This is a picture
of my board
| ABSTRACT | PURPOSE STATEMENT |
| HYPOTHESIS | EXPERIMENT DESIGN |
| MATERIALS | PROCEDURES |
| PROJECT LOG | RESEARCH REPORT |
| RESULTS | CONCLUSION |
| BIBLIOGRAPHY |
This is a picture
of my board
ABSTRACT
The purpose of this experiment
was to determine which organic material produces a compost with the optimum
pH level. The proper pH level is between 6 and 8. The organic materials
were in a ratio of 25:1, carbons to nitrogens. The nitrogens were
cow manure, horse manure, the house hold wastes, and biosolids from a local
sewage treatment plant. The carbons were dried grass, twigs, etc.
Briefly the procedure involved composting the nitrogens with the carbons in soda bottle bioreactors. Daily temperatures were taken and recorded while these materials were composting. I used litmus paper to take the pH level at the end of the experiment. I also used a pH probe to get the final pH results.
The results indicated that all of the compost produced in the bioreactors fell within the optimum pH level.
My conclusion was that all of the compost had the correct pH level.
The purpose of this project is to determine which kind of organic materials creates the compost with the optimum pH level, cow manure, horse manure, biosolids, household, or the bioreactor with everything in it. The proper pH level is between 6 and 8.
I chose to do this project because the landfills are filling up. Soon we won’t have any more room for all of our garbage. I am hoping people will realize this and look at my project and say “ Composting is a good idea!” and they will resort to composting in their own backyards or through community composting projects.
The way that my project can benefit society is through composting. Composting gives back to the earth so future generations will be able to have enough “good” soil to grow food.
The hypothesis of this experiment is that the pop bottle bioreactor containing the combination of horse & cow manure, biosolids and the household wastes, will have the optimum pH level. The bioreactors just containing household wastes, horse manure, cow manure, or the biosolids will not meet the ideal pH level, which between 6 and 8.
According to According to Cornell University if your carbon nitrogen ratio is perfect (25:1) than your pH level will be perfect.
The manipulated variables are the temperature created in each bottle, the moisture content, rate of evaporation, and the shaking of each bottle to add oxygen.
The responding variable is the pH level in each of the bioreactors compost.
The constants in my experiment are:
· 1 liter bottle
· 2 liter bottle
· time
· thermometer
· pH paper
· meat grinder
· test tubes
· amount of compost put into test tubes
· rubber stoppers
· amount of water put into test tubes
· number of times I tested for pH.
ITEM QUANTITY
1 Liter bottles-clear
15
2 Liter bottles-clear
15
Grease pencil
1
Thermometers
15
Penny nail
1
Knife
1
pHydrion papers 87
1 roll
Meat grinder
1
Home diet scale
1
Nitrogens
Cow manure
1 oz per bottle
Horse Manure
1 oz per bottle
Biosolids- Yakima sewage treatment plant
1 oz per bottle
House hold wastes
1 oz mixture/bottle
potato peelings, lettuce, coffee
grounds,
apple peelings, cabbage bits,
egg shells,
asparagus ends
Carbons
1 oz mixture/bottle
Dried grass clippings
Hay
Dried flower stems
Dried leaves
Dried pine needles
Buckets
2
Strapping tape
Apron
1
Rubber gloves
1 pair
Clear packing tape
1 roll
Scissors
1 pair
Water
Distilled water
225 ml
Size #2 test tube
17
Size #2 rubber stopper
17
Test tube holders
3
Glass stir rod
1
Tweezers
1
Graduated cylinders
1- 10ml
1- 20ml
Scupula
1
Scale
1
Petri dish
1
Pipette
1
Evergreen Garden Compost
1 bag
Li’L Beaver Fresh Water Bark Compost
1 bag
PROCEDURES
Making the Bioreactors
1. Take labels off the 1- liter bottles and the 2- liter bottles.
2. Cut 1/4 the way down from the top of the 1 and 2 liter bottles but
don’t cut it all off. Just cut around so there is a joint that will
be able to bend to allow the 1 liter bottle to slip into the 2-liter bottle.
