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Difference between revisions of "Ecological dry toilets at Pedregal"

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*is great for off grid systems that do not have access to a municipal sewer system
 
*is great for off grid systems that do not have access to a municipal sewer system
 
*it is cheaper then installing a municipal waste treatment system
 
*it is cheaper then installing a municipal waste treatment system
*in order to work it does not require the addition of more water, a precious resource better drank then flushed down the toilet in most communities.   
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*in order to work it does not require the addition of more water, a precious resource better drank then flushed down the toilet in most communities.  <ref> Soil and Water Conservation Committee, State of Alabama.  "Block and Gravel Inlet Protection". http://swcc.alabama.gov/pdf/Handbooks&Guides/2006_sections/12%20Sediment%20Control%20(practices)vol1.pdf </ref>
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#Aerobic Decomposition: <br /> Before using each of the cement chambers, deposit 5cm of dry dirt on the floor.  While the chamber is in use organisms present in the dirt are introduced to the excrement and help to decompose the waste.   
 
#Aerobic Decomposition: <br /> Before using each of the cement chambers, deposit 5cm of dry dirt on the floor.  While the chamber is in use organisms present in the dirt are introduced to the excrement and help to decompose the waste.   
 
#Alkaline Decomposition:<br /> During the time that the excrement is covered and sealed without the presence of water, light, or air the lime and ash chemically burns the parasites so that after a few months the compost is free of parasites.   
 
#Alkaline Decomposition:<br /> During the time that the excrement is covered and sealed without the presence of water, light, or air the lime and ash chemically burns the parasites so that after a few months the compost is free of parasites.   
#[http://en.wikipedia.org/wiki/Anaerobic_digestion Anaerobic Decomposition]:<br /> At the center of the pile the lack of oxygen creates anaerobic conditions where different microbial organisms help to break down the waste and can help fix higher levels of nitrogen, since the ammonium nitrogen can not volatilize out of the pile.
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#[http://en.wikipedia.org/wiki/Anaerobic_digestion Anaerobic Decomposition]:<br /> At the center of the pile the lack of oxygen creates anaerobic conditions where different microbial organisms help to break down the waste and can help fix higher levels of nitrogen, since the ammonium nitrogen can not volatilize out of the pile.<ref> Soil and Water Conservation Committee, State of Alabama.  "Block and Gravel Inlet Protection". http://swcc.alabama.gov/pdf/Handbooks&Guides/2006_sections/12%20Sediment%20Control%20(practices)vol1.pdf </ref>
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==Construction==
 
==Construction==

Revision as of 19:00, 18 September 2010

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Intro

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Benefits

  • effective at eliminating odor from addition of lime or ash
  • doesn't attract flies
  • reduces human contact with contagious illnesses
  • produces composted fertilizer that is rendered safer for human use as parasites are killed and the bacteria count is reduced
  • prevents contamination of groundwater, since it is closed during composting
  • is great for off grid systems that do not have access to a municipal sewer system
  • it is cheaper then installing a municipal waste treatment system
  • in order to work it does not require the addition of more water, a precious resource better drank then flushed down the toilet in most communities. [1]


How it Functions

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  • Urine is separated from solid excrement
  • There are two chambers, while one is in use, the others contents are being converted into compost


1. Separating the Urine

The special design allows the urine to be separated from the solid waste. The urine is lead to an absorption well dug close to the bathroom or it can be captured into a separate receptacle so that after it has been diluted in water it can be utilized as a fertilizer. The solid excrement meanwhile enters the interior of the chamber that is in use.

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2. Drying the Fresh Excrement

After just depositing fresh excrement in the toilet add one cup of mix of either 3 dirt to 1 lime or 3 dirt to 1 ash on the top. This mix helps avoid the presence of flies and eliminates odors. When the toilet is sealed in an environment without light, oxygen, or water this mix also helps chemically burn parasites in the excrement. BE CARFEUL not to add to much lime or ash if using the finished compost for fertilizer, since the mix can make the compost become too basic for use on most plants.

