Lesson 3 - Water SAQ
This lesson allows you to test yourself on the material covered in the Water lesson and determine the level to which you have met the learning outcomes.
Suggested Response - Q6
** What are the main advantages of sand filters and ultrafiltration systems? When would you recommend a sand filter instead of ultrafiltration?
Response:
A sand filter has the following advantages:
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It is able to handle larger particles without clogging.
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It can be useful for water with a high iron content when used along with aeration.
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It is older technology and potentially easier to operate.
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It is potentially cheaper.
An ultrafiltration system has the following advantages:
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It has a smaller footprint.
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It is a virtually continuous system, with less need for backflush and regeneration.
Thus, a sand filter is recommended instead of ultrafiltration if the water contains a lot of particulate matter or metal such as iron, and if the space allows. If the overall water consumption is not critical (i.e. excess water is available at low cost), then the cost of backflushing and potential losses will be less important and this could also mean a sand filter is a better choice.