Trenchless sewer rehabilitation

Trenchless sewer rehabilitation


Renovate and repair without digging!

Root damage, leaks, static failure: sewage pipe systems are increasingly outdated. However, the wider public remains unaware of the condition of underground networks. Each driver is a witness to the poor condition of crumbling roads, however faulty pipes and sewage remain unseen underground. Their critical condition only rarely becomes noticeable at ground level – namely when faulty piping causes flooding, undermining and collapsed surfaces after major downpours. In many German cities and councils those responsible are successfully dealing with the backlog of refurbishment projects. Clever keyhole technologies have been around for around half a century, capable of refurbishing pipes and sewage networks with almost no effect on the infrastructure at surface level.


Faulty sewage pipes cause damage to road surfaces and thus put road safety at risk.

Leaking pipe systems can cause major damage to the soil and affect the environment. In the event of extra filtration of waste water there is also a risk of contaminating ground water.

Infiltrations from the soil equally have consequences. Ground or stratum water penetrating into pipe systems increases the total waste water quantity. The cleansing efficiency of water treatment plants is negatively affected in this way as a result of dilution, causing additional costs to the public.


Compared with invasive construction, keyhole refurbishment is significantly less costly. Installing a resin-coated fibre hose in existing piping does not require as many members of staff, it significantly cuts the time a diversion of waste water is necessary during construction and there are no downstream costs to regenerate the road surface.



Refurbishment projects are generally approached at select points within the sewage network, like a minimally invasive procedure. Life at surface level continues almost as usual during keyhole refurbishment – good news for commuters, traders and council representatives.



Pipes and sewage from a single source: cutting-edge refurbishment methods can create continuous structures across long distances without the need for joints. They will consequently not leak and are protected from root damage.



Depending on the framework conditions, keyhole refurbishment procedures take as little as a single day. As a result, they are ideal for urgent construction measures where roads, pedestrianised zones or parks must be conserved.


Environmentally friendly

Keyhole refurbishment procedures are amongst the most CO2 -friendly technologies in civil engineering. They can reduce emissions by approximately 80 to 85% compared with open procedures since excavated materials, equipment use and transport needs are cut almost to zero.



Thanks to modern refurbishment methods it is also possible to reach pipe systems that would not be accessible using conventional methods – for instance under bodies of water, housing or in nature reserves. In addition, keyhole procedures are also suitable for challenging conditions, such as arches and differences in altitude. We also provide other refurbishment methods for major, special-purpose as well as oval profiles in addition to hose linings.



Keyhole refurbishment methods were established throughout Germany more than 30 years ago and have been common throughout Europe for half a century. Depreciation periods of 50 years are usually specified for cutting-edge refurbishment technologies – the expected service life is much longer.



Sewage refurbishments have long since become an established branch of civil engineering and no longer represent a specific niche within the industry. A growing part of sewage networks and systems are maintained using cutting-edge refurbishment procedures. Throughout Germany a host of experienced engineers, implementing companies and test laboratories are available to sewage network operators and council clients as trusted partners.



The resins used as part of refurbishments are chlorine-free (non-halogenated) hydrocarbon substances. Once they have fully cured they do not react with the environment. This is verified as part of standard laboratory tests run during refurbishment projects. The long, expected service life will also make recycling less of an issue. Hose linings can easily be thermally recycled. The calorific value of applied resins corresponds to that of crude oil.

Pipe lining is a common procedure for trenchless pipe rehabilitation. This involves inserting a resin-impregnated glass-fibre or plastic hose (pipe liner or inliner) into the sewer which is then cured to a new “pipe-in-pipe” thermally or by UV light. The areas of application rage from free-flowing pipes to pressurised mains (drinking water, gas and wastewater) and a pipe size range of DN 100 – 2500 mm.


The flow of water within the section due for refurbishment is diverted using methods such as inflatable pipe barriers



Dedicated robots clean the old pipe and inspect the sewage system


Robot-based milling

Obstructions such as penetrating roots are removed



Installation is carried out from the sewage system before the resin is cured using heat or UV light



Connecting pipes are reconnected and samples from the construction site are analysed at laboratories


Optional: refurbishment of connecting pipes and sewage systems

In the area of trenchless sewer rehabilitation of wastewater systems, the pipe liner process with UV curing has proven to be the most reliable, quickest and most economical rehabilitation version.


Since the early 90s, the Brandenburger Group operates with UV-curing technology along with glass-fibre as reinforcement and base material. Our company has steadily continued the development of UV-curing technology as well as the quality of the employed materials. Our pipe liner products are manufactured from base materials with characteristics that satisfy highest chemical and mechanical requirements.

Brandenburger has redesigned and improved all components of the GFRP liner which has so reliably served our customers over the years. The advantages with the new generation of light-curing GFRP pipe liners BB2.5 include increased transparency and dramatically improved external protection. Even greater wall thicknesses can now be cured more quickly. In addition, the new generation of liner also provides increased safety and easier handling at the construction site.


Advantages of economical, environment-friendly sewer rehabilitation with UV pipe liners:


  • Short duration of the rehabilitation work – no need to dig trench
  • Minimum disturbance of local residents
  • Hardly any disruption to traffic due to minimum place requirement of site equipment
  • Sewer immediately usable on completion of refurbishment work
  • TV inspection of the product before final hardening
  • Minimal impact on the internal diameter of the sewer


For more information see the list of construction site reports of our customers