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3. Alternating the Use of the Chambers

  • Chambers are used at alternating times. When one is full, seal the top with a mix of dirt, bolt down the seat cover, and leave to sit, meanwhile using the alternate chamber.

During this time the closed chamber creates an anaerobic environment that gets to high enough temperatures to destroy most pathogens and the action of the lime or ash helps to chemically burn parasites within the waste.

  • A little bit before the second chamber is full, is the time to empty the primary chamber that has been sitting composting and now the waste is ready for use as a high quality fertilizer. After emptying and cleaning out this primary chamber it is ready for reuse and for being resealed.

Process of Decomposition

  1. Aerobic Decomposition:
    Before using each of the cement chambers, deposit 5cm of dry dirt on the floor. While the chamber is in use organisms present in the dirt are introduced to the excrement and help to decompose the waste.
  2. Alkaline Decomposition:
    During the time that the excrement is covered and sealed without the presence of water, light, or air the lime and ash chemically burns the parasites so that after a few months the compost is free of parasites.
  3. Anaerobic Decomposition:
    At the center of the pile the lack of oxygen creates anaerobic conditions where different microbial organisms help to break down the waste and can help fix higher levels of nitrogen, since the ammonium nitrogen can not volatilize out of the pile.[2]


Construction

Creating the Chamber and House

The double chamber:

  1. Foundation:
    Construct on a foundation of cement 1cm thick to prevent humidity from entering the chamber and to prevent contact between the fresh solid waste and the ground and groundwater. In areas that flood easily it is recommended to raise the foundation with 20cm of rock or more fixed with wire mesh and covered with the 10cm of cement as a top to prevent water from entering.
  2. Walls of Chamber:
    Build the walls of the chambers with dried adobe blocks, rock and mortar, or ferrocement. Pedregal used cement. Each chamber should be separated by a partition wall of similar thickness, which will also act as structural support to the upper part of the bathroom. It is essential that the inside of the chambers has some kind of polished coating, if using something other then cement, in order to counteract the decomposing action of excrement and bacterial organisms on the walls. This coating also helps to prevent moisture from entering the chambers. Each of these chambers should have its own side door to allow for compost removal individually. Doors should be 30cm wide and as tall as the walls.
  3. Top of Chamber:
    A concrete slab the width and length of the outer walls should be made with a hole for each chamber, these holes will act as the opening to the chamber and the place for the toilet seat.
  4. Hole or Seat:
    Whether just using the hole or adding a toilet seat the urine must be separated using a small triangle shaped cup added to the front of the hole/seat. This cup should also have a small hole in the bottom where a tube is attached and this tube leads out to an outside absorption chamber under the ground or to a separate collection chamber.

The house:

  1. It is built on top of the slab of the chambers and can have the size, design and materials you want. Just make sure there is good ventilation and that it does not allow the passage of water into the chambers. Pedregal included a PVC pipe that runs along the outside of the house and encourages decomposing gases to escape to the outside where it will not disturb users. Pedregals structure was also made of bamboo mats woven together and placed with small openings to allow for ventilation as well as windows above breast height. [3]


Most Common Problems

  • Urine tubes getting disconnected or clogged accounts for around 24% of the composting toilet systems not in perfect condition. [4]

Alternative Human Waste Treatment Systems


References

  1. Soil and Water Conservation Committee, State of Alabama. "Block and Gravel Inlet Protection". http://swcc.alabama.gov/pdf/Handbooks&Guides/2006_sections/12%20Sediment%20Control%20(practices)vol1.pdf
  2. Soil and Water Conservation Committee, State of Alabama. "Block and Gravel Inlet Protection". http://swcc.alabama.gov/pdf/Handbooks&Guides/2006_sections/12%20Sediment%20Control%20(practices)vol1.pdf
  3. Soil and Water Conservation Committee, State of Alabama. "Block and Gravel Inlet Protection". http://swcc.alabama.gov/pdf/Handbooks&Guides/2006_sections/12%20Sediment%20Control%20(practices)vol1.pdf
  4. Mehl, Jessica. Pathogen Destruction and Aerobic Decomposition in Composting Latrines: A Study from Rural Panama. 2008