Difference between revisions of "Composting Chamber"

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|{{Language-box|english_link=Composting Chamber|french_link=Chambre de compostage|spanish_link=Camara_de_Compostaje|hindi_link=coming soon|malayalam_link=coming soon|tamil_link=coming soon | korean_link=coming soon | chinese_link=Coming soon | indonesian_link=Coming soon | japanese_link=Coming soon}}
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Input1=Organics|Input2=Excreta|Input3=Faeces| Input4=Dry Cleansing Materials |Input5=|
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Output1=Compost| Output2= Effluent| Output3= | Output4= | Output5=
 
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|[[Image:Composting_chamber.png |right|500px]]
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<br>
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----
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<br>
  
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[[Image:Icon_composting_chamber.png |right|80px]]
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'''Composting refers to the process by which biodegradable components are biologically decomposed by microorganisms (mainly bacteria and fungi) under aerobic conditions. A composting chamber is designed to convert excreta and organics into compost. Compost is a stable, inoffensive product that can be safely handled and used as a soil conditioner.'''
  
'''Composting refers to the process by which biodegradable components are biologically decomposed under aerobic conditions by microorganisms (mainly bacteria and fungi). A Composting Chamber converts excreta and organics into Compost. Compost is a stable, inoffensive product that can be handled safely and used as a soil conditioner.'''
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<br>
 
 
 
This technology usually requires four main parts:
 
This technology usually requires four main parts:
  
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# an access door to remove the mature product.
 
# an access door to remove the mature product.
  
A Composting Chamber can be designed in various configurations and constructed above or below ground. UDDT can be used as a User Interface for specifically designed Composting Chambers. Anal Cleansing Water should not be added to the composting chamber as it could cause anaerobic conditions, foul smells and reduced collection capacity.
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Excreta, organics, food waste and bulking material (such as wood chips, sawdust, ash or paper) are mixed in the chamber. There are four factors that ensure the good functioning of the system: (a) sufficient oxygen, provided by active or passive aeration; (b) proper moisture (ideally 45 to 70% moisture content); (c) internal (heap) temperature of 40 to 50 °C (achieved by proper chamber dimensioning); and (d) a 25:1 C:N ratio (theoretically) which can be adjusted by adding bulking material as a carbon source. In practice, these optimal conditions are difficult to maintain. As a result, the output product is often not sufficiently stabilized and sanitized, and requires further
 +
treatment.
  
There are four factors that will ensure the good functioning of the system:
+
===Design Considerations===
 
+
A composting chamber can be designed in various configurations and constructed above or below ground, indoors or with a separate superstructure. A design value of 300 L/person/year can be used to calculate the required chamber volume. Ventilation channels (air ducts) under the heap can be beneficial for aeration. More complex designs can include a small ventilation fan, a mechanical mixer, or multiple compartments to allow for increased storage and degradation time. A sloped bottom and a chamber for compost withdrawal facilitate access to the final product. A drainage system is important to ensure the removal of leachate. Excessive ammonia from urine inhibits the microbial processes in the chamber. The use of a [[Urine Diverting Dry Toilet | Urine-Diverting Dry Toilet]] (UDDT, U.2) or [[Urinal | Urinal]] (U.3) can, therefore, improve the quality of the compost.
#sufficient air (oxygen), provided by active aeration (pumped air) or passive aeration;
 
#proper moisture (ideally moisture content should be between 45–70%);
 
#internal (heap) temperature of 40–50°C (can be controlled with proper chamber dimensioning); and
 
#a 25:1 carbon to nitrogen ratio (theoretically) which can be adjusted by adding an external source of carbon such as toilet paper, wood chips, and/or vegetable scraps.
 
 
 
It is appropriate to assume a design value of 300L/person/ year to calculate the required chamber volume.
 
