In October 2019, a targeted conversion was carried out at a municipal wastewater treatment plant during ongoing operations. The rake head and washing press, which were built in 1996, were replaced. The existing base frame of the old rake could be retained, so that no structural adjustments to the channel or tile floor were necessary. Since the conversion, the plant has been running reliably in 24/7 operation and demonstrates how existing systems can be modernized economically and efficiently.