About Our Systems The Aero-Tech Model is an extended aeration, activated sludge process. In the activated sludge process, microorganisms remove soluble contaminants from the wastewater, utilizing them as sources of energy for growth and production of new microorganisms. The organisms tend to be flocculent and form clumps, or floc that physically entrap particulate organic matter. The organic matter is attacked by extracellular enzymes that solubilize the solids to make them available to the microorganisms as a food source. The conversion of the organic matter from soluble to biological solids allows for the removal of the organic matter by settling of the solids in the treatment process. Extended aeration is a modification of the activated sludge process in which the microorganisms are allowed to remain in the treatment process for long periods of time. The large inventory of biological solids in the process provides a buffer for shock loading of organic matter.