  
 +
<br>
 
{{procontable | pro=
 
{{procontable | pro=
- The compost that is removed is safe to handle and can be used as a soil conditioner. <br> - Can help reduce the volume of solid waste generated by diverting organic material into the composting unit. <br> - Can be built and repaired with locally available materials <br> - Long service life. <br> - No real problems with flies or odours if used correctly. <br> - Low-moderate capital costs depending on emptying; low operating costs. <br> - High reduction of pathogens. <br> - Does not require constant source of water. | con=
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- Significant reduction in pathogens <br>
- Leachate requires secondary treatment and/or appropriate discharge. <br> - Requires expert design and construction supervision. <br> - May require some specialized parts <br> - May require long start up time.
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- Compost can be used as a soil conditioner <br>
 +
- No real problems with flies or odours if used and maintained correctly <br>
 +
- Organic solid waste can be managed concurrently <br>
 +
- Long service life <br>
 +
- Low operating costs if self-emptied
 +
| con=
 +
- Requires well-trained user or service personnel for monitoring and maintenance <br>
 +
- Compost might require further treatment before use <br>
 +
- Leachate requires treatment and/or appropriate discharge <br>
 +
- Requires expert design and construction <br>
 +
- May require some specialized parts and electricity <br>
 +
- Requires constant source of organics <br>
 +
- Manual removal of compost is required
 
}}
 
}}
  
==Adequacy==  
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===Appropriateness===  
Although simple in theory, Composting Chambers are not always easy to operate. The moisture must be controlled to prevent anaerobic conditions, the ratio of carbon and nitrogen must be well balanced and the volume of the unit must be such that the temperature of the compost pile remains between 40 to 50°C. However, once the composting process is well established, the system is quite robust.
+
Since this technology is compact and waterless, it is especially suited in areas where land and water are limited, or when there is a need for compost. It can also be installed in rocky areas, or where the groundwater table is high. In cold climates, a composting chamber should be indoors to ensure that low temperatures do not impede the microbial processes. This technology cannot be used for the collection of anal cleansing water or greywater; if the reactor becomes too wet, anaerobic conditions will cause odour problems and improper degradation.
  
Depending on the design, Composting Chambers can be used indoors with the comfort and convenience of a flush toilet.
+
===Health Aspects/Acceptance===
 +
If the composting chamber is well designed, the users will not have to handle the material during the first year. A well-functioning composting chamber should not
 +
produce odours. If there is ample bulking material and good ventilation, there should be no problems with flies or other insects. When removing the final product, it is
 +
advisable to wear protective clothing to prevent contact with (partially) composted material.
  
This technology is appropriate to almost all areas, but since it is compact and waterless, it is especially suited to warm climates and to areas where land and water are limited. In colder climates, a Composting Chamber can also be used indoors to ensure that low temperatures do not impede the composting process. A Composting Chamber cannot be used for the Collection and Storage/ Treatment of anal cleansing water or greywater; if the reactor becomes too wet, anaerobic conditions will form and there will be problems with odour and improper degradation.
+
===Operation & Maintenance===
 +
Although simple in theory, composting chambers are not that easy to operate. The moisture must be controlled, the C:N ratio must be well balanced and the volume of the unit must be such that the temperature of the compost pile remains high to achieve pathogen reduction. After each defecation, a small amount of bulking material is added to absorb excess liquid, improve the aeration of the pile and balance the carbon availability. Turning the material from time to time will boost the oxygen supply.
  
==Health Aspects/Acceptance==
+
A squeeze test can be made to check the moisture level within the chamber. When squeezing a handful of compost, it should not crumble or feel dry, nor should it feel
If the Composting Chamber is well designed and constructed, there should be no reason for the users to handle the material for at least the first year, and thus, little opportunity to come in contact with pathogens. A well functioning Composting Chamber should not produce odours, and should be easy to maintain. If there is ample cover/bulking material there should not be problems with flies or insects.
+
like a wet sponge. Rather, the compost should leave only a few drops of water in one’s hand. If the material in the chamber becomes too compact and humid, additional bulking material should be added. If a UDDT is used, some water should be added to obtain the required humidity. Depending on the design, the composting chamber should be emptied every 2 to 10 years. Only the mature compost should be removed. The material may require further treatment to become hygienically safe (e.g., [[Co-composting | Co-Composting]], see T.16). With time, salt or other solids may build up in the tank or drainage system. These can be dissolved with hot water and/or scraped out.
  
