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First African Biogas Forum

17.11.2016

Bavarian Innovation Award on Wastewater Treatment 2016

The municipality of Theres, Unterfranken, Bavaria, was awarded the Bavarian Innovation Prize 2016.The new groundbreaking concept for the replacement of an aged waste stabilization pond which was developed by AKUT will obtain a natural way of treatment combined with an inexpensive way of operation.

The innovative design for the combined sewage treatment comprises a raw wastewater filtration wetland in the first stage and a nitrification wetland as secondary treatment.

Energy efficient wastewater treatment

In her laudatory speech the Bavarian minister for environment, Ulrike Scharf, accentuated the pilot character of the system for Bavarian municipalities in the rural area. She praised the possibility of high quality treatment without the requirement of electrical energy supply.

Standard technical treatment systems need extra energy for aeration, motor driven actuators and pumping.

In this case flow through wetlands is solely driven by force of gravity. The key technical component for establishing intermittent flow to the optimized filtration wetlands is a self-regulating mechanical siphon. The two siphons are capable of transporting even raw wastewater with high flow rates to both treatment stages. By floating the filter surface within a short period of time the best distribution and a maximum of natural oxygen input is achieved. No extra energy for aeration (aerobe treatment and nitrification) is consumed. These siphons are robust and minimize operational work. A model of this siphon was demonstrated at the AKUT booth in Munich at IFAT 2016.

Innovative wetland systems substitute inefficient waste stabilization ponds

The treatment of combined sewage in constructed wetlands in Germany is a virgin territory. For this purpose we can rely on tremendous expertise of our French neighbours. More than 3,000 so called “French Systems” with two-stage raw wastewater treatment are serving French municipalities. These systems have successfully suppressed conventional stabilization ponds because of their very good overall performance and stable operation conditions. 20% of these systems treat combined sewage.

The DWA expert group on small treatment systems has intensively checked the French approach. Together with experts from the research institutes IRSTEA and UFZ main design criteria have been fixed for separate and combined sewage treatment. The minimum surface area for treatment is 2 and 2.5 m² respectively. By describing these systems in the revised guideline for design, construction and operation of constructed wetlands DWA-A 262 (draft April 2016) a new boost for wetland technology in Germany is expected.

 

Foto (left to right): Prof. Dr.-Ing. Jens Nowak (AKUT Berlin), Price winner Matthias Schneider  (1. Mayor of Theres), Ulrike Scharf (Minister of Environment, Bavaria), Dipl.-Ing. Reinhard Müller (AKUT Hesse)

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