enviromental engineering exam 2!!!

reservior

defined location and/or form of an element

flux

mass movement in/out of reservior over time (at steady state if min=mout)

two common oxidized forms of carbon

CO2, CO

two reduced forms of carbon

CH4, C6H12O6

oxidizing C atoms releasing useable energy?

aerobic environment (burning methane)

reducing C atoms releasing useable energy?

anaerobic environments (landfills, intestines, wetlands)

reactive nitrogen (Nr)

not stable (NH3,NH4, NO3-, NO2-,N in biomolecules)

one common oxidized form of nitrogen

NO3-

one common reduced form of nitrogen

NH3

nitrogen fixation 

N2 to N in biomolecules

nitrification

NH3/NH4 to NO3-

denitrification

NO3- to N2

anthropogenic sources of excess P in water

fertilizer, wastewater, and detergents

major problem by excess P 

eutrophication 

accumulation term, dm/dt

steady state=0

reaction term, mrxn

no chemical reactions=0

m

mass (kg or g)

m dot

mass flow rate (kg/s, g/min)

Q

volume flow rate (L/min, m³/s)

V

volume (L, m³)

C

concentration (mg/L=ppm, micro/L=ppb)

p

density (g/mL, kg/m³)

k

rate constant (first order) time^-1

advantage of CMFRs over PFR

handles spikes in toxicants well, distrubutes evenly

advantage of PFR over CMFR

more efficient, less materials

limitations of ideal reactor models vs real life

imperfect mixing, non-uniform conditions, non-ideal flow

5 major reserviors in carbon cycle

atmosphere, permafrost, fossil fuel reserves, CO2 gas, biomolecules

major fluxes in carbon cycle

burning fossil fuels +cement production, photosynthesis, respiration, ocean/atmosphere gas exchange

flux increased by fertilizer production

nitrogen fixation

nitrification is more dominant in aerobic environments

bacteria need oxygen to convert  NH3 to NO3-

eutrophication

excess N and P are plant fertilizers which cause algae blooms, algae dies and sinks to botttom of lake becoming food for microrganisms, booming microbial population comsumes O2 causing lake to become anerobic, lake cant support animal life and produces smelly byproduct