Drying Technology
The aerobic tank is a structure that maintains the dissolved oxygen content suitable for the growth and reproduction of aerobic microorganisms through aeration and other measures to treat pollutants in the water.
The function of the aerobic tank is to allow the activated sludge to perform aerobic respiration, further decompose organic matter into inorganic matter, and remove pollutants.
Problems in the aerobic tank will also lead to abnormal conditions in the sewage treatment operation and affect the effluent indicators.
"What are the problems?
"What is the original cause?
Sludge Bulking
The dissolved oxygen in the aerobic tank is low or high for a long time.
The sludge age of the aerobic tank is too long, and the oxygen consumption increases, resulting in insufficient dissolved oxygen.
Long-term low or high aerobic pool load.
The water temperature of the aerobic pool is too high (the probability of occurrence in summer is relatively large).
Unbalanced nutrition or lack of nutrition (low N and P).
Influent pH problem.
The supernatant sludge is finely fragmented and difficult to settle.
The aerobic tank sludge has insufficient nutrients or an unbalanced ratio of nutrients.
The sludge load of the aerobic tank is too high (the effluent is turbid, the COD is high, the sludge is finely crushed after the sedimentation of the aerobic tank and the supernatant is turbid).
The sludge load of the aerobic tank is too low, the aeration is excessive, and the finely divided sludge produced after the sludge is oxidized (the COD removal rate of the aerobic tank is low, and the effluent COD is high).
The sludge load of the aerobic tank is too low, the sludge residence time is long, and the over-aeration leads to poor sludge flocculation (the sludge structure is loose but the COD removal rate is high or not low).
Low COD removal efficiency
Aged sludge in aerobic ponds, long sludge age.
The aerobic tank has high sludge load, short sludge age, large return flow and short residence time.
The sludge load of the aerobic tank is low, and the long-term high dissolved oxygen causes the sludge self-oxidation (low removal rate, high dissolved oxygen), more fine sludge, less active sludge.
Insufficient dissolved oxygen in the aerobic pool.
Insufficient nutrients or unbalanced ratio of nutrients.
The COD removal rate of the hydrolysis acidification tank is low, the hydrolysis effect is poor, and the effluent COD concentration is too high.
The raw water contains toxic substances and the sludge is poisoned.
The impact load of the aerobic tank is large or the sludge expansion phenomenon occurs in the aerobic tank.
Sludge Floating
The impact load of the aerobic tank is large or the sludge expansion phenomenon occurs in the aerobic tank.
The pH value fluctuates. When the pH is less than 5, the flocculation will decrease to form activated sludge deflocculation.
Temperature, generally suitable temperature range for aerobic activated sludge is 15-35℃.
If the DO (dissolved oxygen) is too high, the sludge activity may be very good in the short term, because the metabolism is fast and the organic matter is decomposed quickly, but after a long time, the sludge is beaten lightly and brokenly, like a smog like a wind blowing Pool surface (easy to cause blockage of MBR membrane).
Low DO, the sludge will be gray if it is hypoxic, black if it is hypoxic for too long, and there are often small bubbles.
The sludge floats caused by the accumulation of mud at the bottom of the pool, and the sludge decomposes to produce CH4 and H2S and then floats.
Due to the unstable water temperature and sludge load under the operating conditions of wastewater, the lack of nutrient source of microbial species in the water quality will cause the bacteria to be converted into microfilament bacteria, generally called filamentous bacteria multiply and cause activated sludge floating.
Bubble Problem
White foam, large amount of foam, fragile, indicating that there are more detergents in the influent water.
Brown or gray, indicating that the mud is too old or aging, or the sludge is broken and adsorbed on the bubbles.
Other colors, indicating that they contain other color-producing substances.
Dissolved Oxygen Problem
The consumption of dissolved oxygen will affect the activity of the sludge. A good activated sludge requires a large amount of oxygen. The dissolved oxygen in the mixed solution will disappear quickly after sampling. It will not disappear after a few minutes. At this time, the biological phase of the microscopic examination shows that the protozoa has atrophy mutation.
