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Design and Specifications Sludge age averages 30-40 days and is dependent .on system timing, which is based on effluent testing. As the height of the mixed liquor increases in the aeration chamber, a float switch starts the system microprocessor which, in turn, starts the mitred-liquor transfer pump (MLT) and transfers a fixed volume (batch) of mixed liquor to the clarifier. The MLT pump is controlled by time, and the actual programming allows for two or three minutes' pump overrun to overflow the mixed-liquor into a weir which returns floatables to the aeration chamber for reprocessing. Batch time in the clarifier is determined:by the amount of time necessary for the remaining bacte- ria and dead cells (which flock together once deprived of food and oxygen) to settle, separating the supernatant from the sludge. This time period is sufficient to allow flocculation and settling, but is not long enough to encourage an anaerobic condition. Average time is 65 minutes. Since settling takes place under quiescent, static conditions, no coagulants are needed, nor are they recommended. After settling has occurred, the microprocessor initiates the supernatant transfer pump (SNT), which transfers the supernatant into the ozone contact chamber. While the supernatant is in transit, ozone is injected into the transfer line. By injecting ozone directly into the transfer Iine, !.r short-circuiting (which can take place when injection takes place directly into the contact tank) is prevented. After the supernatant transfer is complete, the ozone injection switches from the transfer line to a circulating pump located in the bottom of the contact tank. Ozone injection then continues for a minimum of 50 minutes, thus assuring complete pathogen kill. NOTE: The ozone generator is rated at twice the grams/hour required for potable water treatment and will negate the need for chlorination should the permitting agency not mandate its use. Many states have totally banned the use of chlorine for any form of water/wastewater disinfection and are relying completely on ozone and ultraviolet. The chemical disinfectant potential (V) of ozone is 2.07 as op- posed to 1.36 for chlorine as HCLO or 0.25 as an ion. Ozone causes immediate destruction of bacteria and viruses as opposed to merely altering the DNA to pre- vent replication, as is the case with ultraviolet. After the SNT pump transfers the supernatant from the clarifier, the clarifier sludge return (SLR) pump returns 100% of the sludge from the clarifier to the aeration chamber for reprocessing. This complete recycling of sludge takes place 14.7 times in every 24-hour period. The returned sludge, along with the fresh incoming waste, becomes the food source for new cell growth and a carbon source for the portion of the nitrificatian/denitrification process which takes place in the aeration chamber. This returning of 100% of the sludge for reprocessing 14.7 times per day is largely the reason that the Bio-Pure system generates very little disposable sludge. a Because of this 100% returned-sludge`process, the Bio-Pure system is capable of removing an average of 96.4% of nitrates. The 100% returned activated sludge (RAS) provides dead bacterial i 4