GIRE-097-2-2
46
6. Chemical Cleaning Procedure
(1) Element Chemical Cleaning Procedure
Firstly please slowly inject the chemical via the permeated water nozzle into the elements
until it percolates through the membranes. Do not apply too high pressure (>10 kPa or 100
mbar) when injecting the chemical. Some injecting methods are shown below.
a. Chemical Cleaning with the chemical tank located at the bottom (Fig.VIII-1)
(i)
Confirm that the chemical injection valve is closed and that the chemical feed
pump is stopped.
(ii)
Provide the chemical tank with specified amounts of chemical.
(iii) Stop filtration, stop aeration and close the filtrate valve.
(iv) Start the chemical feed pump and check that the chemical circulates.
(v)
Slowly open the chemical injection valve to start injecting the chemical.
(vi) After injecting the specified amount of chemicals to the elements, stop the
chemical feed pump.
(vii) Hold the equipments for 1 to 3 hours.
(viii)
Close the chemical valve, open the filtrate valve, and start aeration. Then,
restart filtration operation.
* The chemical may remain in the permeated water in an early stage of
filtration (for a period of 2 or more intermittent cycles). Send back the
permeated water to the raw water tank, or dispose of it in accordance with
applicable legal standards for waste disposal. Before restarting the normal
operation, check the pH and/or Cl concentration of the permeated water.
Fig.VIII-1 Chemical Cleaning with Chemical Tank Located at Bottom
Module
Low water level of
Membrane
Submerged Tank
Chemical
Injection Valve
Permeated
water valve
Chemical
Feed Pump
Chemical tank
Open
1,000 mm (=10 kPa) or less
