In the second half of the nineteenth century, sewers were introduced into European cities to carry sewage and wastewater out of the towns, for disposal on land and into water bodies, and, later, for treatment. Prior to the introduction of sewage systems, cities suffered from stink and filth, and from epidemics and diseases - e.g. typoid and cholera - that are caused and enhanced by inappropriate disposal of human excreta. What, at that time, was an achievement in public hygiene and health, not only has become a very expensive system to maintain and operate, but is also to be regarded as a wasteful management of natural resources and hence as not sustainable.

(1.) The needs of two-thirds of the world population in regard to clean drinking water and sanitation are not met, about three billion people are lacking adequate sanitation. Water-borne diseases are the single most important cause of death and disease in developing countries, 80 % of all diseases and 25 % of all deaths in developing countries can be attributed to polluted water, but 69 % of India's population have no sanitation coverage. We recognize the need for sanitation and hygienic disposal of human excreta.

(2.) On the other hand, agriculture is suffering from lack of soil nutrients, and production of chemical fertilizers is energy-intensive. Theoretically, the nutrients in domestic wastewater and organic waste are nearly sufficient to fertilize crops to feed the world population, and, depending on soil and plant type, the excreta of one person can provide enough nutrients for 200 to 400 sq.m. agricultural production area. Within a few decades, the world reserves of phosphate are expected to be mined, and access to phosphate sources is likely to cause conflict. 74% of phosphorus in wastewater is found in toilet waste, most of it originating from urine. Yet, nutrients and energy in human excreta go largely unused.

(3.) The need to save water resources has become public knowledge, and measures to do so are easily understood and accepted. The conventional water toilet accounts for 2- to 40 % of the per capita water consumption.

The concept and its application

In order to set up hygienic systems of human waste disposal, to retrieve and re-use the nutrients from human waste, and to economize water use, the concept of ecological sanitation has been developed.

In practice, ecological sanitation includes options such as flush-free (and odour-free) urinals, separation toilets for urine and faeces, dry and composting toilets, dehydration devices for composting of faeces, use of faeces or excreta for the generation of biogas, vacuum sewers and flush systems operating on minimal amounts of water etc.

The hardware of these technologies has been developed in some parts of the world, mainly in Norwegian countries, and it needs to be developed in India too. Appropriate facilities are to be designed and mass-manufactured, to be made available and affordable, and various solutions - combinations of technologies and modules - need to be found for different social and economic contexts.

Ecological sanitation insists on maximum possible re-use of nutrients from human excreta. Urine uncontaminated by faeces requires minimal processing and can easily be re-used in farming and gardening. In order to avoid spread of pathogens, human faeces requires composting, either in a dry toilet without water, or if mixed with small volumes of wash or flushing water in a separate composting module, possibly dehydrated with the help of solar energy, or is to be digested in a biogas plant for recovery of methane gas and subsequent use of the dried sludge as fertilizer.

In a water-rich environment such as West Bengal and India's North-East, wastewater may be treated to an extent that it can be re-used for fish-farming or other water-intensive farming systems.

In this context the use of EM technology comes in handy as it can help to eliminate odours, to assure hygienic conditions in toilet rooms, toilets, and urinals, to compost wastes, to improve sewage treatment, to hygienize and improve aquaculture etc.

We promote this approach to a sustainable system of public hygiene and sanitation, give advice on options and technologies, and help in bringing stakeholders together to implement ecological sanitation.

More information can be found on the following websites:
www.gtz.de/ecosan
www.ecosanres.org
www.ecosan.nl

In urban conditions, ecological sanitation goes together well with practices of urban agriculture. In its efforts to "close loops" the concept also goes along with concerns of ecological and sustainable agriculture. It is also obvious that the concept of ecological sanitation in its efforts to "close loops" goes along with concerns and concepts of ecological and sustainable agriculture in general. However, the organic farming sector that aims at "certifiability" will encounter problems as standards of cultivation are in general puristic, and some organic farming schools have reservations to use human excreta, even in small amounts. The interfaces of ecological sanitation and urban agriculture and organic farming require a lively discussion to find sustainable technological solutions for human life on the planet. AuroAnnam takes part in this discussion.