PDS AP Environmental Science 8th Period 2011-12

Pikachu, quick use thunderbolt!

Critical Hit!

Foe’s Blastoise fainted.

For the millions of you that have played Pokemon, it seems obvious that electricity is water’s kryptonite; they don’t mix! But in the world of modern science, nearly twenty percent of all electricity comes from hydroelectric plants (imagine that Ash!). Source: Friedland and Relyea Environmental Science for AP

To illustrate the vast potential of Hydroelectricity as an alternative energy source, check out this brief video of China’s Three Gorges Damn, the largest in the world.

Here’s a current article about the dam!

Hydroelectric power uses dammed reservoirs to direct the flow of water through a penstock and then past a turbine that generates electricity. Watch this short video to see what I’m talking about, and if you don’t have time for the video, check out the diagram.

Diagram

Hydro electricity takes “hydro” and a substantial initial investment, and not all countries have the water and resources to make hydroelectric dams. The good new is that hydroelectricity emits no pollutants once constructed, and there are other ways to generate the hydroelectricity without a large river such as, run-o-the-river and tide. These use the same concepts, but don’t have reservoirs to direct the flow.

Get it? Got it? Good.

P.S.

Things to consider:

fish ladders: for migratory fish during their mating season.

Siltation:  the plague o’ hydroelectric dams! Silt from the water builds up behind the dam and has the potential to clog the penstock.

Tags: energy, renewables, water

I missed the video that you guys watched in class. To what extent do I have to understand stormwater?

Today we visited one of Charlotte’s waste water treatment plants (Mallard Creek),  and did some water testing at Reedy Creek Nature Preserve!

The waste water treatment plant was all about going to “away”. When you flush things down the toilet or pour something down the drain, you are sending things away. Well here at the treatment plant, there is no away. Everything has to be sorted and dealt with (from diamond rings to latex condoms–lots of latex condoms.)

Aerial View ( I took all plant photos)

First the inflow comes to the bar screens where large pieces of debris and various other things (condoms, tampons, toilet paper, plastics) are raked out. The plant screens out the solid objects or grit, after allowing the water to settle in the settling tank

Then the water, still a murky brown, goes to a primary clarifier. Here the oils and greases float to the top, and the solids condense at the bottom as sludge. It’s sludge, not poop.

Primary Clarifier

Next the water goes to the aeration basin. Here the plant has a “farm” of microbes and bacteria that consume the organic matter. The basin is constantly aerated to supply the microbes with oxygen, and sometimes the nearby Cheerwine plant with give the plant their waste sugar water to feed the microbes. On days like that, you better believe that denitrification is working.

Aeration Basin

The plant CAN deal with up to 12 MGD (millions of gallons a day), but they average around 8.5.

Fun Fact: If you fell in the aeration basin, you would sink to the bottom and drown. Do you know why? ….

because the DO (dissolved oxygen) is so high that the water is too light for our dense bodies.

Next, the water goes through some secondary clarifiers (which look identical to the first), and finally, to be filtered and disinfected before reentering the stream. The disinfecting process is done with giant UV lamps that sanitize the water; the lamps destroy any pathogen’s/bacteria’s/organism’s genes beyond reproductive potential, so it’s safe! (Safe for the stream…not drinking.)

UV disinfectant

Here's the process outlined

Meanwhile, the sludge goes to an anaerobic digestor, where the methane is burned off, and the remaining solid (known as cake) is sent to animal farms for crop fertilizer.

After the treatment plant, we went to Reedy Creek and tested the waters in Dragonfly Pond. The pond did not have particularly high numbers in general (a fairly low DO and a fairly low nitrate/phosphate level). We took tests on pH, temperature, and fecal coliform presence. Fecal coliform is bacterium that comes from feces (poop), and it’s important in water sanitation. Many people were walking their dogs around the pond, so it’s no surprise that coliforms were present; furthermore, the phosphate/nitrate level makes sense considering there is no farm or lawns to runoff their fertilizers into the pond. Lastly, without a fountain to mix oxygen into the pond, it was free standing, so the low DO makes sense as well. It is important to remember that our sample was taken at the edge of pond, where the temperature is warmer; thus the do is lower. Had we taken a sample fifteen feet underwater in the center of the pond, we would probably have a much higher sample.

