Content Notice

The following articles are taken from the MC aktiv publication and curated by Buidling Chemical Supplies Ltd. Content contained is therefore the property of MC-Bauchemie Müller GmbH & Co. KG.

Changi Water Reclamation Plant

Singapore is Building the Largest Covered Sewage Treatment Plant in the World

The project Changi Water Reclamation Plant (CWRP) in Singapore represents in every aspect an unparalleled construction project. For this gigantic undertaking land reclamation was carried out in order to construct the world's largest, covered sewage treatment plant. It is planned to replace all existing local plants in Singapore.

The CWRP is a compact and closed sewage treatment plant built using the latest technology. It is designed to treat 800,000 cubic metres of wastewater daily and can be extended to a daily maximum capacity of 2,400,000 cubic metres. An area of 14,000 square metres with particular chemical and mechanical loads had to be coated. MC is the worldwide leader in the field of mineral based coatings and its products Konusit KK 10 and KK 30 offer the perfect solution for these particular demands.

Training Courses

The innovative products and the personal commitment of the branch manager in Singapore, Willie Kay, providing assistance to the client were decisive factors in the selection of MC as suppliers on the CWRP project. MC started in January 2004 with a number of test runs and preliminary work. The technical consultancy was provided by Eugen Kleen and Michael Goldschmidt, MC Bottrop, who presented to the customer, the consultants and contractors in Singapore the technical advantages and applications of the Konusit coating system.

The safety issue was given a particular emphasis in this project. Each of the employees participating in the application had to be well trained and confident in the use of the materials.

A number of presentations were given on site demonstrating surface preparation techniques and application methods. Frank Erdmann (also from MC-Bauchemie, Bottrop) not only presented these training sessions but also acted as consultant on the site in Singapore for a number of weeks and carried out the tests in Bottrop. For the employees of the sub-contractors HRC Harvest Resources Pte Ltd. and WAK an additional 3-day product training course was held in Bottrop.

Training Courses

Harvest Resources developed special purpose made equipment with a spray capacity of 400 square metres per day for the CWRP project. It is equipped with a cooling system in order to counter the effects of the high humidity and temperatures.

The MC employees Jamaludin Bin Ismail, MC Singapore, as well as Frank Erdmann and Eugen Kleen from MC Bottrop provided advice and consultancy on site.

The CWRP project was a challenge with regards to technological as well as logistical aspects and would not have been possible without the excellent coordination of the resources of Singapore and Bottrop. Changi is an example of the teamwork of employees from MC branches in different parts of the world and the successful completion of projects of this magnitude.

Wastewater Quality Vastly Improved

Krakow's Plaszow II Water Treatment Plant - Complies with EU Norms

Since becoming a member state of the European Union, Poland has had to comply with many new environmental regulations, one of them being wastewater treatment. The country simply has too few treatment plants and it is planned to address this shortage over the next few years aided by EU-funding. Old plants will be upgraded to modern standards and sufficient new plants will be built to meet the demand.

Plaszow II, the waste water treatment plant in Krakow, was built in 1976 and is no longer meeting modern technical standards. Its capacity is also insufficient to meet the demands of the city's 757,700 inhabitants. To comply with EU regulations, an extension to and restoration of the plant became imperative. S.A. (MPWiK S.A.) Krakow, who manage water supply and sewage for the council, commissioned the project to Hydrobudowa Slask S.A. from Katowice. The expansion of the mechanical part of the plant is aimed at raising the throughput capacity from 132,000 m3 to 656,000 m3. In order to improve the quality of the wastewater, an additional biological purification plant with six primary and twelve secondary sedimentation basins also needs to be built. Furthermore, the project consisted of the restoration of all concrete elements and the implementation of durable surface protection on the secondary sedimentation basins. The specifications for the surface protection of these basins stipulated that the applied membrane should be water vapour permeable. Yet again MC was able to secure the contract due to its well-established reputation as leader in the field of mineral surface protection systems and injection technology for concrete repair and leak sealing.

Hungarian Bridge

Following a detailed technical analysis of the existing plant, the best solutions to ensure secure and lasting protection were selected. The time-tested Zentrifix repair range was used for the re-profiling of the concrete structure, while injection with polyurethane resins MC-Injekt 2300 and MC-Injekt 2300 NV was chosen to seal cracks. This method is particularly suited for application in the critical sphere of water structures. For the surface protection of the splash zone on the primary and secondary sedimentation basins MC-RIM F was applied, a mineral system with above average performance properties.

