PDS AP Environmental Science 8th Period 2010-11

-Solar energy has become a very popular way to provide energy or electricity for many different buildings and homes. There are two main ways to make use of solar energy:

1. Passive Solar Energy – Uses the light and heat from the sun without using and collectors or solar panels. This technology mainly deals with the building’s design and structure. (Ex : Having windows to allow sun to pass through and warm area up or having black, thick walls to capture the heat and help hold it)

2. Active Solar Energy – This technology uses things such as solar panels and grids to capture the sun’s energy. (Ex : Many houses have solar panels on their roofs to absorb the solar radiation for heat or heating water)

-Although many people want solar energy used for their homes, a lot of people do not want to go through the trouble to put the panels on their homes for their own reasons. That is when people decided that something else had to be done; they came to the conclusion of “midsized solar farms”. This is becoming so popular because it is a clean way to gain access to renewable energy.  The following is a picture of a midsized solar farm in San Francisco:

http://www.npr.org/2011/03/16/134341220/midsize-solar-installations-grow-at-light-speed

They are also doing this in places like Sacramento where people only have to pay 11 dollars a month for electricity provided from solar panels that are 30 miles away from downtown. Click here to read more on these midsized solar farms.

-This video talks about Spain’s solar energy problems and solutions that are currently taking place. Here there are hundreds of mirrors focusing on a tower of water to create great amounts of steam that produces electricity to thousands of homes. One of the problems is that when it is not sunny, there is no electricity. However, they have found a solution to this problem. They stock up on the energy for when it is dark or cloudy and the extra heat they collect is stored for the times when there is so sun out to create the steam needed for electricity. Both of these examples of solar technology usage prove that solar power has become increasingly accessible to people around the world today. Use of solar technology will continue to increase as technologies improve, prices fall, and government support increases.

On any given day, each one of goes to the bathroom at least a few times, and most likely without any thoughts of where our waste is going or what it will become. After venturing to the Mallard Creek Wastewater Treatment Facility; however, what happens when we flush, at least for me, is a much more prevalent thought. When we got to the treatment facility and stepped off of the bus, I think almost every single one of us had something to say about the smell, but little did we know that the worst was still to come. My group began our tour in the office building looking at an aerial view of the entire facility.

aerial view of Mallard Creek Wastewater Treatment Facility

As you can see, it’s pretty big and pretty spread out. It is designed this way so that each process is separate. One important feature to note that may not be apparent from the above image is that the facility is located on a long, gradual hill. Rather than pumping the water between processes, the water is pumped only one time from its initial incoming from the sewage to the top of the hill. For the remaining processes, the water flows down hill so that less energy is used and the process is more efficient in general.

The treatment process begins when we flush the toilet, and our sewage waste travels through a series of piping systems to one of Charlotte’s multiple wastewater treatment plants. As the wastewater reaches the end of the piping system, it flows into somewhat of a temporary holding tank with screen systems attached. This system is comprised of bar screens, which reach into the water and anything solid such as toilet paper, condoms, tampons, dead goldfish, etc. get trapped on the screens, which pull these objects out of the water and dispose of them in a dumpster along with any “grit” like undigested corn, gum, etc.–all of which most likely ends up in a landfill. Next, a cyclone type machine spins the still heavy water down a tube and it is moved into a system of clarifiers.

heaps of gross gunk from our sewage...toilet paper, condoms, tampons...and it smelled HORRIBLE

this machine sorted through the "grit" which consists of corn, sand, gum, etc

In each cone-shaped clarifier, the wastewater’s velocity is slowed and the solid components of the water, the “sludge,” settle to the bottom. After the clarifier allows the solids to settle to the bottom and the oils settle on top, giant rotating weirs move circularly around each clarifier, scraping the bottom where the solids have accumulated and the surface of the water, and the resulting somewhat cleaned water moves on to the next step. The removed sludge is transported to an anaerobic digester which heats and spins the wet mixture and is then dried for fertilizer for crop land or a landfill.

The heart of the facility is found in the aeration tank. The aeration process is a biological process that takes 6-8 hours as organisms are used to break down the excessive ammonia and nitrite found in the water. As a product of these aerobic organisms at work, the water in the tank is coated with a thick layer of light, brown bubbling foam. (We were all surprised to learn that this foam was not floating poop.) The aeration tank can be thought of as a “zoo of microorganisms,” and the water is oxygenated so that the aerobic microorganisms can effectively break down the bacteria and solids in the water. From the aeration tank, the water is moved on to more clarifiers and as the solid, heavy water once again settles to the bottom, it is scraped and drained out and back into the aeration tank to feed microorganisms. At this point, the water is (believe it or not) 99.9% cleaned.

This is a photo of the products of the aeration process. Note the brown foam on top.

(fun fact: As Emily and I reflected upon the horrible idea of jumping into this foamy tank, our tour guide noted that legend has it that because of  the way the tank works with suction and because SO much oxygen is produced, there is no surface tension to this water and so if you jumped it, you would immediately sink 20 feet to the bottom and basically drown in poop. We decided this would be the worst possible way to die.)

After the water moves from clarifier > aeration tank > more clarifiers, the water must be filtered one more time before it can be disinfected and released back into the environment. The water is moved from the last clarifiers to another large tank where mixers churn the water so that it does not become septic. In these tanks, traveling bridge filters use dividers with anthracite coal and sand to filter the water. The traveling bridge works by forcing the water through the sand so that the particles collect in the sand and charcoal leaving the water cleaner and without solids.