After the fun “hands-on-stuff”, we had to trek back indoors and listen to a park naturalist. She explained the values of Bio-indexing. Basically, the organisms living in a body of water indicate the health of that water. If there are lots of organisms that are very sensitive that pollutants, then the water must be relatively untouched (otherwise those organisms wouldn’t survive). On the other hand, if a body of water only contains organisms that are very resistant to toxins, then you have a problem on your hands. Next, we looked at pictures/descriptions of aquatic bugs.

AHHH!

Tags: urban areas, wastewater treatment, water, water pollution

Friday, the class displayed their countries on the demographic transition stages (see image). The first thing Mr. Willard noted was how none of us put our countries in the Stage 1 (pre-industrial) stage. Why not stage 1? because in modern countries death rates are dropping off and birth rates are steadying, as modern medicine blurs the lines between developed and developing. Of course their are exceptions, parts of Pakistan are still tribal and resemble a stage one country, but that’s not all of Pakistan.

Next, we analyzed specific trends in countries. For example, what does the prereproductive (>14) age group tell us about the future of a country? Well it depends. In a country like Japan the startlingly small group suggests that in the next twenty years the population will continue to shrink. On the contrary, a country like Nigeria has such a huge young generation that their population will explode out of the sheer momentum of growth. Afghanistan has a similar drastic looking stage 2.

Finally, we concluded with two population powerhouses, China and India. China’s strict family planning coupled with its new economic policies have rendered its population with steady growth and improved standard of living. The problem is  China is beginning to “gray” (a population with fewer and fewer working citizens). None the less, it is impossible to ignore the efficacy of their one-child-policy.

India is a bit of a conundrum. Southern India is industrialized and steady, but northern India is exploding in population and suffering from poor health and sanitary conditions. The southern standards haven’t bled into the north yet. There is hope though because India’s AGR has continued to diminish for the last 20 years, so it is on its way to becoming a stage 3 country. We need to keep in mind that India’s AGR is still double that of China, and India is expected to overtake the China as the most populous country. India’s democracy has not been as effective as China’s totalitarian methods of population control.

On a side note, there are two other age indicators the reproductive (15-49) and the post-reproductive (50+). These age groups generally denote wars, famines, or diseases that have ravaged the country; although, there is a myriad of possibilities when it comes to demographic analysis.

Tags: demographics, population

Jordan told us that Taiga receives between “20 and 200 cm” of rainfall, and I want to know if this is accurate because it’s confusing my biome ranking a bit. That’s more rainfall than the grasslands, but the Taiga is much less productive. Does the temperature keep much plant life from growing? I just need some clarification.

I’m a little confused because there’s a huge section for this on the study guide, but the book only says “its important in sending signals between cells”. I remember in AP bio that these help in muscle contraction, but can anyone clarify?

This diagram illustrates a trophic level pyramid. You’ll notice that at each step the quantity of Kilo Calories (the same measurement of energy you would see on your cereal) decreases by ninety percent; this is because energy conversion isn’t that efficient, and that’s the big lesson to take away. Speaking of inefficiency, every ecosystem is dependent on the sun as their basic source of energy, but plants only photosynthesize about one percent of the available energy. That’s pretty whack.

Environmental scientists calculate the amount of energy available to consumers with the equation GPP (Gross Primary Productivity) – R (Respiration or energy lost as heat) = NPP (Net Primary Productivity)

In conclusion, it’s important to remember that energy flow and efficiency ties back to the second law of thermodynamics, which states that energy remains constant but its ability to “do work” lessens.  As seen in the diagram, energy is not just “disappearing” it’s dissipating into the atmosphere as heat energy (increasing the universes Entropy–but that’s another lesson) and the remaining (but lesser) energy is used for “work”.

This is a good example of a foodweb. They can be helpful in descerning trophic levels in context

Tags: ecology, ecosystems, energy

I believe trash is the biggest problem. We have a massive culture of wastefulness; granted, recycling exists, but the massive footprint we leave is ridiculous. So many problems stem from trash: where to put it (landfills aren’t forever, and trash is everywhere), depletion of resources (because its more affordable to keep a factory mass-producing than it is to reuses old products), habitat destruction (self explanatory), alteration of climate/ pollution (carbon dioxide and other chemicals [that are dumped into the air, water, and onto the land ] can pose irreversible damage to our environment), and many more that I’m sure I’m not totally aware of. YIKES!