the substances and soils used in their product and making this information transparent. Soil management and quality assurance in the mixing plant where the Flowable Backfill is produced are therefore of particular importance.

Conflicting objectives: need to firm up quickly, but not be too firm for later re-excavation

Obviously, for many suppliers there is a conflict of objectives between rapid walkability and buildability and the later re-excavation capability (using a spade) of the material. Only one provider (RSS Flüssigboden) succeeded in fulfilling these criteria in the system tests with very good or good results throughout. The four remaining suppliers showed clear deficiencies in at least one of these criteria in the test.

Pulling out the shoring can lead to massive surface fractures

Pert of the evaluation involved the removal of simulated shoring from the test trenches. In individual cases, pulling the shoring led to massive surface fractures, which can lead to uncertainty at the construction site about the success of the backfilling process and necesitate. However, in the testing, the observed cases did not show any effects on the load situation in the subsoil. Where fractures did occur, the manufacturers are required to adapt the materials accordingly or to specify suitable times for pulling the shoring.

Quality assurance on the construction site

The test results show that there are important assessment criteria that should be checked in construction site practice in the course of internal and external monitoring of a Flowable Backfill installation. This applies in particular to the flowability, walkability, build over ability, and bedding properties as well as the lifting of shoring. Furthermore, the manufacturer should provide the composition of the materials used, including the soil material, in a transparent and verifiable manner. It may also be appropriate to check the homogeneity of deliveries to site, i.e. the extent to which variations in properties between batches can be observed.

In the run-up to this product test, 16 manufacturers of Flowable Backfill were researched who offer their products for use in sewer construction. However, only six suppliers were in a position to offer a nationwide service such that the product could be used in North Rhine-Westphalia for both the test fields in Burscheid and in the performance tests at IKT in Gelsenkirchen. Moreover, one of these products was not pumpable at the time of the award of the contract, so ultimately only five products were used and compared in the system tests. Consequently, an expansion of the delivery areas for more products and also new and further developments of products are desirable. IKT testing could then underpin their quality.

Possibility for retesting

Not been involved in this product test? Your material can do that too? Then there is an opportunity to prove it in follow-on testing – the same tests under the same conditions with the same evaluation criteria. At the end there is a score and a place in the results table. And if you want, you can also get a seal.
Talk to us!

Improving the image of Flowable Backfill

The IKT-Compare product test shows that in principle, Flowable Backfill is already a suitable technology for sewer construction. Not for all products, but compositions can be optimised, and at some point the ideal case will become the norm.

IKT-Compare product test “Flowable Backfill in Sewer Construction”
to the results table of this product test (in English) (PDF)
Download the product test report (in German) (PDF)

Contact persons

Dipl.-Ing. (FH) Serdar Ulutaş, MBA
Head of IKT Product Testing
phone: +49 209 17806-32
e-mail: ulutas@ikt.institute
Dr Iain Naismith
IKT Project Manager UK and International
phone: +44 7983 605219
e-mail: naismith@ikt.institute

 

Short liners are often the first choice for repairing local damage in house connections. But, can they deal with seriously damaged pipes? The results of the new IKT-Compare project “Short Liner for House Connections” are now available.

IKT institute has found in its most recent IKT-Compare project that in principle short liners (also referred to as patch or point repairs) can make good quality repairs to house connection pipes, even when the pipe is severely damaged. Eight short liner systems were tested and achieved scores ranging from “VERY GOOD” to “SATISFACTORY”. The evaluation did find significant differences in performance between the systems that were examined.

Twinbond Liner was the best performer with a score of VERY GOOD (1.2). Second place went to epros DrainPacker (Trelleborg) also graded VERY GOOD (1.4). Bodenbender Point-Liner-System (1.7), Berolina Repair System (2.5), Cosmic TopHat system (2.5) and MC Konudur LM-Liner (2.5) each received a GOOD grade. Alocit short liner (2.7) and I.S.T. Spot Repair System (2.9) were graded SATISFACTORY.

The project has been undertaken in co-operation with twelve sewer network operators which wanted to understand the strengths and weaknesses of this widely used technology. It has been funded by the North Rhine-Westphalian Ministry of the Environment and the network operators.

Download table of results
Download product test report (German)

Tough testing of short liners

A rehabilitation using a short liner should be able to restore the structural stability of a pipe, secure its hydraulic performance and seal a damaged area. For this reason, the IKT Compare team and the network operators involved placed particular emphasis during testing on the water tightness, operational reliability and structural stability of the rehabilitation. The particular focus was resilience external water pressure.

