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Composting Chamber

Applicable to

Application level

City

Household

Neighborhood

Management level

Household

Public

Shared

Inputs

Faeces Excreta Organics
+ Dry Cleansing Materials

Outputs

Compost Effluent
Author/Compiled by
Eawag (Swiss Federal Institute of Aquatic Science and Technology)
Dorothee Spuhler (seecon international gmbh)
Executive Summary
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.
Advantages
Significant reduction in pathogens
Compost can be used as a soil conditioner
No real problems with flies or odours if used and maintained correctly (i.e., kept dry)
Organic solid waste can be managed concurrently
Long service life
Low operating costs if self-emptied
Disadvantages
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
In Out

Faeces, Excreta, Dry Cleansing Material, Organics

Fertiliser, Compost/Biosolids, (Fertigation Water)

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, 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 or Urinal can, therefore, improve the quality of the compost (see also urine diversion components).

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).

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.

Applicability

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.

 

Library references

Technology Review of Composting Toilets

This GIZ publication explains the design, use and operational requirements of composting toilets. Ample examples for composting toilets from around the world are included in the publication to show that these types of toilets have a wide range of applications under a variety of circumstances (for wealthy or poor people; for cold, hot, wet or dry climates; for urban or rural settings). The appendix contains a listing of suppliers.

BERGER, W. ; (2011): Eschborn: Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) URL [Accessed: 06.02.2012]

The Composting Toilet System Book

The Composting Toilet System Book is an impressive, comprehensive, reader friendly, and practical guide to choosing, planning and maintaining composting toilet systems for those seeking an alternative to traditional sewer and septic tank systems. It explains the technologies, sources, applications, greywater issues, and regulations relevant to a composting toilet system for the home, whether manufactured or site-built.

DEL PORTO, D. ; STEINFELD, C. ; (1999): A Practicle Guide to Choosing, Planning and Maintaining Composting Toilet Systems, an Alternative to Sewer and Septic Systems. Concord: Center for Ecological Pollution Prevention (CEPP)

The Humanure Handbook

A comprehensive book on recycling human excrement without chemicals, high technology or pollution. Well written, practical, and thoroughly researched, this self-published book is built on nearly twenty years of experience by the author, who tells us about every aspect of dealing with excrement on the home-scale level. Only available for free as web book.

JENKINS, J. ; (2005): A Guide to Composting Human Manure. (= 3rd Edition ). Grove City: Joseph Jenkins Inc. URL [Accessed: 16.08.2010]

Toilets That Make Compost

This book describes in an easy-to-understand and picture-based way how to construct three different low cost sanitation solutions, namely arborloos, fossa alterna and urine diversion toilets.

MORGAN, P. EcoSanRes (2007): Stockholm: Stockholm Environment Institute

Composting Toilets

Factsheet including information related to microbial die-off rates and health risks.

U.S. EPA (1999): (= Water Efficiency Technology Fact Sheet, EPA 832-F-99-066 ). Washington: United States Environmental Protection Agency, Office of Water URL [Accessed: 16.08.2010]
Further Readings

Technology Review of Composting Toilets

This GIZ publication explains the design, use and operational requirements of composting toilets. Ample examples for composting toilets from around the world are included in the publication to show that these types of toilets have a wide range of applications under a variety of circumstances (for wealthy or poor people; for cold, hot, wet or dry climates; for urban or rural settings). The appendix contains a listing of suppliers.

BERGER, W. ; (2011): Eschborn: Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) URL [Accessed: 06.02.2012]

Basic overview of Composting Toilets (with and without urine diversion)

The publication explains the purposes of urine diversion, its benefits and challenges, possibilities of urine treatment and reuse in agriculture. It provides an overview on design and operational aspects for equipment needed, such as waterless urinals and urine diversion toilets. An appendix with a worldwide listing of suppliers for waterless urinals and urine diversion toilet pedestals and squatting pans is also available.

GTZ (2010): (= Technology Review ). Eschborn: German Agency for Technical Cooperation (GTZ) GmbH URL [Accessed: 22.11.2010]

Toilets

The first part of a sanitation system is the „user interface“, i.e. the toilet, pedestal, pan or urinal. It is an important part of the sanitation system because this is the part the user comes in contact with. Acceptance of a sanitation system therefore often mainly depends on the acceptance of the user interface. This paper gives an overview on developments of different technologies for user interfaces (UDDTs and urinals). The contributions present developments in different geographical regions: South America, East Africa and the Eastern Europe, the Caucasus and Central Asia (EECCA) countries.

