Batchpur: Small energy-efficient sewage treatment plant

In Germany, there are still numerous households that are not connected to the public sewage system. Around two million small sewage treatment plants, each large enough for a four-person household, are in operation in this country. These small sewage treatment plants consume at least approx. 600,000 megawatt hours of energy per year. Now the company Batchpur has developed a small sewage treatment plant which thanks to various optimisations, achieves a saving of more than 50 per cent in terms of energy.

A conventional small sewage treatment plant consumes 292 kilowatt hours of energy a year. Although this doesn’t appear to be very much at first glance, when added up across Germany, it quickly produces an annual energy consumption of 600,000 MWh. Medium-sized company Batchpur has thus invested a lot of its development work in optimising the energy efficiency of its plants. It has improved pressure sensors, stepper motors and transformers, and has registered a total of 30 patents and patent applications as part of this development project.

Engine for progress:

  • half the energy consumption of the average small sewage treatment plant
  • continuous further development (more than 30 patents and patent applications)
  • development of pressure sensors, stepper motors and transformers
  • “Zero-C” concept offsets CO2 emissions

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Photo: Batchpur GmbH & Co. KG

Using energy efficiency as a sales argument for a global market

With their low energy consumption, the optimised small sewage treatment plants offer an interesting sales argument for an important market, and not only in Germany. In France, for example, there are around 10 million decentralised waste water treatment plants - a market that is even bigger than the German one - and the demand in newly industrialised countries is even greater.

Moreover, it easy to transfer the basic technical principles of the project, e.g. the innovative stepper motors, to other applications where they are also capable of saving electricity. The technology can be applied wherever solenoid valves have previously been used to regulate airstreams.

Climate-neutral operation thanks to carbon offset payment

“Even low energy consumption is still energy consumption,” says Annemarie Boller, Managing Director of Batchpur. “This is why we’ve developed the Zero-C concept.” Batchpur supports an afforestation project that saves the same quantity of greenhouse gases as is generated by the operation of the small sewage treatment plants over a period of two years. The offset process is certified by the ARKTIK organisation and bears the TÜV seal. This ensures that 100 per cent of the identified CO2 emissions are indeed compensated for.

Background to the technological development:

The water levels in the decentralised waste water treatment plants are now measured not by a sensor within the medium itself, but to the exact centimetre by a pressure sensor in the control mechanism. This increases the accuracy and, depending on the waste effluent level, is capable of feeding in the exact amount of energy via the dynamic ventilation system.

In addition to this innovation, the solenoid valves have been replaced with stepper motors. Solenoid valves have to be constantly supplied with electricity while opening up the compressed air supply. In contrast, the newly installed stepper motors require an electricity supply of approx. 500 milliamperes for only around 3 seconds to open the outlet. The subsequent ventilation, which can for last several hours, then no longer requires any electricity.

The third technical innovation is an electronic transformer (typical systems still only use conventional transformers on the control board), which is capable of reducing the power during standby mode to 1 watt, equating to a reduction of 60 per cent. These successes have been documented in a report by the Waste Water Test Institute (Prüfinstitut für Abwassertechnik) of the RWTH Aachen University of Applied Sciences.

Partners and sponsors

  • Batchpur GmbH & Co. KG
  • Ingenieurbüro Bokatec

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