Presentation on theme: "Ecological Sanitation [ Black Soil for the World‘s People ]"— Presentation transcript:
Ecological Sanitation [ Black Soil for the World‘s People ]
The pathogen cycle People contaminate the environment and are infected by it!
Some sanitation facts People without access to safe drinking water in the year 2000: 1100 Million ( = 18 % of world population ) About 4 billion cases of diarrhoea occur each year: –leading to 2.2 million deaths, predominantly among children, –representing 15% of child deaths in developing countries. For the latest data see the latest "The state of the world's children“ report from UNICEF, and UNDP‘s "Human Development Report“. People without access to sanitation facilities in the year 2000: 2400 Million ( = 39 % of world population ) Polluted water is estimated to affect the health of 1.2 billion people worldwide, and contributes to the death of 15 million children each year.
...some more sanitation facts The global human waste output (excrements) in the year 2000, is estimated to be 8.5 million tons each day ~ 49 million US$. Chlorine by-products, used to reduce the risk of infectious disease, are associated with a substantial portion of the cancer cases (bladder, rectal, colorectal and liver cancer) from drinking water supplies. Some diseases that are caused (or supported) by unhygienic sanitation & faecal contaminated drinking water: Cholera, Typhoid Fevers, Diarrhoea, Dysentery, Infectious Hepatitis, Malaria, Polio, Schistosomiasis Worldwide, 5.3% of all deaths and 6.8% of all disabilities are caused by poor sanitation hygiene, and water. 900 million rural Chinese people excrete about 450 million tons of organic fertilizer each year - worth 2.6 Billion US$!
Breaking the pathogen cycle Sanitation is the first and most effective point for blocking pathogens from faeces - when faeces are sanitized at the place of defecation almost no pathogens will enter the environment. To prevent illness pathogens must be blocked, so that humans are not exposed to them by inhalation and ingestion.
The nutrient cycle The fertilizing equivalent of excreta - nitrogen (N), phosphorus (P), potassium (K) - each of us produces, is nearly sufficient for a person to grow his own food!
Nutrients in excrements The mineral plant nutrients per person and year (in kg) are: Nutrient urine (500 ltr. / year) faeces (50 ltr. / year) Total Required to grow 250 kg of cereals Nitrogen (N) Phosphorus (P) Potassium (K) Urine: comprises 90% of the volume of human waste it also contains about 80% all the mineral plant nutirents (N, P, K) Faeces: contain most of the carbonaceous (C) organic matter in our excrements carbon increases the water holding capacity and nurtures healthy soil organic matter serves as a soil conditioner and humus replenisher an asset not shared by chemical fertilizers!
Closing the nutrient cycle Faeces: –contain less minerals (N, P, K) than urine –contain the most carbon (C) in our excrements –contain a lot of pathogens they must be sanitized prior to usage sanitized faeces can be safely composted together with other garden & kitchen organic wastes applying the resulting compost to the soil restores the soil’s humus layer Urine: –is a good natural mineral (N, P, K) fertilizer –contains only few pathogens and heavy metals – thus urine is a clean fertilizer mixed with water (5–10 litre water / 1 litre urine) it can be used for crop irrigation
What is ecological sanitation? –Needs a lot of water to flush away faeces and urine. +Conserves water: uses either minimal water or even better: no water at all! The flushing toilet system:The ecological toilet system: –Excrements, flushing water, household greywaters and indus- trial wastewaters are mixed. +Excrements are processed near to the point of ‚production‘ without industrial contaminants. –The output of modern wastewater treatment plant cannot be safely used as agricultural fertilizer – their effluents even contaminate rivers and the sea. +Sanitized and co-composted faeces enrich soil‘s humus layer and nutrients in urine are returned to the soil as fertilizer – nothing is contaminated. +Breaks the pathogen cycle by flushing away excrements. +Breaks pathogen cycle by storing and sanitizing excrements. VS
What about the pit latrine? 2.8 billion people use them – pit latrines have several disadvantages: Often pit latrines are disdained because of smells and flies - especially during the rainy season: Certain disease vectors breed in humid pits - flies and mosquitoes like the humid environments of the latrines. These vectors are spreading pathogens and cause diseases like Malaria! They cannot be used in areas with impenetrable ground, or with high water tables, or where flooding is a problem, or in densely populated areas where space is limited - even a deep hole will fill after some years of operation, so the pit latrine has to be relocated, causing space problems in small urban yards. Risk of groundwater contamination, threatening the drinking water: Increased nitrate levels in groundwater are caused by leakage from pits. Pit latrines often collapse during the rains, by groundwater entering the pit – latrines get waterlogged due to high water tables. Households with family wells in their yards have to keep their latrines at a safe distance from the water point (at least 10m, rather more).
Eco-San benefits (1) EcoSan tries to do both: Break the pathogen cycle-> no contact with unsanitized faeces Close the nutrient cycle-> reuse urine & faeces as fertilizer & soil conditioner Therefore it has a double effect on people’s health by: 1. reducing disease 2. improving the nutrient intake
Eco-San benefits (2) Safely recovering, and reusing human wastes as soil conditioner & fertilizer offers several benefits, including: increases household food security - everybody surely can afford this fertilizer for his own gardening! creates jobs - in collection / composting systems / urban agriculture improves living conditions – safe, fly-free, pleasant smelling & cheap toilet for everybody healthier children – can learn more and better and are happier! healthier people – can work better and earn more and are also happier! reduces the amount of chemical fertilizers imported for food production - reducing the dependence on chemical fertilizers, and saving money for schools, hospitals, etc. retains valuable resources – instead of wasting them reduces effluents to receiving bodies - rivers, lakes, the sea
Eco-San benefits (3) While being attractive all over the world, especially developing countries can benefit from Eco-San: In southern tropical climates, composting toilets or dry sanitation systems and combinations with reed bed filters may be more feasible and efficient. Combined composting toilets and filter systems may be appropriate for countries where sanitary ablution (anal cleansing with water as opposed to paper usage) is practised. The higher temperature in many of the developing regions and the more concentrated urine, obtained from toilets or latrines that do not use flushwater, increase the pathogen inactivation rate. The low risks for transmission of infections through urine support the implementation of urine separation. In combination, improved sanitation and higher nutritional status could significantly improve public health in developing countries.
