What abnormal phenomena will occur in the aerobic pool?

①Aerobic sludge turns black or white (dissolved oxygen is low or too high)

②The supernatant of the aerobic tank is turbid (the sludge adsorption performance becomes poor or the dissolved oxygen is too high, which leads to the disintegration of the sludge, and the organic matter cannot be oxidized if the dissolved oxygen is too low)

③ The sludge foam returning from the secondary sedimentation tank becomes thicker (the sludge stays in the secondary sedimentation tank for too long, and the activity of the sludge becomes poor after denitrification)

④Increase of foam in the aerobic pool (judging by the color and viscosity of the foam, whether it is caused by the change of the sludge itself or by the substances added in the production)

⑤The removal rate of the aerobic tank decreased (specific analysis reasons: sludge activity, sludge load, dissolved oxygen, sludge concentration, water temperature, etc.)

⑥ Sludge expansion in aerobic pool (control by increasing sludge discharge and adjusting nutrient feeding, stabilizing water intake, ensuring sufficient dissolved oxygen and suitable water temperature)

⑦When the aerobic sludge is used for the sedimentation ratio, the supernatant is turbid and the fine mud is more (the sludge load is too high or the sludge disintegrates, the microscopic examination of the sludge structure is loose, and the bacteria micelles are thin)

⑧ Fewer aerobic microorganisms, loose structure, and thin bacterial micelles (load is too low or too high, dissolved oxygen is insufficient, sludge bulking occurs, and nutrients are insufficient)

⑨The dissolved oxygen in the aerobic tank is high for a long time, the effluent is turbid and the COD is high (the sludge load is low for a long time, the sludge disintegrates, the bacteria micelles are oxidized, and the oxygen is not consumed)

⑩ Sludge aging (the causes of sludge aging include long mud age and low load, etc., sludge aging makes the effluent worse, there are many fine mud and rotifers, and the oxygen consumption increases)

What abnormal phenomena will occur in the secondary sedimentation tank?

① There is scum and scum (the sludge is aged or the sludge age is short, and the sludge stays in the secondary sedimentation tank for too long)

②The effluent is turbid, with high COD and odor (insufficient dissolved oxygen in the aerobic pool, short residence time in the aerobic pool)

③The effluent is turbid, the COD is not very high, and there is a lot of finely divided sludge (the aerobic tank is full of dissolved oxygen, the sludge load is small, and the sludge is aging)

④The effluent is turbid, the COD is high, and there is a lot of finely divided sludge (insufficient dissolved oxygen in the aerobic tank, the sludge is aging, and the sludge load is large)

⑤The effluent is clear and the COD is high (sludge bulking phenomenon occurs in the sludge of the aerobic tank)

⑥ Finely crushed sludge tumbling (there is a problem with the sludge in the aerobic tank, it is recommended to add nutrients and adjust the appropriate sludge age)

⑦ The mud layer of the secondary sedimentation tank is too high (sludge expansion phenomenon or small reflux ratio in the aerobic tank)

⑧The water surface of the secondary settling tank is bubbling (the sludge stays in the secondary settling tank for too long)

⑨ The return sludge is black, smelly and sticky (the sludge residence time is too long and the return ratio is small)

⑩The color of the effluent becomes darker (the physicochemical effect becomes worse, the effect of the anaerobic tank becomes worse, or the sludge in the aerobic tank becomes bulky)

Why is the supernatant clear but the COD is high when sludge bulking occurs in aerobic tank sludge?

① Filamentous fungi have a strong adsorption effect, and a large number of filamentous fungi have a net capture effect, so the supernatant is clear

②The filamentous bacteria protrude out of the bacterial micelles in large quantities, blocking the bacterial micelles from obtaining sufficient oxygen, and failing to oxidize and convert organic matter into inorganic matter

③The bacteria micelles cannot get enough oxygen, the reproductive activity is reduced, the bacteria micelles become thin and the activity decreases

What is the reason for the turbidity of the effluent of the anaerobic tank?

①The sludge load in the anaerobic tank is too high

②The effluent of the primary sedimentation tank has a lot of suspended matter

③The concentration of sludge in the anaerobic tank is too high

④Unbalanced nutrients in anaerobic tank

⑤ The temperature of the influent water in the anaerobic tank is too high

What are the reasons for the tumbling and turbidity of the fine sludge in the secondary sedimentation tank?

