Membrane Storage Products

Why store membranes?

Membrane elements are a lot like pipes. They can provide a dark, wet environment for microorganisms (bugs) to grow. The condition that keeps bugs in check is the normal rapid flow of water through the element.

When the flow is turned off due to an equipment problem or a planned shutdown, the bugs can take advantage and start forming large colonies on the membrane surface that are protected by slime blankets. These slime layers cut down the elements productivity when put back into service. And they can be difficult to remove during membrane cleanings.

Membrane Storage Products

Product Info Sheet Safety Data Sheet
Memstor

Memstor

Memstor is a formulated product that is used for the storage of membrane elements either within the membrane system, or when the elements are bagged and stored outside the membrane system. Elements can be stored in Memstor for at least six months and as long as 1 year.

In practice, the first step in the process of membrane element storage is to clean. Any foulant on the membrane can act as a safe haven for the bugs.

Storing elements in the membrane system.

Next you have to decide whether to store in the system, or remove the membranes for storage in bags or containers. To store in the system, you use the systems clean-in-place (CIP) equipment. You will make up enough Memstor solution to fill the pressure vessels containing the elements plus enough to fill the piping and pump to push the solution through the system. To calculate/estimate the proper volume, use five gallons of Memstor solution per 8×40 inch membrane and add 10% for piping. For 4×40 inch elements use 1.5 gallons of Memstor solution per element plus 10%.

For example, the calculation for a membrane system containing 10-8×40 inch elements is as follows:

12 elements x 5 gallons Memstor/element X 110% = 66 gallons of Memstor

Remember to account for any water remaining in the system. You can either drain the system or use the volume in the system and add enough water to the CIP tank to make up the total volume calculated using the formula above.

Next, start the CIP pump to circulate the water though the system and back to the CIP tank. Start adding the Memstor powder to the circulating water in small enough portions that no clumps form.

Continue circulating Memstor solution until the return line from the membrane system no longer has bubbles. At this point the system is filled with no air pockets and the CIP pump can be turned off.

Storing elements in bags or containers.

First, the membranes must be cleaned. Next, make up 5.5 gallons of Memstor solution per 8×40 inch element. For 4×40 inch elements, make up 2 gallons per element. The mix ratio is one pound of Memstor powder to 6 gallons of good quality water.

If you plan to use bags, the bags must be heavy enough so they will not be easily punctured. Think of the bags that the membrane elements were shipped in.

The next step is simple. Put the cleaned membrane in the bag and fill with Memstor solution. Tie the bag off.

If you use a container to store the membranes, please keep in mind that membrane elements float. So you will have to find a way to keep the elements submerged or flip them over every few days so that both ends remain wet by the Memstor solution.