Construction started in 2004 and is expected to be completed by 2006. Damian Czopek, Sales Manager for SouthEast Poland and technicians Janusz Woronicki, Dariusz Kaluzny, and Andrzej Hanuszewicz make up the MC-Poland team on site. They assist the project in questions of application technology.

Surface Protection for Water Retaining Structures

Water is one of the most precious resources on earth. This is why the utmost care and technical competence are required to ensure the demands in terms of safety, durability and environmental friendliness vital for drinking water and wastewater treatment plants are met. What's more, these plants represent huge national domestic assets that must be maintained and preserved.

Water Retaining Structure Protection

Concrete is indispensable in the construction of these structures. Decades of practical experience have demonstrated that concrete will only perform and be durable when a reliable surface protection system is applied. This protection is necessary to protect the concrete against the physical and chemical stresses that it is subjected to. The primary objective is to maintain a coherent leak-proof barrier for surfaces in permanent contact with water.

For drinking water applications the primary concern is to protect against contamination and maintain the water quality in compliance with the strict standards imposed by local, national and international standards. Leaks in the concrete surface - caused by hydrolytic corrosion - inevitably spoil the quality of the water.

Water Retaining Structure Protection

Structures in the wastewater industry must withstand the constant stresses imposed by continuous chemical, bio-chemical, mechanical or thermal exposure, to ensure that people and the environment are not harmed. Aggressive substances act upon unprotected concrete surfaces and lead to progressive corrosion.

Unprotected concrete surfaces in hydraulic structures are unable to withstand these permanent stresses in the long run and massive damage is the potential consequence. High repair costs will then follow. MC has developed MC-RIM, a highly durable, mineral coating system that has huge advantages compared with traditional systems, particularly as it increases utility intervals. Its application is recommended as preventive protection in new buildings or as subsequent surface protection in the course of repair measures.

Water Retaining Structure Protection

The outstanding properties are valued by engineers and operating companies as cost-efficient and technically beneficial They are an important factor in making MC the leader in this highly critical area of application. Many high-profile projects all over the world are testimony to MC-RIM's success and confirm, in-situ, the durability of this surface protection system.

Performance Range of MC-RIM

  • Mineral surface protection system
  • High water vapour diffusion properties
  • Water absorption according to EN 12390-8
  • Resistant to highly aggressive water and soil according to DIN 1045, part 2
  • Highly resistant to chloride migration
  • Surface protection in the wastewater industry from ph 3.5 to ph 14
  • Surface protection in the landfill industry
  • Lining of hydraulic lifting plants
  • Surface protection in drinking water storage tanks and concrete elements in drinking water protection zones
  • Resistant to neutral cleaning agents
  • Tested and approved according to DVGW
    • Process Sheet W 270
    • Process Sheet W 347
    • Process Sheet W 300

Repair of the Drinking Water Storage Tank Kiimmelberg

From May 2006 the 6,000 cubic metre Kiimmelberg drinking water tank near Kronach in Upper Franconia can again be filled to capacity. Earlier, extensive repair work had to be carried out on the two tank chambers with a tank remaining at least in partial operation. Truly a challenge for both engineers and applicators.

Just like so many municipal drinking water storage plants in Germany, the elevated Kiimmelberg tank (county of Lichtenfels) was in need of urgent repair. It was, however, out of the question to simultaneously close down both water chambers, each holding 3,000 cubic metres, for the duration of the repair works, as just under 20,000 residents of Kronach depended on the water supply.

For this reason a reliable and durable repair concept was required, while ensuring a totally dust-free atmosphere for each chamber that remained operational at the same time.

The repair concept

In spring 2005 an inspection of the entire internal tank surface was carried out. It emerged that the concrete coat had been too thin in all areas which had led to widespread surface damage, particularly in the soffits areas. Under the degraded render coat substantial cracks, concrete spalling and corroded reinforcing were evident.

The Planning Office EBS from Schwarzenach upon Saale put together a repair concept consisting of two phases so that one of both chambers could continue operating during repair works.

