Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
21 Cards in this Set
- Front
- Back
|
The 3 classes of public water systems |
1) Community - public system, provides to same population all times of year 2) Non-Transient Community - public system, supplies small number of people, same portion of every year, not home system (school, work, etc) 3) Transient Non-Community - public system, does not supply same people all year (rest-stop, gas station, etc) |
|
|
Where deficiencies in water systems originate |
1) Distribution system problems (pipe break) 2) Improper groundwater treatment 3) Untreated groundwater 4) Plumbing problems (household level) 5) Other 6) Improperly treated surface water 7) Untreated surface water |
|
|
Microorganisms responsible for outbreaks |
1) Bacteria (Salmonella, E-coli, Legionella) 2) Viruses (Norovirus, Hep-A) 3) Parasites (Cryptosporidium [97%], Giardia) 4) Chemicals (Lead, Nitrate, Copper, Cleaning solvents) |
|
|
6 Classes of contaminants EPA regulates |
1) Inorganic chemicals 2) Organic chemicals 3) Microorganisms 4) Radionucleides 5) Disinfectants 6) DBP's |
|
|
Characteristics of groundwater |
1) Typically uncontaminated 2) May contain aesthetically/economically undesirable pollution 3) Susceptible to new and old surface spills 4) Water quality effected by well depth |
|
|
Characteristics of surface water |
1) More prone to heavy pollution 2) Impacted by runoff and spills 3) Forms are rivers, lakes, oceans, reservoirs |
|
|
3 Properties of a coagulant |
1) Trivalent in charge 2) Non-toxic 3) Easy to remove |
|
|
2 Factors that make colloids stable / hard to remove |
1) Most surfaces are negatively charged 2) Subject to Brownian Motion |
|
|
Definition of water hardness |
Characterization of water resulting from presence of polyvalent cations |
|
|
5 Reactions in softening process |
1) Add lime = CO2 (destroys H2CO3 buffer) 2) Add lime = HCO3 (raise pH) 3) Add lime = Mg to be removed (raise pH) 4) Add lime = required excess (drives reaction speed) 5) Add soda ash = NCH to be removed |
|
|
Definition of velocity gradient with respect to mixing |
The velocity gradient in mixing is the process by which different streams / bodies of water with different velocities are introduced to each other to achieve mixing |
|
|
Parameters that affect mixing efficiency |
1) Tank geometry 2) Tank mixing vs. in-line mixing 3) Contact time 4) Equipment constraints 5) Impeller type |
|
|
Purpose of sedimentation process |
To allow any suspended particles in the water to settle out due to gravity, resulting in cleaner water. Sedimentation must happen in a reasonable amount of time |
|
|
Purpose of coagulation |
Chemicals / compounds are added to the water to neutralize the surface charges, which will allow the particles to come together |
|
|
Purpose of flocculation |
Flocculation is a slow mixing, which promotes the particles to come together, making it easier for them to settle out due to gravity |
|
|
Type 1 settling |
1) Known as discrete settling 2) Particles settle out by themselves 3) Settle at a constant velocity |
|
|
Type 2 settling |
1) Known as flocculant settling 2) Size of particles is constantly changing 3) Velocity increases due to floc size |
|
|
Type 3 settling |
1) Known as hindered settling 2) Particles at the bottom interfere with other particles trying to settle 3) Happens at concentrations >1000mg/L |
|
|
Purpose of filtration in water treatment plant |
1) Remove excess particles to desired levels 2) Separate suspended/colloidal solids in water by passing through a porous medium |
|
|
2 Ways filters are classified |
1) Media type (sand, coal, dual-media) 2) Loading rates (slow sand, rapid sand, high-rate sand) |
|
|
6 Qualities a disinfectant must posses |
1) Capable of destroying organisms of interest 2) Capable of handling expected ambient conditions 3) Non-toxic to humans/animals, also not unpalatable / objectionable 4) Cost-efficient and safe 5) Easy to determine its concentration in water 6) Must provide residual disinfection |
