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Air and we’ll move into water.
Again, any questions about air pollution,
criteria pollutants, where we’re going to go?
Okay. The primary water pollutants that we’re most concerned about are pathogens,
being a bacteria and viruses.
Nonhazardous organic compounds,
just organics that we generate through on a day-to-day household use
that are discharged to surface waters.
Hazardous compounds, which can be toxic and otherwise,
and acidity, salt, and heat.
This is an example of a pathogen problem.
This is cryptosporidium.
It’s basically a protozoan parasite that likes to find a home in cattle.
And I’m a Wisconsin boy as you know and in the city of Milwaukee,
they went through a cryptosporidium outbreak in '93
that killed 100 people and infected over 400,000.
Wisconsin is the dairy state.
Cattle generating manure were the ultimate source of this cryptosporidium runoff
from these agricultural fields to surface waters,
made their way to the city of Milwaukee water treatment plant.
The plant was not designed to treat cryptosporidium.
So this, they didn’t have the disinfection capabilities
to handle cryptosporidium and so that passed through the water treatment system
and wound up infecting about 100,000 people.
You know in the old days, you know bacteria and viruses
were the things we really worried about.
But now we’ve got other chemicals to deal with
that can make their way into our water supply.
In surface water, again bacteria, things like the cryptosporidium issue
that we just talked about and nutrients can be discharged
and make their way into our water supplies.
Does anybody know where Ann Arbor’s water comes from?
You open the tap, where did it come from?
I heard somebody say the Huron River. Correct.
About two-thirds of your water comes from the Huron.
About a third of it comes from ground water.
What happens when you flush the toilet?
Where does that water go?
Do we know? Does anybody know?
Flush the toilet. Where does your water go?
The environmental engineers in this class have to know.
Well, the city has a water, wastewater treatment plant
and it discharges to the Huron River.
So our source water that we then discharge as wastewater,
we clean up, and it becomes somebody else’s drinking water down the road.
So surface water is a potential source of nutrient pollution
and bacterial pollution because of the way we use water.
Most of the population of the United States gets its drinking water
from surface water, whether it’s a river, a lake,
or one of the Great Lakes, or some stream.
Now ground water is another important water source primarily
for people that live outside of urban areas.
Our ground water can be impacted by petroleum hydrocarbons,
often the result of leaking underground storage tanks.
So this map shows the blue dots are all the potential underground
storage tank locations and frankly you could probably
just paint all of that dark blue,
because every single gas station out there has an underground storage tank
and you know those were all basically upgraded in the late '90s, most of them leak.
Most of them you know release gasoline and its constituents to ground water.
Nitrates are another issue.
Nutrients from fertilizer use can lead to nitrate concentrations,
greater than 10 milligrams per liter
and you’ve got a potential for blue baby syndrome.
So, you have to make sure we keep fertilizer usage out of our water supplies.
All right, any questions about where our water comes from?
Well again, we’ll get into this in a little more detail,
but as an engineer you now know that we you open your tap,
your water comes from the Huron River and ground water,
and when you send it down the toilet it winds up
to be somebody else’s drinking water downstream.
All right, let’s talk about the potential pollutants that we have to deal with.
We talked a little bit about wastewater treatment.
When we send organic wastes down the toilet,
it basically goes to a wastewater treatment plant
where it’s essentially converted to bacteria or slug,
which are then managed further, but we discharge water that has,
that is typically very low concentrations of organic in nitrogen and phosphorous.
The issue with that is that if we send high organic wastewater into our surface waters,
we can certainly lead to, it can lead to growth of algae,
which eventually die off and knock out that, that surface water.
Okay. Nutrients again I just mentioned that.
Nitrogen and phosphorous are things we have to keep out of our water supplies.
Typically phosphorous is the rate limiting growth substrate for algae.
I think, I’m sure all of you are too young,
but back in the day phosphorous was taken out of laundry detergents
because of this problem of, of algal blooms downstream,
because most of the wastewater treatment plants couldn’t handle
the phosphorous that was being discharged.
If we have algal blooms and the algae die off
and we wind up depleting oxygen from that surface water,
we can of course have fish kills and so on,
but it leads to the term eutrophication,
which is essentially a surface water body that’s,
that’s got too many nutrients in it.
Okay. The, now the, the discharge of organic wastes
and nutrients are really all regulated by the Clean Water Act.
And so wastewater treatment plants like Ann Arbor
have very strict limits on what they can discharge
in terms of organics, total suspended solids, and phosphorous.
Here are just some pretty pictures of algae.
You can have blooms of algae in a surface water
that can come in all sorts of nice colors.
But the bottom line and this can even happen here in Ford Lake locally,
again you get these algal blooms, the algae die off,
they essentially, the bacterial actions degrading the algae
will suck up all the oxygen leaving nothing for fish and so on.