Water Retaining Structure Protection Water Retaining Structure Protection

Drinking water tanks are naturally subject to much more stringent requirements than other structures, given that their objective is to protect our most essential life source from contamination and to ensure a consistent level of water quality. The water tightness of the concrete surface is a prerequisite for this and the use of a high-performance surface protection system is therefore indispensable.

The DVGW process sheets W 316 and W 300, published in 2003 and 2005, for the first time introduced binding regulations regarding the composition and also the application of cement-bound building materials in the coating of drinking water storage tanks.

During the repair of the elevated drinking Kiimmelberg water tank MC-RIM was used, a product certified and approved in accordance with the new regulations. It was developed specifically for the surface protection of construction surfaces and meets all necessary requirements stipulated in the DVGW process sheets articular to drinking water storage.

High water-tightness and extremely low porosity mean that MC-RIM establishes an excellent protection against hydrolysis and leaching - as may be experienced in drinking water vessels. Hydrolytic corrosion, responsible for many a short-lived repair, is thus effectively prevented.

As a base coat MC-RIM was applied at 15 mm thickness, and as a top coat the much finer MC-RIM F, which has a maximum aggregate size of only 0.5 mm, was applied, reinforcing the sealing property through subsequent sanding down of the surface. The entire layer thickness of the surface protection system totals 20 mm.

After completion of the first phase in January 2006, the second chamber has now also been completed and put into operation. The repaired surface area of walls, soffits and bases of both chambers amounts to 10,000 square metres.

Properly Surfaced with ombran FT

Oil and grease trap waterproof again

Obtran Surfacing

The national highway B 481 between Greven and Emsdetten has an oil and grease trap which protects the environment in the event of a disaster involving hazardous materials transportation. During a routine inspection leakiness and first damage to the concrete of the structure were detected.

The responsible offices of the federal road construction for Northern Westphalia in Minister then tendered the repair works, specifying a coating system complying with DIN EN 858-1.

The engineering company selected had initially suggested different coating systems. The experts finally decided to use ombran FT. This is a silicate-hybrid coating system from MC which impressed mainly because of its technical properties and the existing accreditation for oil and grease traps. The concrete repair specialist V.O.B. from Apen in Lower Saxony was awarded the contract for the repair works.

Obtran Surfacing

The total surface to be restored comprised around 630m2 . Shortly after the start of the repair works it became apparent that the concrete had suffered much more severe damage than specified in the tender. The heavy corrosion appearances were due to chloride stress. As a consequence a new overall concept had to be developed, since it became necessary to carry out extensive repair to the concrete prior to the coating itself. The experts settled on ombran R for the reprofiling works, a repair mortar specially designed for damp areas.

Despite the unexpected additional works the repair could be successfully completed within the intended time frame. The oil and grease retainer was operational again after a very short time.

Drinking Water Symposium 2008

The protection of drinking water - our most important life source - and its flawless provision, pose one of the greatest challenges worldwide. Hence, in new build as in the repair of drinking water structures, comprehensive know-how and innovative technologies are a must.

As a leading company in the area of mineral based surface protection systems for drinking water structures MC offers experts from the water industry a platform for dialogue plus competent information during international symposia on the topic. More than one hundred participants from sixteen nations attended this year's conference in Bottrop. The popularity of this event clearly highlighted the importance of continuous dialogue between international partners.

Drinking Water Symposium 2008

Well-known speakers from science and industry, as well as MC specialists, presented innovative technologies and discussed points of interest from current regulations during the two-day event.

One of the core items in the conference agenda was the recently approved surface protection system MC-RIM PW. It is setting new standards in drinking water structures due to the integrated DySC technology (Dynamic SynCrystallisation). During its lifetime the purely mineral coating even manages to increase impermeability and resistance and in this way builds up outstanding long-term protection. Attendees were able to gain a clear picture about the new product family in practical demonstrations. In addition to these demonstrations live demonstrations of injection technology for the drinking water sector were also organised.

Renew - Repair - Restore

ombran MHP successful below ground in Minden

The wastewater disposal concept of the town of Minden intends to spend several million euros by 2012 on extensive sewage pipe works. Pipes have to be renewed, restored and repaired. The town Minden overall has over 600km of pipeline networks with approximately 15,000 manholes. The 80,000 inhabitants of the former diocese in North Rhine Westphalia will hardly be aware that the works are going on: a lot of the work is done out of sight below ground – without causing interruptions to the traffic above ground.

