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EASY What is the primary purpose of removing suspended solids in water treatment?

  • To improve water clarity
  • To remove dissolved ions
  • To reduce disinfection costs (correct)
  • To remove heavy metals
  • What is the size of suspended solids that can be removed in the first stage of water treatment?

  • Less than 1 micron
  • Exactly 2 microns
  • Greater than 2 microns (correct)
  • Less than 0.5 microns
  • What happens to suspended solids if not removed in water treatment?

  • They are not affected by gravity
  • They dissolve as ions
  • They float to the surface
  • They cause deposits, erosion, and plugging of equipment (correct)
  • What type of water is likely to have high levels of suspended solids?

    <p>River and lake water</p> Signup and view all the answers

    What is the purpose of a settling pond or basin?

    <p>To slow or delay the velocity of water and allow suspended solids to settle</p> Signup and view all the answers

    How do clarifiers differ from settling ponds?

    <p>Clarifiers have features that promote the continuous removal of solids deposited by sedimentation</p> Signup and view all the answers

    What is the typical residence time for water in a clarifier?

    <p>An hour or two</p> Signup and view all the answers

    How is water introduced in a typical clarifier?

    <p>From the center</p> Signup and view all the answers

    What is the primary function of the filter in the treatment process?

    <p>To catch suspended solids in the water</p> Signup and view all the answers

    What happens to the pressure drop across the filter as it screens out more solids?

    <p>It increases</p> Signup and view all the answers

    What is the primary use of activated carbon filters in industry?

    <p>To remove chlorine from municipal source water</p> Signup and view all the answers

    What happens to the chlorines in water when they pass through an activated carbon filter?

    <p>They are reduced to non-oxidative chlorides</p> Signup and view all the answers

    What is the result of heating carbonaceous material to about 1000°C with steam?

    <p>The material is transformed into activated carbon</p> Signup and view all the answers

    What is the purpose of backwashing and regenerating activated carbon filters?

    <p>To restore the filter's effectiveness</p> Signup and view all the answers

    What is the unique property of activated carbon that makes it useful for adsorption?

    <p>Its high surface area to mass ratio</p> Signup and view all the answers

    What is the equivalent surface area of one teaspoon of activated carbon?

    <p>A football field</p> Signup and view all the answers

    What is the purpose of adding alum or synthetic polymer coagulant in the clarifier?

    <p>To speed up the settling time of particles</p> Signup and view all the answers

    What is the main function of a clarifier?

    <p>To remove suspended solids from the water</p> Signup and view all the answers

    What type of particles are less than 1 μm in size and carry a slight electric charge?

    <p>Colloidal particles</p> Signup and view all the answers

    What is the purpose of the rake in the clarifier?

    <p>To remove particles from the bottom of the clarifier</p> Signup and view all the answers

    What is the purpose of the filter medium in a pressure filter?

    <p>To trap suspended particles in its pores</p> Signup and view all the answers

    What is the consequence of inadequate backwash flow in a filter?

    <p>Trapped solids will not come free</p> Signup and view all the answers

    What is the purpose of the filter-aid in a filter-aid tubular filter?

    <p>To pre-coat the tubes and prolong the filter run</p> Signup and view all the answers

    What is the purpose of the compressed air in the upper part of the filter housing in a filter-aid tubular filter?

    <p>To force water through the tubes in the reverse direction during backwashing</p> Signup and view all the answers

    What type of filters are similar to an oil filter in an automotive engine?

    <p>Cartridge filters</p> Signup and view all the answers

    What is the consequence of excessive backwash flow in a filter?

    <p>The filter medium is entrained and removed to waste</p> Signup and view all the answers

    MEDIUM What is the primary purpose of adding alum or a synthetic polymer coagulant in the clarifier?

    <p>To neutralize the particles and speed up the settling time</p> Signup and view all the answers

    What is the function of the rake in the clarifier?

    <p>To remove the sludge from the bottom of the clarifier</p> Signup and view all the answers

    What is the purpose of the filter medium in a pressure filter?

