Wastewater & Excreta Disposal Flashcards by Joan Ravalo

Differentiate sewage from sullage

Sewage: excreta + significant food residue + toxic chemicals

Sullage: residue fr washing, bathing, lab process, tech process

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When solid fraction is high, turbidity happens. What treatment is needed?
A.primary
B.secondary
C.tertiary

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When organic fraction is high, secondary treatment is needed. What happens here?
A.eutrophication
B.accumulation
C.oxygen depletion

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Tertiary treatment is needed when eutrophication happens. What wastewater fraction is intense here?
A.solid fraction
B.nutrients
C.toxic components
D.AOTA

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How are toxic components treated?
A.primary
B.tertiary
C.adsorption
D.disinfection

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How are non-filterable solids treated?

Coagulants are used to remove, so that neg charged ions will form flocs & become heavy

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Which is false?
A.when water is turbid, organisms are deprived of solar energy and oxygen
B.increase in water depth leads to overflowing and flooding
C.fish may experience laceration due to turbid water

B - dapat reduction

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Oxygen Sag Curve shows
A. Which part still has DO
B. How polluted water is
C. How river can purify itself
D. AOTA

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How does the river recover DO?

Re-aeration –> turbulence –> unwanted gases escape –> DO again –> equilibrium

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Organic decomposition yields \_\_ while inorganic decomposition yields \_\_
A.sulfur dioxide
B.carbon dioxide
C.methane
D.ethane
2 answers

B and C

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DifferentIate highly eutrophicated body of water @ daytime vs that at night. Explain mechanism also

Daytime - algae produce lotsa O2 - alkaline water

Nighttime - algae produce no O2 but lotsa CO2 - acidic water

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The ff may cause fish kills except
A.rapid pH change
B.salinity
C.temperature change
D.air pressure

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How can sewage lead to methemoglobinemia?

Urea –> ammonia –> nitrite –> nitrate
This process uses DO
Nitrate-contam water utilizes O2 @ blood
MetHbnemia!

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Which is used for primary treatment of wastewater?
A.activated sludge
B.trickling filter
C.septic tank
D.disinfection house

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Main process @ primary treatment before water displacement
A.aeration
B.sedimentation
C.disinfection
D.coagulation

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Which is not used for primary treatment of wastewater? (Arrange remaining ones left!)
A.activated sludge
B.screen
C.sedimentation tank
D.comminutor
E.scrapper

B
E
D
C

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Biological reactor filled with gravel coated with slime containing microorganisms ; where is this used?

Trickling filter

Veterans Hospital

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Enumerate four most common sources of wastewater

Domestic
Industrial
Storm water
Agri runoff

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Sequence the steps @ trickling filter
A.The microorganisms present in the slime-coated gravels digest the organic matter in the wastewater.
B. The perforated pipe rotates, and wastewater is uniformly distributed.
C. Water will be chlorinated and will now be discharged in a body of water
D. Underneath the reactor, perforated pipes collect the treated water.

B
A
D
C

Not part of activated sludge mechanism. Please also arrange sequentially the rest!
A. aerator
B. aeration tank
C. lift station
D. trickling fliter
E. clarifier

(D is the answer for first question; the remaining ones have the sequence C B A E)

Which is false?
A. Lift station has comminutor part.
B. Aeration tank has blower room, which provides O2 for microbes
C. The water flows immediately toward clarifier after the aerator stage.
D. Water obtained after activated sludge is used to water plants.

it stays first for 1-2 days

False about sludge drying beds
A.Sludge is compacted (to remove remaining water), dried, composted and used as soil conditioner.
B. The liquid component (leachate) is not treated anymore.
C. When the microorganisms (which remove the organic matter) in the sludge die from the processing, the sludge is brought back to the aeration tanks to supply the microorganisms with oxygen or these microorganisms are cultured separately.

further treatment is done!

