Alongside sewage from 20 municipalities of the Kirchberg Association of Municipalities, the large sewage-treatment plant located in the Hunsrück region of Germany also processes the wastewater and effluent containing de-icer from Frankfurt-Hahn Airport. The Kyrbachtal project not only created an important basis for water pollution control but, at the same time, used synergies and, thus, saved costs.
Project 1: Hahn Airport Construction Work
When it was founded on Jan. 1, 2002, the Hahn Airport Special-Purpose Association for public development of the entire airport facility – with the exception of the airport security area – also became obliged to dispose of the wastewater and effluent produced by the site. This also includes decontamination of the sewage occurring there. However, connecting the wastewater of the airport to the existing Dill group sewage network, which is part of Kirchberg Association of Municipalities, was initially agreed only as a provisional measure as regards sewage treatment in the area. Eventually, this arrangement became inadequate in view of the major growth in employment and passenger figures. Flughafen Frankfurt-Hahn GmbH, the body responsible for the traffic facilities in the airport’s flight security area, is responsible for disposing of the wastewater containing de-icer produced during the winter months as the result of aircraft and runway de-icing, since the officially permissible separating criterion for admission into bodies of water was exceeded.
To date, all the wastewater containing de-icer initially had to be transported by tanker and then transferred by a pipe to Dill sewage-treatment plant, so as to be able to decontaminate it there in a pipeline-bound system. However, only a part of the de-icing wastewater was able to be accepted and decontaminated owing to the limited capacity, despite having boosted the efficiency of the existing sewage-treatment plant.
The required pressure pipe for transporting the wastewater containing de-icer was constructed by prime contractor Sonntag Baugesellschaft GmbH & Co. KG, Dörth. This project involved laying around 10 km of SIMONA SPC pipes, 250 x 22.7 mm, in construction lengths of 20 m. SIMONA SPC pressure sewage pipe was selected in order to protect the pipe from external damage during laying. Manufactured by means of coextrusion, the SIMONA SPC protective-jacket pipe is a multi-layer pipe that includes a protective layer. It consists of a polyethylene core pipe (PE 100) that is provided with an outer, abrasion-resistant and scratch-resistant protective casing comprising modified polypropylene (PP) (pipe structure in accordance with PAS 1075, Type 3).
After many years of investigations, planning measures and negotiations between those involved and the water authorities, concepts for solving the waste-water problem in the Kirchberg Association of Municipalities ultimately resulted in the decision to construct a new group sewage-treatment plant in Kyrbachtal in the district of Sohrschied, as a joint solution which was both the most ecological and, at the same time, the most economical.
Interesting facts: Installation Methods
Static Ploughing Method
Ploughing is the fastest and what is probably the most economical technique for laying new plastic pipes. The method hardly disrupts the soil and is thus very gentle on the environment. A plough and a laying box are pulled in with the aid of a cable winch. The trench closes behind the plough after the pipe has been admitted into the soil through the laying box.
The cutting method is used in the case of firm ground with open laying without a sand bed. SIMONA SPC pipes are able to withstand the higher stresses and offer excellent resistance to slow crack growth and point loads. This guarantees increased protection during laying and during operation when exposed to loads which cannot be calculated easily.
Project 2: New Group Sewage-Treatment Plant with Non-Pressure Pipelines
As the body responsible for wastewater disposal, the Kirchberg Association of Municipalities was obliged, upon completion of the initial phase of equipment installation, to execute the so-called third decontamination stage for the existing Dill and Kirchberg-West municipal sewage-treatment plants in order to meet legal environmental requirements. The required wastewater treatment system would have required substantial constructional and technical input at two locations, involving significant investments costs. However, due to the construction of a central group sewage-treatment plant with state-of-the-art technology, rehabilitation and extension of the three smaller sewage-treatment plants of the Kirchberg Association of Municipalities were no longer necessary. Moreover, the new installation guarantees an essential improvement in water quality owing to the better operational performance. This improvement in water quality is a key benefit for the entire region.
Originally, construction planning of the group sewage treatment plant was centered around a conventional concrete structure between the distributor structure and the activation basin. Owing to a proposal on the part of SIMONA, a decision was taken, however, in favor of a monolithic PE 100 shaft d = 1,060 x 62.1 mm with an overall height of 8 m. All 1,200 m of d 560 to d 900 mm, SDR 17.6 pipes laid at the sewage-treatment plant included SIMONA SIMOFUSE integral electro-fusion joints.
