Chap9 Flashcards Preview

Water/Waste Water Treatment > Chap9 > Flashcards

Flashcards in Chap9 Deck (24):

9.1c 5 problems associated with TSS

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


9.2a. 5 analytical tech available for detecting TSS

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


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

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


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

their surface to volume ratio is so high


9.4ii) the surface properties that stabilizes colloids

surface charge


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

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


9.1 a TSS

particles that are removed by 0.45-micron filters



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


disperse phase

the solute with colloidal mixtures


disperse medium

the solvent


tyndall effect

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



suspended matter the interferes with the passage of light


9.1b 5 sources of turbidity in the natural water

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


9.1b 4 sources of TSS in industrial water

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


how terminal velocity depends

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


9.5a how coagulation and flocculation served to destabilize colloid

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


13.1 discuss the nature of material causing turbidity

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


13.8 turbidity of WWTP operation

changing the chemical dosage


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

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


7.2 stability to hydrophobic colloids in water

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


7.3 factors affect the primary charge on colloid

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


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

the addition of counter-ions with higher charge


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

form hydroxide precipitates, colloid entrapped in the precipitates


9.4a type of particles can be detected in tyndall effect

colloid 1jum to 1nm