==Upgrading==  
+
===Upgrading===  
 
A simple Composting Chamber can be upgraded to include a small ventilation fan, a mechanical mixer, or multiple compartments to allow for increased storage and degradation time.
 
A simple Composting Chamber can be upgraded to include a small ventilation fan, a mechanical mixer, or multiple compartments to allow for increased storage and degradation time.
  
==Maintenance==  
+
===Field experiences===
Depending on the design, the Composting Chamber should be emptied every 2 to 10 years. Only the completelymature compost should be removed. With time, salt or other solids may build up in the tank or in the leachate-collecting system, which can be dissolved with hot water and/or scraped out. A squeeze test can be used to check the moisture level within the Composting Chamber. A squeeze test requires the user to squeeze a handful of compost. The compost should not crumble and feel dry, nor should it feel like a wet sponge. Rather, the compost should only leave a few drops of water in the user’s hand.
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The following projects utilize composting chamber methods.
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<br>
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{|style="border: 2px solid #e0e0e0; width: 40%; text-align: justify; background-color: #e9f5fd;"  cellpadding="2"
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|- style="vertical-align: top"
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|[[Image:akvorsr logo_lite.png|center|60px|link=http://akvo.org/products/rsr/]]
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|- style="vertical-align: bottom"
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|[[Image:project 789.jpg |thumb|center|140px|<font size="2"><center>[http://rsr.akvo.org/project/789/ RSR Project 789]<br>MWA-LAP: <br>Colombia</center></font>|link=http://rsr.akvo.org/project/789/ ]]
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|[[Image:project 790.jpg |thumb|center|140px|<font size="2"><center>[http://rsr.akvo.org/project/790/ RSR Project 790]<br>WaSH program in <br>Rural Bangladesh</center></font>|link=http://rsr.akvo.org/project/790/ ]]
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|}
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<br>
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===References===
  
 +
* Berger, W. (2011). [https://www.susana.org/en/knowledge-hub/resources-and-publications/library/details/878 Technology Review of Composting Toilets. Basic Overview of Composting Toilets (with or without Urine Diversion)]. Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH, Eschborn, DE.
  
==References==
+
* Del Porto, D. and Steinfeld, C. (1999). The Composting Toilet System Book. A Practical Guide to Choosing, Planning and Maintaining Composting Toilet Systems, an Alternative to Sewer and Septic Systems (Book). The Center for Ecological Pollution Prevention (CEPP), Concord, MA, US.
* Elizabeth Tilley et.al (2008). [http://www.eawag.ch/organisation/abteilungen/sandec/publikationen/publications_sesp/downloads_sesp/compendium_high.pdf Compendium of Sanitation Systems and Technologies] ([http://www.eawag.ch/organisation/abteilungen/sandec/publikationen/publications_sesp/downloads_sesp/compendium_low.pdf low res version]). Department of Water and Sanitation in Development Countries ([http://www.sandec.ch/ Sandec]) at the Swiss Federal Institute of Aquatic Science and Technology (Eawag). (Provides a full overview of sanitation systems.)
 
  
* Del Porto, D. and Steinfeld, C. (1999). The Composting Toilet System Book. A Practical Guide to Choosing, Planning and Maintaining Composting Toilet Systems, a Water-Saving, Pollution-Preventing Alternative. The Center for Ecological Pollution Prevention (CEPP), Concord, Massachusetts. (Comprehensive installation and maintenance for pre-fabricated units.)
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* Hill, G. B., Baldwin, S. A. and Vinnerås, B. (2013). [http://sustainablesummits.org/wp-content/uploads/2017/07/Hill-Baldwin-Vinneras-2013-Composting-Toilets-Misnomer-PUB.pdf Composting Toilets a Misnomer: Excessive Ammonia from Urine Inhibits Microbial Activity yet Is Insufficient in Sanitizing the End-Product]. Journal of Environmental Management 119 (2013): 29-35.
  