Next, the water is moved from the filtering system to the disinfection stage. Originally, chlorine was used to disinfect the water; however, the problem with the chlorine treatment was that even though it killed every single microorganism in the water, as the water was then released into the environment, the chlorine continued to kill everything in its path which proved destructive to the stream or creeks the water was released into. Recently, more and more wastewater facilities have begun to use UV rays to disinfect the water. This process works by using the damaging properties of UV rays to basically microwave the microorganisms in the water, scrambling their DNA so that they can’t reproduce. This means that when these organisms reach the environment once again they will decrease and die out in population.

The result of this entire process is a relatively clean water that is suitable and safe for the environment, but not for direct contact with people. After all steps have been completed, sewage > clarifier > aeration > more clarifiers > filters > disinfection, the water is either released into a nearby water source, in this case Mallard Creek, or it is put in some sort of a holding tank. At the facility we visited, some of the water was mixed with hyperchloride which is not safe water for humans but can be used to water golf courses, for example, for free. The remaining solid waste from this entire process is heated for about 45 days, the resulting products being a small amount of water, gases, etc. which are spun into a black material which is used for fertilizers which can’t be used to grow crops but instead are used for growing grass which farmers can turn over to increase an areas fertility, etc. We all wondered what happened when there was a big rain and all of the rainwater filled up the open clarifiers, aeration tank, etc. The facility is built to contain about 20 million gallons of water, so rain is not a problem. There is also a rain retention basin in the middle of the facility as well which can hold up to 50 million gallons of water and stores rain water and excess raw sewage.

The last part of our day consisted of testing the water in Dragonfly pond at Reedy Creek Nature Preserve for turbidity, pH, temperature, phosphate, nitrate, and dissolved oxygen/%DO saturation. (We assumed coliform bacteria to be present)

this is my group conducting our lab tests next to Dragonfly Pond.

1 of 7 tests we conducted, turbidity is measured in jackson turbidity units by chart to the right of water container.

After conducting these physical/chemical tests, we moved to the lab where we focused on bioindex which is basically how clean a body of water, such as a stream, is based on what organisms it can support. All organisms have a different toleration for pollution, an example of an animal that can live in very clean water being a mayfly or a stonefly, while the dirtiest waters are home to organisms like leeches. We used a Dichotomus Key to look at and identify several insects, the process necessary for determining the bioindex of any body of water.

this is what our indoor lab consisted of... as we worked with the Dichotomous Key, we identified bug larvae and then looked at their adult form...

Images source: Derrick Willard

Hey guys I just wanted to ask you guys what you think the free response will be/what you think is most important to study for a possible free response…obviously everything is but I mean like what sub topic would be most likely to be the free response topic…

I was thinking LD50 with maybe a graph and explaining why it is different between animals and people/ why it is complicated between different individuals? But I’m not sure..

My other question is something that Mr. Willard suggested I do for advice today at help session and I think it is a really good idea. For those of you who have done well on your exp.-design questions or you just feel like you really get it, what’s your secret? I.e. what do you do when you read the question? Do you have a certain order of steps or any insight into how to be successful on them?

Can someone please explain the difference between commensalism and mutualism? I understand mutualism for the most part, but I wrote down lichen and tree as an example of commensalism, but i’m not really sure what that means….

Today we began an introduction to ecology. Where as our previous biology courses focused on the biological makeup and functions of organisms, environmental science has a huge focus on ecology, which focuses on the relationships that exist between organisms and their physical surroundings.

We began by looking at the levels of organization of life:

Biosphere
Biome (ex. SW U.S.=temperate desert)
Ecosystem* (location)
Community (“a group of groups”)
Population
Organism (species)
Organ systems
Organ
Tissues
Cell

It is important to be wary of the counter intuitiveness of these various terms. For example, we often look at the term “community” and think of a community in which people live, i.e. community as a location. However, in this context, a community refers to the collection of several different populations (or species) of organisms as one big group—a “group of groups of organisms.”

Ecosystems* are the center of ecology. Ecosystems have 2 components: biotic and abiotic. The biotic component represents the community of organisms that exists in the ecosystem, while the abiotic component (abiotic meaning, without, no-living) represents the limiting factors on the particular ecosystem.

The limiting factors of an ecosystem are: pH, temperature, water, nutrients (especially N, P, S) and light, and they limit what can survive in the ecosystem, thus controlling the range or law of tolerance for survival. An example of this is the necessary pH of 6-8 in bodies of water needed to sustain the life of the fish that live there. If the pH is changed and, for example, drops to a pH of 3-4, the fish will die and the entire ecosystem will be affected.

The last thing that we discussed was the idea that in an ecosystem, nothing exists alone. Each organism has both a habitat, or an “address,” and a niche, which is basically their understood “occupation” or “job.”

Primary producers, or autotrophs, are at the bottom of the pyramid as they create biomass (dry mass) simply by the process of photosynthesis. The second level consists of primary consumers, or herbivores that consume the producers, which are generally plants. The next levels consist of secondary and tertiary consumers, or heterotrophs, that are carnivorous and consume the primary consumers. As far as habitat and job go, Mr. Willard’s analogy may help. You could say, “Banking is my job, and my habitat is the bank and my house.” while a rabbit could say, “Eating plants and then feeding snakes, owls, and other predatory animals is my job, and the forest and my burrow is my habitat.”

I think that the earth’s biggest problem is overuse of our non-renewable or potentially renewable resources. Because of the fact that everyone is settled into their particular lifestyle, large scale change in our impact on the earth has not yet been possible. People do not understand that the resources we use in the most abundance may not be around forever. And if these resources were to suddenly run out, what would the world do?