ECOSAN CLUB (2011): (= Sustainable Sanitation Practice , 6 ). Vienna: Ecosan Club URL

Guidelines for the safe use of wastewater excreta and greywater. Volume IV. Excreta and Greywater Use in Agriculture

Volume IV of the Guidelines for the Safe Use of Wastewater, Excreta and Greywater recognizes the reuse potential of wastewater and excreta (including urine) in agriculture and describes the present state of knowledge as regards potential health risks associated with the reuse as well as measures to manage these health risks following a multi-barrier approach.

WHO (2006): Geneva: World Health Organisation URL [Accessed: 26.02.2010]

Ecological Sanitation - revised and enlarged edition

This book is one of the most fundamental and important books that defined the concept of ecological sanitation. The first version came out in 1998 - this version presents the findings of over ten years of research and development in ecological sanitation supported by SIDA (Swedish International Development Cooperation Agency).

WINBLAD, U. ; SIMPSON-HERBERT, M. ; (2004): (pdf presentation). Sweden: Stockholm Environment Institute URL [Accessed: 04.08.2010]

The Humanure Handbook

A comprehensive book on recycling human excrement without chemicals, high technology or pollution. Well written, practical, and thoroughly researched, this self-published book is built on nearly twenty years of experience by the author, who tells us about every aspect of dealing with excrement on the home-scale level. Only available for free as web book.

JENKINS, J. ; (2005): A Guide to Composting Human Manure. (= 3rd Edition ). Grove City: Joseph Jenkins Inc. URL [Accessed: 16.08.2010]

Human Excreta Treatment Technologies - prerequisites, constraints and performance

The thesis consists of three papers, the first of which investigates incineration of faecal matter as a treatment and sanitation method using a locally fabricated incinerator made of steel sheets. The second and third papers investigate composting of faeces and food waste at two size scales, using 78-litre and 216- litre wooden reactors.

NIWAGABA, C. ; (2007): (= Licentiate thesis ). Uppsala: Swedish Agricultural University (SLU), Department of Biometry and Engineering

Smart Sanitation Solutions

Smart Sanitation Solutions presents examples of low-cost household and community-based sanitation solutions that have proven effective and affordable. A wide range of innovative technologies for toilets, collection, transportation, treatment and use of sanitation products that have already helped thousands of poor families to improve their lives is illustrated.

NWP (2006): Examples of innovative, low-cost technologies for toilets, collection, transportation, treatment and use of sanitation products. (= Smart water solutions ). Amsterdam: Netherlands Water Partnership (NWP) URL [Accessed: 13.04.2010]

Guidelines for the safe use of wastewater excreta and greywater. Volume IV. Excreta and Greywater Use in Agriculture

Volume IV of the Guidelines for the Safe Use of Wastewater, Excreta and Greywater recognizes the reuse potential of wastewater and excreta (including urine) in agriculture and describes the present state of knowledge as regards potential health risks associated with the reuse as well as measures to manage these health risks following a multi-barrier approach.

WHO (2006): Geneva: World Health Organisation URL [Accessed: 26.02.2010]

Composting Toilets

Factsheet including information related to microbial die-off rates and health risks.

U.S. EPA (1999): (= Water Efficiency Technology Fact Sheet, EPA 832-F-99-066 ). Washington: United States Environmental Protection Agency, Office of Water URL [Accessed: 16.08.2010]

Construction of Ecological Sanitation Latrine

This document sets out the principles for adopting an ecological sanitation approach, as well as providing guidance on the construction ecological sanitation latrines and their operation. It is intended to support sanitation field practitioners and WaterAid in Nepal ’s partners in the delivery of appropriate services and technologies to fit the needs of different users. .It is also equally hoped that this document will be of value to other organisations and sector stakeholders involved in sanitation promotion and ecological sanitation.

WATER AID (2011): Kathmandu: Water Aid URL [Accessed: 19.10.2011]

Methods of Using "Toilet Compost" in Agriculture

This document gives a simple overview over toilet compost, its preparation and fields of application.

