Start of MBR Operation(Manual)

May 27, 2021

                                   



1.  Clean Water Operation 

(1)    Check the following items prior to module(s) operation: 
a.    Check that the air diffusion pipe and the filtrate water pipes are properly connected to the module(s).
b.    Check that the element block is securely installed on the aeration block.
c.    Remove any protective materials covering the membrane tank. Check that the membrane tank is completely free of dust and debris. The presence of soil and dust may cause damage to the module.
d.    Open the air discharge valve on the filtrate line to release any air from the filtrate side of the elements before introducing clean water into the membrane tank.
e.    Introduce clean water (tap water or filtered water) to the membrane tank. Fill the tank up to the recommended operating liquid level.
f.    Close the air discharge valve located on the filtrate line, after filling the membrane tank.
 
Open the air discharge valve before feeding clean water to the membrane tank. Close the air discharge valve after feeding water.
 
Do not use natural ground water for clean water operation, as it may contain much amount of iron, manganese, calcium, and silica which may cause the clogging of the membrane pore.
 
(2)    Clean water operation 
After feeding clean water to the membrane tank, follow the recommended procedures below to start the clean water operation.
a.    Start the blower to supply air to the air diffusers. Check that the required amount of air is supplied to the air diffusers and the diffused air is being distributed evenly within each module.
*    White foaming may occur in the membrane tank during clean water operation. The foaming is caused by the leaching of residual biodegradable hydrophilic components contained in the membrane after the manufacturing process. Foaming is normal and does not adversely affect the membrane filtration process but if you want to remove this, do not use silicone-based anti-foaming agent which may cause choking of membrane pores.
b.    When using one blower to supply air for multiple modules, check that the recommended amount of air is evenly supplied to each module. If the distribution of air is found not to be evenly distributed between modules it may be necessary to modify the air line header piping inside diameter to achieve uniform air distribution to each module.
c.    Check the system controls and associated control components for proper operation and proper sequence of operation. 
d.    Start the clean water filtration process. At the initial operation of suction pump, priming (filling the suction piping with water) may be needed for proper pump suction and in that case avoid pressurizing the filtrate side of Toray Submerged Membrane Module for MBR over 10kPa. Measure and record the trans-membrane pressure and water temperature at designed filtration rates (at normal, maximum and minimum flow rates). It is beneficial to periodically record flow rates and TMP values. 
e.    Stop the clean water filtration process and discontinue the air supply as soon as the above tests have been satisfactorily completed.
 
Do not conduct clean water operation for a long time. Clean water operation may cause membrane clogging.
 
Keep the membranes wet once they get wet. If the membranes are allowed to dry out, the permeability of the membranes may be permanently reduced.
 
Avoid pressurizing the filtrate side of Toray Submerged Membrane Module for MBR over 10 kPa.
 


2.    Seeding Sludge Injection

Do not attempt to produce filtrate from any wastewater that has not first been seeded with activated sludge. Failure to do so will result in severe clogging of the membrane pores 
Follow these steps when seeding sludge in the membrane tank with activated sludge:
(1)    Locate a nearby wastewater treatment facility that treats wastewater similar in composition to the wastewater to be treated with the Toray Submerged Membrane Module for MBR. Make arrangements to transport some of that healthy, activated slugged from the nearby wastewater facility to the facility needing the seeding sludge. Activated sludge with higher MLSS concentration and higher MLVSS/MLSS ratio is preferable. Initial MLSS concentration of the membrane tank should be at least 3,000 mg/L or higher. Higher than 7,000 mg/L is preferred.
(2)    Supply the seed sludge through the <3mm screen to the tank.
(3)    Begin feeding the raw wastewater as soon as possible after the activated sludge has been introduced into the membrane tank.
(4)     Do not use seeding agents.
(5)    Do not use silicone-based anti-foaming agent which may cause choking of membrane pores.

 
Prior to introduction of any seeding sludge into the membrane tank pass all sludge through a 3 mm or less mesh screen device.

   

3.    Actual Filtration Operation

After successfully seeding the sludge within the membrane tank, start the air supply to the diffusers, start sludge circulation, activate the filtration process and the raw wastewater feed.
Pay particular attention to the following operational parameters:
(1)    The condition of the seeded activated sludge may not be optimal for membrane filtration until such time the food to microorganism ratio (F/M) has been optimized. To avoid fouling the membrane elements while the activated sludge is evolving, operate the MBR well below the designed flux rate. This is especially important until the activated sludge MLSS concentration approaches 7,000 mg/L. Gradually increase the flux rate as the condition of the activate sludge improves.
(2)    At the initial operation of suction pump, priming (filling the suction piping with water) may be needed for proper pump suction and in that case avoid pressurizing the filtrate side of Toray Submerged Membrane Module for MBR over 10kPa.
(3)    Sludge parameters such as MLSS and sludge filterability (see (11) in the page 39) should be checked frequently to assess the actual sludge condition.
(4)    Check the air diffuser cleaning procedure and associated automated valves for proper operation. Details for the procedure are given in the chapter VIII.
(5)    Once the filtrate water flow has stabilized, please measure and record the trans-membrane pressure and the liquid temperature. Details for operation control are given in the next chapter.

 
The air scour should be stopped when the filtration process is suspended. There are two exceptions:
1) During the normal relaxation period.
2) When the activated sludge requires air for normal metabolic processes. However, under these conditions the amount of air flow directed to the diffuser should be reduced to just the amount required to maintain sludge viability.
 
Avoid pressurizing the filtrate side of Toray Submerged Membrane Module for MBR over 10kPa.
                                   
[Notice]
This content does not intend to guarantee the results of application of the information provided herein or the safety and the compatibility of this product.
Before using this product, the user is asked to check for its safety and compatibility with the intended purpose.
This content is subject to revision from time to time.
Unauthorized use or reproduction of this content is forbidden.

[Remarks]
This content is extracted from “Submerged Membrane Module for MBR TORAY “MEMBRAYTM” Instruction Manual”(the Manual).  Please refer to other contents stated in the Manual.
( https://www.water.toray/knowledge/manual/ )