    <p>To remove the suspended particles from the water</p> Signup and view all the answers

    What happens to the filter cake in a filter-aid tubular filter when it needs to be replaced?

    <p>It gets removed and replaced with new filter-aid</p> Signup and view all the answers

    What is the purpose of the compressed air in the upper part of the filter housing in a filter-aid tubular filter?

    <p>To force water through the tubes in the reverse direction during backwashing</p> Signup and view all the answers

    What is the consequence of inadequate backwash flow in a filter?

    <p>Trapped solids will not come free, making the backwash ineffective</p> Signup and view all the answers

    What is the purpose of a clarifier in water treatment?

    <p>To remove suspended solids from the water</p> Signup and view all the answers

    What type of particles are less than 1 μm in size and carry a slight electric charge?

    <p>Colloidal particles</p> Signup and view all the answers

    What is the result of excessive backwash flow in a filter?

    <p>The filter media gets removed to waste, making the filter ineffective</p> Signup and view all the answers

    What type of filters are similar to an oil filter in an automotive engine?

    <p>Cartridge filters</p> Signup and view all the answers

    What is the primary purpose of the filter in the treatment process?

    <p>To remove suspended solids from the water</p> Signup and view all the answers

    What happens to the water as it passes through the filter?

    <p>It gets clarified and sent to the next stage</p> Signup and view all the answers

    What is the purpose of monitoring the pressure drop across the filter?

    <p>To determine when to replace the filter cartridge</p> Signup and view all the answers

    What is the primary use of activated carbon filters in water treatment?

    <p>To remove taste or odors from the water</p> Signup and view all the answers

    What is the result of adsorption of organics onto the activated carbon?

    <p>The removal of taste or odors from the water</p> Signup and view all the answers

    What is the unique property of activated carbon that makes it useful for adsorption?

    <p>High surface area to mass ratio</p> Signup and view all the answers

    What is the purpose of backwashing and regenerating activated carbon filters?

    <p>To restore the filter's effectiveness</p> Signup and view all the answers

    What happens to the carbon atoms during the production of activated carbon?

    <p>They are removed as they react with steam</p> Signup and view all the answers

    What is the primary benefit of removing suspended solids in the first stage of water treatment?

    <p>Removing heavy metals and reducing other treatment costs</p> Signup and view all the answers

    How do suspended solids behave in water?

    <p>They sink or float with gravity</p> Signup and view all the answers

    What is the primary difference between a settling pond and a clarifier?

    <p>The residence time of the water</p> Signup and view all the answers

    Why is filtration used to remove suspended solids from groundwater?

    <p>Because it is necessary to remove suspended solids that are not removed by settling or clarifying</p> Signup and view all the answers

    What is the purpose of the continuous removal of solids deposited by sedimentation in a clarifier?

    <p>To prevent the accumulation of solids at the bottom of the clarifier</p> Signup and view all the answers

    What happens to the suspended solids in a settling pond or clarifier?

    <p>They settle to the bottom by gravity</p> Signup and view all the answers

    Why is it necessary to remove suspended solids from water?

    <p>To prevent operational issues in the treatment process</p> Signup and view all the answers

    What is the result of water flowing through a settling pond or clarifier?

    <p>The suspended solids settle to the bottom of the tank by gravity</p> Signup and view all the answers

    HARD What is the primary benefit of removing suspended solids in the first stage of water treatment?

    <p>Reducing the need for disinfection</p> Signup and view all the answers

    What is the primary purpose of a clarifier?

    <p>To remove suspended solids from the water</p> Signup and view all the answers

    What is the primary difference between a settling pond and a clarifier?

    <p>A clarifier has a continuous removal of solids</p> Signup and view all the answers

    Why is filtration used to remove suspended solids from groundwater?

    <p>Because filtration is a more effective method</p> Signup and view all the answers

    What happens to suspended solids in a settling pond or clarifier?

    <p>They settle to the bottom</p> Signup and view all the answers

    What is the primary purpose of a settling pond or basin?

    <p>To reduce the velocity of water</p> Signup and view all the answers

    What happens to the pressure drop across a filter as it screens out more solids?

