Advances in Aeration Technology, 1993 Environmental Conference Proceedings

Application of aeration equipment for the treatment of biodegradable organic wastewaters has become more complex due to more stringent effluent requirements and energy considerations. At present, the design engineer is faced with many alternative methods of aeration/mixing but few tools to determine which methods are most appropriate.

The authors have developed a basic design approach that allows the engineer to preview as many different aeration/mixing methods as desired to determine via operation, maintenance and capital costs, the method of choice.

On-site testing includes the use of the actual aeration device, applied to the actual mixed liquor at the energy input level range anticipated. This approach eliminates many of the problems associated with such process testing conducted in the past. The results of this testing establishes the basic design criteria of alpha for each aeration device, beta and oxygen uptake rate. It also indicates changes in the process in staged or plug flow biosystems.

In conjunction with the on-site testing, influent and effluent samples are collected for analysis. These analysis along with at least twenty-four (24) months of plant data form a basis for the design of the selected aeration system to be compared.

Each aeration system selected for comparison/evaluation is then design. The capital cost to install each system is then estimated. The operation and maintenance costs are developed from the anticipated power usage and maintenance information. Finally, an economic comparison is developed to establish which aeration system is most appropriate.

In summary, this design approach is most useful in eliminating bad choices and selecting aeration/mixing systems that will perform as required. An example of this technique on a large industrial aeration facility will be presented.