3. Label the bottles “ 1” through “15” both sizes, 1 and 2 liter,
with the grease pencil.
4. Poke five holes with a nail in the bottom of the 1- liter bottles.
Making the Compost
1. Gather the carbons (dried leaves, dried grass, twigs etc.)
and the nitrogens (cow & horse manure, biosolids from sewage treatment
plant, household waste products etc.)
2. Take the nitrogens and measure out 1 oz and mix it with 25 oz of
carbons as follows-bottles 1,2,3 get horse manure plus carbons, bottles
4,5,6 get cow manure plus carbons, bottles 7,8,9 get biosolids plus carbons,
bottles 10,11, 12 get household waste products plus the carbons and
bottles 13, 14, 15 get a combination of all the nitrogens plus the carbons.
3. Add 75ml of water to every bottle. Shake well. Insert
the one liter bottles into their corresponding 2 liter bottles.
4. Put the thermometer in the bottles so that it is in the compost,
then tape the flap of the 2 liter bottle down.
5. Twice daily at 8 am and 6 pm shake the bottles and record
temperatures. Water was added if the bottles needed it or the leachate
was poured back into the bottles.
6. Compost was considered “done” when the temperatures fell. Temperatures
no longer recorded, thermometers washed and returned to school science
lab.
7. Compost was allowed to cure until January 10, ‘01. It was
checked periodically to see if was water was needed to keep in moist “like
a wet sponge” and shaken.
Procedures for Testing pH with pH Probe
1. Take the tape off of the 1 liter bottles.
2. Using the scupula mass out 5g of compost out of one of the bottles.
3. Place the 5g of compost into a test tube and label it.
4. After you do that with all of the bottles place 15ml of water into
each test tube, stopper and shake.
5. Let the compost sit in the water over night.
6. Set up pH probe.
7. In the morning shake a test tube and place the pH probe into the
water and wait for a reading. Do this for all of the test tubes twice,
and record the results.
8. When you are done clean up the mess.
PRE-LOG
May 6, ‘00
Today I started my experiment my parents and I went to a field
to get manure and hay. My parents helped me construct the compost
can. First I marked spots were I was going to drill holes, then after
all the places were marked I drilled the holes with the supervision of
my dad. When we were done we put a layer of dirt, food scraps, weeds,
shredded paper and hay. Then I wetted it down. After all that I put
the lid on it, and left it in the sun. Compost thermometer has been
ordered.
June 1, ’00
Narrowed down my project from a big garbage can compost to a
soda bottle bioractor as described by a Cornell University web page.
June 6, ‘00
Today I wrote a letter to the Coca-Cola asking if they could
donate 15 1-liter bottles with the caps and 15 2-liter bottles with the
caps. I also decided that I am going to use bioreactors instead of
using the garbage can composting.
June 12, ‘00
Today I called the Coca-Cola bottling Co. and they told me I
could have the bottles.
June 16, ‘00
Today I read and highlighted things in internet articles.
June 18, ‘00
Today I wrote a letter to the Selah Sewage Treatment plant asking
them if they would donate sewage to use for my science project.
June 20, ‘00
My dad and I picked up the 1-liter bottles for the science project.
The Coca-Cola Co. didn’t have the 2-liter bottles for me.
July 3, ‘00
Today I started to fill out my applications so I can officially
start my project. I also called Mr. Eisley to sign the papers but
he wasn’t in his office. Then I called the Selah treatment plant
to see if I could have some sludge/ biosolids but they said that I couldn’t.
This treatment plant produces liquid sludge. This isn’t what I need.
July 10, ‘00
Mom called and ordered pH paper from “Science Kit & Boreal
Laboratories”. The guy from the Yakima treatment plant called and
said that it was okay that we could come and get some sludge.
July 13, ‘00
I got my apron from Mr. Brown, I also got my gloves, and mask
from my dads work.
July 19, ‘00
Applications sent to Mr. St. Clair.. Received pH papers.
