441 Midterm 1

A successful engineer needs to realize the importance of life-long learning and continuously update knowledge and job skills

To express contaminant concentrations in water, 1 ppm is equivalent to 1,000 mg/l

Removing carbon dioxide (CO2) in water will increase the pH of the water

Adding salts to a water sample will raise its boiling point

Coliform is commonly used as an indicator microorganism with regards to water quality

Our drinking water needs to be both potable and palatable

Saturated dissolved oxygen (DOsat) concentration in water open to air is ~30 mg/L @ 20 degrees celsius

The sulfate buffer system controls the pHs of our ambient rivers and lakes

The concentration inside a plug flow rector (PFR) is the same as the reactor effluent

Batch reactors are operated under unsteady state

Na2CO3 is the chemical formula for soda ash

Chloride ion (Cl-) is considered as part of the hardness in water

Coagulants are added to the coagulation process to destabilize the colloidal particles

Colloidal particles in our ambient water typically carry positive charges

For a coagulation/flocculation process, the velocity gradient of coagulation is larger than that of flocculation

For three reactors in parallel, the entire flow goes through all the three reactors

In a lime-soda softening process, carbonate hardness is harder to remove than non-carbonate hardness

In a lime-soda softening process, magnesium ions are harder to remove than calcium ions

In zone/hindered settling, particles will accelerate downward until reached a terminal velocity

The hydraulic loading rate can be used to determine the top surface area of a sedimentation tank

According to Schultz-Hardy rule, Al+3 is a more effective coagulant than Na+

For coagulation/flocculation, the velocity gradient of flocculation > that of coagulation

For coagulation/flocculation, typical hydraulic detention time for coagulation is about 20 minutes

In discrete particle settling, a particle will accelerate downward until reached its terminal velocity

Saturated dissolved oxygen (DOsat) concentration in water open to air is ~150 mg/L @ 20 degrees celsius

To express contaminant concentrations in water, 1ppm is equivalent to 1.0 g/L

Na2CO3 is the chemical formula for hydrated lime

Compared to CFSTRs, PFRs are a better type of reactors for chlorine contact tanks

The hydraulic loading rate is often used to determine the water depth of the process tank

____ tests are often used in bench-scale studies to determine optimal coagulant and dosage

According to Stokes Law, the terminal velocity of a 30μ particle would be ___ times faster than that of a 10μ particle

Alkalinity of water is its capacity to neutralize

BOD5 values represents the amount of biodegradable ___ in water samples

For water balance, precipitation = infiltration + evapotranspiration + storage + ____

For water quality, conductivity is an on-line indicator of ___ solid concentrations

Give a commonly-used unit for power: ____

Hydraulic detention of a process tank = ____ / Influent flow rate

MCL = Maximum ____ Level

pH + pOH = ___ at 20 degrees celsius

SDWA = ____ Drinking Water Act (Note: it is a federal regulation for drinking water)

The oxidation state of sulfur in sulfate (SO4-) equals to

TSS = FSS + ____

Two sources of water for drinking water supply: surface water and ____

Weight density of water = 9.81 kN/m^3 = ____ lb/ft^3 at 4 degrees celcius

A water treatment plant contains filtration, flocculation, coagulation, and sedimentation (put thesefour unit processes/operation in a right order)

Groundwater and surface water are two main sources for potable water supply.

More constant water composition - groundwater or surface water?

Higher dissolved oxygen concentration - groundwater or surface water?

Higher pathogen concentration - groundwater or surface water?

TDS = VDS +

For water quality, turbidity is an on-line indicator of ___ solid concentrations

The oxidation state of carbon in carbonate ions (CO3= ) equals to ___

After lime and soda softening, the magnesium concentration in water should be kept below ___ mg/L to prevent formation of hard scale.

According to Stokes Law, the terminal velocity of a 10-μ particle would be ___ times faster than that of a 2-μ particle of the same type

VSS+FSS=

TDS+TSS=