The two WWTPs Lynetten and Damhusaen are situated directly at Copenhagen harbour. Lynetten is Scandinavia’s showcase plant par excellence and counts a large number of numerous international visitor groups every week.
The sewer system of the Danish capital is very old and flat with the result of enormous amounts of deposits being present in the sewers. In the event of heavy rainfalls, these deposits are carried along into the sewage treatment plant. The previously installed screen pumps with 10 mm bar spacing had great problems to cope with this situation. The plant operators, Lynettenfallesskabet l/S, were therefore looking for an alternative solution.
At IFAT 2008, the customer thoroughly examined various screening system and liked the HUBER solution with the perforated plate belt screen. He preferred the HUBER EscaMax® screen not least for its sturdy design, unique cleaning system and good experience made with it in applications of similar size. The positive experience the customer had made with the two HUBER Grit Washers RoSF 4 supplied in 2000 was another key to success.
We bidded together with our long-time partners Dansk Stahlmontage A/S and won the tender. In April 2009, we received the order to supply six of the longest size of HUBER EscaMax® screens (size 9000 x 2252) and two Wash Press units type WAP 6 SL. While HUBER manufactured and delivered the technical equipment required to meet the process requirements, our Danks Stahlmontage A/S took over the installation of the machines.
On WWTP Lynetten, a flow rate of 2080 l/sec is cleaned per screen, which is a plant capacity of 750,000 PE. Owing to the Wash Presses the hygienic situation inside the screen room has significantly improved. Also downstream clarification processes profit because process-relevant materials, such as faeces, etc., are washed out and returned. The screenings are transported to the Wash Presses by 32 m long launder channels, which very reliably work already with only a minor slope. The interaction of WAP/SL and launder channel leads to enormous savings in operating costs as screened wastewater is used as transport medium, very much to the delight of the Danish plant operators. The customer is enthusiastic about the alternative launder channel technology which has eliminated operating problems previously caused by clogged or even worn screenings conveyors.
Installation of the machines was not only a technical but also logistic challenge for HUBER because the six screens had to be mounted without interrupting the WWTP operation. All six screens were therefore replaced one after the other over a period of three months. The first screen of the 743,000 € order was put into operation in September 2009. Initially, the order conditions had included several guarantees but due to the high satisfaction of the operator with the HUBER equipment these were cancelled during the three-month installation phase. Customer satisfaction was also one of the main reasons that we received another order in January 2010 for the supply of two Sludge Acceptance Plantsto WWTP Lynetten.
6 HUBER EscaMax® screens supplied also for WWTP Damhusaen
Moreover, the order for the project Damhusean was included in the Lynetten project. Lynettenfallesskabet I/S are the plant operators also in this case and site requirements were similar. We supplied again six HUBER EscaMax® screens and two WAP 6 SL Wash Presses. Only the WWTP capacity of 250,000 PE is smaller than that of the Lynetten plant so that screen size 6000 x 1752 mm with 8 mm perforated plate was sufficient. Each screen must be able to handle a flow rate of 1,305 l/sec.
The great challenge for HUBER in this project was the extraordinarily high amount of grit. But HUBER had the optimal solution also in this case. In collaboration with Dansk Stahlmontage A/S the customer showed himself impressed throughout the entire course of the project. Owing to the innovative HUBER solution failure of screens under storm conditions, transport problems with conveyors and disposal problems due to insufficient screenings washing and compaction have definitely become a thing of the past. In both inquiries it was noticed that the amount of screenings separated by the 8 mm perforated plate screens had increased by up to ten times. A volume reduction of up to 70% is achieved through intensive screenings washing in the two Wash Press units that receive the screenings from two launder channels.