Term
| What is yield equal to in bacterial growth? |
|
Definition
mass bacteria generated/mass food consumed
=fs/1.42 |
|
|
Term
| What two items does the available energy to bacteria go towards? |
|
Definition
| Energy for maintenance/upkeep and energy available for new cell growth |
|
|
Term
| What is the equation for calculating the energy used for new cell growth? |
|
Definition
dGs = dGp/K^m + dGc + dGN/K
dGs = energy for cell growth
dGp = energy of converting C-source to pyruvate
dGc = energy to convert pyruvate to cells (+31.4 kJ/(mg-e-)
dGn = energy to convert N-source to NH4+
K = efficiency (typically ~60%)
m = +1 if dGp>0, -1 if dGp<0 |
|
|
Term
| What is the equation used to determine the fractions of energy used for upkeep and for synthesis? |
|
Definition
K*dGR (fe/fs) = -dGs
dGR = energy of combination for e-donor to e-acceptor
fe = fraction of energy for upkeep
fs = fraction of energy for synthesis/growth
fe + fs = 1 |
|
|
Term
| What is the constant for g COD cell/g VSS? |
|
Definition
|
|
Term
| What does an anaerobic digester do to organic carbons? |
|
Definition
| convert them to CO2 and CH4 |
|
|
Term
| About how much of digester gas is methane? |
|
Definition
|
|
Term
| About how much of natural gas is methane? |
|
Definition
|
|
Term
| What is the sequence of biological processes in an anaerobic digester? |
|
Definition
| hydrolysis -> acetogenesis -> methanogenesis |
|
|
Term
| What happens in the hydrolysis phase of anaerobic digestion? |
|
Definition
| Large organic molecules -> lipids & proteins & carbs -> fatty acids & amino acids |
|
|
Term
| What kind of organisms perform hydrolysis? |
|
Definition
|
|
Term
| What kind of organisms perform acetogenesis? |
|
Definition
|
|
Term
| What happens in the acetogenesis phase of anaerobic digestion? |
|
Definition
| fatty acids & amino acids -> acetic acid & H2 |
|
|
Term
| What happens during the methanogenesis part of anaerobic digestion? |
|
Definition
CO2 + H2 -> CH4 (H2 is e-donor)
CH3COOH -> CH4 + H2O |
|
|
Term
| What kind of organisms perform methanogenesis? |
|
Definition
|
|
Term
| What conditions do methanogens prefer? |
|
Definition
| pH 6.6-7.6, yet their processes lower the pH, thus they need a lot of alkalinity. Strict anaerobes. slow growing with low yield. |
|
|
Term
| What temperature is mesophilic? |
|
Definition
|
|
Term
| What temperature range is thermophilic? |
|
Definition
|
|
Term
| How does temperature affect growth rate? |
|
Definition
| As temperature increases, growth rate increases |
|
|
Term
| What is SRT equivalent to in anaerobic digesters? |
|
Definition
|
|
Term
| What does a fatty acid look like? |
|
Definition
| Carbon chain with =O and -OH on the end |
|
|
Term
| What is acetate's formula? |
|
Definition
|
|
Term
|
Definition
| rate of evacuating cells from a system (with Q) is greater than their rate of growth. => end up with little to no biomass. |
|
|
Term
| What are the characteristics of Class A biosolids? |
|
Definition
coliform < 1000 MPN/g
prepared by a PTRP (process to further reduce pathogens) which consists of composting, incineration, thermophilic digestion. Stabalization processes -> reduce pathogen levels |
|
|
Term
| Can class A biosolids be sold to the public? |
|
Definition
|
|
Term
| What are the characteristics of class B biosolids? |
|
Definition
coliform < 2,000,000 MPN/g
PSRP (process to significantly reduce pathogens)
Anaerobic digestion, lime stabilization, air drying
Use has site restrictions |
|
|
Term
| What lad applications are biosolids used for? |
|
Definition
|
|
Term
| What restrictions and concerns arise with the land application of biosolids? |
|
Definition
Restrictions: setbacks, depth-to-groundwater
Concerns: Heavy metals |
|
|
Term
|
Definition
| A suspended growth secondary treatment process. Open basin often with an earthen liner (clay), no clarifier |
|
|
Term
| What is the permeability of a lagoon liner? |
|
Definition
|
|
Term
| If the lagoon depth is less than 2m, what is the typical width of the clay liner? |
|
Definition
|
|
Term
| What is the H:W ratio in lagoons? |
|
Definition
|
|
Term
| ***What kind of liner do lagoons have? |
|
Definition
| PVC or HDPE liner, UV stabilized, <2x10^-10 m/s, if lagoon <2m deep, liner ~1mm thick |
|
|
Term
| Which speciation is more toxic, CrVI or CrIII? |
|
Definition
|
|
Term
| Which speciation is more soluble, CrVI or CrIII? |
|
Definition
|
|
Term
| What are some advantages of lagoons? |
|
Definition
| Energy efficient, low cost, low operations and management requirement, low skill requirement for operators, can handle shockloads |
|
|
Term
| What are some disadvantages of lagoons? |
|
Definition
