Step by step forward to the ideal sewage plant

The sewage plant Kaiserslautern (Germany) has succeeded in significantly reducing both, the sewage duty and the energy costs for the generation of process air for the aeration basins, in three steps. Thanks to the reduced sewage duty resulting from the basic changes of the aeration basins in the year 2008, the modification costs of 1.3 million EUR had been amortised after only three years. The replacement of the two existing turbo compressors against two new Aerzen rotary lobe compressors of series Delta Hybrid led to an additional energy saving of approx. 13 % of process air generation. Since then, the entire energy consumption per month could be reduced from approx. 250,000 to only 140,000 kWh. During field test, it is investigated whether the energy efficiency can still be improved any further by the replacement of additional turbo compressors – however, this time against the turbo blowers of the new Aerzen series ‘AT Turbo Generation 5’ provided with air bearings. Some first results represent another annual savings of energy, amounting to approx. 60,000 EUR and less maintenance costs of approx. 15,000 EUR per year