For years the department "Wastewater and Roads" of the Municipal Services Minden (SBM) has been using ombran products in the restoration of its sewage pipeline network. Primarily the fast setting expanding mortar ombran W and the re-profiling mortar ombran R have been used. Immediately after the re-profiling and coating system ombran MHP for sewage pipes and walkable sewers was launched on the market the product was also applied in Minden -with great success -by now approximately 75 restored manhole structures (approx. 750 m2) pay testimony to it.

Prior to applying the coating, ombran W is still used to stop water ingress, where needed. Where the swellable filler mortar meets its limitations with regard to waterproofing the town of Minden now also swears by using the Konudur Injection Device. Fast and economical, this innovative injection system is able to stop even heavy water in leakage. When the water ingress has been stopped ombran MHP is applied. With this system the sewer structures are completely restored. In the next few years about 1,500 manholes are going to be restored in Minden - roughly 300 each year. Based on past successes ombran products are intended to be used in these future works, as well.

Certified Rehabilitation of Manholes

In the German sewage system more and more manholes need maintenance. But there are not yet any special training courses about how to plan and carry out such repair work successfully. Therefore MC-Bauchemie has created a training course with practical elements to provide with the expertise required for this important task.

Manholes in sewage systems primarily serve for ventilation and access. The proportion of manholes in need of repair in Germany is currently assumed at 10 to 20 . Since their lasting and economical maintenance is technically demanding, a high degree of competence is expected from contractors and their staff. However this necessary expertise has practically not been available from training courses.

CROM course

This gap has now been filled by the CROM (Certified Rehabilitation of Manholes) course by MC-Bauchemie organised for this purpose. The specially developed training concept is addressed particularly to processors and consists both of theoretical principles and practical applications. The course includes extensive information about defects and their causes, preparation methods, such as sealing injections and underground treatment. Further topics included coatings, building materials technology, quality control and industrial safety. In the practical part the knowledge that has been acquired can immediately be implemented, for example by re-profiling a practice manhole with the appropriate materials.

Tensile Strength Testing Tensile Strength Testing

After the successful launching in 2010 the second CROM course was held during the first half of this year in MC-Bauchemie's training centre in Bottrop. Under the supervision of Prof. Karsten Korkemeyer of the Construction Management and Organisation Department of Kaiserslautern Technical University and MC-Bauchemie's ombran department, thirty five participants completed the course and passed the final test. Those equipped with the relevant certificate can demonstrate that they are eminently qualified to perform these complex maintenance operations.

In view of the great interest and positive response encountered, a course on manhole rehabilitation is also planned for the coming year. It will be held in Bottrop from 28th February to 1st March 2012.

The revolution in protecting sewage treatment structures

For 25 years now, MC-RIM has enjoyed a market-leading position in the surface protection of concrete construction components found in sewage treatment facilities. Now with MC-RIM PROTECT PLUS, MC has developed a completely new all-in-one system. It meets the current state of the art for concrete technology and it is revolutionary in its simplification of the application as well as in providing extra-long protection for sewage structures exposed to particularly harsh conditions.

The concrete structures of sewage plants are exposed to mechanical, chemical, physical and biological effects each and every day. MC-RIM has been used for 25 years now in protecting these elements against damage. The new all-in-one system, MC -RIM PROTECT PLUS, is now even more efficient: it combines the latest concrete technology expertise with simpler and safer application and an even longer service lifetime. "With MC-RIM PROTECT PLUS, we have developed a perfectly coordinated high-tech all-in-one system for all concrete surfaces in sewage plants, which will delight applicators and planners," explains Werner Baumgart, concrete technologist and product manager with Protection Technologies at MC.

"Even covered construction elements, which are exposed to particularly aggressive environments in areas where air is present, can be given better and safer protection with our new product system." Numerous test certificates from Kiwa MPA Bautest GmbH are a testimony to the products' outstanding good resistance against the penetration of chloride, their excellent resistance to chloride diffusion, sulphate and acid attack, and their low porosity.

