New Turbo Blower Reduces Costs And Energy Consumption
Having exchanged a 19 year old turbo compressor for a turbo blower of the new “AT Turbo Generation 5” series, the wastewater treatment plant Arnsberg-Wildshausen is now making considerable savings, both in terms of energy and money.
In Arnsberg-Wildshausen Ruhrverband (Essen) operates a biological wastewater treatment plant. It treats the sewage of 48,000 inhabitants and that of a paper factory as well. Air required in the aeration basin is generated in the central air station. Until November 2012 three approximately 19 year old adjustable turbo compressors, which had been connected in series and had been run according to the load- dependent air requirement of the three aeration basins, were in operation there. For normal requirements one unit supplied the required air volume, for higher requirements two units were in use, and during peak times all three units were running.
Replacement instead of expensive maintenance
The waste water from the paper factory has been pre-treated since 2008 and con- sequently the volume of waste water in the aeration basins has fallen, such that only two turbo blowers are required for the generation of the activation air.In 2012 one of the three old turbo units in the central station was showing significant signs of wear. Therefore, instead of an extensive and very costly refurbishment, it was decided that this old unit should be replaced with a new turbo compressor.
Markus Droppelmann, group manager “Obere Ruhr” at “Ruhrverband” in Essen:
»I saw the new turbo blowers for the first time at IFAT in Munich in 2012. All in all, selecting this as a replacement has provided considerable advantages for us.«
By taking this step they simultaneously wanted to increase the energy efficiency and to improve supply safety in the aeration basins.
As far as their performance data was concerned the new turbo blowers series “AT Turbo Generation 5” were nearly identical with the old unit to be replaced. For this replacement a detailed calculation of profitability showed a potential energy saving of between five and six per cent, so the exchange would pay for itself within five to eight years.
This period shortens further when taking into account the anticipated costs for the fundamental reconstruction or procurement of spare parts for the old unit. Furthermore, with the new unit any problems inherent in the old unit’s design no longer exist. In the old units an oil supply of 19.5 litres had been used for lubrication and cooling. At full load operation and with high temperatures in summer, the considerable heating up of the oil often resulted in the unit automatically coming to a standstill, so sufficient air supply to the aeration basins was no longer guaranteed.
Turbo blower as base load unit
As base load unit, the new Aerzen turbo blower supplies 80 per cent of normal requirements on its own. A second old unit is switched on as peak load unit for only five hours each day. “We have been operating the new turbo blower for more than six months, around the clock, as base unit in continuous operation. Up to now it has completely met our expectations”, says Markus Droppelmann at Ruhrverband.