July 31, ‘00
Today I got my project okayed and I can start it soon.
It was okayed by Mr. St. Clair.
EXPERIMENT-LOG
August 1, ‘00
Today I cut the top on the 2-liter bottles and took off the labels.
I also tested out the pH papers in the big composting pile that we have
out back.
August 2, ‘00
Today I took the labels off of the 1-liter bottles and then put
the numbers on the 1-liter and 2-liter bottles, 1 to 15. And cut
the tops of the 2-liter bottles. Went to the Yakima Sewage Treatment
plant and got the biosolids. On the way home got cow and horse manure.
-Observations of biosolids- It smelt like ammonia. It was black, and heavy and it was squishy.
When I came home I put the stuff into the bottles. Carbons and nitrogens-25:1 ratio. Wore my apron and my gloves to stuff the materials into the bottles.
Bottles 1, 2, and 3 contain horse manure.
Bottles 4, 5, and 6 contain cow manure.
Bottles 7, 8, and 9 contain biosolids.
Bottles 10, 11, and 12 contain household wastes.
Bottles 13, 14, and 15 contain everything (horse & cow manure,
biosolids, and household wastes).
A friend’s dog ate the last bite of “everything”. It couldn’t
have been all bad because he is still barking.
August 3, ‘00
Today I loosened up the compost in the bottles, added 75ml of
water and added the thermometers.
3:00pm- thermometers went in.
6:00pm- checked thermometers.
August 4, ‘00
8:00am- checked temperature in bottles and took the 1st pH test.
12:30pm- made signs for bottles when we take pictures.
6:00pm- took temperature, and added 50ml of water. Shook the
bottles to add air.
Found worms in bottles 4 and 5. There was no leachate in bottles 15, 14, 11, 10, 9, 8, 6,4. 50ml of water was added to these 8 bottles. The bottles that had leachate, the leachate was poured back into the bottles.
August 5, ‘00
8:00am- because I was gone mom took the temperatures for me.
No water was added. Bottles 4, 6, 7, 8, and9 had no leachate in the
2-liter bottle but the rest of the bottles did. The leachate was
poured back into the bottles.
6:00pm- took temperatures, 50m; of water was added to all the bottles.
August 6, ‘00
8:00am- took temperature no water was added. Bottles 2, 11, and
13 had no leachate in the bottom of the bottle but all of the others did
and the leachate was recycled back into the bottles.
6:00pm- took temperature, added 50ml of water to each.
August 7, ‘00
8:00am- took temperatures no water was added bottles 6, 7, 8, 9, 10,
11, and 12 had no leachate in the bottom but all of the other bottles did
and the leachate was recycled back into the bottles.
6:00pm- took temperatures, added 100ml of water to each bottle.
August 8, ‘00
8:00am- took temperatures, bottles 5, 6, 7, 8, 9, and 10 had no leachate
the bottles that did have leachate the leachate was recycled back into
the bottles. No water was added.
6:00pm- took temperatures, added 100ml of water of water to all bottles.
Temperatures seem to be at their highest.
August 9, ‘00
8:00am- took temperatures. All bottles except 15 had leachate
the leachate was recycled back into the bottles. Also took the pH
with the litmus paper. All bottles were pretty soaked.
7:00pm forgot 6:00pm time- didn’t add water because all of the bottles
had a lot of leachate , so I put the leachate back into bottles.
August 10, ‘00
8:00am- took temperatures, put leachate back into bottles.
6:00pm- took temperatures, added 100ml of water to all the bottles.
August 11, ‘00
8:00am- took temperatures and found that 1 of my bottles had been blown
over by the wind. Temperatures have dropped from 95? average to 85?.
6:00pm- took temperatures and added 50ml of water.
-since I went to my grandmas house so I took the science project
with me.
August 12, ‘00
8:00am- temperatures were taken bottles were shook- all had leachate
in the bottles.
6:00pm- took temperatures, recycled leachate back into bottles, didn’t
add water.