Tensile Strength Testing

So simple and flexible

The system delivers many new benefits, particularly from the technical application perspective. The new products in the MC-RIM PROTECT PLUS range are mostly single-component- the only exception being MC-RIM PROTECT PLUS-BSK, which is used for areas exposed to biogenic sulphuric acid corrosion. This not only saves a tremendous amount of time but a great deal of expense too. It also greatly minimises the level of risk during application, and technical safety is enhanced. Plus, the fact that bonding courses are hardly needed anymore saves the applicator a whole step in the work process, reduces the working time and also simplifies the process.

MC-RIM PROTECT PLUS also delivers greater flexibility in relation to the application: apart from application by hand, it can also be applied using the wet and this is new - the dry gunning process. Greater flexibility is also afforded by its workability to 35 degrees Celsius and the large available range in selecting the layer thickness, i.e. between 5 and 15 mm. Compared to MC-RIM, consumption is a full 10 percent less.

Better and safer

Specially inter-coordinated binder technology in combination with the Dysc• technology means that a highly resistant cement matrix can be established, the like of which can be found nowhere else. "We have tested our technology in various research projects. In all of the tests the system scored extremely well against sulphates and acids, but also performed extraordinarily well against chloride diffusion, stunning even the experts of cement technology," says Product Manager Werner Baumgart.

Long-life protection

MC-RIM PROTECT PLUS therefore fulfils the most important conditions for long-life concrete protection in sewage structures.

The all -in -one system delivers:

  • A high resistance against chlorides and chloride diffusion
  • Protection from sulphate attack
  • High mechanical resistance
  • Low porosity thanks to Dysc technology
  • High acid resistance to pH values of between 3.5 and 14; MC-RIM PROTECT-BSK resists an even lower pH value range

MC-RIM PROTECT PLUS is also open to water vapour diffusion. There is no risk of osmosis. This then successfully combats the risk of losing bonding strength or stripping due to rising damp. All these properties deliver unique physical construction stability and a very long lifetime, which will be every bit the equal of the long-term experiences had with MC-RIM.

In the first few months of the year, Werner Baumgart, Rafael Sass and Moritz Koch presented the new product system through numerous workshops and training courses conducted both inside and outside the company. Customers and partners have already been able to test it for themselves and the feedback has been positive from all concerned.

Introducing the all-in-one system:

MC-RIM PROTECT

is the lead product in the new MC-RIM family. It can be applied by hand or with a gun and it is highly resistant to sulphates. It possesses a fibre-reinforced surface coating and resists pH values of between 14 and 3.5.

MC-RIM PROTECT-MR

is designed for surfaces exposed to high mechanical abrasion, but it also delivers the same level of protection against chemical, physical and biological attacks as MC -RIM PROTECT. It is similarly fibre-reinforced and can be applied by hand or by gun.

MC-RIM PROTECT-H

is designed for application on horizontal surfaces. It can be applied by hand or by pump. MC-RIM PROTECT-BC provides a suitable bonding course for the application.

MC-RIM PROTECT-BC

is a system component which can be used as a highly sulphate-resistant, mineral bonding course for MC-RIM PROTECT-H.

MC-RIM PROTECT-BSK

is especially designed for application in particularly aggressive settings: when used in areas exposed to biogenic sulphuric acid corrosion, the product provides a highly acid-resistant surface.

MC-RIM PROTECT-C

is a highperformance post-t reatment agent with a wax dispersion base, and was developed for application in combination with MC-RIM PROTECT, MC-RIM PROTECT-MR and MC-RIM PROTECT-H.

Duct Repair Work with Robot Technology

Cracks, formation of broken fragments, leaking sockets and faulty connecting branches are typical types of damage in non-accessible ducts. A universally applicable system of duct robots and repair material that can deal with the most varied tasks is needed to repair these: the Kasro 2K-grouting system by ProKasro and the low viscosity injection grout Konudur Robopress 07 by MC-Bauchemie show particularly innovative performance features. Two strong partners have got together here, who both have many decades of experience in duct repair work.