MORGAN, P. ; (2010): Stockholm : Ecological Sanitation Research (EcoSanRes), Stockholm Environment Institute (SEI) URL [Accessed: 20.06.2013]

The Toilet That Makes Humus

This easily understandable presentation deals with making humus in shallow pits by means of the Fossa alterna. Foci are set on: - How the Fossa alterna works (in Zimbabwe, Mozambique, Malawi) - Stages of construction - Routine management - Changing pits - Potential problems - Hand washing devices - Humus from the Fossa alterna - Enhanced growth of vegetables with “Fossa humus”

MORGAN, P. ; (2004): An Account of the Fossa Alterna System and its Usefulness in Rural and Peri-Urban Communities. Stockholm : Ecological Sanitation Research (EcoSanRes), Stockholm Environment Institute (SEI) URL [Accessed: 20.06.2013]

Plant Trials Using Fossa Alterna Humus

The ultimate proof of the usefulness of eco-humus and urine in agriculture is to demonstrate its effect on plant growth and yield directly. This chapter describes a series of trials in which the growth and yield of vegetables planted in humus derived from the Fossa alterna were studied.

MORGAN, P. ; (2004): Stockholm : Ecological Sanitation Research (EcoSanRes), Stockholm Environment Institute (SEI) URL [Accessed: 20.06.2013]
Case Studies

UDD Toilets with Reuse in Allotment Gardens.

Case study on an urban agriculture project with urine reuse in Northern Mindanao, Philippines.

HOLMER, R. SuSanA (2009): (pdf presentation). (= SuSanA case study ). Cagayan de Oro Philippines: Sustainable Sanitation Alliance URL [Accessed: 11.08.2010]

Improved traditional composting toilets with urine diversion, Leh, Jammu and Kashmir State, India - draft

In Leh, a small town in Jammu and Kashmir, people try to replace traditional sanitation systems by waterborne toilet systems. This project tries to revitalise the traditional ecological sanitation practice that is threatened to fall into oblivion. Different improvements of the traditional Ladhaki toilets are suggested. Due to an extremely dry climate, it is possible to process human excreta indoors without prior diversion of urine, by using a combination of soil composting and dehydration.

DAWA, S. ; KREUTZER, G. ; PANESAR, A. ; (2009): (= SuSanA - Case Studies ). Eschborn: Sustainable Sanitation Alliance (SuSanA) URL [Accessed: 02.08.2010]

Introducing Low Cost Productive Sanitation in a Peri-Urban Settlement

The following presentation deals with low cost ecological toilets (Fossa alterna) which were introduced at Hopley Farm, a settlement close to Harare, Zimbabwe. The presentation addresses the following topics: - How the alternating shallow pit system works - Local agricultural practice - Linking sanitation to agriculture - Testing for effect of urine - Linking sanitation to forestry

MORGAN, P. ; (2010): Stockholm : Ecological Sanitation Research (EcoSanRes), Stockholm Environment Institute (SEI) URL [Accessed: 20.06.2013]

Ecological Sanitation in Malawi

This illustrative presentation on ecological sanitation in Malawi, focuses on the concept of ecological sanitation, types of eco-toilets and basic methods of recycling nutrient from human excreta.

MORGAN, P. ; (2010): Stockholm : Ecological Sanitation Research (EcoSanRes), Stockholm Environment Institute (SEI) URL [Accessed: 20.06.2013]

Experiments with Ecological Sanitation and Pit Emptying in Maputaland, South Africa

This document describes the experimental design of ecological sanitation and pit-emptying trials in Maputaland, South Africa. It describes the situation found at field visits in 2000 and 2003.

MORGAN, P. ; (2003): A Description of Visits Made in 2000 and 2003. Stockholm : Ecological Sanitation Research (EcoSanRes), Stockholm Environment Institute (SEI) URL [Accessed: 20.06.2013]

The Arborloo Book for Ethiopia

This booklet describes how to make a toilet which is both low cost and easy to make. Builders and artisans are not required, once the householder has learned the basic methods of construction.

MORGAN, P. ; (2007): How to Make a Simple Pit Toilet and Grow Trees and Vegetables. Stockholm : Ecological Sanitation Research (EcoSanRes), Stockholm Environment Institute (SEI) URL [Accessed: 20.06.2013]

Lessons from a Low Cost Ecological Approach to Sanitation in Malawi

Low cost Ecological Sanitation programs in Malawi have led to the building of over 11,000 compost-producing toilets since 2003. While the toilets are affordable and simple to construct, the fact that they convert human waste into valuable odour-free compost, enables cost recovery for households and is a prime driver in popularizing EcoSan designs. This field note summarizes the lessons learned thus far in Malawi’s efforts to popularize ecological sanitation.

MORGAN, P. ; (2007): Washington: Water and Sanitation Program (WSP) URL [Accessed: 20.06.2013]

Ecological Sanitation in Southern Africa

This document describes the ecological sanitation situation in South Africa, focussing on the range of technological options, promotional methods and recycling methods and the problem areas.