August 13, ‘00
8:00am- temperatures were taken, all of the bottles had leachate in
them.
7:30pm- temperature was taken, no water was added all the bottles had
plenty of leachate to recycle.
August 14, ‘00
8:00am- temperature was taken, I didn’t get the chance to shake the
bottles.
6:00pm- temperature was taken, shook the bottles, I didn’t need to
add water to the bottles.
August 15, ‘00
8:00am- temperature was taken, shook the bottles and I didn’t add any
water.
6:00pm- bottles with out leachate still felt damp so no water was added.
August 16, ‘00
8:00am- temperature was taken, shook the bottles, no water was added-
bottles still felt wet to the touch.
6:00pm- took temperatures, and added 100ml of water to each bottle.
August 17, ’00
8:00am- took temperatures, and put leachate back into bottles.
6:00pm- took temperatures, and put leachate back into the bottles, I also added 50ml of water.
August 18, ’00
8:00am- took temperatures, and put leachate back into bottles.
6:00pm- took temperatures added 50ml of water and put leachate back
into bottles.
August 19, ’00
8:00am- took temperatures, and put leachate back in to bottles.
6:00pm- took temperatures, and put leachate back into bottles.
August 20, ’00
8:00am- took temperatures of bottles and put leachate back into bottles.
6:00pm- took temperatures and added 75ml of water.
August 21, ’00
8:00am- took temperatures and put leachate back into bottles.
6:00pm- took temperatures and added 75ml of water.
August 22, ’00
8:00am- took temperatures and put leachate back into bottles.
6:00pm- took temperatures and no water was added.
August 23, ’00
8:00am- took temperatures
12:00pm- added 100ml of water- I added the water now because I will
not be home tonight I am going to Seattle.
August 24, ’00
8:00am- took temperatures and put leachate back into bottles.
6:00pm- took temperatures, added 50ml of water to each bottle.
August 25, ’00
8:00am- took temperatures and put leachate back into the bottles, 9
and 11 didn’t have leachate.
6:00pm- took temperatures.
August 26, ’00
8:00am- took temperatures, 9 and 11 didn’t have any leachate
in the bottles, put leachate back into bottles.
6:00pm- took temperatures.
August 27, ’00
8:00am- took temperatures.
10:30am- observations- Bottles 1,2,3- compost is loose but is breaking
down, smells- musty, color- brown. Bottles 4,5,6- color- dark brown, smell-
fowl, has broken down more than 1,2, or 3. Bottles 7,8,9- color-
black, smell- really bad, clumped together a lot except for bottle 9 isn’t
clumped together. Bottles 10,11,12- color-brown, smell-yet hay/grass,
it’s dry and loose. Bottles 13,14,15- color-dark brown, smell- none,
13 is clumped together, so is 14, 15 is loose.
Water was added to bottle 11 and 15- 50ml of water each.
6:00pm- took temperatures. –brought bottles into garage because the wind was knocking the bottles over.
August 28, ’00
8:00am- took temperatures, and put leachate back into bottles.
6:00pm- took temperatures.
August 29, ’00
8:00am- took temperatures, and added 100ml of water.
6:00pm- took temperatures, put leachate back into bottles.
-put new tape on bottle 4.
-put bottles into garage because the wind was knocking them over.
August 30, ’00
8:00am- took temperatures, put leachate back into bottles.
6:00pm- took temperatures, shook bottles and added 50ml of water.
August 31, ’00
8:00am- took temperatures, put leachate back into bottles.
6:00pm- took temperatures, put leachate back into bottles.
September 1, ’00
8:00am- took temperatures.
6:00pm- took temperatures.
September 2, ’00
8:00am- took temperatures.
6:00pm- took temperatures, and added 100ml of water.
September 3, ’00
8:00am- took temperatures.
6:00pm- took temperatures, put leachate back into bottles, put new
tape on bottle 10 and 13.
POST- EXPERIMENT LOG
September 7, ’00
11:45am- bottles all shook, leachate put back into bottles. Bottle
4, 50ml of water was added temperatures not needed but all between 30?-40?
