Filter Wash Process

Introduction: Filter Wash Process

At any traditional municipality water plant, filtration is the last and most important step in the treatment process. Over time however, debris and particles from the water will be collected in the sand/rock media of the filter. After about 200 hours of operation, these filters must be cleaned to ensure water passes through at the same rate. As particles buildup, water passes through slower. Ensuring that each filter is adequately washed is a typical job task every week. Follow these steps to properly wash a filter.

Step 1: Disclaimer:

Always wash a filter with someone nearby. This is just a precaution, as sometimes water may overflow from the filter, causing damage and possible harm. Also, do not lean over the walls of the filter. Falling in would result in bodily injury.

Step 2: Shut Off “Influent Valve”

The influent valve is the main source of water coming in. Closing this stops any new water going to be purified from entering the filter.

Step 3: When the Water Level Gets Low, Shut of the “Effluent Valve”

The effluent valve is at the bottom of the filter where purified water leaves. This completely shuts off any water being treated from leaving.

Step 4: Open the “Drain Valve”.

The drain valve will be kept open throughout the duration of washing, as the filthy water will be drained into the sewers.

Step 5: After Filter Has Drained, Open “Surface Wash” Valve, and Allow a Few Minutes to Operate.

Surface wash spinners are similar to the arms in a dish washer machine. These spin throughout the duration of the wash cycle to spray the sand/rock media to cleanse it.

Step 6: Open the “Backwash Valve” to Allow Water to Rise Through the Media, Cleaning the Filter.

Backwashing is the process of forcing water in a reverse direction. Water is forced upwards to remove the debris that collects over the course of filter operation.

Step 7: Allow Time for Water to Clean the Filter, Then Shut Off the “Surface Wash” and “Backwash Valve” Once the Filter Water Seems to Be Clear.

Closing both will stop the cleaning process, allowing the last of the filthy water to be drained.

Step 8: Close the "Drain Valve"

Once the drain is shut, the water level in the filter we even out. Filter must wait a day before use to allow time for settling of the media.

Step 9: Record the Amount of Water Used in Cleaning of the Filter.

In this case, 21,185 gallons of water was used to clean the filter. This task generally takes between 15-20 minutes to complete.

Step 10: Filter Wash Complete. Notice the Difference in the Clarity of Water, As Well As Condition of Media From the Before and After Images.

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    5 years ago

    Very interesting. A video of this in action would be really cool.



    Reply 5 years ago

    Nevermind, I just saw the link to the video. very cool!


    5 years ago

    Great information on water filtration! Thanks for sharing.


    Tip 5 years ago on Step 1

    No materials are needed in order to wash a filter. All water being used to clean has been saved in a water tower specifically for this purpose.