ISAT 321 Exam 2

Where does weather come from?

-the rotation of the earth creates large-scale prevailing winds

-tilt provides seasons

Coriolis effect

-prevailing winds

-curves to the right in northern hemisphere

-curves to the left in southern hemisphere

Hadley Cells

Dry adiabatic lapse rate

-how long it takes a dry parcel of air to rise (-10 degrees Celsius per km)

-used as a standard for measuring atmospheric conditions

Stable conditions

-air unable to mix

-line to the right of the dry adiabatic lapse rate

unstable conditions

-air is able to mix

-line to the left of the dry adiabatic lapse rate

lofting plume

stack is above inversion layer

coning plume

-neutral atmosphere

-line is on the dry adiabatic lapse rate

looping plume

-unstable conditions

-air moving up and down

fanning plume

-stable conditions

-vertical movement is limited, so plume goes horizontal

fumigation plume

-stack is below inversion layer

-most dangerous

inversion

ambient temperature increases with elevation

radiation inversion

nocturnal cooling of earth's surface of clear winter nights; ground cools more quickly than air

subsidence inversion

-sustained high pressure systems

-descending air warms more than air below it

Gaussian Dispersion Model: C

ground level concentration at some point

Gaussian Dispersion Model: Q

source strength

Gaussian Dispersion Model: sigma y and sigma z

standard deviation of the dispersion

Gaussian Dispersion Model: u

wind speed at the elevation of the centerline of the plume

Gaussian Dispersion Model: y

distance horizontally

Gaussian Dispersion Model: H

effective stack height

Why is indoor air quality important?

we spend a lot of our time inside, so we are exposed much more to indoor air pollutants

emissions

where the pollutants come from

exposures

how we are exposed to these pollutants

pollutants that are less concern indoors

-SOx

-NOx

-O3

pollutants that are equal concern indoor and outdoor

-CO

-PM

pollutants that are greater concern indoors

-Radon

-asbestos

-hazardous air pollutants (HAPs) and VOCs

-biogenic contaminants

Radon entry

Enters homes through foundation cracks and groundwater.

radon

naturally occurring radioactive noble gas

why is radon a concern?

It breaks down into lead over time and can cause lung cancer

how to mitigate radon?

add tubes and fans to your house to blow the basement air/radon directly outdoors

Asbestos Health Effects

-inhalation can cause: mesothelioma and asbestosis

Asbestos Abatement

-ban and phase-out (now overturned)

-leave in place and encase to prevent it from becoming airborne

-removal if airborne

Hazardous Air Pollutants (HAPS)

-known to cause cancer or other serious health impacts

Volatile organic compounds (VOCs)

-common air contaminants, and many synthetic materials inside buildings emit them

HAP and VOC sources

-paints, carpets, electronics, fabrics, composite wood

-cleaners, air fresheners, cosmetics

-smoking, cooking, wood stoves, dry cleaning

Managing Indoor VOCs

-source control: product selection, product testing and labeling, allow for degassing, eliminate source activities

-ventilation: natural ventilation, mechanical HVAC, exhaust venting

Ozone air purifiers: "junk science"

-generates ozone to "purify air"

-oxidize and reduce many odor causing organics, but pushes ozone into your space

why are freshwater resources scarce?

not a lot of usable water on earth, despite the fact that there is so much (only about 2.5%)

domestic water usage

-partially consumptive

-public supply

-private wells

agricultural water usage

-consumptive

-irrigation

-livestock

industrial water usage

-mostly non-consumptive

-mostly for cooling

in-stream water usage

-non-consumptive

-hydroelectric power

-recreation

-navigation

which usage is dominant?

agricultural, then industrial

What is the first step in drinking water treatment?

Preliminary treatment: screens, primary settling

What is the purpose of coagulation in drinking water treatment?

Neutralizing particle charges: alum

What is flocculation in the context of drinking water treatment?

Sticking particles together so they can settle

What does softening refer to in drinking water treatment?

Removing hardness to reduce scale formation

What is the process of sedimentation in drinking water treatment?

Removing flocculated particles

What is the purpose of filtration in drinking water treatment?

Removing smaller particles

What is disinfection in drinking water treatment?

Killing harmful microbes

What is fluoridation in drinking water treatment?

Adding beneficial chemicals

chlorination byproducts

-trihalomethanes

-toxic

-reduced by reducing the chlorination levels

what effects water runoff?

-rainfall and intensity

-drainage area

-soils

-land use

-topography

-antecedent soil moisture

what is the impact of land use on runoff?

effects how much water can infiltrate. for example, in cities there is a lot of runoff due to impervious surfaces

estimating pollutant loads

-L = A + C

-L: load in mass of pollutant

-A: area for a given land use

-C: export coefficient for each land use type

JMU BMPs

-detention and retention ponds

-underground detention

-bioretention filter (rain gardens)

-sand filter

-green roof

-tree in a box

-oil/water separator

-storm filter treatment system

-hydrodynamic separator

stormwater regulation and control

-not really regulated unless you are an industry

-use BMPs for control

Why do we need wastewater treatment?

-to protect human health from pathogens in the waste

-to protect the environment from ecological effects of various pollutants like pathogens, solids, nutrients, and more

Septic system

A relatively small and simple sewage treatment system, made up of a septic tank and a leach field, often used for homes in rural areas

primary wastewater treatment

-screens and grit chambers: remove debris and very large particles

-primary clarifier: remove suspended particles

bioreactor (wastewater)

biologically degrade waste using microbes

return activated sludge

recycling a portion of sludge keeps beneficial microbes in the bioreactor

trickling filter (wastewater)

-microbes grown on fixed media

-waste is allowed to trickle through media

rotating biological contactor

microbes grown on media that is rotated in and out of the water

final clarifier (wastewater)

settle microbes produced in biological reactor

disinfection (chlorine) (wastewater)

-kill remaining microbes

-contact time and residual chlorine concentration are critical

-dichlorination required

nitrogen cycle

-Ammonification: organic N -> ammonia

-Nitrification (aerobic): ammonia -> nitrite -> nitrate

-denitrification (anaerobic): nitrate -> gaseous nitrogen

phosphorous removal (wastewater)

incorporation into sludge