The SIMONA SIMOFUSE product range provides an advanced joining method for plastic pipes. The electro-fusion coil, which is fully integrated and concealed in the polyethylene, guarantees a homogeneous, high-strength joint that is permanently tight – in line with DVS Guidelines. SIMOFUSE offers increased efficiency when installing pipe systems and guarantees absolute tightness and total protection against in-growing roots. This provides the basis for faster laying without complex welding preparations, such as scalping the ends of the pipes for instance.
Mode of Operation of the Sewage Treatment Plant
Wastewater containing de-icer from Hahn Airport and untreated wastewater are metered into the activation basins via the distributor structure. The share of effluent containing de-icer is around 200,000 cu m annually. The wastewater is admitted into the activation basin via the PE shaft structure, which performs a metering and monitoring function. The height difference between inlet and outlet of the activation basin is 6.50 m. When metering, the system operates on the basis of the principle of communicating pipes, i.e. the height level in the shaft corresponds to that in the activation basin. The wastewater in the activation basin is kept circulating by means of agitators. The biological degradation processes are initiated by means of air injection and the supply of oxygen. The wastewater that is decontaminated in this way then flows through a final sedimentation basin (10). Only then can it be supplied to the receiving water body. The Kirchberg Association of Municipalities, Hahn Airport Special-Purpose Association, Flughafen Frankfurt-Hahn GmbH and the environment have benefited greatly from the new, jointly used sewage-treatment plant.
The new sewage-treatment plant that was planned in accordance with the state of the art has a far better decontamination capacity compared to old sewage treatment plants, as a result of which it is able to contribute more extensively towards water pollution control.
Project 3: Kyrbachtal Connecting Systems
The Kirchberg Association of Municipalities commissioned the construction of the transport system for municipal wastewater and the installation of a pressure pipe for wastewater containing de-icer done in three construction lots. Lot 1 involved constructing the pipeline route of the Dill sewage-treatment plant which was to be shut down through to the new Kyrbachtal group sewage treatment plant. This involved laying 2,200 m of SIMONA PE 100 pressure pipes (d 250 x 22.7 mm), 2,040 m of PE 80 CoEx SIMOFUSE (d 500 x 28.4 mm) and 180 m of PE CoEx SIMOFUSE (d 630 x 35.7 mm) pipes. Lots 2 and 3 involved connecting Kirchberg-West sewage-treatment plant and Dillendorf pumping works to the new sewage-treatment plant using a total of 4,200 m of PE 80 CoEx SIMOFUSE (d 400 x 22.7 mm) pipes. A central solution to ensure the protection of water quality with outstanding environmental benefits and maximum eco-efficiency.
As the newly constructed plant processes the effluent from Hahn Airport Special-Purpose Association and the wastewater containing de-icer from air traffic of Flughafen Frankfurt-Hahn GmbH, as well as the municipal wastewater from the Dill and Kirchberg-West sewage-treatment plants of the Association of Municipalities that were decommissioned, the first expansion stage – covering a population equivalent of 28,000 – made it the largest sewage treatment plant in the Hunsrück region.
Both investment costs and operating expenses associated with the new plant are calculated precisely on the basis of specific allocation formular, so that all those involved and, thus, also the citizens of the Kirchberg Association of Municipalities only have to pay for the share attributable to their use. The plant is designed in such a manner that it can be extended in a second expansion stage to cover a total population equivalent of 41,000. Consequently, not only the SIMONA pipes with their excellent chemical resistance to effluent containing deicer but also the entire pressure pipe system, matched specifically to the local topography, proved their worth when implementing this major project. The firmly bonded, tight connection with SIMONA SIMOFUSE also offered many advantages when installing pipes in the groundwater along the Kyrbach waterway. With the products used, SIMONA delivered a comprehensive plastics-based solution for the Kyrbachtal group sewage-treatment plant.
Dipl.-Ing. Wolfgang Krämer and Dipl. Betr. Bianca Glöckner are with SIMONA AG, Kirn, Germany.