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==References==
==References==
The Complete Book of Composting, J.I. Rodale Editor-in-Chief, Rodale Books Inc. Emmaus, Pennsylvania. 1971. Complete Book Of Composting
The Complete Book of Composting, J.I. Rodale Editor-in-Chief, Rodale Books Inc. Emmaus, Pennsylvania. 1971.
 
Compost Microorganisms, Nancy Trautmann and Elaina Olynciw, Cornell University Science and Engineering,
http://www.css.cornell.edu/compost/microorg.html
 
The Good Life, Helen and Scott Nearing, Schocken.1990
 
Building for Self- Sufficiency, Robin Clarke, Universe Books, New York. 1977
 
A great website provided by the EPA http://www.epa.gov/epaoswer/non-hw/composting/index.htm
 


[[Category:Engr305]]
[[Category:Engr305]]

Revision as of 06:59, 8 May 2008

Template:305inprogress

What is compost?

Compost is a mixture of decaying organic materials (plants) that is used for to fertilize and condition land . Compost can be anything from a pile of sticks and brush to food scrap bins using worms to digest organic materials (vermiculture). The main purpose of compost is to recycle food and garden wastes in to fertile soil.

Nature recycles the Essentials of life

As plants grow, huge amounts of organic materials are strewed across landscapes in the form of leaves, needles, branches, and other leafy matter. These “dead” materials are broken down by an armada of bacteria, fungi, insects, birds and animals to produce topsoil. Mostly by consuming plant material and excreting a more broken down form, all of these “composters” recycle important plant nutrients like nitrogen and carbon back in to the soil profile to be absorbed by the next season’s growth. This process is very slow adding just inches of soil every thousand years.

How Does this do anything for me?

The very same bacteria and fungi from nature can break down your kitchen scraps and grass clippings and create nutrient rich soil. As these microbes break down your wastes they generate huge amounts of heat that speed up the breakdown process. In most of nature, soil development is a multi-year process, but warm compost piles can break down huge amounts of material in just a few months!

Why does CCAT want a Composting system?

CCAT has had several composting bins throughout the years. All of the other systems have either broken down due to age, were taken apart during the multi-year moving process, were not efficient, or are too accessible to rodents. I attempted to fix all of these problems by designing a more permanent system out of non-biodegradable materials. More on the design later...

There are many benefits that come from Composting:

  • Eliminates yard and food scraps from the waste stream. According to the EPA, 23% of our current waste stream is yard/food material.
  • Breaks down large materials in a shorter period of time than natural decomposition, ie branches
  • Compost can be used to amend CCAT soils to increase agricultural yields, improve the physical and chemical properties, increase soil stability (prevents erosion), and increasing topsoil quantity and health.
  • Breaks down weed seeds and certain pathogens with high temperatures. “cleans the soil”
  • Promotes microbial growth, the main factor in breaking down rock materials in to a size usable as plant nutrients. Encourages earthworm production important ecosystem engineers.
  • Soil loss, decreased nutrient availability and lower microbial populations are all very important environmental issues that are of major concern. If every person were to take their organic materials from the waste stream and return it to the soil through composting, all three of these issues could be significantly reduced in severity.


Description of Project

This comprehensive composting system will be a system that decomposes kitchen and yard wastes. A three-tiered system will allow for multiple phases of compost to be “curing” simultaneously. Finished compost material will be used to amend CCAT’s present and future garden soils. Ideally, the system will be maintained year round. Compost can work year round especially in milder climates such as Coastal California.

