EcoEng Newsletter No. 11, September 2005

When Indian Ecology Meets Swiss Engineering

Lessons learnt from Ecosan in Rajendra Nagar slum, Bangalore

Content No. 11/05
Title page / Index
From the editors
Faces: H.v.Bohemen
Review: EE Book
Overview, Etnier
Kirk et al.
Composting (ch. 4)
Fecal composting
Policy Finl, Mattila
Desert infrastruct.
Writers' Fund
Ecosan Durban 05
Good bye T. Rohrer
Various issues:
Joe's Corner
Mailing list
By Urs Baier & Alexandra Baumeyer

HSW University of Applied Sciences
Waedenswil, Switzerland

Urs Baier:
Born 1957 in Switzerland.
4 years of diploma studies in biotechnology at the ETH Technical University in Zurich, Switzerland
Ph.D. studies at ETH in environmental biotechnology on the subject of thermophilic sludge treatment.
9 years of industry practice as R&D manager in wastewater treatment, biogas technologies, and sludge treatment.


Ecological Sanitation in an Indian Slum

  In 2001, in Bangalore India, a source separation toilet project was started [which allows separate collection of urine, feces and washwater, the editor], to improve the living conditions of slum dwellers and to stop the pollution of both soil and water by fecal contamination. A collaboration between seecon GmbH in Wolhusen, Switzerland, and ACTS Academy of higher education in Bangalore, India, implemented toilets and sanitary arrangements in slum areas and transformed the attitudes of the population dwelling in them.

The ideas behind this project are manifold:

  • to improve the living conditions in the slums and to reduce the risk of spreading diseases by establishing toilet centers;
  • to develop the commercial production of compost and fertilizer by collecting urine and feces separately;
  • to generate an income for the development of the slum by selling fertilizer and charging for the use of the toilet;
  • to give slum-dwellers self-responsibility by instructing them how to operate the toilet themselves; and finally
  • to change the attitudes of people and encouraging them to consider human excreta as a valuable resource.

Through this project, a toilet center has been installed in the Rajendra Nagar slum and a composting area has been developed on the Rayasandra campus of ACTS, where human excreta can be transformed into compost and urine is stored and used as fertilizer. The toilet in the Rajendra Nagar slum became open to use in June 2001 and has been fully accepted by the locals since then [1].

Figure 1: Source separation of urine, feces and water at the Eco-Toilet in the Rajendra Nagar slum, Bangalore, India
  The collected feces are brought to the campus of ACTS academy and composted at a compost facility there. ACTS academy, seecon GmbH, and HSW University of Applied Sciences joined in 2003 to perform an in-depth analysis of nutrient and mass flows of the compost facility in Bangalore [2].Tests for hygienic properties of the compost were also included in the study, nutrient availability was tested with standardized plant growth tests, and technological attempts at system optimization were set up.

During the six-month testing period, a number of topics were addressed which made clear, that even with a solid scientific knowledge the unexpected can happen.


Sanitizing without heat

  Hygiene facts of Rayasandra's compost are: tomato seeds lose their ability to sprout and grow after 29 days exposure in compost, although temperature never exceeded 40 °C. Helminth eggs (tapeworm, Taenia sp.) were detected in mature compost but were not viable. E. coli concentrations in mature compost dropped by 4 – 5 orders of magnitude compared to raw feces, down to a level of 800-4000 CFU per ml [CFU = colony forming units, the editor].
Figure 2: Composting facility at Rayasandra campus, Bangalore, India
  Sanitizing, meaning the inactivation of plant seeds and of potentially pathogenic microorganisms in compost, is [usually] fully attributed to thermal processes. Temperatures of 65 - 74 °C are usually reached in well maintained (= aerated) composts due to the microflora's exothermal reactions. Most quality-enforcing compost regulations demand a period of 14 days at temperatures of 55 °C or higher to achieve a conforming end product [3]. These temperatures were by far not reached in the compost piles observed in Rayasandra. Maximum temperature topped at 39 °C with an average at 35 °C.

Lesson learned: end product quality (sanitizing, absence of indicator organisms) does not necessarily reflect process quality (lack of high temperature phase). The compost obtained is of good hygienic quality, the composting process itself is not. Pathogen and weed seed reduction can be attributed to an uncontrolled high pH regime (8.2 < pH < 9.6) and not to controllable high temperature phases. Further process optimization will enforce a proper temperature regime by making sure the heaps are frequently turned over.


