Trenchless sewer rehabilitation: Luxembourg shines, too
The Grand Duchy of Luxembourg now is also completely up to date in terms of sewer rehabilitation. This is demonstrated by a project in the Luxembourgian municipality of Pétange. In cooperation with Swietelsky Faber Kanalsanierung GmbH from Alzey, BRG Lux GmbH from Holzthum installed two DN 1000 GFRP pipe liners here. They are part of the Brandenburger liner system, which is based on light curing technology.
The rehabilitated DN 1000 collection drain was situated between this road construction project and another one running parallel to it underneath he adjacent residential buildings.
A DN 1000 mixed water collection drain is part of the backbone of Pétange's sewage grid, a town of 15,000 inhabitants in Luxembourg. This concrete sewer, which is a former creek piping and which was integrated step by step into the public mixed water grid is also used for rainwater overflow. Therefore, it often reaches the brinks of its hydraulic capacity. Thus, Pétange's municipal wastewater utilities were facing a serious problem when this important sewer proved to be in dire need of renovation during the course of inspections. Fractures, corrosion, displaced and rooted sleeves, as well as a variety of connection pieces that were not professionally installed turned the connection drain into a high-priority project. Very soon, the planners from the Luxembourg engineering firm of Dahlem, Schroeder & Associés s.a.r.L., who had been commissioned by the municipality, realised that the problem could not be solved with an open renewal. The position of the pipe alone definitely ruled this out. While its end manholes were both situated within the area of open street renewal projects and could thus be renovated during their implementation, the collection drain itself, which connected two parallel streets, traversed a residential area. Parts of it were even situated underneath buildings. Naturally, open construction activities were out of the question here.
In the pursuit of a trenchless renovation solution, and after due deliberation of all technical and economic aspects of the potential solutions, a decision was soon reached in favour of the pipe lining technology, and in turn also in favour of an implementation with a light-curing solution. In this process version, the pipe liners are not thermally hardened with hot water following calibration. Instead, the exposure of the pipes, which are impregnated with photo reactive UP resin, to a specifically defined dose of UV radiation enable the curing reaction. It turns the liner into "pipe in within the pipe", which is structurally self-supporting and flush with the old sewer. This technology version, which is historically younger compared to the thermal hardening processes, has increasingly gained ground in recent years. Nowadays, it is the most commonly used pipe lining technology.
Among its advantages that were also beneficial in Luxembourg was a very swift execution of construction work combined with comparatively sparse but highly mobile construction site equipment. The Brandenburger liner procedure (with an ADV 75 type glass-fibre liner) was implemented in the Pétange project. The construction was carried out by BRG Lux GmbH, the domestic rehabilitation company, in cooperation with the Alzey branch of the Sietelsky Faber GmbH sewer rehabilitation company. What was remarkable with the Pétange project was not only the diameter of the liner, which was substantial with DN 1000 (for many years, such diameters were a typical "home match" for the hydraulic process versions). With two conduits measuring 70 or even 122 metres, quite significant dimensions also had to be covered lengthwise. With a wall thickness of 9.1 mm, the 122-metre liner weighed no less than 5.3 tons. The liner installation into both conduits with a winch was carried out through shaft structures that were demolished and reconstructed during the simultaneous road construction project. During the installation, the liner was protected against damage by a plastic foil that was laid out in the base. Following its complete installation, the glass fibre tube was sealed at both ends with insulating sealers and was then extended positive locking in the sewer with compressed air. Afterwards, one of the pressure locks was opened for a few minutes in order to install the UV lamp train, which had previously been tested for its readiness for use. The liner tolerates the temporary decrease in pressure without collapsing within the sewer. Prior to the actual curing process, the liner is restored to the set internal pressure anyway. The lamp train checks that the installed liner is properly fitted to the old pipe in its entire pipe length and does not show any deformations. While it is pulled to the opposite sewer, where the actual curing begins "in a cold state", a small camera in the front of the lamp train records the internal state of the liner prior to the curing – thus, potential irregularities can be detected and corrected in time.
The operational liner with underlying protective foil. Following the renewal of the shaft structures, the open liner ends are professionally connected to them.
In the Pétange collection drain, the lamp train cured the UV reactive UP resin in the liner with 12 x 400 watt light output at a velocity of the lamp train of 15 centimetres per minute. There is a direct link between light output, reaction temperature of the liner and the velocity of the run through the sewer. Thus, all of these parameters are not only precisely predefined according to the geometry and wall thickness of the liner, but their compliance is precisely measured and recorded during the hardening. This gapless and fully automated process conduct and documentation is a central element of quality assurance in the Brandenburger liner procedure. In the end, it also produced the desired result in Pétange: An exemplary cured and watertight liner with a wall thickness installation of 8.4 millimetres. It ensures that the mixed water collection drain at Pétange can reliably play its crucial role for several more decades.
(Photos : BRG Lux / Swietelsky-Faber)
Contact:
Brandenburger Liner GmbH & Co. KG
Taubensuhlstrasse 6
D – 76829 Landau
Phone: +49-6341-51040
E-mail: info@brandenburger.de
BRG Lux GmbH
Uwe Wilhelm
1, route de Diekirch
L – 9834 Holzthum
Phone: +352-2617 6070
E-mail: uwe.wilhelm@brg-lux.com
Swietelsky-Faber GmbH Kanalsanierung
Christian Heuss
Alzey branch
Albiger Straße 12
D – 55232 Alzey
Phone: +49-6341-510 4279
E-mail: heuss@gmx.de
>> Osthofen, Germany |
 |