Test set-up damage scenarios

For this project IKT built eight identical 1:1 scale rigs, in its large-scale test pit (15m by 6m by 6m), into which suppliers installed their short liners. Each rig comprised a length of sewer to which were attached one house connection pipe on the same level as the sewer pipe and two house connection pipes from a higher level. The house connection pipes were prepared with defined areas of damage, including milled patterns of cracks, the removal of some or all of the joint seals and broken sections. A total of 64 damage patterns were produced – eight in each of the eight test rig setups.

These patterns of damage were arranged as follows:

• Test Setup I (the lower house connection pipe, to which a 2m head of external groundwater was subsequently applied): cracks, a broken joint, a radially displaced joint and a joint displaced at an angle
• Test Setup II (the two higher house connection pipes, to which a 1m head of groundwater pressure was subsequently applied): a defective change of pipe material, defective change of pipe diameter and material from cast iron DN 150 to PVC DN 125, a defective change of pipe diameter and material from clay pipe DN 150 to PVC DN 125, and a break in the joint of a 45 degree bend

Following installation of the eight different short liner systems into separate test rigs, an extensive testing programme began, starting with initial visual inspection and leak tests. This was followed by short-term and long-term external water pressure tests, high-pressure jetting at different pressures and using different types of nozzle, simulated backing-up of water, changing groundwater levels, and cleaning with rodding devices.

Frequent visual inspections and leak tests were undertaken as the programme progressed. Finally, when the test rigs were exhumed from the test-pit, the cross-section reduction was measured and the adhesive tensile strength and ring stiffness of the installed liners were assessed.

Grading of performance

In addition to physical tests, the QA/QC procedures were examined. The laboratory results were validated through in-situ observation of the same systems being installed at actual construction sites. The final scores in this IKT Compare test are based on these three evaluations. The range of grades applied is from VERY GOOD (score of 1.0) to INSUFFICIENT (score of 6.0).

Weighting of scores: Water Tightness counts for the most

To derive the final scores the results of the 1:1 scale testing system tests were given a 85% weighting and the results of the QA/QC evaluation 15%. For the 1:1 scale test score, the three test criteria were weighted as follows: “water tightness” (60 percent), “operational reliability” (20 percent) and “structural stability” (20 percent).

The assessment of QA/QC comprised five criteria: the installation manual, the available training courses, the system’s DIBt (German Government’s approval body) approval, external production monitoring, and a comparison between the installations observed in the laboratory and in the field. The results for each criteria were given a 20% weighting in the final QA/QC score.

In addition to the test criteria used to derive the comparative scores of the systems, supplementary information was collected and presented that would be of interest to the end user. These include results from internal pressure tests undertaken after the rigs were excavated and the adhesive tensile strengths of the liner bonding to the host pipe. The preparatory measures undertaken by the installer, such as initial inspection, substrate preparation and cleaning, were documented. Also presented are: the number of on-site working days, the number of installation staff, the time required for preparatory work and installation, and the costs.

What the systems can do

In this IKT Compare project, the system suppliers demonstrated that serious damage to house connections can be reliably sealed using short liners, including breaks, cracks, misalignments and deflections. In particular, the Twinbond and Trelleborg systems proved to be the most reliable under permanent groundwater load, jetting, simulated backflow events and changing groundwater levels. For this they were deservedly awarded the score of 1.0 for water tightness.

Special Challenges

In principle, it was also shown to be possible to seal the changes in nominal diameter and pipe material in Test Setup II. However, four of the systems came up against their performance limits here, showing weak points, which led to infiltration. In one case, gushing water was visible immediately after installation. Therefore, changes in diameter and material require special attention during installation.

Results of Test Setup I

All eight short liners showed very good to satisfactory results for the four damage patterns in Test Setup I: cracks, broken joint, radially displaced joint and joint displaced at an angle. No infiltration was observed during the whole test period. However, about half of the systems showed visual abnormalities in the form of moisture and/or discoloration at some locations, but without the formation of droplets.

Structural stability assured

The structural stability testing of the short liners showed that they basically have reliable adhesive and load-bearing performance. For products with full-surface bonding of the liner to the host pipe, hardly any abnormalities were observed, i.e. no crack formation, no excessive deformation, no stability failure nor large-surface loosening of the adhesive bond. Five systems showed partial loosening of the adhesive bond at points of changing diameter or pipe material, albeit without any consequences.

The Cosmic system is not intended to bond over the full-surface, only at the start and end of the liner. However, the supplier was able to submit a static proof which confirmed the structural stability of the short liner observed in the test.

Operational activities

The test scenarios simulating sewer operation, such as high-pressure jetting, water backing-up in the pipe, and changing groundwater levels, had no significant effects on system performances.

