Mitsubishi STERAPORE 5700 Series Instruction Manual page 49

Table 7-2 Examples of Effluent Quality Related Problems and Responses
Item
BOD Abnormal quality of incoming raw
COD water.
Decline in MLSS.
Lack of aeration.
SS Damage or disconnection of pipes on
Turbidity the suction side.
Membrane leakage.
T-N If denitrification is insufficient,
-Abnormal quality of incoming raw
water.
-Poor mixing in the anoxic tank.
-Decline in the MLSS concentration.
-Rise in the ORP value.
-Poor circulation of activated sludge.
If nitrification is insufficient,
-Abnormal quality of incoming raw
water.
-Decline in MLSS concentration.
-Lack of aeration.
-Poor circulation of activated sludge.
T-P Abnormal quality of incoming raw
water.
Insufficient addition of coagulant.
Hexane extracts Abnormal quality of incoming raw
water.
Decline in MLSS concentration.
Total coliform Lack of sterilizer.
Leakage of the suction pipe.
Membrane leakage.
＊1 If, taking design water quality (Table 6-1 Example of Design Water Quality (for a septic tank))as an example, if
NO -N in treated water is 15 mg/L or greater (depending on circulation ratio and other factors).
3
＊2 If, taking design water quality (Table 6-1 Example of Design Water Quality (for a septic tank))as an example, if
NH -N in treated water is 2 mg/L or greater.
4
STERAPORE 5700 Series (FF) Instruction Manual
Probable Cause(s)
1
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2
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Response(s)
Check the quality of raw water.
Adjust amount of sludge extraction.
Adjust the air flow rate to a proper value
(proper value: DO > 1mg/L).
Inspect and repair pipes on the suction side.
Inspect the membrane for leaks, then repair or replace the
membrane.
Remove any foreign matter in the tank.
Check the quality of raw water.
Check the operating state of the submerged mixer in the
anoxic tank.
Decrease the amount of sludge extraction. (Take note of a
lack of DO due to an increase in the MLSS concentration.)
Adjust the ORP value so it is in the proper range.
Adjust the circulation pump flow rate.
Check the quality of raw water.
Decrease the amount of sludge extraction. (Take note of a
lack of DO due to an increase in the MLSS concentration.)
Adjust the air flow rate to make DO fall in the proper range.
Adjust the circulation pump flow rate.
Check the quality of raw water.
Inspect and repair coagulant pipes.
Adjust the amount of coagulant added.
Check the quality of raw water.
Decrease the amount of sludge extraction. (Take note of a
lack of DO due to an increase in the MLSS concentration.)
Replenish sterilizer.
Inspect and repair suction pipes.
Inspect the membrane for leaks, then repair or replace the
membrane.
Chapter 7 Troubleshooting
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