The Kronach-Süd wastewater association in the Upper Franconia region of Bavaria now also relies on a MicroTurbine from VTA for the conversion of digester gas into electricity. Among the factors determining this decision are the extremely low NOx and formaldehyde emissions.
Not everything that’s getting a little older is as attractive as Schloss Oberlangenstadt. The impressive Tudor-style building – one of a total of eight (!) castles in the market town of Küps – can be found on the way to the treatment plant run by the Kronach-Süd wastewater association. While it may be much younger than the castle, this 25,000-PE treatment plant has been in operation since as far back as 1979. It therefore requires successive adjustments to keep it up to date with the best available technology.
With the generation of electricity and heat from digester gas, the association, which in addition to Küps also includes the municipality of Weißenbrunn and the Kronach district of Neuses, has now taken a forward-looking step: two gas engines that had reached the end of their service life were replaced by a CR30 MicroTurbine from VTA. In addition to its particularly low maintenance requirements and low maintenance costs, the unparalleled low emission values of this innovative technology were not the least of the factors that won over the 13 association council members.
Limit values are easily met
‘With regard to exhaust gas values, in particular, the general conditions have seen crucial changes in recent years’, explains Bernd Rebhan, mayor of Küps and chairman of the Kronach-Süd wastewater association. For example, the revised German TA Luft (technical instructions on air quality control) also sets out more stringent limits for digester gas utilisation, especially for nitrogen oxides (NOx) and formaldehyde.
For combined heat and power plants or gas engines, this makes complex adaptations for exhaust gas purification necessary. However, the VTA MicroTurbine meets these requirements with no problem whatsoever and remains far below the required values. This can also be seen at the new plant in Küps, where NOx values below 9 mg/m³ and formaldehyde values below 5 mg/m³ are measured.
More than punctual delivery
‘Our experience with VTA and the MicroTurbine has been excellent’, says a satisfied Bernd Rebhan looking back over the past few months. After the decision-makers had visited several MicroTurbines in the immediate and wider area and given the green light for the investment in autumn 2018, installation of the MicroTurbine was completed so quickly that it was up and running before Christmas.
The perfect preparatory work by the staff at the plant made its contributed to this. ‘VTA not only delivered on time, but earlier than agreed. We were very pleased about that’, emphasises Daniel Neumann, the treatment plant’s manager.
This investment was the first step towards optimising the utilisation of digester gas by the Kronach-Süd wastewater association. Further goals are now improved sludge dewatering by replacing the existing belt filter press and increasing gas production. In conjunction with the VTA MicroTurbine, the people in Küps are thus creating the conditions for economical, climate-friendly and future-oriented power and heat production.
Field report from the VTA Group’s scientific journal “Laubfrosch”, issue 82
‘Our experience with VTA and the MicroTurbine has been excellent.’