Brief
The Nürtingen wastewater treatment plant is designed for a capacity of 75,000 equivalent inhabitants (EW) in the mechanical section. After preliminary treatment, the wastewater is split 50:50 between the trickling filter system and the activated sludge system. The biological stage of the plant has a capacity of 37,500 EW for each section. It consists of a single-stage activated sludge system and a trickling filter system that share the mechanical stage. The trickling filter system includes a denitrification filter and three nitrification filters, along with intermediate and final clarification stages. The activated sludge system operates with two parallel aeration tanks featuring simultaneous denitrification and shared final clarification. Both sections are equipped for targeted phosphorus removal. Coagulant dosing occurs at the inlet of the final clarifier 1 and in the effluent shaft of the aeration system. The sludge is stabilized anaerobically. The effluent from the treatment plant is discharged into the Neckar River. Plans include decommissioning and demolishing the trickling filter system, constructing additional aeration volume, and renovating the final clarification to reliably meet nitrogen discharge values in the future. Additionally, it is planned to operate two separate aeration systems together with the existing two-lane final clarification. The existing aeration system will continue to operate with simultaneous denitrification. The new aeration system will also utilize simultaneous denitrification in circulation tanks. The new aeration system will be built at the site of the decommissioned N-trickling filters 1 and 2. In the future, the existing aeration system will only receive 37% (previously 50%) of the inflow water volume. Furthermore, the maximum combined water inflow will be reduced from 620 l/s to 540 l/s based on pollutant load calculations. The distribution of wastewater to the two aeration systems will be adjusted through modifications to the existing preliminary treatment outlet. After the aeration tanks, the wastewater will be collected in a newly constructed distribution structure and distributed 50:50 to the two existing final clarifiers. The return sludge from the final clarifiers will also be collected in the distribution structure and then distributed to the aeration tanks in a ratio of 37:63 (37% existing aeration, 63% new aeration). The site for the distribution structure will be the area freed up after the deconstruction of the nitrification trickling filter 3. The construction of the second aeration system will also require the renovation of final clarifier 1 and the construction of storage and dosing stations for coagulants and an external carbon source. The Nürtingen wastewater treatment plant is located between several water protection areas of zones III and III A, with its floodwater inlet situated at the level of zone I and II or II A on the opposite bank of the Neckar River.
