During the concept stage for the optimization of the biological treatment, the projected energy savings were approx. 72,000 €/year. Considering a capital investment of 420,000 €, the amortization time would have been approx. 6 years.

A recent analysis revealed an actual energy conservation of 30% (see diagram), which exceeded the expectations. Based on the actual energy costs of 19.8 ct/kWh and a monthly energy conservation of average 53,500 kWh, the actual savings amount to 127,300 € per year, reducing the amortization time to approx. 3.3 years. The total energy consumption of the biological stage in relation to the load has improved from 26.2 to 20.6 kWh/(PECOD*year). The following diagram demonstrates the savings during the individual optimization stages. The average outlet parameters in terms of overall nitrogen concentration are far below 5 mg/l.