How to condition and biofilm-form a biological aerated filter?
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The company has installed a new aerated biological filter, which is used to carry out further treatment of the wastewater from the previous processing stage. Now I would like to describe my method of acclimatization; I appreciate any feedback you might have. The company’s existing activated sludge is used as the microbial strain, with 20% of this sludge mixed with the wastewater after it has been treated, and then the mixture is left to undergo anaerobic fermentation for two days before fresh wastewater (with a COD level of around 300) is added. It has been operating for over a week now, and the COD level in the effluent remains essentially unchanged – the same amount of COD is present in both the incoming wastewater and the effluent. In my opinion, there are three possible reasons: 1. Low COD in the incoming water: Since the treated water has low biodegradability, the bacteria lack food to consume. 2. The temperature is low now: It was measured at just 11 degrees. 3. The dissolved oxygen level is too high, around 8.0. I would appreciate some guidance from the teachers.
1. During cultivation and film formation, the influent concentration is much higher than that during normal operation, which facilitates the formation of a biological film and helps with its establishment； 2. The aeration volume is too high; the DO level reaches 8, causing the membranes attached to the surface to be damaged. It is sufficient to keep the DO value between 2 and 3 ； 3. If the biodegradability of the treated effluent is too low, using this method is not very effective; it is better to employ physical and chemical treatment methods such as coagulation sedimentation and chemical oxidation ； 4. At relatively low temperatures, the period required for membrane formation is longer; it is necessary to check the growth of the membrane after one month ；
1. How can the DO level reach 8? I remember that the saturated dissolved oxygen level in natural water is only 9 ppm; the aeration is too intense； 2. There should still be significant room for degradation of COD300. What type of water is the poster treating, what are the processes used in the initial stages, and what is the B/C ratio? ； 3. The incubation time is too short; at such low temperatures, it should take at least a month to see any results ； 4. Has all the sludge been lost?
The DO level is high; we’re trying to find solutions. A frequency converter has now been installed on the fans, and I measured it yesterday – it was around 7.0, with a downward trend. The company deals with wastewater containing methamine (monomethylamine, dimethylamine, trimethylamine) as well as DMF. We use completely mixed aerated tanks, which consist of two stages. I haven’t carried out B/C testing, as the company doesn’t have the necessary facilities or testing equipment, and they won’t allow such tests to be done. As for the sludge loss issue mentioned by the person above, how can we detect it? Anyway, the water in our aerated filters remains relatively clear during aeration, and the water in the sedimentation tank isn’t very turbid either.