    <p>It increases</p> Signup and view all the answers

    What is the primary benefit of removing suspended solids in the first stage of water treatment?

    <p>Reducing the need for disinfection</p> Signup and view all the answers

    What is the primary mechanism by which activated carbon filters remove taste or odor from water?

    <p>Adsorption of the organics onto the activated carbon</p> Signup and view all the answers

    What is the primary advantage of using activated carbon filters in industry?

    <p>They can selectively remove chlorine and other oxidizing agents</p> Signup and view all the answers

    What is the primary reason why filters need to be replaced in the water treatment process?

    <p>The pressure drop across the filter becomes too high</p> Signup and view all the answers

    What is the primary purpose of heating carbonaceous material to about 1000°C with steam?

    <p>To create a large surface area for adsorption</p> Signup and view all the answers

    How does the filter material catch suspended solids in the water treatment process?

    <p>Through a physical barrier that traps the solids</p> Signup and view all the answers

    What is the primary benefit of using filters in the water treatment process?

    <p>To remove suspended solids and clarify the water</p> Signup and view all the answers

    What is the primary purpose of monitoring the pressure drop across the filter?

    <p>To determine when the filter needs to be replaced</p> Signup and view all the answers

    What is the primary advantage of using activated carbon filters in water treatment?

    <p>They can remove a wide range of contaminants from water</p> Signup and view all the answers

    What is the primary reason why colloidal particles are difficult to remove in a clarifier?

    <p>They carry a slight electric charge</p> Signup and view all the answers

    What is the purpose of the distribution plate in a pressure filter?

    <p>To distribute the water evenly onto the filter medium</p> Signup and view all the answers

    What happens to the filter cake in a filter-aid tubular filter when it needs to be replaced?

    <p>It is removed and replaced with new filter aid</p> Signup and view all the answers

    What is the primary advantage of using a filter-aid tubular filter over a pressure filter?

    <p>It has a longer filter run</p> Signup and view all the answers

    What is the consequence of excessive backwash flow in a pressure filter?

    <p>The filter medium is removed and needs to be replaced</p> Signup and view all the answers

    What is the primary purpose of adding a coagulant to the water in a clarifier?

    <p>To neutralize the electric charge of colloidal particles</p> Signup and view all the answers

    What is the purpose of the compressed air in the upper part of the filter housing in a filter-aid tubular filter?

    <p>To force the water through the filter in the reverse direction</p> Signup and view all the answers

    What is the primary difference between a cartridge filter and a pressure filter?

    <p>The type of filter medium used</p> Signup and view all the answers

    What is the consequence of inadequate backwash flow in a pressure filter?

    <p>The filter cake is not removed</p> Signup and view all the answers

    What is the primary purpose of using a clarifier in water treatment?

    <p>To remove suspended particles</p> Signup and view all the answers

    Study Notes

    Water Treatment Stage 1: Removal of Suspended Solids

    • Suspended solids are particles greater than 2 microns that do not dissolve as ions and can be removed by gravity.
    • Removing suspended solids also removes other harmful substances like heavy metals and reduces treatment costs.
    • Suspended solids can cause operational issues like deposits, erosion, and plugging of equipment if not removed.

    Settling Pond/Basin

    • A settling pond or basin slows or delays the velocity of water, allowing suspended solids to settle to the bottom by gravity.
    • Examples of common settling basins are cooling water basins and inlet water basins.

    Clarifier

    • A clarifier is a large settling tank that uses gravity to settle out particles.
    • Clarifiers have features that promote the continuous removal of solids deposited by sedimentation.
    • Residence time for water in a clarifier is around an hour or two, compared to a number of days for a typical settling pond.
    • Water flows from the center of the clarifier to the bottom, then upwards to the weirs, and particles settle out and are removed by a rake.

    Coagulation

    • Colloidal particles (less than 1 μm in size) can be difficult to remove in a clarifier due to their slight electric charge.
    • Alum (aluminum sulfate) or a synthetic polymer coagulant can be added to neutralize the particles, allowing them to combine and settle to the bottom of the clarifier.