Good QA/QC

There were no issues with quality assurance: seven out of the eight systems fulfil all the criteria for quality assurance and receive a grade of 1.0. The Cosmic system does not have a DIBt approval and so gets a grade of 2.0.

Conclusion

In conclusion the IKT Compare project “Short Liners for House Connections” has demonstrated that short liners can renovate even severely damaged sewer pipes. However, changes in diameter and material require special attention during installation as they might cause serious problems. It is important to select the right system for the task, to understand the limitations of individual systems, and apply the necessary QA/QC before, during, and after installation.

Download table of results
Download product test report (German)

Contact

IKT ‑ Institute for Underground Infrastructure, Germany
Serdar Ulutaş, MBA, Dipl.-Ing. (FH)
phone: +49 209 17806-32
email: ulutas@ikt.institute

 

Can wastewater manholes be rehabilitated so that they remain permanently watertight? What are the benefits and the drawbacks of mortar coating, plastic coating and lining. What quality can be expected? This first comparative product test in this field gives you the answers!

“Now for the manholes” – this is a train of thought in the repair/rehabilitation departments of many wastewater network operators. There is, indeed, little point in rehabilitating wastewater pipes without paying attention to the numerous defective manholes. This is particularly true in water infiltration zones, since a really watertight sewer network can only be achieved provided the manholes are also rehabilitated.

Under test: thirteen manhole rehabilitation methods

Which of the many manhole rehabilitation methods should we choose? Which one will seal reliably and durably? Which is suitable in which situation, and which are not suitable? Thirteen commercially available methods have now been analysed in IKT‘s “Manhole Rehabilitation” Comparative Test. The results range from GOOD to ADEQUATE, with one method failing the test.

Contact

Serdar Ulutaş
Dipl.-Ing. (FH), MBA
T: +49 209 17806-32
E: ulutas@ikt.de

 

This research project involves the development of a test programme to comparatively test and evaluate the inspection procedures and equipment currently available for site drainage systems. Practical experience is to be gathered in pilot deployments in cooperation between the Meyer-Entsorgung disposal company and the City of Osnabrück. In addition, general recommendations for action to provide both the public and system operators with assistance prior to the actual inspection are to be drafted, based on experience from the City of Osnabrück. The project is receiving funding from the German Federal Environmental Foundation (DBU).

Title

“Comparative assessment of innovative inspection procedures and equipment for site drainage systems and recommendations for action for preparation of the inspection (Phase I: Actual-condition survey, test programme and recommendations for action)”

Project management

IKT ‑ Institute for Underground Infrastructure gGmbH

Project participants

• August Meyer Entsorgung – Technische Dienstleistungen GmbH & Co. KG (disposal organisation)
• City of Osnabrück

Client

German Federal Environmental Foundation (DBU)

Contact

Christoph Bennerscheidt
Dipl.-Ing.
T: +49 (0) 209 17806-25
E: bennerscheidt@ikt.de

 

In the summer months, in particular, odour emissions from sewers cause odour nuisances and thus higher levels of complaints from residents. Sewer-system operators are in general obliged to find a remedy for such problems.

Odour filters installed in waste-water manholes are coming into increasing use. In addition, further products which release special active ingredients in the waste-water manhole shaft are also used. The aim of this Comparative Test was that of testing the odour filters for waste-water manholes available on the market together with the participating sewer-system operators for their fluid permeability, cleaning performance and easy usability, and to perform a comparative assessment of their quality. Products which release special active ingredients into the waste-air leaving such waste-water manholes for the suppression of such odours were also tested.

Title

IKT Comparative Test “Odour filters”
with supplementary testing of other products for use in waste-water manhole shafts in case of odour nuisance

Downloads

(German versions only)
Table of results
Test Report (127 pages)
Short Report (31 pages)

Clients

• Kiel (capital of state of Schlewig-Holstein) – urban drainage utility
• City of Ahaus
• City of Frankfurt am Main
• Hamm urban drainage utility (Lippeverband water authority)
• Hannoversch Münden urban drainage utility
• Ludwigshafen urban drainage utility
• Cologne urban drainage utilities
• Düsseldorf urban drainage utility
• Magdeburg municipal utilities
• Leverkusen municipal utilities
• Burscheid municipal utilities

Comparative Test participants

• University of the German Federal Armed Forces, Munich, Institute of Water Resources
• University of Stuttgart, Institute for Sanitary Engineering, Water Quality and Solid Waste Management (ISWA)
• University of Kassel, Department of Urban Water Management within the Institute for Water, Waste and Environmental Management (IWAU)

Contact

Thomas Brüggemann
Dipl.-Ing.
T: +49 (0) 209 17806-18
E: brueggemann@ikt.de