Literature Review

Types of Composting Systems

There are many ways to build a compost pile. As long as each design fits the needs of the users, almost any design can be an efficient composting system. Below are a few of the shapes and sizes and purposes of different composting bins

Singlebin.JPG
Single Bin- A stationary bin where new material is applied to the top of the bin and processed compost is removed from the bottom or left to further decompose.
Tumbler.jpg
Compost Tumbler- Many systems are available that use a round cylinder to house the compost. Rotating the barrel is effectively turning the compost. These bins are very efficient for small amounts of material and for the user who wants a minimal amount of work to manage their compost.
Blockbin.jpg
Block Bin- Concrete blocks or bricks can be used to build a makeshift container. Not suitable for kitchen wastes as not secure from rodent access- would need additional barriers
CCATvermi.jpg
Vermiculture - Using worms to process organic material is a very exciting sector of composting. Red wrigglers are a very fast way of processing huge amounts of material. Worms are sensitive to high acidity and waterlogged compost- citrus is a not able to be processed in this system. Worm castings, a by-product of the worms consuming food, can be used as a great soil amendment rich in nitrogen and other nutrients. To see more information on the worm bin pictured here, check out CCAT's Vermicomposting Bin
Multi-stage.jpg
Multi-stage bins- Several cells contain compost in different stages of decomposition. This system is the most forgiving (almost any material can go in the bins) and of conventional systems-meaning not vermiculture- is able to process the most compost in the shortest time.

Advantages of Compost Farming

  • General fertility of the soil is increased
  • Mechanical structure is improved- clay soils looser, sandy soils more cohesive
  • Ease of cultivation-reduces effort in farming due to improved soil quality
  • Increases water holding capacity
  • Prevents hardening of soil- a major cause of soil erosion
  • Earthworms multiply- artificial fertilizers kill worms, provide pores/increased breakdown
  • Increases Microbial populations- Fungi and bacteria extend plant root matrices, increased nutrient uptake
  • Increases topsoil layer- builds rich medium for roots
  • Darkens color of soil- absorbs heat more readily, increases plant/microbe growth
  • Compost kills weed seeds- nutrient robbing weeds are kept to a minimum
  • Pest/Disease prevention- Healthy plants don’t attract as many bugs
  • Humus counteracts toxicity- Salt and Aluminum is decreased in potency

Factors in Composting

The key elements to building nutrient rich compost are organic materials, proper moisture and aeration. Other factors such as particle size, climate, and time also affect compost.

Organic Materials

Creating healthy compost requires that you feed the organisms good food. The little beasties that do our dirty work of chewing up the material like almost anything that is made of plant matter. Kitchen rinds, veggie leftovers, husks, even rotten plants are all delicacies. Avoid substances such as dairy products and meats. These wastes create odor problems and can attract flies and other rodents . Maintaining the proper nutrient balance is also important for creating balanced compost. Adding grass clippings, kitchen wastes or manure supplies nitrogen and little carbon while sticks, hay, and leaves provide almost exclusively carbon.

Moisture Content

Composting microorganisms need a decent amount of water to survive. Desiccation (drying out) damages the microbial populations and the overall effectiveness of your compost pile. Saturating the pile decreases the amount of oxygen available to microbes causing the material to sit and rot as opposed to breaking down. Many materials that can be added to a compost pile contain moisture but often times it’s not enough. Rainfall will affect this factor so monitor the soil around your pile for excessive moisture. Cover the pile with a tarp, lid etc. to prevent too much water from entering the compost pile. A good moisture content will not drip any water from a handful of compost just resting but will if you squeeze the material; like a sponge.



Criteria

  • Easy Upkeep- Composting requires periodic turning and maintenance. The design and location should make it easy to use the compost system
  • Esthetically pleasing- Composting is an important Appropriate Technology and should be presented in a manner that will appeal to everyone
  • Durable Design- Compost incorporates moisture, heat, and microbial action. These factors combine to break down materials, including you compost bins, in a short time. The bins must be made of materials that will endure the composting process as well as external environment conditions.
  • Security- Compost piles can be potential food sources for rodents. The design of the bins must prevent rodent access while maximizing airflow
  • Flux Capacity (Thanks Doc!)- CCAT experiences huge variation in the amount of material produced by the grounds depending on whether school is in session or not. The bins must be designed to accommodate a large variation in amounts of matter.