| large surface area requirement, smells, must dredge periodically, can leak, little control over performance |
|
|
Term
| What factors influence Q in a lagoon? |
|
Definition
| evaporation, precipitation, WW flowrate |
|
|
Term
| When do you dredge a lagoon? |
|
Definition
| When it's filled with solids at 1/3 depth. Sludge judge! |
|
|
Term
| When is there no discharge from a lagoon? |
|
Definition
| When Qin (flow+precipitation) = evaporation |
|
|
Term
| What is required for a lagoon to discharge into a river or a lake? |
|
Definition
|
|
Term
| Is an NPDES permit required for a wetland or infiltration pond? |
|
Definition
|
|
Term
| How is oxygen supplied in an aerobic lagoon? |
|
Definition
| photosynthesis and henry's law (diffusion). May also use mechanical aerators such as surface aerators and coarse/fine bubble diffusers |
|
|
Term
| About how deep is an aerobic lagoon? |
|
Definition
|
|
Term
| What is the BOD loading for an aerobic lagoon? |
|
Definition
|
|
Term
| How deep are facultative lagoons? |
|
Definition
|
|
Term
| What is the required DO level in an aerobic lagoon? |
|
Definition
|
|
Term
| What is a facultative lagoon? |
|
Definition
| Has aerobic and anaerobic sections |
|
|
Term
| What is the cycle that occurs in the aerobic portion of facultative lagoons? |
|
Definition
| Algae -> (New cells) and O2 -> (+organic waste=) bacteria -> (new cells) and CO2 -> algae |
|
|
Term
| What is the reaction that occurs in the anaerobic section of a facultative lagoon? (like in a digester) |
|
Definition
| Organic waste -> organic acids and alcohols -> CO2 + NH3 + H2S + CH4 (offgas into atmosphere) |
|
|
Term
| What is the typical BOD loading for facultative lagoons? |
|
Definition
|
|
Term
|
Definition
| What does not pass through the membrane |
|
|
Term
|
Definition
| What passes through the membrane |
|
|
Term
| What is the pore size range for microfiltration (MF)? |
|
Definition
|
|
Term
| What does microfiltration remove? |
|
Definition
| turbidity, TSS, protozoa, some bacteria |
|
|
Term
| What is the flux of a MF membrane? |
|
Definition
|
|
Term
| What is the pore size range for ultrafiltration (UF)? |
|
Definition
|
|
Term
| What is the flux of an UF membrane? |
|
Definition
|
|
Term
| What does ultrafiltration remove? |
|
Definition
| large molecules, most bacteria, some viruses |
|
|
Term
| What is the pore size range for nanofiltration (NF)? |
|
Definition
|
|
Term
| What does nanofiltration remove? |
|
Definition
| small molecules, hardness, viruses |
|
|
Term
| What is the flux of a NF membrane? |
|
Definition
|
|
Term
| What is the pore size range for reverse osmosis (RO)? |
|
Definition
|
|
Term
|
Definition
| very small molecules, ions |
|
|
Term
| Do membranes degrade pollutants? |
|
Definition
| No - they only concentrate the pollutants |
|
|
Term
| What is Qf and what does it equal? |
|
Definition
Qf = Qp + Qc
Qf is the dirty water entering the membrane system |
|
|
Term
| What makes water pass through a membrane? |
|
Definition
| Pressure exerted or vacuum created on one side to encourage flow |
|
|
Term
|
Definition
Transmembrane Pressure.
TMP = ((Pf + Pc)/2) - Pp |
|
|
Term
| What does a rising TMP indicate? |
|
Definition
| membrane fouling. May need backwash |
|
|
Term
| What is the water recovery equal to? |
|
Definition
|
|
Term
| What is the pollution rejection rate equal to? |
|
Definition
| R = (Cf-Cp)/Cf = 1- Cp/Cf |
|
|
Term
| What is the membrane flux equal to? |
|
Definition
|
|
Term
| What is membrane fouling and why is it bad? |
|
Definition
| When pores clog. Membranes can rip or detach from housing or support material. |
|
|
Term
| How do you solve membrane fouling? |
|
Definition
| Clean the membrane, often via backwashing |
|
|
Term
| How do you select your membrane option? |
|
Definition
| Determine feed water type and match with appropriate membrane. Use the SDI. |
|
|
Term
|
Definition
| Silt density index. A filtration test where you pass 500 mL of raw water through a 0.45 um pore size filter with 47mm diameter at 210 kPa. Repeat test multiple times using the same filter. |
|
|
Term
| What is the equation for SDI? |
|
Definition
SDI = 100[1-ti/ts]/ttot
ti = time for initial 500mL
tf = time for final 500mL
ttot = sum of all times |
|
|
Term
| What is the SDI range for NF? |
|
Definition
|
|
Term
| What is the SDI range for RO with a hollow fiber? |
|
Definition
|
|
Term
| What is the SDI range for RO with a spiral wound? |
|
Definition
|
|
Term
| How much height do you add to an ion exchange unit? |
|
Definition
| 1m for inlet, 0.5m for resin support, 1xheight for fluidization |
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