Design and construction of aeration systems for optimum operation of large wastewater treatment plants

Abstract

The construction and operation of large wastewater treatment plants are very important tasks today. Choosing the optimum process design can help to keep initial costs low. Careful operation and modern equipment reduces the operational costs. Taking into account the huge demand (Anonymous EEC-Report 1990) for new wastewater treatment plants or plants which need to be upgraded after the new EEC legislation concerning sewage treatment came into force in May, 1991 (Anonymous EEC-Guideline 1991) it is quite clear that only cost-effective processes supported by energy-efficient equipment are the answer to economical wastewater treatment. Regarding the operational costs for biological treatment, approximately 70% of the total energy consumption is used for the activated sludge part of the treatment plant, i.e. for the stirring and aeration systems (Höfken et al. 1992). That shows how important the proper design of such systems is and implies that only innovative and energy-efficient equipment should be used. This paper presents theoretical considerations for the design of aeration systems for aerobic processes. These considerations lead to recommendations for the construction and the operation of aeration systems.