After a project preparation period of 3 years, WEHRLE was able to sign the contract for the extension of the leachate treatment plant of the Eko Dolina Landfill on 16 June 2015.
The existing osmosis plant with concentrate recirculation into the landfill body was commissioned in 2006. As a result of the concentrate recirculation, ammonia nitrogen and the chloride concentrations in the leachate were constantly increasing in the old section of the landfill. This led to a significant increase in the use of sulphuric acid and energy consumption. The effectiveness of the plant was more and more reduced, leading to the necessity of a hydraulic extension. Experts advised not to treat the leachate biologically. Due to the lack of alternatives, an invitation to tender for the extension of the existing plant was published in spring 2012.
At that time, WEHRLE participated in the invitation to tender, offering a very interesting price. The client visited the WEHRLE stand at the IFAT Trade Fair 2012 and, in this context, also the biological leachate treatment plant of the Munich North-East Landfill.
Due to the visit of the biological leachate treatment plant in Munich, it was decided to carry out a test for biological leachate treatment on the Eko Dolina site. The test was accompanied by the Gdansk Polytechnic. After those tests had been successfully finalised, it was decided to implement an upstream biological contaminant removal with nanofiltration as pre-stage of the existing osmosis plant in order to improve the overall performance and yield of the entire plant.
The first step of the concept ordered, which was based on a public invitation to tender, consists of an ideal biological treatment of the leachate. In this step, the nitrogen compounds which have meanwhile reached very high levels are also removed to a large extent. Afterwards, the persistent substances are concentrated in a nanofiltration plant. Those concentrates are led into the existing osmosis plant, where the quantity is again significantly reduced. After commissioning of the new concept, only quantities of 5 to 15 % are led back into the landfill. Since the biologically degradable substances have been removed in the membrane bioreactor plant, the recirculation of the remaining quantities is not a problem and will result in decreasing leachate concentrations in the future after the commissioning. The further increase in concentration is thus durably stopped and makes a sustainable operation possible.
Agnieszka Stacha-Elsner, Sales Manager Poland, points out: ”The concept for Eko Dolina, which has now been ordered for the second time, will be another example for a successful optimisation and improvement of osmosis plants. We are glad to show this on the Eko Dolina Landfill once again and hope other landfill operators will follow this path.“