Okay, we’ll talk now about hazardous chemicals, both organic and inorganic.
The types of organic chemicals that we have to deal with
are often volatile organic compounds that come from industrial sources.
Some of the more typical ground water contaminants are chlorinated solvents.
Things like perc or tetrachloroethylene, or trichloroethylene.
Those are very common degreasing solvents
that used to be used by all sorts of industries.
The problem with these chlorinated solvents is that
they’re very persistent in the environment.
They’re pretty tough to degrade and so these plumes like in that Welbourne site,
you can have plumes of chlorinated solvents that can go on for miles.
Now that’s not going to be the case typically for petroleum for the,
the primary constituents of petroleum, benzene, toluene, ethylbenzene, and xylene.
Those compounds, I mean they came from the ground.
They, they’re organic and bacteria have adapted pretty well
to degrading petroleum constituents.
So you won’t see mile long plumes of kind of those basic constituents of gasoline.
What you will perhaps see are long plumes of MTBE.
That’s a gasoline additive that was used to increase the octane of gasoline.
MTBE does not degrade very easily. It’s fairly recalcitrant.
So MTBE is very miscible in water.
It will move with ground water flow and MTBE plumes can be quite long,
because there just aren’t good natural processes to deal with those.
Pesticides, herbicides, are another issue of course in Great Lake states,
especially in the Great Plains where we have high volume industrial agriculture.
Compounds like atrazine can be found in ground water some distances from their source.
Okay. Metals are another class of compounds that we have to be concerned about.
Mercury is an interesting one because again
it’s a constituent of power plant emissions.
Mercury deposited in Michigan from power plants in Chicago are,
are a true problem because we’ve got background levels of mercury
that we had nothing to do with, but they found their way to our state.
Arsenic is naturally occurring.
The arsenic cleanup standard is 10 ppb,
but arsenic can also wind up in our ground water
due to other industrial practices.
So anybody here from kind of the western part of the state?
What’s one of the, one of the major agricultural activities
in the western part of the state?
Soy and corn and fruit.
Fruit, fruit of course lot of blueberries, cherries, apples, peaches, and so on.
Well, when fruit processors get fruit ready for, for packaging and canning,
they generate wastewater that has high amounts of organic in it.
And the way that most of these fruit processors used to deal with it
is they’d send their wastewater to a lagoon, they’d aerate it,
have some bacterial degradation of those organics and
essentially run that wastewater through ground water infiltration basins.
Well what would happen is that that organic wouldn’t be completely degraded.
It would wind up in ground water where it would be
degraded by the, by the soil bacteria.
This would lead to anaerobic conditions and when some of these metals go
from an oxidized state to reduced state they mobilize and
so you can have plumes of arsenic and manganese and so on
that migrate again quite a ways down gradient from those sources of contamination.
So again, that fruit processor didn’t discharge arsenic,
didn’t discharge manganese, but they created conditions in the subsurface
that led to the migration of those compounds.
Radionuclides not a huge issue in Michigan
unless you’re in the oil and gas business and
you’re pulling out brines in 10,000 feet below the ground’s surface.
But again it’s, it’s an issue that can make its way into water
but, but not, not too easily.
I’m just going to briefly touch upon toxicity.
This graph doesn’t mean a lot to you now, but it will after Tuesday.
But this is a very typical dose response curve
that measures the given dose of a chemical versus the mortality
and so LD50 is a very common parameter
that we use to identify the dose responsible for 50% mortality with a given chemical.
Again, toxicity and risk assessment is going to drive what we do as engineers.
A couple of more higher profile examples of water pollution
the Exxon Valdez spill was, was quite awhile ago,
but again we had our spill, the BP spill in the Gulf that you know is,
is under investigation and a source of a lot of fines and lawsuits and so on.
But industrial pollution, you know discharges from manufacturing and,
and even from fruit processors and so on is really controlled now
by the NPDES permit program.
NPDES stands for National Pollutant Discharge Elimination System.
It’s a program it’s essentially an EPA program that’s delegated to the states.
But any, I can’t just stick a pipe into a river and discharge whatever I want to.
I have to get a permit.
And this is typically under this NPDES permit program
where I have to tell the state of Michigan I’m going to discharge
such and such a concentration of oils, fats, or grease, or metals,
and the state will look at that discharge and look at other discharges
into that receiving water and identify whether,
you know what kind of limits are going to be set up for that discharge.
Non point sources of pollution can be quite significant.
I talked a little bit about atrazine,
but other you know herbicides and pesticides that are applied in,
in large areas can lead to contamination of surface water and ground water.
We don’t spray DDT anymore,
but that’s a bit of a classic photo of spraying of a pesticide,
but you know we’ve got again a lot of legislation
that drives how those chemicals can be applied.
Hazardous wastes are a whole other category amongst themselves.
I mean we, you know someone will say well take me to a hazardous.