* Drescher, S., Zurbrügg, C., Enayetullah, I. and Singha, MAD. (2006). Decentralised Composting for Cities of Low- and Middle-Income Countries – A User’s Manual. Eawag/Sandec and Waste Concern, Dhaka. Available: http://www.sandec.ch
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* Jenkins, J. (2005). The Humanure Handbook. A Guide to Composting Human Manure (Book). 3rd Ed. Jenkins Publishing, Grove City, PA, US.
  
* Jenkins, J. (1999). The Humanure Handbook-2nd Edition. Jenkins Publishing, Grove City, PA, USA. Available: http://www.jenkinspublishing.com (Theory, history, and do-it-yourself guide to composting toilets.)
+
* U.S. EPA (1999). [https://nepis.epa.gov/Exe/ZyNET.exe/200044ES.TXT?ZyActionD=ZyDocument&Client=EPA&Index=1995+Thru+1999&Docs=&Query=&Time=&EndTime=&SearchMethod=1&TocRestrict=n&Toc=&TocEntry=&QField=&QFieldYear=&QFieldMonth=&QFieldDay=&IntQFieldOp=0&ExtQFieldOp=0&XmlQuery=&File=D%3A%5Czyfiles%5CIndex%20Data%5C95thru99%5CTxt%5C00000015%5C200044ES.txt&User=ANONYMOUS&Password=anonymous&SortMethod=h%7C-&MaximumDocuments=1&FuzzyDegree=0&ImageQuality=r75g8/r75g8/x150y150g16/i425&Display=hpfr&DefSeekPage=x&SearchBack=ZyActionL&Back=ZyActionS&BackDesc=Results%20page&MaximumPages=1&ZyEntry=1&SeekPage=x&ZyPURL Water Efficiency Technology Fact Sheet. Composting Toilets]. EPA 832-F-99-066. U.S. Environmental Protection Agency, Washington, D.C., US.
  
* USEPA (1999). Water Efficiency Technology Fact Sheet: Composting Toilets- EPA 832-F-99-066. US Environmental Protection Agency, Washington. Available: www.epa.gov/owm/mtb/comp.pdf (Information related to microbial die off rates and risks.)
+
===Acknowledgements===
 +
{{:Acknowledgements Sanitation}}

Latest revision as of 01:30, 9 September 2020

English Français Español भारत മലയാളം தமிழ் 한국어 中國 Indonesia Japanese
Applicable in systems:
2
Level of Application
Household XX
Neighbourhood X
City

 

Inputs
Organics, Excreta, Faeces, Dry Cleansing Materials


Level of management
Household XX
Shared XX
Public X

 

Outputs
Compost, Effluent
Composting chamber.png




Icon composting chamber.png

Composting refers to the process by which biodegradable components are biologically decomposed by microorganisms (mainly bacteria and fungi) under aerobic conditions. A composting chamber is designed to convert excreta and organics into compost. Compost is a stable, inoffensive product that can be safely handled and used as a soil conditioner.


This technology usually requires four main parts:

  1. a reactor (storage chamber);
  2. a ventilation unit to provide oxygen and allow gases (CO2, water vapour) to escape;
  3. a leachate collection system ; and
  4. an access door to remove the mature product.

Excreta, organics, food waste and bulking material (such as wood chips, sawdust, ash or paper) are mixed in the chamber. There are four factors that ensure the good functioning of the system: (a) sufficient oxygen, provided by active or passive aeration; (b) proper moisture (ideally 45 to 70% moisture content); (c) internal (heap) temperature of 40 to 50 °C (achieved by proper chamber dimensioning); and (d) a 25:1 C:N ratio (theoretically) which can be adjusted by adding bulking material as a carbon source. In practice, these optimal conditions are difficult to maintain. As a result, the output product is often not sufficiently stabilized and sanitized, and requires further treatment.

