week 3 - organic contam Flashcards
what are straight chain compounds
carbon compounds connected in a straight line
what are examples of straight chains
solvents, petro, kerosene, diesel, oil/waves, greases and asphat
what straight chain class is c5-c7
solvents, thinners, mineral spirits, alcohols
what straight chain class is c6-c9
petrol
what straight chain class is c10-c18
kerosene
what straight chain class is c12-c18
diesel
what straight chain class is c15-c20
oils/waxes
what straight chain class is >c20
waxes, greases and asphalt
characteristics of heavier molecules
higher boiling points, viscosity and solubilities
what is miscible
can be mixed with water
is a NAPL (non aqueous phase liquid) immiscible or not
they are immisiclbe because they are dense (DNAPL) and sink in ground water or light (LNAPL) and floats on top such as diesel
What is BTEX
benzene, toluene, ethylbenzene and xylene - aromatics in petrol products and are water soluble
what travels further in an underground fuel leak
dissolved phase (water soluble aromatics such as BTEX)
why does petrol have a strong smell
due to the fast evaporation of aromatics
what are the remediation objectives
what contaminants, management strategies (treating source, treating pathway and remove receptor), site specific local requirements and financial input
what is monitoed natural attenuation (MNA)
leave it alone and monitor it, let organisms handle the pollutants.
what is air sparging
pumping air into aquifer with vapour extraction so volatiles can be removed
what is soil vapor extraction
removal of contaminated groundwater or NAPL by vapours.
this can be done with a combination of slurping and bioventing (using microorganism)
what is chemical oxidation (ISCO)
adding oxidising chemical can either break down molecule into harmless molecules or compounds can be converted to less toxic.
oxiding chemicals are sent down a well and spaced very few metres. they are usually very hazardous and require 3.1 g O2/g BTEX. this can be followed by bioventing.
what is permeable reactive barriers
retard while degradation occurs or they can attenuate
what is an ex situ method of treating contam that is quick
excavating and landfill
what is biotreatment ex situ
hydrocarbin degradation in oxygenated treatment systems by land farming. this happens by manipulating the nutrients, water, temperature etc.
digging into the ground to promote degradation by biotic and abiotic factors
what are biopiles
artificially oxygentated, vaccum extracted heap and the VOCs are filtered out
what is ex situ thermal treatment
HC desorb from soil at higher temps and can degrade which turn into CO2 and water, however its expensive but commonly used in explosives and PCBs
what do you need for groundwater monitoring
where the wells should be (downgradient or upgradient)
what do you measure, when
compliance point, targent concentration and sentinel wells
what are in situ remediation for contaminated soil
biodegradation
air sparing
soil vapour extraction
in situ chemical oxidation
PRB
what are ex situ remediation for contaminated soil
dig and haul
biotreat
thermal treatment
soil washing
chemical stabilisation/immobilisation
what are ex situ remediation for contaminated water
pump the NAPL (works best for light produces or recently released)
pump and treat (breaking pathway and treating groundwater - plume method_
what are some PRB reactive media
GAC and ZVI (reductive dissolution)
what method is commonly applied to PAH (polycyclic aromatic hydrocarbons)
soil washing - agitation and cleaning of contaminated soil. larger grain sizes are easier to wash.
describe a treatment for contaminated soil ex situ
- water + contaminated soil goes into a trommel
- gets mixed together and then put into a hydrocyclone (coarse soil) or clarifier (fine soil)
- gets filtered once more then its clean
water gets treated elsewhere
what are some issues with pump and treat of NAPL
residual NAPL will remain after treatment. need to consider a treatment train of the contaminated water.
what sort of treatment for contaminated water is good for pump and treat
air stripping/bio venting or filtering through GAC. if there are inorganics present,
