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(Co-) composting (Small-scale)

Author/Compiled by
Bhushan Tuladhar (Environment and Public Health Organization (ENPHO))
Dorothee Spuhler (seecon international gmbh)
Executive Summary

Composting at the household level is an important method for managing organic waste, which is normally the largest portion of household waste. Composting reduces the environmental impacts of waste and the produced compost is essential for improving soil fertility and structure. Besides the organic waste, composting can also be applied as secondary treatment for faeces and excreta collected in urine diversion and composting toilets. Degradation of organic material is a natural process, but composting allows us to control and accelerate this process by optimising the environment for microbial activity in the waste. Composting involves three stages: preparation of the waste by adjusting its size, moisture content and carbon-nitrogen ratio; degradation of waste in pits, piles, vessels or vermi-composting; and finally preparing finished compost by curing and screening.

Advantages
As organic waste creates problems such as smell, leachate, flies and rodents, and emission of methane – a greenhouse gas – in landfill sites, composting of organic waste reduces these problems at the landfill site
Production of compost at home will encourage the use of organic farming and reduce the need for chemical fertilisers
Household composting reduces the amount of waste that needs to be collected and managed, thus reducing the cost of solid waste management
In areas where waste collection and management systems are not effective, household composting will reduce haphazard waste disposal and its related environmental impacts
As private scrap dealers generally do not collect organic waste, household composting will help increase the recycling rates
Separation of organic waste and composting at the household level ensures that the remaining waste is clean and easier to recycle
Household composting is a simple practice that anyone can do at home with minimum resources
Household composting can be an educational tool for young children at home
Disadvantages
If not done properly, household composting can cause problems such as smell, leachate, flies and rodents
Composting requires a little space, especially compost pits or piles
In houses without gardens or flower pots, the compost may not be of much use
In Out

Faeces, Excreta, Organic Solid Waste

Compost/Biosolids

Municipal solid waste management starts at the household level as households are the main source of waste in most urban areas. Waste minimisation and managing of waste as close to the source as possible are the two most important tools for reducing cost and improving efficiency of waste management systems. Thus, waste recycling at the household level is very important.

Organic matter such as food waste and yard waste are the main components of household waste. Other types of waste generated by households include inorganic components plastics, metals, glass, and inert materials such as soil. The portion of organic waste in household waste is generally higher in developing countries. In Nepal, for example, over 65 % of the total waste is organic waste.

 

Compost bin in Kathmandu (left) and Compost barrel in Bangladesh (right). Source: ENPHO (left) and Waste Concern (right)

Compost bin in Kathmandu (left) and Compost barrel in Bangladesh (right). Source: ENPHO (n.y.) (left) and WASTE CONCERN (n.y) (right)

Organic waste can be recycled at the household level to produce animal feed, biogas (i.e. anaerobic digestion small-scale; anaerobic digestion of organic waste) or compost. Among these options, composting is probably the most simple and common method for recycling household organic waste. Composting is the process of optimising the environment in the waste for microbial activity to decompose organic matter into valuable nutrients for the soil. Household composting involves the following three stages: waste preparation, degradation of waste and finishing of waste.

Waste Preparation

A volunteer explains composting options in Siddhipur. Source: S. Pradhan, ENPHO

A volunteer explains composting options in Siddhipur. Source: Sapc. Pradhan, ENPHO (n.y.)

Waste needs to be sorted and prepared for rapid degradation. This includes the following steps:

  • Mix the waste to ensure that the carbon to nitrogen ratio (C:N) is close to 25 – If the waste has too much carbon (normally brown waste such as dried leaves) it should be mixed with waste that has high nitrogen content (also known as green waste such as green grass clippings). Kitchen waste only normally has a suitable C:N ratio for composting.
  • Chop the waste into small pieces. Large pieces of organic waste should be cut to small pieces to accelerate the composting process.
  • Adjust the moisture content to about 50 per cent. A compost pile with 50% moisture should feel moist but water should not be dripping from it.
  • Add a starter such as mature compost or effective microorganisms (EM) to speed up the composting process.

Degradation of Waste

Once the waste is converted into raw material for composting, the waste can be degraded using one of the methods mentioned below. The degradation process should be controlled by maintaining adequate temperature, moisture and aeration. There are different types of vessels for composting at this stage: composting in pits, composting in piles, in-vessel composting and vermi-composting.

