1.Cleaning of membrane module aeration pipe
Fouling at the orifice of the aeration pipe will cause uneven aeration and membrane blockage. In order to prevent membrane blockage, please clean the aeration pipeline once a day (it is recommended to set an automatic valve for automatic cleaning of the aeration pipeline). During cleaning, release the pressure in the aeration pipe by opening the exhaust valve, make the sludge flow back into the aeration pipe, and discharge the sludge through the air flowing through the aeration pipe.

（1）Stop filtering operation;
（2）Open the air release valve. Through this operation, the sludge of the membrane immersion tank enters the aeration pipe from the aeration vent countercurrent and is discharged together with the air.
（3）Keep discharge valve open for 3-5 minutes;
（4）Close the discharge valve, cleaning is completed;
（5）Start filtering again.

Two, MBR flat membrane component cleaning
The continuous accumulation of membrane contamination will lead to the rise of the transmembrane pressure difference, when it increases to a certain extent, chemical (liquid) cleaning is required. Chemical (liquid) cleaning cycle and reagents shall be determined as follows:
(1) When the transmembrane pressure difference under the same filtration flux is 35kPa higher than the initial stable operation, or once every 3 months (it is recommended to clean industrial sewage once a month), chemical (liquid) cleaning should be carried out in a shorter time between the two.
(2) When the membrane pollutants are mainly biological organic pollutants, regular alkaline washing is used to control the membrane pollutants. When it is mainly inorganic pollution, the method of pickling is used to control it.

Note: 0.8㎡/ piece -3L/ piece, 1.0㎡/ piece -4L/ piece, 1.5㎡/ piece -5L/ piece
Calculation of drug quantity:V=N×Y×C1÷C2×100%
V：The amount of total solvent（kg）
N：Number of membrane elements (pieces)
Y：Dosage of liquid required for single membrane element (L/ tablet)
C1：Concentration of diluted solution（mg/L）
C2：Concentration of solvent before dilution（mg/L）
 

A.membrane component maintenance cleaning

1、Alkaline cleaning

a.Add sodium hypochlorite solution into the dosing drum, and then add water to configure 3‰ (5‰) mixture.
b.Stop the filtration operation, close the outlet valve, and close the fan aeration.
c.Open the dosing valve of the membrane assembly and pour all the agents into the membrane assembly separately.
d.After injection, soak for more than 8H.
e.After soaking, turn on the fan and aerate for more than 1-2h.
f.Open the outlet valve, open the suction pump, discharge cleaning liquid pickling.

2、Pickling

a.Add oxalic acid or citric acid into the filling tank, and then add water to prepare the mixture.
b.Stop the filtration operation, close the outlet valve, and close the fan aeration.
c.Open the dosing valve of the membrane assembly and inject the agent into the membrane assembly.
d.After injection, turn on the fan aeration, soak for more than 5H, and aerate the whole process.
e.After soaking, open the outlet valve, open the suction pump, and start the filtration operation.
 

B.Membrane component recovery cleaning

Membrane component recovery cleaning must be set up with a cleaning pool, and fixed aeration base, connected aeration pipe.
a.Stop the filtration operation, close the outlet valve and stop aeration;
b.Slowly open the liquid valve, began to inject a certain amount of liquid medicine;
c.After injection, set for a certain time;
d.After alkali soaking, aerate for 1 hour, and maintain aeration state during pickling soaking;
e.Close liquid valve.
f.In the cleaning tank to configure the cleaning required liquid medicine;
g.Stop the filtration operation, close the outlet valve and stop aeration;
h.Remove the bolt of flange between water collecting pipe and water collecting main pipe;
i.Lift the membrane box along the guide rail and put it into the cleaning tank;
j.Aeration cleaning of the membrane box and soaking for the required time;
l.After cleaning, lift and restore the membrane box, tighten the bolt of the flange between the water collecting pipe and the water collecting main pipe;
m.Start aeration, open outlet valve, restart filtration operation.
 

C.Offline physical cleaning of membrane components

When the membrane element in restorative cleaning cannot solve the problem, it is necessary to remove the membrane element from the membrane assembly, put it on the flat ground or in a clean container, wash the membrane surface with a pressure water column or a soft sponge.