Chap9

Question 1

9.1c 5 problems associated with TSS

Answer 1

1. Aesthetics: turbid water associated with wastewater
2. Filterability: remove TSS to reduce the cost of cleaning the filters
3. Disinfection: pathogens can be protected, encased in the particles
4. pumping: SSolid damages the pumping system
5. corrosion: the fluid flow rate is low ->form “oxygen concentration cells” under sediment

Question 2

9.2a. 5 analytical tech available for detecting TSS

Answer 2

1. XRF (X-ray Fluorescence)
2. XRD (X-Ray Diffraction)
3. PSA(particle size analyzer)
4. SDI (silt density index): old, done in field and involved in membrane and applied P
5. Turbidity: used for drinking water

Question 3

9.3b. 6ways to improve the separation of SS from water

Answer 3

1.Increase the terminal velocity Vt:
-increase the density btw 2 media
-size of particles as large as possible
-gravitational force by centrifugation
-adjusting Temps ->change the viscosity of the continuous phase
2.

Question 4

9.4i) Surface contributes so much to the properties of colloids?

Answer 4

their surface to volume ratio is so high

Question 5

9.4ii) the surface properties that stabilizes colloids

Answer 5

surface charge

Question 6

9.5b. is the coagulation and flocculation used in sedimentation filtration, centrifugation or w cyclones

Answer 6

Sedimentation: clarification could be used prior to filtration to reduce loading.
cheaper clarification procedure used -> larger tanks built on real estate issues -> high cost of centrifuges and cyclones

Question 7

9.1 a TSS

Answer 7

particles that are removed by 0.45-micron filters

Question 8

Colloid

Answer 8

mixtures where the solute is btw 1micron and 1 nano in diameter and not homogeneous solutions

Question 9

disperse phase

Answer 9

the solute with colloidal mixtures

Question 10

disperse medium

Answer 10

the solvent

Question 11

tyndall effect

Answer 11

the scattering of light as a light beam passes thru a colloid

Question 12

turbidity

Answer 12

suspended matter the interferes with the passage of light

Question 13

9.1b 5 sources of turbidity in the natural water

Answer 13

• collodal rock particles
• soil flood conditions resulting large suspended
• dometic waste
• industrial enffluent
• bateria growing contribute to Organic suspended matreial

Question 14

9.1b 4 sources of TSS in industrial water

Answer 14

• water pumped from undergd
• sludge produced from LS and ZD (zero discharge evaporation)
• sludge produced from municipal WWT centre
• water involved in oil & gas

Question 15

how terminal velocity depends

Answer 15

• large diameter -> faster velocity
• the acceleration felt
• greater the # in density -> the faster velocity
• as the viscosity decreases the settling will be faster

Question 16

9.5a how coagulation and flocculation served to destabilize colloid

Answer 16

Coagulation: have suspended particles that have a surface charge, keeps particles apart thereby stabilizes the colloid

Question 17

13.1 discuss the nature of material causing turbidity

Answer 17

1. river water during a flash flood: a great amount of topsoil contribute to turbidity
2. polluted river water: OM is food for bac to grow up and produce additional turbidity
3. domestic WW: N,P source of food for algae which also contribute to turbidity

Question 18

13.8 turbidity of WWTP operation

Answer 18

changing the chemical dosage

Question 19

26.4 b Conditions and why 180C used as the drying temp

Answer 19

used for total dissolved solids analysis for water supplies to remove all mechanically occluded water

Question 20

7.2 stability to hydrophobic colloids in water

Answer 20

due to their size and electrical properties and it’s affected by the chemical nature of the colloid and the chemistry of the dispersion medium

Question 21

7.3 factors affect the primary charge on colloid

Answer 21

the character of the colloid
the pH
general ionic characteristics of the water

Question 22

7.4 mechanism addition of an electrolyte bring about the destabilization of colloid in water

Answer 22

the addition of counter-ions with higher charge

Question 23

7.5 mechanism of Al(III) and Fe(III)

Answer 23

form hydroxide precipitates, colloid entrapped in the precipitates

Question 24

9.4a type of particles can be detected in tyndall effect

Answer 24

colloid 1jum to 1nm