Design

I went through many design phases and even changed the design several times. I proposed several designs to CCAT that I felt would be appropriate. With a little guidance I determined that CCAT needed a large system able to process a lot of garden material that was easy to use. I have included all of the designs I drafted. Not all of the designs were meant for CCAT per se but are viable designs that have been used by many a gardener. The designs are presented in order from easiest and cheapest to build to most involved and costly. However the management time for each system varies as does the functioning purpose. For example, simple chicken wire bins are simple and cheap to construct but can be visually displeasing and cumbersome to turn the piles. On the other hand, a three tiered vertical system takes a lot of time and money to construct but the management process takes a fraction of the time.

Flatgroundgo.jpg
Stand Alone System- This desgin can be made very easily with palettes or wood scraps. Block bins as pictured above are also appropriate.
Vermiculture.jpg
Vermiculture Maze- this system is a continuous horizontal system. An S shaped bin allows a large amount of material in a compact space. This design is perfect for worms because they will migrate from processed compost to fresh undigested food.
Hillsidego.jpg
Three-tiered Hillside system- Similar to the design I chose, this system builds the bins in to a hillside. This makes turning easy- gravity assisted compost turning!! This system is really nice in that the bottoms of the bins can be left as dirt or use a more solid base. Potential water-logging and therefore anaerobic conditions are really not desirable for aerobic composting. Furthermore, the only really appropriate hillside for this system was located right next to the kitchen. Having a potential rodent food source right next to the kitchen is not appropriate.
Stackedtiergo.jpg
Three tiered stand alone system- This is the design that was chosen. Maintains the benefits of the hillside system while being in a more appropriate location. Repairs can be done easily if all sides of the bins are exposed.

Construction

  • First I selected a site for the compost bins. A three celled system takes up quite a bit of space so I decided to build up instead of out.
  • Next I took a pre-assembled floor(by a fellow CCATer) made of Trex.
  • Third I built a base frame to guide the vertical posts that will hold the sides of the bins. I decided to use recycled wood for the frames of the entire bin. This was to eliminate some of the torsion that Trex can experience under pressure.
  • I took two six foot Trex posts and sat them in concrete blocks.I then filled the extra space around the post with gravel. The Post wedged itself in to the block adding weight, stability and translating the weight all the way to the cement pad the bins are resting on.
  • Building up the sides, I left about 1 inch gaps in between the Trex boards- this is for airflow
  • Now I had one really big square bin that needed to be divided in to two cells. I used concrete blocks and another floor of Trex to raise the floor of the second tier about a foot above the final Tier.
  • I began to build the first cell separately so I wasn't building a box four feet in the air. Again I began with a wood frame for the base, added Trex boards for the bottom, and built up the sides leaving one inch between boards.
  • After completing cell one, I placed it on top of the other two cells.
  • I added a vertical cross beam that secures all three boxes to each other.
  • Next I cut tin roofs and doors for each of the cells. Roofing is important to keep the incessant precipitation out of the compost. The doors make it easier to turn a pile from one cell in to the next.


Cost Table

Material Cost/unit Total cost
Trex 2.09 /ft None-recycled from CCAT stores, around $300 new
Concrete blocks ~ $1/ea none-recycled
Corrugated Tin .50c/lb $40

Discussion

Quantify compost quantity per time- I had no idea how much material CCAT would be producing throughout each season. This varies on kitchen wastes and garden refuse both factors which can dramatically shift depending on growing season and whether school is in session. Optimize for Input sources and Output users- Who are the input users (kitchen users and gardeners) and how easy is it for each of these groups to access the piles. Piles are a little far from kitchen to be really easy to access. Also who is the output user- is the pile in a place that makes transferring heavy soil easy


References

The Complete Book of Composting, J.I. Rodale Editor-in-Chief, Rodale Books Inc. Emmaus, Pennsylvania. 1971.

Compost Microorganisms, Nancy Trautmann and Elaina Olynciw, Cornell University Science and Engineering, http://www.css.cornell.edu/compost/microorg.html

The Good Life, Helen and Scott Nearing, Schocken.1990

Building for Self- Sufficiency, Robin Clarke, Universe Books, New York. 1977

A great website provided by the EPA http://www.epa.gov/epaoswer/non-hw/composting/index.htm

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