enumerate 3 tertiary treatment processes for wastewater

Reverse osmosis
Distillation
Oxidation

identify which type of treatment pond: utilises solar energy, for pathogens, does not need high skill
A. waste stabilisation pond
B. maturation pond
C. facultative pond
D. anaerobic pond

``` identify which type of treatment pond: receives raw wastewater, deepest. A. waste stabilisation pond B. maturation pond C. facultative pond D. anaerobic pond ```

``` identify which type of treatment pond: water stays here for 11 days, second deepest. A. waste stabilisation pond B. maturation pond C. facultative pond D. anaerobic pond ```

``` identify which type of treatment pond: rapid entry of water, photo-oxidation, pH > 9 A. waste stabilisation pond B. maturation pond C. facultative pond D. anaerobic pond ```

``` identify which type of treatment pond: water stays here for 30 days, shallowest A. waste stabilisation pond B. maturation pond C. facultative pond D. anaerobic pond ```

False about pit latrines constructed on dry soil A.Aquifer will not be contaminated B.Situation in mountainous areas C.Normally,movement of groundwater: 1-3 m D.If the soil is rocky, movement of groundwater slows down

D | speeds up dap at

Which is false? A.Water source: constructed where there is a source of pollution from downstream = no contamination B.Water source: constructed where there is a source of pollution upstream = contamination C.BOTA D.NOTA

C | baliktad

enumerate a septic tank's two chambers, and explain what happens if a septic tank is leaking.

two chambers: digestive & leaching If septic tank is leaking (usually leaching chamber), excreta will infiltrate into soil and may contaminate aquifer, endangering those who utilize the water source

explain what happens if a septic tank is not connected to the sewers

If not connected to sewers, most water displaced from septic tanks when you flush are discharged into open canals or drains (not allowed; must have digestive chamber at leaching chamber)

False about a septic tank A. Efficient in taking out all phases of matter. B. Requires permeable subsoil and piped water C. The liquid separated still contains pathogenic organisms

A. solids lang bc solids settle at the bottom and are digested through the action of anaerobic bacteria developing naturally.

False about septic tank's vent pipe. A.regulates pressure inside the septic tank B.where compressed air is released whenever displacement (when toilet is flushed) happens C.makes toilet harder to flush D.Without it, pressure is generated inside the septic tank. too much --> waste in the house.

C | easier :)

``` vent pipe of septic tank regulates pressure c/o __ A.sulfur dioxide B.carbon dioxide C.methane D.ethane ```

Which is false? A. If water level is too high for pit latrine, usage can contaminate groundwater B. Conventional pit latrine is appropriate in areas near the seaside C. Pour-flush toilet uses low volume of water D. NOTA

B | mountains dap at

Which is false? A. Pour flush latrines promote Schistosomiasis B. Overhung latrines are common among rivers of NCR C. Pour flush latrine cannot use bulky anal cleansing, bc clogging D.Conventional pit latrine may be breeding site for insects

A - overhung latrines ito applicable

false about Ventilated Improved Pit Latrine A. Liquid portion of excreta seeps in the soil B. Solids are broken into simpler compounds by biological digestion C. Water is used only for drinking,hand washing or cleaning the floor

C | no drinking

Explain purpose of Ventilated Improved Pit Latrine's vent pipe

wind movement creates air draft gases generated inside the pit is absorbed gases passes through the vent pipe going out

state precaution of Ventilated Improved Pit Latrine's vent pipe

 Screen should be placed at the end of the vent pipes to prevent entry of mosquitoes or other vectors

Which sewer system has pipes following roads/streets? A. conventional B. settled C. simplified

A B & C - pipes laid in gardens/sidewalk

Which sewer system has intercepter tank per house & decentralised treatment? In what community is this good for? A. conventional, Metro Manila B. settled, small subdivisions C. simplified, both Metro Manila & small subdivisions

Differentiate settled sewer system from simplified sewer system

simplified - no septic tank

Which sewer system has deep excavation? A. conventional B. settled C. simplified

disadvantage of conventional sewer system, aside from cost?

may generate gases when water | stays inside the pipe especially during dry season  corrosion

enumerate 2 advantages of small bore pipes

Being smaller in size, sewers will be economical | No risk of stream pollution