C.
-I haven’t been able to take temperatures in the morning because school has started.
September 9, ’00
Observations- 1,2,3- Dark brown, starting to break down a lot,
not very clumped. 4,5,6- almost black dark brown, starting to clump
together, breaking together. 7,8,9-Black, very clumped together,
breaking down. 10,11,12- Dark brown, not very clumped,
starting to break down. 13,14,15- black, clumped together, breaking
down.
October 1, ’00
Took temperatures. I took the thermometers out of the bottles
and washed them because my teacher Mr. Brown wants them back. I also
took out the thermometers because the compost is ready to cure. I
wrote an email to Cornell University asking what was the best way to let
compost to cure.
October 3, ’00
Email reply said to just let them sit in their bottles.
Just don’t let them get too dry.
October 18, ’00
Shook bottles and added water to bottles.
October 22, ’00
Shook and added water to bottles. Observed bottles as well,
some smell like they’re done but don’t look like they are done, and some
look don’t look done but smell done.
October 26, ’00
Shook bottles and added 15ml of water.
November 2, ’00
Shook bottles and put the leachate back into bottles. 7,8,9
look like they are done cureing but they don’t smell like it.
November 8, ’00
Shook bottles and put leachate back into the bottles.
November 20, ’00
Shook bottles and put leachate back into bottles, and added 20ml
of water.
December 5, ’00
Today we went to our school library at 11:35. We went there
so that we could write or look up what our projects are going to be.
I looked through the library for stuff on composting, in the world book
encyclopedia, but I didn’t find anything.
December 6, ’00
My science class went to the library again at 11:33, I
tried to find more information.
December 13, ’00
-I took observations-
Bottle #
Observations
1. Smells like dirt, looks moist, light brown doesn’t look like dirt
yet.
2. Smells like dirt, looks moist, dark brown, looks similar to dirt.
3. Smells like dirt, looks moist, dark brown, looks similar to dirt.
4. Smells like dirt, looks moist, dark dark brown, looks like dirt.
5. Smells like dirt, looks dry, light brown, looks similar to dirt.
6. Smells like dirt, looks moist, brown, doesn’t look like dirt.
7. Doesn’t smell like dirt, looks moist, black, doesn’t look like dirt.
8. Smells like dirt, looks moist black, looks like dirt.
9. Smells like dirt, looks moist, black, looks like dirt.-has mold.
10. Smells and looks like dirt, light brown looks moist.
11. Smells like dirt, looks moist, light brown, doesn’t look like dirt.
12. Smells like dirt, looks moist, dark brown looks similar to dirt.
13. Has no smell, looks moist, dark brown, looks similar to dirt.
14. Smells like dirt, looks moist, black, looks like dirt.
15. Smells like dirt, looks moist, black, looks like dirt.
According to bottle 15 the temperature is 17?C. I added 100ml of water to bottle 5 because it was so dry. I shook bottles and put leachate back into bottles if they had any.
December 20, ’00
Today I worked on the purpose statement and the experiment design.
December 28, ’00
I finished my graphs.
December 29, ’00
I worked on my research report.
December 30, ’00
I read through The Rodale Book of Composting and worked on my
research report.
January 3, ’01
In class I read out of the book The Rodale Book of Composting.
January 4, ’01
In class I worked on my research report and read through The
Rodale Book of Composting.
January 7, ’01
Today I checked on my bottles to make sure that the compost was
moist enough.
NEED H2O
HAD LEACHATE DIDN’T NEED H2O
Bottle # 15 Bottle #14 Bottle #14
Bottle # 1 Bottle # 5 Bottle # 2
Bottle #13 Bottle # 11
Bottle #12 Bottle # 5
Bottle #8 Bottle # 10
Bottle #7 Bottle # 3
Bottle #6 Bottle # 9
Bottle #4
January 8, ’01
Today my class went to the library and I read out of the book
The Rodale Book of Composting.