Nitrification without oxygen

  Ammonia nitrogen in compost of a mixture of waste paper and excreta decreased from initial values of 3000 – 4500 mg NH4-N per kg of compost dry matter down to 40 - 60 mg NH4-N per kg D.M. within 16 – 18 weeks without significant formation of nitrate. During this period, when the compost was not turned and aerated sufficiently, pH stayed high at 8.2 - 9.4. Only after pH fell below 8.0 was there a clear formation of nitrate, often accompanied by elevated nitrite levels.

In Europe it is quite common to check compost maturity during a post-thermophilic phase based on nitrification. Ammonia nitrogen, an easily accessible parameter, shows a dynamic behavior and will decrease as a result of nitrate-producing nitrification processes. Adequate oxygen supply by aeration or turning as well as a physiologically acceptable pH of 6.7 – 8.0 are prerequisite.

Lesson learned: Ammonia nitrogen is not a reliable parameter to check compost maturity in fecal compost (as it would be in lignocellulose material). Due to the high initial ammonia concentration and an elevated pH value, ammonia losses during the initial composting process are evaporative rather than microbial. Elevated temperatures will increase evaporation. Further process optimization will concentrate on initial pH control.


Let scavengers become nutrient managers.

  The battle for the rehabilitation of scavengers is in everybody's mind in India. [Scavengers] provoke the reservation and disgust of their neighbors and of some observers. The eco-toilet project necessitates the transport of the material to the composting place to be transformed into compost. This method of transport, although very different from the bhangi system of carrying the excreta on the head, is considered by some people as a form of scavenging. This is not scavenging, however: the material transported is a substrate for the composting process and the transport is carried out with carts and a truck. The material is never actually carried. The population's perception of the project still needs to be improved.

Lesson learned: Material leaving the human body might be excreta - as soon as it is collected, transported and treated, it is a valuable substrate and nutrient source and should be labeled and communicated this way.


Be clean, be aware and stay alert!

  "Cleanliness is next to godliness" is a conclusion M.K. Gandhi arrived at during his peaceful opposition to the British Empire and struggle for the rights of the poor in India. The general awareness of hygiene in rural India is usually high. Life and work, as miserable they may be, are characterized by a high level of bodily hygiene. From the very beginning of Rajendra Nagar's eco-toilet and Rayasandra's composting facility operation, it was clear, that high personal hygiene standards as well as a profound sense for environmental hygiene were to be crucial factors for the story's success. A "Manual for hygiene and maintenance of industrial health and safety standards" was introduced in 2001, designating unclean "red areas" and defining (amongst others) detailed procedures for material handling, workers health control, and composting process control.

After more than three years of operation of the nutrient transport scheme and the composting facility, many recommendations are no longer strictly adhered to. The workers motivation and awareness of their own role as nutrient managers has somewhat faded away. Without their proper sense for horticulture, agriculture, and nutrient management, it was sometimes easier to dump a whole drum of urine at the foot of one single banana tree instead of storing and "managing" the nutrients. A lack of understanding of the basic principles of composting led to "workload minimization" rather than process optimization. Care for personal safety precautions is easy to neglect if not under the sharp eyes of the supervisor or even the European professor.

Figure 3: Salt deposits from urine over-fertilization
  Lesson learned: Don't just tell people hygiene precautions and composting principles but convince them to work together towards a better future (including personal hygiene and compost).

Rajendra Nagar's eco-toilet and Rayasandra's composting facility have proved to be valuable and working concepts for poverty reduction, hygiene promotion, and social security improvement over the past 3 years. Environmental aspects such as compost hygiene and nutrient management must be on the agenda in the near future to assure a successful multiplication of the hitherto successful single story.



  [1] Heeb J. et al. (2000): Ecological engineering – three case studies, Waste Recycling And Resource Management in the Developing World, B.B. Jana, R. D. Banerjee, B. Guterstam and J. Heeb (Eds), University of Kalyani, India and International Ecological Engineering Society, Switzerland.

[2] Baumeyer A. (2004): New Toilets for Indian Slums – Nutrient Mass Balance of a Co-Composting Plant in Bangalore, India. Diploma Thesis SBT00, HSW University of Applied Sciences, Waedenswil, Switzerland

[3] Baier U. (2005) Total Quality and Safety Management for Anaerobic Digestion and Composting of Biological Wastes. Proceedings ADSW2005 Conference on Anaerobic Digestion of Solid Wastes, Copenhagen, Denmark. (in press)

© 2005, International Ecological Engineering Society, Wolhusen, Switzerland