①The sludge load in the aerobic tank is too small, the aeration is excessive, and the sludge is oxidized by itself, resulting in poor flocculation of the sludge and dispersion of the sludge structure (the water is turbid and there are many suspended solids)

②The sludge load in the aerobic tank is too large, the dissolved oxygen is insufficient, the adsorption performance of the sludge becomes poor, and the organic matter is not completely decomposed.

③The load of the secondary sedimentation tank is too high, or the water distribution of the secondary sedimentation tank is not uniform, and the phenomenon of gravity flow occurs, and the local flow rate is too fast to carry the sludge up

④ The reflux ratio of the secondary sedimentation tank is too large, the mud layer in the secondary sedimentation tank is too low, and the water flow stirs the mud layer too much (the reason is less)

⑤ The excessive discharge of sludge in the aerobic tank leads to the short sludge age of the aerobic tank, and the newly synthesized sludge flocs are difficult to settle (the water is clear and there are many suspended solids)

⑥The sludge age of the aerobic tank is too long and the sludge is aging

⑦Insufficient nutrients in aerobic tank sludge or unbalanced ratio of nutrients (proportion of N and P is too high)

⑧Sludge bulking phenomenon occurs in the sludge in the aerobic tank, the sedimentation is poor, the sludge layer in the secondary sedimentation tank is high, and the water flow takes the sludge out (this will happen if the SVI value is too high or too low)

⑨The ammonia nitrogen content in the sewage of the aerobic pool is too high

What is the reason for the phenomenon of scum and sludge in the secondary settling tank?

① The reflux ratio of the secondary sedimentation tank is small, the sludge residence time is too long, and the sludge is carried up by gas after anaerobic denitrification

②The aerobic tank enters a large amount of physicochemical sludge and anaerobic sludge, and because part of it cannot be converted into aerobic sludge, it becomes a scum discharge system

③ Corruption and deterioration of sludge in aerobic tank

④The aerobic tank has a lot of foam, which is mixed with sludge/suspended matter and floated in the secondary sedimentation tank

⑤The sludge concentration in the aerobic tank is low (the sludge load is high) or the dissolved oxygen is too high (possibly)

⑥The sludge in the aerobic tank is aging or the sludge age is too short, the flocculation is poor, and the COD removal rate and treatment effect are poor

What is the reason for the lack of dissolved oxygen in the aerobic pool?

①The sludge concentration in the aerobic tank rises rapidly or the sludge is aged, resulting in an increase in oxygen consumption

②There are a lot of suspended matter in the effluent of the anaerobic tank, which consumes a lot of dissolved oxygen after entering the aerobic tank

③ The blower fails to stop running or the pressure of the blower is not enough (this situation is rare)

④ The COD of the effluent of the anaerobic tank suddenly increased a lot, or the influent suddenly increased, and the impact load was large, resulting in a large load of the aerobic tank

⑤ The aeration head is seriously damaged or blocked, and the aerobic pool has more foam

What is the cause of sludge bulking in aerobic tanks?

①The dissolved oxygen in the aerobic pool is long-term low or long-term high (possibly)

②The sulfide content of raw water or anaerobic effluent is too high, which leads to the proliferation of sulfur bacteria

③The load of the aerobic pool is low or high for a long time

④The water temperature of the aerobic pool is too high

⑤ Unbalanced nutrition or lack of nutrition (low N and P)

⑥The problem of pH value of influent water

⑦The sludge age of the aerobic tank sludge is too long, and the oxygen consumption increases, resulting in insufficient dissolved oxygen

What are the reasons for the phenomenon of sludge disintegration and supernatant crushing sludge in the aerobic tank?

①The sludge load in the aerobic tank is small, the aeration is excessive, the sludge is self-oxidized, the flocculation of the sludge becomes poor, and the sludge structure is loose (clear, with a lot of finely divided mud, and the COD is not high)

②The sludge load in the aerobic tank is too large, the adsorption performance of the sludge becomes poor, the organic matter is not completely decomposed, and the structure of the sludge is scattered (turbid, opaque, high COD)

③ Too much sludge discharge in aerobic tank leads to too short sludge age in aerobic tank (SVI value is suitable for 70~120, within this range, there is less fine sludge in secondary sedimentation tank)

④The influent water of the aerobic tank contains toxic substances or the sludge is aged, and the sludge age is long (turbid, with finely divided mud, high COD, and many rotifers in microscopic examination)

⑤Insufficient nutrients in the aerobic pool or unbalanced ratio of nutrients (low N and P)

Why do aerobic pools have a lot of foam?