MORGAN, P. ; (2005): Many Approaches to a Varied Need. Stockholm : Ecological Sanitation Research (EcoSanRes), Stockholm Environment Institute (SEI) URL [Accessed: 21.06.2013]

Solutions for Mountain Regions

This Sustainable Sanitation Practice (SSP) issue contains the following contributions: 1. Source Separating Solutions for Mountain Regions, 2. "Gloggnitzer Huette" Sanitation System, 3. Solid Waste Management in Mountain Refuges.

MUELLEGGER, E. ; LANGEGRABER, G. ; LECHNER, M. (2011): (= Sustainable Sanitation Practice , 8 ). Vienna: Ecosan Club URL [Accessed: 01.07.2013]

The ROSA Project

The ROSA project stands for Resource-Oriented Sanitation concepts for peri-urban areas in Africa. This Sustainable Sanitation Practice (SSP) issue contains the following contributions: 1. Introduction to the ROSA Project, 2. From Pilot Units to Large-Scale Implementation - Ethiopia, 3. Implementation of UDDTs at Schools - Kenya, 4. Urban Agriculture for Sanitation Promotion, 5. Operation an Maintenance in Practice, 6. Experiences from Strategic Sanitation Planning, 7. Main Findings and Main Achievements.

MUELLEGGER, E. ; LANGEGRABER, G. ; LECHNER, M. (2010): (= Sustainable Sanitation Practice , 4 ). Vienna: Ecosan Club URL [Accessed: 01.07.2013]

Delivering Water, Sanitation and Hygiene Services in an Uncertain Environment: Thermophilic Composting of Human Wastes in Uncertain Urban Environments

This paper describes the project of constructing a thermophilic composting site in Haiti after the earthquake in 2010. The composting facilities have treated over 500,000 gallons of human waste in the past three years, converting it to pathogen free compost, over 10,000 gallons of which has been sold for use in agriculture and reforestation projects. The experience of thermophilic composting in Haiti is unique in scale and duration and can have global implications for waste treatment in both emergency and development contexts.

KRAMER, S. ; PRENETA, N. ; KILBRIDE, A. ; (2013): A Case Study from Haiti. (= WECD International Conference , 36 ). Oakland: Sustainable Organic Integrated Livelihoods (SOIL) URL [Accessed: 01.11.2013]

Delivering Water, Sanitation and Hygiene Services in an Uncertain Environment: Piloting Ecological Sanitation (EcoSan) in the Emergency Context of Port-au-Prince, Haiti, after the 2010 Earthquake

The earthquake that struck Haiti in January 2010 and the cholera epidemic that followed from October 2010, resulted in one of the largest humanitarian relief efforts in history. Many of the internally displaced persons camps were located in urban neighbourhoods with high groundwater, making onsite sanitation extremely difficult. In response to these unique conditions a small local organization, SOIL, partnered with Oxfam Great Britain to pilot urine diversion EcoSan toilets in camps throughout Port-au-Prince. This briefing paper covers this pilot project from March 2010 through March 2012. During that 2-year period, SOIL’s toilets served over 20,000 people and treated more than 400,000 gallons of human waste, converting it to rich compost.

KILBRIDE, A. ; KRAMER, S. ; PRENETA, N. ; (2013): (= WECD International Conference , 36 ). Oakland: Sustainable Organic Integrated Livelihoods (SOIL) URL [Accessed: 01.11.2013]
Training Material

Constructing Compost Toilets

Technical brief on the construction of composting toilets.

USAID (n.y): (= Water for the World, Technical note ). Washington: United States Agency for International Development (USAID) URL [Accessed: 11.08.2010]

Designing Compost Toilets

Technical brief on the design of composting toilets.

USAID (n.y): (= Water for the World, Technical note ). Washington: United States Agency for International Development (USAID) URL [Accessed: 11.08.2010]

Construction of Bench Style Double Vault Urine Diversion Toilet and Alternatives

The use of Urine Diversion (UD) in dry toilets allows faeces dehydration. Urine can be reused as urea, while faeces are dried in a double vault system of alternate use. The moisture comes out using ventilation pipes. After 2 years the end product can be emptied and reused without having any health risk. Water from washing can be treated in a constructed wetland and reused for instance for irrigation.

HOFFMANN, H. ; (2012): Lima: Rotaria del Peru SAC URL [Accessed: 26.03.2012]
Awareness Raising Material

This is the compact version of the factsheet.

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