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27 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Potable water |
Free from health hazard causing contaminants |
Health |
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Palatable water |
Aesthetically attractive |
Looks |
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4 things used to create standards |
Scientific knowledge, established practices, attainability, educated guess |
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Guideline vs standard |
Guideline is recommended and non enforceable whereas standard is enforcable rule regulated by authority |
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2 types of standards |
Water quality and technology based |
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Water quality vs technology based standard |
Water quality-concentration limits and mass loading limits.. looks at specific contaminants Technology-economic analysis, time, doesn't target specific contaminants |
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Assumptions for simple river model |
Only considers kind narrow rivers, min DO requirements meet life form needs |
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2 types of DO production |
Reaeration of o2 from atmosphere Production of o2 by algal photosynthesis |
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2 Do consumption examples |
Bod degradation Benthic biodegration |
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Factors that affect reaeration coefficient k2 |
Stream turbulence (big area big turbulance) Surface area(area between wind&water) Water depth Temperature(high temp high k) |
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Oxygen sag model assumptions |
-Dimensional -Wastewater is mixed with river water immediately -long narrow river -cross sectional area is uniform -uniform velocity |
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2 unit processes and 1 unit operation to treat waste water |
-Chemical -biological -physical |
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Design flow is equal to... |
Flow*reserve% (typically multiply by 1.3~1.5) |
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3 reasons to use coagulants |
-increase effective size -increase velocity -removes turbidity, ss, odour etc |
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Define coagulants |
Positively charged metal ions that attach to nucleus of particulate matter allowing them to increase in size |
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4 hydrolysis mechanisms |
-bridging -enmeshment -double layer compression -charge neutralization |
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3 stages of coagulation |
Rapid mixing, slow mixing, undisturbed settling |
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4 types of settling |
-type 1 discrete -type 2 flocculation -type 3 hindered settling -type 4 compression |
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3 Types of filters |
-slow sand -rapid sand -slow sand-rapid sand-dual media -dual media |
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4 Filtration mechanisms |
-diffusion -sedimentation -interception -straining |
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Define disinfection |
Process that inactivates pathogenic material |
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Define sterilization |
Process that completely destroys all living matter |
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Define primary disinfectant |
Those used directly for inactivation of disease causing organisms |
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Define secondary disinfectant |
Those used to suppress biological regrowth |
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5 factors affecting disinfection |
-turbidity -concentration and size of particles -light transmittance -disinfectant demand materials -pH |
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5 ways to remove organics before chlorination |
-source water protection -enhanced coagulation and softening -activated carbon absorption -chloramines -use multiple disinfectants |
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Factors affecting UV disinfection |
-uv dose -non-ideal flow pattern -water quality(turbidity, transmittance) |
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