The need of repair in public and private duct systems has grown continually during the last years. That is why the new system of robots and material for the repair of connection branches, canal reaches with crack and/or broken fragment formation as well as leaking sockets has been developed. The grouting system works with a separate 2-component feed and two material tanks or 200 litres Konodur resin each. The robot is connected to them by an 80 metre long hose line. Filling and extracting is carried out by an electrically driven pump. The two component resin is only mixed together directly at the damaged spot. The very short reaction time of the material can thus be used to rectify the damage as quickly as possible.

The injection resin Konudur Robopress 07 is ideally suited for use in ducts made of concrete and vitrified clay, as an "interlocking" takes place here with the old pipe material. In plastic ducts the "coating" of the damaged spot with resin provides a locking connection and therefore a sealed system. It penetrates into even the smallest cracks, broken fragments or gaps by means of its very low viscosity, but even large hollow spaces can be filled by it.

The material containers and the hose drum with the 2-K-hose are mounted in an air-conditioned box that ensures constant material temperatures both in summer and winter, so that the resin always reacts comparably even in the case of varying outdoor temperatures.

Camera monitoring and documentation

Three cameras integrated in the robots monitor every single work step- both in the main but also in the connection duct. In addition the electronic control system Flow Control provides the user continuously with all the relevant data. At the same time it checks and documents the grouted amount of material. The complete data collection of every remedial spot also serves the quality assurance during the construction phase.

Practical suitability proven

The new grouting system was able to prove its practical suitability during a corrective maintenance project carried out in Wiesbaden. The renovation of around 400 connecting branches was due to be carried out for the town, of which 200 have been renovated up to now. The execution is in the hands of BRG Kanaltechnik GmbH from Krautscheid. The focal point is on the connections of households to the local sewerage infrastructure. At these trouble areas the typical damage such as concrete corrosion, formation of broken fragments and cracks are found. The special thing about this project is that the sewers to be renovated are partly in drinking water protectorate areas of zone 3. But the Konudur Robepress 07 is even suitable for this area of application. Certificates of environmental compatibility from neutral test institutes are available.

In addition, Konudur Robopress 07 offers further advantages: due to its rapid hardening it can be processed even in strong water carrying ducts or against pressing groundwater. The renovation work in Wiesbaden was thus able to be carried out with a minimum of annoyance to the residents.

At the moment seven constructors are using the system and nine others are interested in it. The MC-Bauchemie specialist division ombran has taken this opportunity to carry out the "1st Applications conference Kasro 2K-grouting system with Konudur Robopress 07" in January 2012.

Duct repair using robot technology

Sewer Restoration under Extreme Conditions

The constantly damp conditions caused by working on a "running" sewer, aggressive chemical erosion caused by water rich in carbonic acid and poor accessibility were the challenges presented by the restoration of the sewer installation at Schwanenplatz in Stuttgart (Germany). These challenges were surmounted with a unique approach to the implementation along with a high-tech product from MC, the hybrid silicate coating, ombran CPS.

Difficult framework conditions

The repair work on the sewer construction at Schwanenplatz was performed under the most difficult of conditions. These included an approximately 1 00-year old access structure, consisting of two chambers each with about 150m2 wall surface area, linking the two walkable sewers- a main artery of Stuttgart's sewer network. So it was impossible to block the flow of waste water at any time during the entire course of the renovation works. This section of sewer is exposed to a particularly aggressive atmosphere. Apart from the types of waste water typical for a large city, it also drains the carbonic acid rich mineral water from the nearby Leuze Swimming pool- water that dissolves lime and attacks the concrete structures of the sewer in a highly aggressive manner. Apart from the actual repair work, this made it all the more important to provide long-term protection to the entrance structure and secure it for decades to come. A complex task for the lead engineering firm, ISAS GmbH based in Fussen, which successfully completed it using special products developed by MC.

Sewer Protection

The solution

ombran CPS was found to provide the ideal protection for the structure. This hybrid silicate coating forms a dense coating matrix impenetrable to damaging substances. When cured, the system also exhibits superior mechanical stability "With ombran CPS we have combined the 'soft' and the 'hard' properties of a polymer resin and a silicate resin, achieving a high level of chemical resistance, particularly in relation to low pH values and bio- genic sulphuric acid corrosion", says Sven MeGmann, Product Manager of the ombran department.

