Questions about energy and sustainability
So far, there is only one small study by Meier and Remy 2020 (in German and French) that allows a comparison. The project “Definition and Standardisation of Key Figures for Processes for the Abatement of Organic Micropollutants in Wastewater Treatment Plants” serves as an initial guide in this area. In the future, the relevant data will be collected to improve the data basis accordingly and to carry out corresponding key figure evaluations periodically.
In Addition, there is a Dutch study in English comparing the key figures of Switzerland, Germany and the Netherlands (www.h2o-watermatters.com, Edition 1/21, removal of micropollutants).
In PAC processes, the carbon production has the main environmental impact. Optimization of carbon production and the resources used is therefore desirable. The EMPYRION project is investigating sustainable activated carbon production from sewage sludge, green waste and wood waste.
In ozonation, on-site electricity consumption for producing ozone and liquid oxygen have the main environmental impact. However, with a regulation strategy, ozone consumption and thus electricity consumption can be reduced.
For wastewater treatment plants with waste heat recovery from the treated wastewater, it is recommended to install the waste heat recovery system decoupled as far as possible and after the micropollutant abatement and post-treatment stages.
At WWTP Neugut, the waste heat from the generators is transferred to the treated wastewater. This slightly heats the treated wastewater more. Independently of this, the heat stored in the treated wastewater can also be used and supplied as district heating to private households in the surrounding area.
Incidentally, the warm air from the generator rooms, which have to be ventilated 10 times per hour, is also directed into other rooms for heating purposes.
It would also be possible to use the cold from the evaporators.