Design Considerations

A composting chamber can be designed in various configurations and constructed above or below ground, indoors or with a separate superstructure. A design value of 300 L/person/year can be used to calculate the required chamber volume. Ventilation channels (air ducts) under the heap can be beneficial for aeration. More complex designs can include a small ventilation fan, a mechanical mixer, or multiple compartments to allow for increased storage and degradation time. A sloped bottom and a chamber for compost withdrawal facilitate access to the final product. A drainage system is important to ensure the removal of leachate. Excessive ammonia from urine inhibits the microbial processes in the chamber. The use of a Urine-Diverting Dry Toilet (UDDT, U.2) or Urinal (U.3) can, therefore, improve the quality of the compost.


Advantages Disadvantages/limitations
- Significant reduction in pathogens

- Compost can be used as a soil conditioner
- No real problems with flies or odours if used and maintained correctly
- Organic solid waste can be managed concurrently
- Long service life
- Low operating costs if self-emptied

- Requires well-trained user or service personnel for monitoring and maintenance

- Compost might require further treatment before use
- Leachate requires treatment and/or appropriate discharge
- Requires expert design and construction
- May require some specialized parts and electricity
- Requires constant source of organics
- Manual removal of compost is required


Appropriateness

Since this technology is compact and waterless, it is especially suited in areas where land and water are limited, or when there is a need for compost. It can also be installed in rocky areas, or where the groundwater table is high. In cold climates, a composting chamber should be indoors to ensure that low temperatures do not impede the microbial processes. This technology cannot be used for the collection of anal cleansing water or greywater; if the reactor becomes too wet, anaerobic conditions will cause odour problems and improper degradation.

Health Aspects/Acceptance

If the composting chamber is well designed, the users will not have to handle the material during the first year. A well-functioning composting chamber should not produce odours. If there is ample bulking material and good ventilation, there should be no problems with flies or other insects. When removing the final product, it is advisable to wear protective clothing to prevent contact with (partially) composted material.

Operation & Maintenance

Although simple in theory, composting chambers are not that easy to operate. The moisture must be controlled, the C:N ratio must be well balanced and the volume of the unit must be such that the temperature of the compost pile remains high to achieve pathogen reduction. After each defecation, a small amount of bulking material is added to absorb excess liquid, improve the aeration of the pile and balance the carbon availability. Turning the material from time to time will boost the oxygen supply.

A squeeze test can be made to check the moisture level within the chamber. When squeezing a handful of compost, it should not crumble or feel dry, nor should it feel like a wet sponge. Rather, the compost should leave only a few drops of water in one’s hand. If the material in the chamber becomes too compact and humid, additional bulking material should be added. If a UDDT is used, some water should be added to obtain the required humidity. Depending on the design, the composting chamber should be emptied every 2 to 10 years. Only the mature compost should be removed. The material may require further treatment to become hygienically safe (e.g., Co-Composting, see T.16). With time, salt or other solids may build up in the tank or drainage system. These can be dissolved with hot water and/or scraped out.

Upgrading

A simple Composting Chamber can be upgraded to include a small ventilation fan, a mechanical mixer, or multiple compartments to allow for increased storage and degradation time.

Field experiences

The following projects utilize composting chamber methods.

Akvorsr logo lite.png
RSR Project 789
MWA-LAP:
Colombia
RSR Project 790
WaSH program in
Rural Bangladesh


References

  • Del Porto, D. and Steinfeld, C. (1999). The Composting Toilet System Book. A Practical Guide to Choosing, Planning and Maintaining Composting Toilet Systems, an Alternative to Sewer and Septic Systems (Book). The Center for Ecological Pollution Prevention (CEPP), Concord, MA, US.
  • Jenkins, J. (2005). The Humanure Handbook. A Guide to Composting Human Manure (Book). 3rd Ed. Jenkins Publishing, Grove City, PA, US.

Acknowledgements

Eawag compendium cover.png

The material on this page was adapted from:

Elizabeth Tilley, Lukas Ulrich, Christoph Lüthi, Philippe Reymond and Christian Zurbrügg (2014). Compendium of Sanitation Systems and Technologies, published by Sandec, the Department of Water and Sanitation in Developing Countries of Eawag, the Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.

The 2nd edition publication is available in English. French and Spanish are yet to come.