As reported by the German Federal Statistical Office (Destatis) in December 2018, a good 97% of the population in Germany (some 80 million inhabitants) was connected to the public sewage system in 2016. Twenty-five years ago, in 1991, this was only about 90% of the population.
According to Destatis, the total length of the sewer network operated in Germany in 2016 amounted to almost 600,000 kilometers. In 2016, around five billion cubic meters of wastewater from households and small businesses was discharged for sewage treatment via the public sewage system. In the German city states, an average of 449 inhabitants were connected to each kilometer of the public sewage system due to the high population density, while in the rural state of Mecklenburg-Western Pomerania the average was 124 inhabitants per kilometer.
What do these figures mean for the suppliers and operators of sewage pumps? The energy efficiency of all technical equipment is one of the decisive factors for the future-proof operation of the sewage network.
In order to identify the need for action and be able to react to it at an early stage, the German Federal Ministry of Education and Research (BMBF) financed the funding measure "Intelligent and Multifunctional Infrastructure Systems for Sustainable Water Supply and Sanitation" (INIS) with a total of 33 million euros.
A particular challenge lies in securing the performance of the infrastructure under various load situations: This requires robust systems that do not fail completely, even in the case of unexpected extreme events, and that are cost-efficient and can be dismantled as well as expanded as needed.
Pumps and associated systems are important control elements for reducing variable costs through low expenditures for electricity, maintenance, and repair, as well as high reliability.
Lot 28 of the Ecodesign Directive deals with sewage pumps. The main question is: How can the energy efficiency of a sewage pump be increased without impairing its functionality? It is clear that the operational safety of the technical systems plays an overriding role for operators of sewage disposal networks.
The industry is anxiously awaiting the outcome of this discussion with Brussels.
Figure 1: Currently, 97% of the population is connected to the public sewage system. Nearly 3% of the population discharges its wastewater into small sewage treatment plants or drainless pits without a public sewage system.