Aerator Pump

No one in the housing forum knew or just wouldn't reply, so thought I would try here. I am having to put in an aerobic septic system as soil conditions near Phayao (think rice farming) is hard pan clay and will not allow any effluent to percolate down into the soil. I have a regular black, round plastic septic tank as the primary tank to settle out solids and give the anaerobic microbes some work to do, then it goes to a secondary concrete ringed with the bottom one having a bottom in it. I used a sanitary tee on the input with an extended down spout and the same on the output so to keep scum layer in tank. From there it will go to a tertiary tank and this one will be the aerator tank. I am hoping to give millions of aerobic microbes a real party atmosphere so they stay happy and in turn make me very happy. So....does anyone have a lead on where I might go to find a heavy duty aerator pump? Thanks in advance.....trex