The implementation

Given the prevailing situation, the restoration of the two chambers had to be performed successively one after the other, with the waste water being diverted into one chamber when works were ongoing in the other. The entire structure is exposed to a high level of dampness, meaning that the restoration work had to be performed in onerous ambient conditions. Following intensive preparation of the substrate and the application of anti-corrosion protection to the exposed steel reinforcement, a suitable mineral substrate was established by applying the special mortar, ombran MHP 15. ombran CPS was then applied by hand. Given the need to permanently ventilate the structure to dry the coated faces and the frequent work interruptions, it was not possible to use a spray application method. Due to the high adhesive strength of the hybrid silicate coating, it was possible to quickly and safely "mesh" the coated areas after the compulsory breaks, ensuring that the works could be executed swiftly.

Sewer Protection Sewer Protection

Permeable, when it has to be

The natural demands placed on coatings in structures in contact with the soil lie primarily in the physical concentration balance between the moist soil and the comparatively drier interior of the structure. A surface protection system, which is impervious to the associated water vapour diffusion, will usually not be able to withstand the capillary pressure. Over time, blisters form or the coating will de-bond- with the consequence that the structure would have to be again restored within a very short time. ombran CPS successfully counters this effect. In the case described this high-tech coating proved effective not merely because of its chemical and mechanical resistance, but because it is readily open to water vapour diffusion. A glimpse into the "Underworld" at Schwanenplatz: The ombran CPS hybrid silicate coating was applied by hand due to the necessity for permanent ventilation.

Large-scale sewer rehabilitation in Hamburg

From October 2.012 to May 2013, the municipal utility Hamburg Wasser (HW) [urban sewerage and sanitation] had a DN 3000 masonry interceptor in the Hamburg sewerage network repaired. Right from the tendering phase, our om bran unit was able to impress the planning engineers. Its speciality repair products were thus extensively used for the successful implementation of this, the largest single project in ombran's history.

The origins of the public sewerage system in the Free and Hanseatic city of Hamburg extend back into the middle of the 19th century. A large portion of the sewerage structures were constructed in the form of masonry conduits, most of which have continued to perform well through to today. The only signs of significant wear and tear are in the mortar joints which are frequently found to be crumbling and prone to leakage. And it was this kind of damage that led the Hamburg sewerage and drainage utility Hamburg Wasser (HW) to initiate a full repair of a 400 metre long section of the "Kuhmuhlenstammsiel" interceptor sewer in the centre of the city. The difficult conditions surrounding the project presented a number of major challenges, such as the dense transport, cabling and piping infrastructure that had to be negotiated, and also poor accessibility- the manholes were up tq 100 metres apart. In two rehabilitation sections totalling 240 metres in length, the main contractor Aarsleff Rohrsanierung GmbH of Rbthenbach an der Pegnitz made extensive use of the sophisticated product technologies available from ombran. The unit supported the project from start to finish, additionally providing MC's extensive repair expertise to keep the work running smoothly.

Spray on Protection

MC sets the standard

The MC product range impressed the planning engineers of HW right from the initial tendering phase. "In order to ensure that the high demands of the project could be reliably met, our product profiles and quality features were actually cited as the reference requirements;' explains Sebastian Scheffer, ombran sales representative responsible for northern Germany. Especially developed for large-area applications in walk-in sewer structures, ombran MHP-SP - a repair mortar suitable for hand trowelling, spraying and pipe spinning - was selected for reprofiling and coating more than 2,000 m2 of sewer and man hole walling. The pre-sealing work was carried out with MC's low-viscosity Konudur injection resins. These quickly foam on contact with water, reliably halting the flow of even pressurised groundwater.

ombran MHP-SP, a mineral-based high-performance coating, offers an optimum combination of good workability and wide application spectrum (reprofiling and coating), while also quickly developing water resistance to allow the early re-commissioning of the rehabilitated interceptor. "Also worthy of note is the exceptional durability of the mortar, with our DySC® technology ensuring that the impermeability of the coating actually increases with service life, enhancing its chemical resistance to the toxins contained in the sewage;' explains ombran product manager Sven Meßmann.

ombran CPS also trialied

A section of the minerally rehabilitated sewer measuring around 30 metres in length was also selected to additionally trial the blue silica-based hybrid coating ombran CPS. This application will enable the special coating material, which is resistant even to biogenic sulphuric acid attack, to once again demonstrate its exceptional properties.