    Filtration

    • Filtration is used to remove the last of the suspended particles after initial removal of suspended solids.
    • Common types of filters include pressure filters, filter-aid tubular filters, cartridge filters, and activated carbon filters.

    Pressure Filter

    • A pressure filter has a filter medium (usually sand, anthracite coal, or calcite) that the water flows through.
    • Suspended particles adhere to the surface of the medium and get trapped in pores.
    • The filtered water is collected in the under-bed collection system.
    • Filters become plugged with suspended particles over time and must be backwashed.

    Filter-Aid Tubular Filter

    • A filter-aid tubular filter consists of a closed cylindrical housing with screen-type cylindrical tubes covered in Dacron or polyethylene filter cloth.
    • A slurry of filter-aid (usually diatomaceous earth or volcanic ash) is fed through the inlet at the beginning of the filter cycle.
    • The filter-aid pre-coats the tubes, and additional filter cake forms, increasing filtration effectiveness.
    • Backwashing involves closing the inlet and outlet valves, opening the drain valve, and using compressed air to loosen the filter cake.

    Cartridge Filter

    • A cartridge filter is a simple system similar to an oil filter in an automotive engine.
    • Water flows around the outer space of the filter and then through the filter, catching suspended solids.
    • The clarified water then goes through the middle of the filter and out to the next stage in the treatment process.
    • The filter cartridge is replaced once the pressure drop across the filter becomes too high.

    Activated Carbon Filter

    • An activated carbon filter is used to remove taste or odors from water, and to remove chlorine, especially from municipal source water.
    • Activated carbon is produced from carbonaceous material, transformed into activated carbon by heating to about 1000°C with steam, and in the absence of oxygen.
    • Each teaspoon of activated carbon has a total surface area equal to that of a football field.
    • Activated carbon filters are not very effective against dissolved solids and should be placed in the process after the removal of solids.

    Water Treatment Stage 1: Removal of Suspended Solids

    • Suspended solids are particles greater than 2 microns that do not dissolve as ions and can be removed by gravity.
    • Removing suspended solids also removes other harmful substances like heavy metals and reduces treatment costs.
    • Suspended solids can cause operational issues like deposits, erosion, and plugging of equipment if not removed.

    Settling Pond/Basin

    • A settling pond or basin slows or delays the velocity of water, allowing suspended solids to settle to the bottom by gravity.
    • Examples of common settling basins are cooling water basins and inlet water basins.

    Clarifier

    • A clarifier is a large settling tank that uses gravity to settle out particles.
    • Clarifiers have features that promote the continuous removal of solids deposited by sedimentation.
    • Residence time for water in a clarifier is around an hour or two, compared to a number of days for a typical settling pond.
    • Water flows from the center of the clarifier to the bottom, then upwards to the weirs, and particles settle out and are removed by a rake.

    Coagulation

    • Colloidal particles (less than 1 μm in size) can be difficult to remove in a clarifier due to their slight electric charge.
    • Alum (aluminum sulfate) or a synthetic polymer coagulant can be added to neutralize the particles, allowing them to combine and settle to the bottom of the clarifier.

    Filtration

    • Filtration is used to remove the last of the suspended particles after initial removal of suspended solids.
    • Common types of filters include pressure filters, filter-aid tubular filters, cartridge filters, and activated carbon filters.

    Pressure Filter

    • A pressure filter has a filter medium (usually sand, anthracite coal, or calcite) that the water flows through.
    • Suspended particles adhere to the surface of the medium and get trapped in pores.
    • The filtered water is collected in the under-bed collection system.
    • Filters become plugged with suspended particles over time and must be backwashed.

    Filter-Aid Tubular Filter

    • A filter-aid tubular filter consists of a closed cylindrical housing with screen-type cylindrical tubes covered in Dacron or polyethylene filter cloth.
    • A slurry of filter-aid (usually diatomaceous earth or volcanic ash) is fed through the inlet at the beginning of the filter cycle.
    • The filter-aid pre-coats the tubes, and additional filter cake forms, increasing filtration effectiveness.
    • Backwashing involves closing the inlet and outlet valves, opening the drain valve, and using compressed air to loosen the filter cake.

