Sludge leakage in the secondary sedimentation tank
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Sludge leakage in the secondary sedimentation tank is quite severe. In the oxidation ditch of Carrousel 2000, the dissolved oxygen level at the water discharge point is generally kept around 2.2 mg/L, with a maximum level of 3.0 mg/L. The flow rate of water entering the system is 30,000 cubic meters per ditch per day; the BOD level of the incoming water is sometimes low, with an average value of 50 mg/L. The effective volume of the oxidation ditch is 14,750 m3, and the MLSS level is generally maintained at 3,000 mg/L. Based on these values, the F/M ratio comes out to 0.0339 (I’m not sure if this value is correct). If it is correct, then the sludge load seems too low The sludge age is generally kept at around 15 days, with an SV30 value of 15 and an SVI value of around 50. I’m not sure how to adjust the process in order to reduce the problem of sludge leakage
I’m not very familiar with the three-channel oxidation ditch; therefore, the analysis below may not be accurate. Please discuss it among yourselves. F/M = 30000*1000*170/3000*14750*1000 = 0.12; here, 170 is calculated based on B/C = 0.3, and the organic content is determined using COD values. This value is relatively low – generally, an F/M ratio of around 0.3 is considered normal. Additionally, considering the sludge parameters mentioned by the poster, the sludge load should not be this low; such a low load would imply a higher SV value. Of course, the above calculations apply more to municipal wastewater, and the results may vary significantly for different types of wastewater. Zero: If SV is around 15, does mud running still occur frequently? ? ? This post was last edited by zfc318 on 2009-3-13 14:17.]
The main reasons for sludge running are basically the following three situations: sludge bulking, sludge denitrification, and sludge putrefaction. 1. Filamentous fungi tend to cause sludge to float to the surface ； First, the sludge load in the aerobic tank is relatively low. Filamentous bacteria have a larger specific surface area compared to flocculated microorganisms. Under conditions where nutrients are limited and controlled, filamentous bacteria with a larger specific surface area are more capable of acquiring substrates than the microorganisms in floccules. As a result, the growth of filamentous bacteria prevails in the aeration tank, leading to sludge bulking. Solution: Increase the water inflow appropriately, reduce the amount of sludge in the aerobic tank, and add more carbon, nitrogen, and phosphorus to the aerobic tank. Secondly, the sludge load in the aerobic tank is high, which can easily lead to oxygen deficiency in that tank. Under conditions of low oxygen, filamentous bacteria thrive, resulting in sludge bulking. Solution: Increase the sludge concentration and aeration volume in the aerobic tank, and appropriately reduce the water inflow volume. 2. The settling time of the secondary sediment sludge is too long, resulting in denitrification ； The floating sludge has a rustish color and contains small bubbles. Solution: Increase the reflux ratio, shorten the sludge age, and remove more sludge. 3. Dead corners inside the tank, sludge **. In this case, check the sludge scraper. Experts can conduct a thorough analysis based on the various parameters you provide, identifying the issues accurately and precisely. However, I don’t understand these things, so I can only offer you these general descriptions; I hope they will be of some use to you.