January 10, 01
Today I went into Mr. McMillen’s classroom after school and measured
the compost. After we measured the compost 5g put them into test
tubes, tamped the compost down, then I added 15ml of water to each test
tube.
Observations- #2 had more moisture so it weighed more than #1. Beaver compost is really dry.
January 11, ’01
In class I did pH testing. I did two trials for each test
tube. I used a pH probe that Mr. McMillen let me use.
January 12, ’01
Today in class I used pH paper to take a different pH test than
the probe. When I was done I started cleaning but the test tubes,
the bell rang so I didn’t get to finish I put the pH paper onto a
piece of paper and labeled them by the numbers of the test tubes/ bottles.
January 15, ’01
Today I reread my research paper and corrected some things.
I also wrote the bibliography.
January 17, ’01
Today I read through my old experiment from last year so I could
remember how to do things like the experiment design, abstract, and just
how to do the journal in general. I also rewrote my hypothesis.
January 19, ’01
Today I got my board from Mr. McMillen and I also typed out my
Hypothesis, Materials, and Bibliography.
January 20, ’01
Today I took pictures of the compost on labeled pieces of paper.
I also wrote a rough draft of my abstract and purpose statement.
January 21, ’01
Today I worked on my research report, I pulled up facts concerning
how much garbage 1 person produced a day/year.
January 22, ’01
Today I wrote on my research report, and I started typing out
my project log.
January 31, ’01
Today my science class went to the library and I worked on my
research report.
February 3, ’01
Today I typed and printed everything for my board.
February 4, ’01
Today I started to glue everything for my board onto the green
pieces of paper.
February 8, ’01
Today I started gluing things onto my board.
February 9, ’01
Today I finished gluing things onto my board. I also finished
typing out my project log.
INTRODUCTION
Compost is the result of the breakdown process of organic wastes. The breakdown process involves temperature, oxygen, microorganisms, moisture, and organic materials.
The reason we need to compost is because the landfills are filling up. And the reason the landfills are filling up is because the average American discards 3.6 pounds (1.6 kg) of municipal solid waste, nearly 1,300 pounds (590 kg) per year. Soon we won’t have enough room for any more garbage. Below is a chart “A YEARLY SNAPSHOT OF U.S. WASTE & RECYCLING” published by Zero Waste America. It clearly shows an increase in the garbage produced here in the United States. Composting is an easy solution for each homeowner to help reduce the influx of garbage in our landfills. Compost is also an excellent additive to soil to grow plants, such as flowers, vegetables, and trees.
COMPOST HISTORY
Composting is a natural act of nature. The oldest existing reference in agriculture for using manure is 1,000 years before Moses was born in the Mesopotamian Valley. The Romans also knew about composting.
Here in America, George Washington, Thomas
Jefferson and James Madison were all supporters of composting.
Each had large farms in which to become strong advocates of composting.
George Washington, after the Revolutionary War, was concerned about
the restoration of his plantation. He hired a farm manager and between
the two of them he saved manure like it was gold. With all his farming
experiences he concluded that sheep dung and the black mould from the Gulleys
on the hillside made the best compost.
Thomas Jefferson was known to use “dung in three different stages of decomposition-fresh or long dung, half purified or short dung, and well-rotted dung.” Jefferson knew the value of fertilizer and since back then it was a chore to haul it around, he just pastured his cattle in the field that needed to be fertilized!
James Madison took the theory of composting a step further beyond his farm. He observed nature at work. He believed a field left uncultivated and unpastured between crops gained more fertility then the field planted year after year.
TEMPERATURE
Temperature is very important when composting,
because it tells us when the microorganisms are at their highest activity
rate, their lowest activity rate, or if they are dead. In a soda
bottle bioreactor the temperature is most likely to peak between
30?-40? C, because they are so small. I t is important to keep the
temperature below 65? C because the hotter temperatures can cause the beneficial
microorganisms to die off.
During the thermophilic stage decomposition occurs most rapidly (40?-60? C), which lasts for several weeks or months depending on the size of the system and the composition of the ingredients. Composting temperatures should take on the similarities of the chart below.