Compost pits

One simple method for composting organic waste is to put it in pits and let it turn into compost over a period of six months or more. This process requires some space and time but the main benefit is that the waste is not visible as it is buried in the pit.

Compost piles

In this method, the waste is put in piles on the ground and regularly turned to allow aeration. The size of the pile may vary depending on the amount of waste and available space, but generally, it should be 1 to 2 m on each side and not more than 1.5 m in height. Chicken wire or wooden planks can be used to keep the pile together.

In-vessel composting

Compost can also be made in made in bags or bins. Normally holes are made in the bin or bags to allow aeration. Compost bins can be made from 100 to 200 litre plastic bins or barrels. In order to allow proper aeration, the bin is normally divided into two sections with a grill separating the two sections. Organic waste is put into the top section and allowed to degrade and once the compost is prepared it is removed from the bottom section. Because of the natural draught created in the bin by the grill and the holes, frequent turning of the waste is not required in this method. Municipalities and NGOs in countries such as Nepal, Bangladesh and Sri Lanka have been distributing compost bins to residents at subsidised rates to promote household composting (TULADHAR 2004; ALI 2004; LEKAMMUDIYANSE et al. 2009).

Vermi-composting

Vermi-composting in Kathmandu (left) and worms used for vermi-composting (right). Source: S. Pradhan, ENPHO

Vermi-composting in Kathmandu (left) and worms used for vermi-composting (right). Source: S. Pradhan, ENPHO (n.y.)

Vermi-compost, ready to use. Source: ENPHO

Vermi-compost, ready to use. Source: ENPHO (n.y.)

This involves the use of special types of earthworms to convert organic waste into worm casting, which is better than ordinary compost in improving soil’s structure and fertility. Vermi-composting is a simple and effective process that can be done indoors in the kitchen itself as it requires very little space and does not cause problems such as odour. Most common worm species for vermi-composting are Eisenia foetida, Lumbricus rubellus, and Eisenia hortensis (KOFF et al. 2007). The worms are placed in bedding made of loose materials such as coconut husk or shredded paper in a shallow box or tub and fed with soft organic matter such as kitchen waste. After about two months the compost can be harvested by putting the compost in the shape of a cone and scrapping off the top layers. The worms go to the bottom of the cone as they run away from light.

Finishing

Plan of bin composting. Source: ENPHO

Plan of bin composting. Source: ENPHO (n.y.)

Once the compost is prepared, it needs to be cured and screened before it is applied in the soil. The composting process is complete when (KOFF et al. 2007):

  • The compost pile’s internal temperature has decreased to within 5 degrees of outside temperature.
  • There is little or no discernible plant material left in the compost
  • The compost has a dark brown, crumbly and rich look (similar to chocolate cake)

Once the compost is ready, it should be left for about a month for curing and then screened using a fine screen. The end product can now be used as soil amendment (use of compost). Any material that has not yet decomposed can go back into the compost pile or bin.

Composting of Faeces and Excreta and Co-composting

Besides organic waste, composting can also be applied as a secondary treatment for faeces and excreta collected in UDDTs (urine diversion dehydration toilets) or vault composting toilets. The process is the same as the one that takes place in any pit-composting toilet (e.g. fossa alterna, arboloo). Composting can also be applied for the secondary treatment of sludge from twin-pits for pour-flush toilets or digest from anaerobic digesters or any other pre-treated sludge. Even better results can be achieved when organic wastes are composted together with faeces in order to optimise the C/N ratio. Co-composting can be done either in the toilet or off-site similar to pure household waste (in compost, compost piles, In-vessel composting Vermi-composting). See also VALLEY VIEW UNIVERSITY (2008) for more information.

Applicability

Household composting is applicable in all households and most institutions that generate organic waste. Certain methods such as compost pits and compost piles require some outdoor space but compost bins can be placed on balconies and vermi-composting can be done indoors as well in an area less than 1m2. Household composting is especially beneficial for households with home gardens or indoor plants that can use the compost. Economic benefits of household composting include reduced cost of waste disposal and reduced cost of fertilisers.
Faeces and excreta form urine diversion dehydration toilets and composting toilets as well as sludge from twin-pits for pour-flush toilets or digestate from anaerobic digesters  or any other pre-treated sludge can also be composted together with organic waste in order to sanitise these products and to increase composting yields. However, when composting such products, special care should be taken since the associated health risk is higher than for kitchen waste.
 