    Cartridge Filter

    • A cartridge filter is a simple system similar to an oil filter in an automotive engine.
    • Water flows around the outer space of the filter and then through the filter, catching suspended solids.
    • The clarified water then goes through the middle of the filter and out to the next stage in the treatment process.
    • The filter cartridge is replaced once the pressure drop across the filter becomes too high.

    Activated Carbon Filter

    • An activated carbon filter is used to remove taste or odors from water, and to remove chlorine, especially from municipal source water.
    • Activated carbon is produced from carbonaceous material, transformed into activated carbon by heating to about 1000°C with steam, and in the absence of oxygen.
    • Each teaspoon of activated carbon has a total surface area equal to that of a football field.
    • Activated carbon filters are not very effective against dissolved solids and should be placed in the process after the removal of solids.

    Water Treatment Stage 1: Removal of Suspended Solids

    • Suspended solids are particles greater than 2 microns that do not dissolve as ions and can be removed by gravity.
    • Removing suspended solids also removes other harmful substances like heavy metals and reduces treatment costs.
    • Suspended solids can cause operational issues like deposits, erosion, and plugging of equipment if not removed.

    Settling Pond/Basin

    • A settling pond or basin slows or delays the velocity of water, allowing suspended solids to settle to the bottom by gravity.
    • Examples of common settling basins are cooling water basins and inlet water basins.

    Clarifier

    • A clarifier is a large settling tank that uses gravity to settle out particles.
    • Clarifiers have features that promote the continuous removal of solids deposited by sedimentation.
    • Residence time for water in a clarifier is around an hour or two, compared to a number of days for a typical settling pond.
    • Water flows from the center of the clarifier to the bottom, then upwards to the weirs, and particles settle out and are removed by a rake.

    Coagulation

    • Colloidal particles (less than 1 μm in size) can be difficult to remove in a clarifier due to their slight electric charge.
    • Alum (aluminum sulfate) or a synthetic polymer coagulant can be added to neutralize the particles, allowing them to combine and settle to the bottom of the clarifier.

    Filtration

    • Filtration is used to remove the last of the suspended particles after initial removal of suspended solids.
    • Common types of filters include pressure filters, filter-aid tubular filters, cartridge filters, and activated carbon filters.

    Pressure Filter

    • A pressure filter has a filter medium (usually sand, anthracite coal, or calcite) that the water flows through.
    • Suspended particles adhere to the surface of the medium and get trapped in pores.
    • The filtered water is collected in the under-bed collection system.
    • Filters become plugged with suspended particles over time and must be backwashed.

    Filter-Aid Tubular Filter

    • A filter-aid tubular filter consists of a closed cylindrical housing with screen-type cylindrical tubes covered in Dacron or polyethylene filter cloth.
    • A slurry of filter-aid (usually diatomaceous earth or volcanic ash) is fed through the inlet at the beginning of the filter cycle.
    • The filter-aid pre-coats the tubes, and additional filter cake forms, increasing filtration effectiveness.
    • Backwashing involves closing the inlet and outlet valves, opening the drain valve, and using compressed air to loosen the filter cake.

    Cartridge Filter

    • A cartridge filter is a simple system similar to an oil filter in an automotive engine.
    • Water flows around the outer space of the filter and then through the filter, catching suspended solids.
    • The clarified water then goes through the middle of the filter and out to the next stage in the treatment process.
    • The filter cartridge is replaced once the pressure drop across the filter becomes too high.

    Activated Carbon Filter

    • An activated carbon filter is used to remove taste or odors from water, and to remove chlorine, especially from municipal source water.
    • Activated carbon is produced from carbonaceous material, transformed into activated carbon by heating to about 1000°C with steam, and in the absence of oxygen.
    • Each teaspoon of activated carbon has a total surface area equal to that of a football field.
    • Activated carbon filters are not very effective against dissolved solids and should be placed in the process after the removal of solids.

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    Learn about the first stage of water treatment, removing suspended solids, and its importance in reducing treatment costs and preventing operational issues.

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