MICROORGANISMS
Microorganisms are needed in composting because they break down the organic matter and help along the process of composting. “In the process of composting, microorganisms breakdown organic matter and produce carbon dioxide, water, heat, and humus the relatively stable organic end product.” During different phases of composting different communities of microorganisms predominate. The initial decomposition is
carried out by mesophilic microorganisms, which quickly break down the readily degradable compounds. They produce heat, which causes the compost temperature to rapidly rise. When the temperature rises over 40? C the mesophilic microorganisms become less competitive and are replaced by others that are thermophilic, or heat loving. The thermophilic phase, high temperatures accelerate the breakdown of proteins, fats, and complex carbohydrates, such as cellulose and hemicellulose.
BACTERIA-The smallest and most numerous in compost
PROTOZOA-Secondary microorganism, they obtain their food from eating the bacteria and fungi.
Rotifers-Same as protozoa.
Fungi-break down the tough debris to allow bacteria to continue the decomposing the compost pile.
Actinomycetes-look like spider webs on the compost, mostly seen in the final stages of composting.
ORGANIC MATERIALS
Compost needs organic materials. The
two major ingredients I concerned myself with in this experiment were carbons
and nitrogen. From here on I will refer to nitrogen as nitrogens.
Carbons are the organic materials like dried leaves, straw, wood chips,
sawdust, or paper. Namely “brown” things, they were green now they
are basically dead.
Research Report (continued)
Nitrogens are items such as vegetable and fruit scraps, coffee grounds, green grass clippings, manure and biosolids. Nitrogens are usually considered “green”. In this experiment the ratio of carbons to nitrogens was 25:1. It can be as high as 30:1, carbons to nitrogen.
MOISTURE
It is not good to have excess moisture in compost
because you could drown the microorganisms. Oxygen diffuses slower
in water than in air and excess moisture reduces oxygen penetration.
This reduction occurs in two ways: 1) Moist compost is hydrophilic
(water lover). Water is strongly held to the surfaces of particles
so as water content increases the thickness of the aqueous film surrounding
each particle increases.
2) A closely related effect is when water fills the smallest pores
first it creates water filled zones between particles which slows down
oxygen diffusion and results in anaerobic clumps. Good compost should
be moist as a damp sponge.
BIOREACTOR
A bioreactor is a name given to an enclosed
container specifically for composting.
I constructed a soda bottle bioreactor, an idea from Cornell University.
This university has an entire department devoted to composting. I
used two different sizes of soda bottles, a one-liter water bottle and
a two-liter pop bottle. In the one liter bottle I poked holes in the bottom
to allow leachate to drain out. The holes allowed excess moisture
to be at a minimum.
PH
PH describes the acidity of compost. The reason we need to measure the pH level is because it helps us follow the decomposition. It also helps to make sure that the acidity level is correct.
BIOSOLIDS
Biosolids are a by-product of municipal wastewater treatment. Biosolids have nutrients and organic matter that are good for crops, soil, and live stock productivity. Before raw sewage solids can officially be called biosolids they must be processed to meet the standards of the U.S. Environmental Protection Agency (U.S.E.P.A).
WHAT DON’T YOU PUT INTO A COMPOST PILE?
Well you don’t put meat, bones, and fatty food wastes because these things can attract animals, such as dogs, cats, and rats. Fatty food wastes can be very slow to break down; the reason for this is because fat can exclude air that compost that the composting microbes need. You also don’t want to put human wastes into compost because it can contain disease organisms that will make people very sick. Diseased plants, chemically treated wood products, pernicious weeds (because they can grow back from the roots), and pet wastes (because dog and cat wastes can carry diseases that can infect humans.).
SUMMARY
Compost is the result of the break down of
organic wastes. I learned this by composting in bioreactors.
I hope that you learned as much as I did from my report.
Composting is something everybody could and should do to save not only
our over flowing landfills by giving back into the environment.