Library references

Sustainable Composting Case Studies and Guidelines for Developing Countries

This publication presents the findings of a research on “Promoting Composting as a Business for the Urban Poor” in the form of guidelines based on case studies from India, Bangladesh, Sri Lanka, Pakistan and Ethiopia.

ALI, M. (2004): Leicestershire: Water Engineering and Development Centre, Loughborough University URL [Accessed: 05.08.2010]

Compost Barrel

This brochure describes the compost barrels, promoted in Bangladesh and explains how to use them. 4

WASTE CONCERN (n.y): URL [Accessed: 05.08.2010]
Further Readings

Wasted Agriculture. The Use of Compost in Urban Agriculture

This report presents the findings of an inventory study of various organisations promoting urban agriculture to see if urban agriculture can be a market for compost made from solid waste.

HART, D. ; PLUIMERS, J. ; (1996): (= UWEP Working Document 1 ). Gouda: WASTE URL [Accessed: 05.08.2010]

Organic Waste. Options for small-scale resource recovery

This book is the first in a series on Urban Solid Waste Recovery, and represents an attempt to document the experiences of recycling activities in cities around the world. It covers the whole waste chain from municipal or agricultural generation of organic waste to different treatment methods, such as composting, co-composting, anaerobic digestion with production of biogas, and briquetting.

LARDINOIS, I. ; KLUNDERT v.d., A. ; (1993): (= Urban Solid Waste Series 1 ). Gouda: WASTE Consultants

Manual for Composting at Domestic Level

This booklet describes the process of composting at the household level and provides instructions for building and operating a compost bin made from a 200-litre water tank.

NYACHHYON, B.L. ; MALLA, G. ; (2005): Kathmandu: Zero Waste Nepal and Rotary Club of Mt. Everest

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

Sustainable Composting Case Studies and Guidelines for Developing Countries

This publication presents the findings of a research on “Promoting Composting as a Business for the Urban Poor” in the form of guidelines based on case studies from India, Bangladesh, Sri Lanka, Pakistan and Ethiopia.

ALI, M. (2004): Leicestershire: Water Engineering and Development Centre, Loughborough University URL [Accessed: 05.08.2010]

Vermicomposting. Guide H-164

Factsheet on the operation and maintenance of vermi-composts.

DICKERSON, G. ; (2004): New Mexico: New Mexico State University, Cooperative Extension Service, College of Agriculture and, Home Economics URL [Accessed: 11.08.2010]

Composting in the Tropics

This booklet describes the principles of composting with focus on the heap method.

HDRA (1998): The Organic Organisation URL [Accessed: 11.08.2010]

Composting in the Tropics II

This booklet follows on from ‘Composting in the Tropics’, which concentrated especially the heap method. This second booklet looks at other methods of producing compost, including variations on the heap method and also describes practices suitable for different climates in the tropics, for example arid areas.

HRDA (1998): The Organic Organisation URL [Accessed: 11.08.2010]

Decentralised Composting in India – Lessons Learnt

The paper discusses the findings of a study of 20 compost plants, ranging in size from household composting to large centralised composting facilities, in Bangalore, Chennai, Pune and Mumbai.

ZURBRUGG, C. ; DRESCHER, S. ; PATEL, A.H. ; SHARATCHANDRA S.C. ; (2002): (= Paper presented at 28th WEDC Conference in Kolkata 18-22 November, 2002 ). Leicestershire: Water Engineering and Development Centre, Loughborough University URL [Accessed: 05.08.2010]

How to Select Appropriate Technical Solutions for Sanitation

The purpose of this guide is to assist local contracting authorities and their partners in identifying those sanitation technologies best suited to the different contexts that exist within their town. The first part of the guide contains a planning process and a set of criteria to be completed; these assist you in characterizing each area of intervention so that you are then in a position to identify the most appropriate technical solutions. The second part of the guide consists of technical factsheets which give a practical overview of the technical and economic characteristics, the operating principle and the pros and cons of the 29 sanitation technology options most commonly used in sub-Saharan Africa.

