How long can a wastewater treatment unit remain shut down?
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In a biochemical treatment system, if the equipment comes to a stop, and if the aeration tank is not supplied with water for an extended period of time or if oxygen supply is interrupted, will this have an impact on the biochemical treatment system? How long can it stay parked for the longest time? Please give me some advice! This post was last edited by li*ch1968 on 2009-4-16 11:53.]
It depends on the wastewater treatment process.
It depends on your treatment process and the actual composition of the wastewater
If the equipment stops operating, if the aeration tank is not fed with water for an extended period, or if oxygen supply is interrupted, this will have an impact on the biochemical treatment system. The maximum duration such a stoppage can last depends on the specific wastewater treatment process and the quality of the wastewater.
I once encountered a case of municipal wastewater treatment using the activated sludge process; after a power outage of 6 days, the sludge turned black, but after 2 days of anoxic aeration (under conditions of very low water volume), the sludge regained its activity. Water quality, process differences, and the conditions prior to stopping aeration all affect its recovery.
In an aerobic system where no water is added for an extended period of time, the nutrients in the aerobic tank become insufficient; as a result, microorganisms are forced to engage in internal respiration. Some of these microorganisms die gradually, some decompose themselves, and others enter a dormant state, waiting for food to arrive. Without aeration for an extended period, most aerobic microorganisms will gradually transform into facultative or anaerobic microorganisms, and a considerable portion of them will die. The impact of the above two factors on biochemical systems increases over time; in short periods of 1–3 days, the impact is minimal, while it becomes more significant after 10 days. In terms of processing efficiency at the time of restart, it exceeds 60%. If more than 30 days pass, the sludge must be re-cultured when the system is restarted. This post was last edited by li*ch1968 on 2009-4-17 13:33.]
It depends on your factory’s treatment processes and the quality of the wastewater; it varies from case to case........................
Our company uses the biological contact oxidation method for wastewater treatment. Under normal operating conditions, the sludge settlement rate is 15–20%. There was once a situation where water supply and oxygen supply were stopped for almost a week; after resuming oxygen supply for 4 hours, the sludge settlement rate was found to be nearly 10%. By adding an appropriate amount of nitrogen and phosphorus fertilizers and gradually restarting the water supply, the system returned to normal after 48 hours.
It usually takes about 7 to 8 days, with a maximum of no more than a month. When recovering, it needs to be cultured for some time longer before its activity can be largely restored. . . :lol
Generally, a stop of about 7 days is acceptable; any longer and problems will arise. The original poster asked about this situation where neither water enters nor oxygen is introduced – under what conditions would such a thing occur? ----------Is there a serious problem with the power system? If not, it’s best to get some air exposure every day.
Aerobic microorganisms die by 50% if aeration is stopped for more than 4 hours; if it goes on for more than 7 days, they generally die all, or some of them transform into facultative anaerobic microorganisms； If more water is not added or only a small amount is added, while maintaining appropriate nutrients and carrying out aeration for 24 hours, it will basically recover ； But after 15 days, it’s almost like restarting.