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  • 1.  Sediment seperation for well water via mechanical method

    Posted 04-19-2016 12:42 PM

    Hello Everyone!

    Currently working on an EWB project for Guatemala and our group is currently trying to figure out a simple way to separate sediment that comes up from a well. We are receiving sediment build up in the tank and would like to eliminate this as much as possible.  We are trying to make this as sustainable as possible by simplicity, one of the things that we want to avoid is a filter that would have to be replaced.

    Something that has been interesting to me is separation of sediment via centrifugal force. Some of the information (very little) that I found points more towards storm water and/or combined sewers which have bigger solids to separate. Also found an interesting machine called Decanter which might be what we are looking for but on a smaller, simpler, home version of that.

    My question come down to this: Has anyone had success in small scale separation of sediment without filters or know of any good resources for centrifugal separation of sediment?

    Thank you for your help in advance!


    ---------PROJECT INFO-------------

    community size: 400 people

    Well pump specs: 1.5 HP @ 100 depth

    Well specs: 25 GPM measure production, Pump max

    Treatment\Tank Size: 13,000 Gallons per day

  • 2.  RE: Sediment seperation for well water via mechanical method

    Posted 04-20-2016 09:57 AM

    I'm relatively new to filtration, but my understanding is that cyclone separators either don't have the flow rate or don't have the filtration level for drinking water treatment. I see them mostly in treating water that is continuously circulated (HVAC or swimming pool).

    Are you trying to avoid media changes? If so, I'd recommend a basket filter, either self cleaning or duplex manual. Screens are available down to 25 micron. Perhaps a series of them if you have that much sediment. 

  • 3.  RE: Sediment seperation for well water via mechanical method

    Posted 04-20-2016 12:14 PM

    The water is currently drinkable since our tank is acting as a clarifier for the system but eventually this will need cleaning and I would like it to not be directly in the tank. I want to remove sediment and wondering if people had experience/knowledge in order to design cyclone separators because I couldn't find much info on it.

    Since a basket filter is something that would have to be bought and not made it could be used if it is available locally and not a high price. Only issue with that would be replacement cost.


    Adrian Fernandez

  • 4.  RE: Sediment seperation for well water via mechanical method

    Posted 04-20-2016 05:33 PM

    I agree that a properly designed and constructed well shouldn't sand.  Redevelopment should be considered.  Do you have good records on the development of the well and sand production during development?

    Cyclone separators are a common solution in the US, and the brand recommended (LAKOS) is a reasonable one.  The key to knowing if a sand separator will work is the grain size distribution and the density of the sand.  Since the sand is building up in the tank, you need to get a sample of the sand and analyze it.  A vendor may be able to help with this.  If the sand is too fine to be effectively removed by a cyclone separator, you may need to consider other options like a filter.  I agree filters should not be your first choice.

    That said, what is the problem with letting this sand settle in the tank?  You can put your outlet some distance above the floor of the tank, and keep the inlet on the other side.  Maybe even baffle the tank a little if you need to.  Then set up a methodology for flushing out the tank on a regular schedule before sand becomes an issue in the distribution system. 

    Erin McCauley

  • 5.  RE: Sediment seperation for well water via mechanical method

    Posted 04-22-2016 10:39 AM

    I agree with Andrew and Erin that a properly constructed well should filter out the sediment and not have sand. In my experience, it can take a little while for the sand pack to be fully compacted and the best solution is redevelopment. I think the redevelopment should be the first course of action because you want the well to produce clear water so as to not require a filter or cleaning out the tank. With most overseas projects in developing areas, you want the maintenance to be as simple as possible since there is not usually an engineer living in country to double check that the maintenance is performed properly.

    Using an arch pump and surging the pump would probably be the most effective method for clearing out the well.

    Let us know if you would like/need anymore information on developing a well further.

    Daniel Ritchie A.M.ASCE
    Project Engineer
    Lawrenceville GA

  • 6.  RE: Sediment seperation for well water via mechanical method

    Posted 04-20-2016 09:57 AM

    A properly constructed well should not produce sand. 

    Either the well screen has too large slot openings, was not properly developed, or should have been gravel packed.

    That said, look at a LAKOS sand separator. 

    Andrew Smith P.E., M.ASCE

  • 7.  RE: Sediment seperation for well water via mechanical method

    Posted 04-20-2016 11:15 AM

    The area that we are in is very gravelly and sandy until you hit a clay strata far underneath. That being said it isn't a massive amount of sand that gets deposited and would like to be able to remove before it gets to the tank.

    I don't know why it would still be producing sand, it has the sleeves and pretty comparable to the United States in regards to design.

    Adrian Fernandez