MONVOIS, J. ; GABERT, J. ; FRENOUX, C. ; GUILLAUME, M. ; (2010): (= Six Methodological Guides for a Water and Sanitation Services' Development Strategy , 4 ). Cotonou and Paris: Partenariat pour le Développement Municipal (PDM) and Programme Solidarité Eau (pS-Eau) URL [Accessed: 19.10.2011]

Compost Barrel

This brochure describes the compost barrels, promoted in Bangladesh and explains how to use them. 4

WASTE CONCERN (n.y): URL [Accessed: 05.08.2010]

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]
Case Studies

Vermi-Composting brings better yields and returns – A farmer shows the way

This is the case of a small farmer who chose to be different from the typical resource-poor farmers struggling to make a living in the degraded drylands. His deep ‘love for life’ has not only earned him a decent living, but more importantly, it has inspired many other farmers to emulate him.

AME FOUNDATION (2007): (= AMEF Case Study Series 6 ). Bangalore: AME Foundation URL [Accessed: 05.08.2010]

Composting at Households in Kitgum Town, Uganda - Draft

A case study on household-level composition in Kitgum, Uganda. The project aims at using composting to develop practical operation and management strategies for peri-urban areas and to demonstrate the safe reuse of faces by co-composting them.

KINOBE, J. ; OLWENY, S. ; NIWAGABA, C. ; (2010): (= Susana Case Study ). Eschborn: Susana URL [Accessed: 16.08.2010]

Solid Waste Management in Nepal. Facsheet

This 12-page factsheet reflects the existing management systems practiced in various areas of Nepal in managing solid waste and contains initiatives of Municipalities; national and local NGOs/CBOs; public and private entities. The paper helps to transfer the lessons and existing practices regarding solid waste management and encourages urban, peri-urban and emerging towns for similar initiatives in urban sanitation.

WATERAID NEPAL ; ENPHO (2008): Kathmandu: WaterAid Nepal Environment and Public Health Organization (ENPHO) URL [Accessed: 05.08.2010]

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]

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

Solid Waste Management. Lecture notes

This document provides an overview of the present state-of-the-art of solid waste production and management. It contains the characteristics of municipal solid waste and describes current waste treatment systems and technologies, as well as non-technical aspects like private sector involvement and financial arrangements.

EAWAG ; SANDEC (2008): (= Sandec Training Tool 1.0, Module 6 ). Duebendorf: Swiss Federal Institute of Aquatic Science (EAWAG), Department of Water and Sanitation in Developing Countries (SANDEC) URL [Accessed: 08.04.2010]

Household Composting with Worms

This 4-page factsheet provides information on making composting by worms at household level.

KOFF, J.P. de ; LEE, B. ; MICKELBART, M.V. ; (2008): (= Home and Environment, HENV-104-W ). Purdue University URL [Accessed: 05.08.2010]
Awareness Raising Material

Home Composting Brochure

The four-page brochure explains the basic of composting and how yard waste and food waste can be composted at home.

CORNELL UNVIERSITY (n.y): URL [Accessed: 05.08.2010]

Instructions for Compost Barrel

This leaflet describes the process of installing and using Compost Barrels. (English).

ENPHO (n.y): Kathmandu: Environment and Public Health Organization (ENPHO)

Options for Household Composting

This poster explains the different options for house hold composting was published to promote composting in Siddhipur, Nepal. (Nepali).

ENPHO (n.y): Kathmandu: Environment and Public Health Organization (ENPHO)

How to Make compost - Poster

This poster illustrates step-by-step instructions to make compost by using compost bin at household level (Nepali).

ENPHO ; UN HABITAT (n.y): Kathmandu: Environment and Public Health Organization (ENPHO)

Vermi-composting - Poster

This poster describes the steps for doing vermi composting at home (Nepali).

ENPHO Kathmandu: Environment and Public Health Organization (ENPHO)

Askai Sticker

This sticker provides messages and slogan on Solid Waste Management. “Askai” is the mascot for solid waste management in Nepal.

JICA (n.y): Kathmandu: Japanese International Cooperation Agency (JICA) and Kathmandu Metropolitan City

Compost Barrel

This brochure describes the compost barrels, promoted in Bangladesh and explains how to use them. 4

WASTE CONCERN (n.y): URL [Accessed: 05.08.2010]

Alternative Versions to

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