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46. Ir System Design Description page 3 that the solids remain suspended within the reactor and that the biomedia does not clog. The aeration promotes growth of aerobic microorganisms, which convert and remove &. biodegradable organic matter. (the organics removed by the aerobic process are the constituents that are measured in the CBOD test.) The treated wastewater, which is now low in carbon but high in ammonia, overflows into the third compartment(Second Aerated Compartment). This chamber is aerated in the same way as the First Aerated Compartment. The.oxygen rich atmosphere in this chamber promotes the growth of nitrifying microorganisms(Nitrosomonas and Nitrobacter), since it is low in carbon and high in ammonia. The nitrifying microorganisms convert ammonia to nitrates utilizing the oxygen in the wastewater. To optimize the contact time and the mean cell residence time, the EnviroServer utilizes a biomedia in the aerated sections. This plastic media is used to supply a support structure for the establishment of a resident biofilm and is specifically developed for optimized biological growth without clogging. The main advantage is that the biomass is attached to the biomedia and will not get flushed out at high input flow rates. This will favor the nitrification process, which is significantly slower than the organic removal. The two-stage aerobically treated wastewater, which is now high in nitrates but low in carbon(low in CBOD)overflows into the fourth compartment (Secondary Clarifier), where final clarification and settling of the suspended solids take place. To promote denitrification, and to remove the accumulated biomass, the wastewater is recirculated by an airlift from the fourth compartment back to the first anaerobic compartment. A volume equal to eight percent of the systems rated capacity is recirculated each hour. Denitrification is facilitated by this recirculation because the bacteria in the first anaerobic compartment use the oxygen from the nitrate molecule in their metabolic process,with nitrogen being released as gas in the reaction. Without recirculation, the small amount of carbon available in the fourth compartment would limit the denitrifiicaiton. �. Furthermore, the recirculation of the biomass prevents accumulation of the biomass in the final Clarifier, eliminating the need for periodic removal. Removing the accumulated biomass also helps to ensure optimum clarifier performance resulting in an eluent with i. low suspended solids. The transfer of the biomass to the first compartment ensures a large vital population of microorganisms for the organic and nitrogen removal processes. +.. The recirculation process also benefits the system in times of low loading. When the water is recirculated, it carries nutrients from the first compartment into the second compartment. Thus the available nutrients are utilized to sustain the population as long