In the hottest sewage treatment process

Sewage treatment process (middle)

2.2 perfect pretreatment system

the key to the operation and management process control of activated sludge treatment of sewage is to maintain the influent water quality, nutrient ratio (BOD ∶ n ∶ P), pH value, water temperature, oxygen supply and oxygen consumption balance in the aeration tank in a relatively stable and balanced state, otherwise the activated sludge may be impacted by water quality load, affecting the sewage treatment effect. In view of the characteristics of large discharge of pulp and paper-making sewage, frequent changes in pH value and high water temperature, the following control systems are adopted in the design of pretreatment process:

2.2.1 pH value regulation control system

first, a fully automatic lime neutralization system is adopted, and a pH meter is set behind the neutralization tank to monitor the pH value after neutralization, and the signal is fed back to the frequency converter of spiral dosing equipment. Gradually increase the speed when the pH value is lower than 6, and gradually reduce the speed when the pH value is higher than 7; Secondly, add a pH value controller at the rear of the primary sedimentation tank. If the pH value of the sewage still cannot reach the range required for biochemical treatment after sedimentation and mixing in the primary sedimentation tank, the pH controller will send an alarm signal and open the electric valve entering the emergency tank, and the sewage will flow into the accident emergency tank temporarily first. The above dual pH value automatic control device effectively ensures that the pH value of sewage after pretreatment meets the requirements of biochemical treatment

Table 1 main design parameter items design parameter processing capacity is normal 33500m3/D, Maximum 40000m3/dcodcr

BOD5

SS

pH

water temperature

selection tank

aeration tank

secondary sedimentation tank

primary sedimentation tank

water inlet

water outlet

water inlet

water outlet

water inlet

effluent

influent

effluent

quantity

effective volume

sludge load

specification

circulating pump flow

dissolved oxygen concentration

quantity

effective volume

sludge load

MLSS

in the national standard of spring testing machine, sludge age

effective water depth

specification

circulating pump flow

dissolved oxygen concentration

quantity

specification

effective water depth

quantity

specification

effective water depth is normal 27100kg/d, and the maximum is 32300kg/d

maximum 11400kg/d

normal 11400kg/d, maximum 13600kg/d

maximum 2040kg/d

normal 6000kg/d, Maximum 7200kg/d

maximum 1080kg/d

0 ~ 14

6 ~ 9

15 ~ 55 ℃

15 ~ 35 ℃

1

915m3

8.1kgco5. Full automatic fixture: from sample size measurement to clamping d/kgvss · d

diameter 12.9m × Depth 8m

1330m3/h

1.5 ~ 2mg/L

1

10623m3

0.6kgcod/kgvss · d

4.3g/l

10d

7.0m

diameter 44.6m × Depth 8m

1915m3/h × Two

1.5 ~ 2.0mg/l

2