①The raw water contains a large amount of surfactant components (from the substances added in the production process, the foam is white, the bubbles are small, light and not sticky)

②The arrival of tiny air bubbles generated after the newly installed aeration head (short-term impact)

③ A large amount of lipid substances or microorganisms are produced during the reproduction of microorganisms (where the microorganisms grow and reproduce themselves, the foam is mud-colored, the bubbles are large and sticky)

④ Sludge denitrification foam (the foam produced by aerobic sludge after denitrification in the secondary sedimentation tank is too long, the foam is viscous and muddy)

What is the reason for the low COD removal rate in the aerobic tank?

①The aerobic tank sludge is aging and the sludge age is long

②The sludge load in the aerobic tank is high, the sludge age is short, the return flow is large, and the residence time is short

③The sludge load in the aerobic tank is low, and the long-term high dissolved oxygen leads to the self-oxidation of the sludge (low removal rate, high dissolved oxygen), more finely divided sludge, and less activated sludge

④Insufficient dissolved oxygen in the aerobic pool

⑤ Insufficient nutrients or unbalanced ratio of nutrients (the ratio of N and P is too high)

⑥ The COD removal rate of the anaerobic tank is low, the anaerobic hydrolysis effect is poor, and the effluent COD concentration is too high

⑦ Raw water contains toxic substances and sludge is poisoned

⑧ The cumulative value of inorganic salts exceeds the specified range

⑨ The impact load of the aerobic tank is large or the sludge bulking phenomenon occurs in the aerobic tank

What is the reason for the low COD removal rate in anaerobic tanks?

①Insufficient sludge concentration in anaerobic tank (return biochemical sludge to anaerobic tank)

②The anaerobic tank enters a large amount of physical and chemical sludge (inorganic matter accounts for the majority)

③Insufficient nutrients in the anaerobic tank or unbalanced ratio of nutrients

④The water temperature exceeds the suitable range of anaerobic microorganisms (over 40℃)

⑤ The pH of the influent water exceeds 10.5 or is lower than 6.5

⑥ The residence time of the anaerobic tank is too short, and it is difficult to reach the anaerobic hydrolysis state (design problem)

⑦ Entering toxic substances

The supernatant of the aerobic tank has a lot of finely divided sludge, and the reason why the finely divided sludge is difficult to settle due to tumbling?

① The aerobic tank sludge has insufficient nutrients or the proportion of nutrients is not balanced

②The sludge load in the aerobic tank is too high (the effluent of the secondary sedimentation tank is turbid, the COD is high, and the supernatant after the sludge in the aerobic tank is precipitated and then the supernatant is finely crushed, and the sludge is turbid)

③The sludge load in the aerobic tank is too low, the aeration is excessive, and the finely divided sludge produced by the self-oxidation of the sludge (the COD removal rate of the aerobic tank is low, and the effluent COD is high)

④The sludge load in the aerobic tank is too low, the sludge residence time is long, and the aeration is excessive, resulting in poor sludge flocculation (the sludge structure is loose but the COD removal rate is high or not low)

How to solve the problem of excessive suspended solids (sludge) in the pulsed effluent of the anaerobic tank?

①Control the physical and chemical sludge in the primary sedimentation tank to enter the anaerobic tank (must)

②Add a siphon sludge discharge pipe at the top of the anaerobic tank (anaerobic bottom sludge discharge is not recommended)

③ Add polypropylene or polyaluminum to the anaerobic tank

④Reduce the amount of water inflow or discharge the sludge at the bottom of the anaerobic tank

How to solve the sludge bulking phenomenon in aerobic tank?

①Increase the sludge discharge first to solve the problem of poor sedimentation effect, and then increase the sludge concentration and reduce the sludge load after improvement.

②Increase the discharge of sludge in the aerobic tank and reduce the sludge age (in serious cases, it should be adhered to for about two months)

③ Control the water temperature within an appropriate range, stabilize the water intake, and keep the aerobic pool with sufficient dissolved oxygen (must)

④Increase the dosing of nutrients in the aerobic pool

⑤ If the mud layer in the secondary sedimentation tank is high, the return flow can be increased, the water inflow of each secondary sedimentation tank can be adjusted, or polyaluminum polypropylene can be added (temporary control measures)