Newly renovated treatment plant in Egaa, Denmark, will reduce energy consumption and increase energy production based on ground-breaking technologies and by using the best possible energy optimising materials
The renovation of Egaa Wastewater Treatment Plant was initiated to gain a maximum energy output. A fruitful collaboration with leading suppliers of technologies, processes and components made this possible.
Cleaning of nitrogen with Anammox-bacteria
With the establishment of a DEMON® Anammox reject water plant the electricity consumption for nitrogen cleaning is reduced. The Anammox bacteria are generated in this process and besides cleaning the reject water, they also clean the waste water in the process tanks without any use of carbon.
Carbon filtering with Salsnes®-filters
Norwegian Salsnes® has developed the strip filters that are used early in the process to filter carbon from the waste water. This reduces the energy consumption for aeration, which previously was about 40 % of the total energy consumption, since less carbon is discharged to the process tanks. The concentration of solid in the primary sludge which is extracted from the strip filters is so high that pre-dewatering can be avoided. The primary sludge and the biological sludge are both pumped to the digestion tank, where the biogas is generated.
AVK knife gate valves with LINAK actuators are installed at the wastewater plant and here seen on a reject water pipeline. The linear actuators were chosen since they are energy efficient compared to actuators using compressed air.
Optimum utilisation of the biogas
Furthermore, optimum utilisation of the biogas is secured by installing a highly effective gas generator plant, where the biogas is used for production of electricity and heat. Also, the excess heat energy is used to produce further 10 % electricity by using an Organic Rankine Cycle (ORC). This helps reach the objective of an energy production of 50 % more than what is consumed.
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