1. In water filtration, van der Waals forces:

    a. keep colloidal particles dispersed

    b. are electrostatic repulsive forces

    c. are electrostatic attractive forces

    d. a and b

    e. all of the above

2. With multimedia water filters, the more difficult particle size to remove from the water tends to be about:

    a. 0.01microns

    b. 0.1 microns

    c. 1.0 microns

    d. 10 microns

    e. no differences among above particle size

3. Glauconite is more commonly known as:

    a. silica sand

    b. greensand

    c. manganese dioxide

    d. resin

4. To remove iron, manganese and hydrogen sulfide, greensand is covered or coated with:

    a. manganese oxide groups

    b. iron oxide groups

    c. sulfonation groups

5 & 6. Reduced forms of iron, manganese and sulfur are 5)_____________, and oxidized forms are 6)____________ in water:

    a. soluble

    b. insoluble

    c. dissolved

    d. suspended particulates

    e. a and c

     f. b and d

7. Greensand is an excellent filter medium to remove suspended particulates from water. (True or False)

8. The capacity of manganese greensand is the greatest for removal of:

    a. iron

    b. manganese

    c. hydrogen sulfide

9. Sodium hypochlorite (chlorine) can be injected into the water upstream of a manganese greensand bed. (True or False)

10. Hydrogen sulfide can strip the manganese oxide coating off of manganese greensand. (True or False)