The original purpose was to see what type of compost has the optimum pH level between 6and8.
pH levels with pH paper
Bottles 1
2 3 4
5 6 7
8 9 10
11 12 13
14 15
8/4/00 6.0 7.0
7.5 5.5 6.0 5.5 7.5
5.5 5.5 5.5
5.5 6.0 7.5
5.5 5.5
8/9/00 6.0 6.0
7.0 6.0 7.0 6.5
5.5 5.5 5.5 8.5
6.5 7.5 6.0
6.0 5.5
11/10/006.0 6.0 6.0 8.0
6.5 6.0 5.0 5.5 5.0
6.0 6.5
6.0 6.5 6.0
6.5
1/11/01 6.0 6.0 6.06.0
5.5 6.5 8.0 7.5 6.5
6.0 7.5 7.0
7.0 8.0 7.5
pH levels with pH probe
1/10/01 1
2 3
4 5 6
7 8
9 10
11 12 13
14 15
1st trial 6.9 7.6
7.3 7.9 7.7 7.5 7.2
7.0 6.9 7.2
7.1 7.6 7.4 7.3
7.6
2nd trial 7.4 7.6 7.3
7.9 7.7 7.4 7.3 7.0
6.9 7.1
7.1 7.5 7.4 7.3
7.7
1/10/01 Beaver Evergreen
1st trial 7.8 6.3
2nd trial 6.8 6.3
Observations
The pH of the compost changed over time.
If you compare the pH level of the pH paper and the pH levels of the pH
probe, the pH probe is more accurate than the pH paper. The smell
of the compost changed over time as well, when the compost was started
it smelled bad, and now it smells like soil. The color also changed
My hypothesis is that the bottle bioreactor with everything (horse & cow manure, biosolids, and household wastes) will have the optimum pH level out of all of the compost bottles. The optimum pH level is between 6 and 8.
My results indicated that all of the compost produced using horse manure, cow manure, household wastes, biosolids, or a combination of everything had the optimum pH level. All of the different nitrogens would produce a good compost when put in the 25:1 ratio with carbons (dried grasses, etc).
If I were to do this experiment over I would have a greater variety of nitrogen producers in each compost bottle. Also I would check the pH level more often and use a grow light instead of the sun for a more consistent heating and light to the compost. It would also take longer but start with more compostable material in each bottle
Building a Soda Bottle Bioreactor, “Building a Soda Bottle Bioreactor”, http://www.cfe.cornell.edu/compost/soda.html , 4/22/00
Campbell, Stu, Let It Rot, Storey Communications Inc. ©1975
Compost Microorganisms “The Phases of Composting” http://www.cfe.cornell.edu/compost/microorg.html 4/19/00
Compost Physics “Compost Physics”, http://www.cfe.cornell.edu/compost/physics.html, 6/14/00
Compost Research Possibilities, “Ideas for Student Research Projects”, Cornell University, http://www.cfe.cornell.edu/compost/researchideas.html, 4/18/00
Cornell Composting, Composting in Schools, “Monitoring Compost pH,
http://www.cfe.cornell.edu/compost/physics/hitorph.html , 6/14/00
D. Sullivan, Fertilizing with Biosolids, Oregon State University © 1998
Excess Moisture “Excess Moisture” http://www.cfe.cornell.edu/compost/odors/excess.moisture.html, 4/19/00
High-Tech Bioreactors “High-Tech Bioreactors” http://cfe.cornell.edu/compost/bioreactors.html, 1/30/01
Martin, L. Deborah and Gershumy, Grace, editors, The Rodale Book of Composting, Rodale Press Inc. © 1992
The Beauty of Compost Heaps, “Compostables with the Mostables”, http://www.boldweb.com/greenweb/compost.html , 4/22/00
The Beauty of Compost Heats, “Creating Your Compost Heap” http://www.boldweb.com/greenweb/compost.html, 4/22/00
What Not to Compost, “What NOT to Compost”, http://net.indra.com/~topsoil/What_NOT_to_Copmpost.html
, 4/22/00