The lack of adequate data on the aerated lagoon system prompted the developer to construct an aerated lagoon pilot plant to determine its feasibility for treating domestic sewage. The pilot plant was a circular lagoon 81 ft in diam at the surface and 65 ft in diam at the bottom, 4 ft below the surface, with a volume of 121000 gal. The side slopes were coated with fiberglas matting coated with asphalt to prevent erosion. The pilot lagoon was located as shown in Figure 1 to serve the area just south of the existing housing area. The major contributor was a shopping center with houses being added to the system as the subdivision developed. The pilot lagoon was designed to handle the wastes from 314 persons with a 4 -- day aeration period. Initially, the wastewater would be entirely from the shopping center with the domestic sewage from the houses increasing over an 18 -- month period. This operation would permit evaluation of the pilot plant, with a slowly increasing load, over a reasonable period of time.

The pilot plant was equipped with a 3 -- hp turbine aerator (Figure 2). The aerator had a variable speed drive to permit operation through a range of speeds. The sewage flow into the treatment plant was metered and continuously recorded on 24 -- hr charts. The raw sewage was introduced directly under the turbine aerator to insure maximum mixing of the raw sewage with the aeration tank contents. The effluent was collected through two pipes and discharged to the Blue River through a surface drainage ditch.