SU0003122 - Laserfiche WebLink

Home Browse Search

' r i J !i During manually controlled operational checking, the clarifier will not be filled to the overflow weir unless the aeration chamber has been filled to the standby level switch. Manually control the mixed liquor transfer (MLT) pump until the desired level is reached in the clarifier. Continue manual operation to.#start the discharge pump. If the liquor in the chlorine contact chamber has not remained at least 20 minutes for chlorine contact, the liquor should not be discharged without regulatory authorization. Next,.the chlorine return (CLR) pump can be momentarily operated to check its operation in the same manner. The CLR pump is not required in some inst a Ilations, so check your blueprints to be sure. C. BIOLOGICAL BUILDUP AND STABILIZATION FM As with all other biological sewage treatment systems, this system requires a period of time to build up the biologically active solids to an ,acceptable level of efficiency. This buildup can be accomplished within ten days under normal loading conditions. Before biological buildup occurs, the odorklof the liquor in the aeration chamber will be similar to dishwater except when the influent is anaerobic or septic tank effluent. As the buildup progresses, the odor may vary slightly. When biological stabilization occurs, the liquor has an earthy odor and the color becomes dark brown. If the operator carefully observes these changes in odors and colors during the buildup period, it will be easy to recognize a regression to such conditions at any future time. Septic tank effluent may be very dark brown or blackish in color. Initial odor will be of ammonia and will dissipate rapidly once Fexposed 'to the oxygen within the aeration chamber. During this constant aeration, sulfides will be released into the atmosphere. It is recommended that the building be vented€I If septic tank effluent contains bluing dyes r typical of those found in RV holding-tank chemicais, the color will reflect colors of the E� dye. Since these dyes are generally inorgak ic, some color may be apparent in the final discharge. E� During startup period, the operator should make daily tests of percent solids. The settled sludge should reach a level of 30 to 40%. If settled sludge level does not build up, or if after a period of satisfactory operation the sludge level falls below 30%, excess aeration should be suspected. This condition is corrected by decreasing the time the aeration pumps run during the standby period or by throttling the air valves on the air feed lines. However, the aeration pumps should never be set to operate for less time than it takes to maintain a minimum level of dissolved oxygen. Any time less than 3 out of 15 minutes will not give enough mixing of the activated sludge in the aeration chamber. If, after operating satisfactorily for a period of time, the liquor in the aeration chamber changes from dark brown to a gray or black and the solids appear thicker than before, with about 45% sludge in the settling test, a'kdeteriora#ing condition is present. If the plant is not under continuous organic loading, overcome `this condition by placing the MLT switch in manual (M) mode, thus allowing. the MLT, pumps to run continuously. This procedure may be applicable only at night when flows into the plant are at a minimum. The foregoing procedure can be continued a long as desired until the liquor in the aeration has been brought to an acceptable'rcondition; that is, solids to be less than 35 to i 40%. If this procedure cannot lower the percentage of solids, sludge wasting is indicated. E r i f : F 2 I I i {