Non-Eco-San problems Failure to close the nutrient cycle has resulted in: 1.)reduction of the soil’s humus layer (loss of soil fertility) (need for more watering) (increased risk of flooding!) 3.) production and use of artificial fertilizers (since World War I) 2.) increased use of pesticides (healthy soil has been destroyed) 4.) nutrient and Chlor (Cl) overload (loss of biodiversity) in coastal and marine waters (toxic algae blooms) (fish & coral dying)
Sanitizing urine Sanitizing urine is not necessarily required, since urine from healthy people is also healthy: In a healthy individual the urine is sterile in the bladder. Some people drink their morning urine as a preemptive health care measure (to be more resistant against diseases). However, in areas where diseases like bilharzia, typhus, cholera, hepatitis A & B, tuberculosis or HIV/AIDS are endemic, urine should be sanitized prior to usage! Sanitizing urine by storing it in tanks: nitrogen in stored urine converts to ammonia, and the pH rises to about 9 a low dilution with water should be sought – this will help to kill pathogens temperatures should tend toward a warmer environment (20°C or more) Necessary storage time (at 20°C) : 6 months, when cross-contaminated with faeces 1 month for clean urine (no faecal contaminations)
Sanitizing faeces Here are 4 approaches to sanitizing faeces: 1.Dehydration (desiccation): Dehydration to below 5 % of solids - in dry warm climate achievable within 4 months - will lead to complete inactivation of all worm eggs (also Ascaris eggs, which are the most resistant pathogens). 2.Pasteurisation: 70°C for one hour will kill as good as all pathogens. 3.Aerobic composting: When composting the digesting aerobe bacteria will create high temperatures °C kills pathogens within days. Temperatures around 55-65°C kill all types of pathogens (except bacterial spores) within hours. 4.Anaerobic digestion: Takes longer than composting and produces unpleasant smells (SOH 4 ).
Composting (1) The 6 composting essentials are: 1. Organic matter : ( carbon (C) and nitrogen (N) ) Carbon is energy food for microorganisms. Nitrogen provides protein needed by the microorganisms to break down carbon. 2. Microorganisms: The microorganisms produce heat and transform organic matter into compost. Good sources of microorganisms are soil and finished compost. 3. Air: Composting bacteria are aerobic, which means they need air and cannot live in water, so air is necessary because they need a lot of oxygen (O 2 ) to do their job. 4. Water: Water is needed in a compost pile to keep the pile moist, but not wet. 6. Time: If the previous 5 are present, compost is generated - whether within a month or a year. 5. Temperature: When the ground is frozen the bacteria are inactive – temperatures above 20°C are nice.
Composting (2) The C-N ratio: Since most of the job of composting is done by microorganisms the compost pile has to offer them a balanced diet of carbon (C) and nitrogen (N) to be attractive for them. Unfortunately the C-N ratio of our faeces and urine is not a good diet! Carbonaceous organic matter must be added to the compost pile, such as: wood shavings, grain husks, straw, ashes, soil, paper, … Humus: During composting, the volume of the material is reduced by about 90% - the remaining 10% is humus, filled with the minerals that were withdrawn from the soil where the food was grown. All composted biological material becomes humus. Earthworms: Vermiculture - adding earthworms for composting - is a very satisfactory method for obtaining a stable compost of high quality, with nutrients readily available for plant assimilation.
Arbor Loo - composting toilet The Arbor Loo is a simple composting toilet with a portable slab, pedestal and superstructure over a shallow pit: maximum 1 meter in depth pit can be unlined, or with a protec- tive ring beam securing the pit head and raising the latrine slightly above ground level. Wood ash and soil are added after each use to reduce fly breeding and odour. Layers of organic matter, such as leaves, can be added as well to assist in the de- composition process. When the pit is about 70% full: the slab and superstructure are removed and mounted over a new shallow pit. The filled and topped pit is then watered down. On the following day a young tree is planted and again well watered.
Double vault composting toilet Both urine and faeces accumulate in the shallow pit together with wood ash, soil and organic plant matter, which is used cover excrements after defecation. When the first pit is nearly full: Slab and structure are moved to the second pit the contents of the used chamber are covered with topsoil between 15 and 30 cm deep and left to decompose When the second pit is nearly full: the mature contents of the first pit are removed they can be easily removed, without any offensive smells – else decomposition is not totally finished they should look, feel and smell like rich compost
Composting toilet with reed bed filter Reed bed filters are used to treat urine and greywater (‘greywater’ = wash water, from dish washing, laundry, shower etc.) The urine is drained from the toilet through a small tube to the exterior of the residence or latrine housing and piped together with the other waste- water into a shallow evapo-transpiration bed: The filter bed is filled with coarse sand It has its own containing walls to prevent seepage (maybe with a thick plastic sheet at the bottom) Reed and if also desired flowers, shrubs and even fruit trees and coconut palms can be planted on the filter bed 1 m 2 of reed bed filter surface area is required per toilet user The reed bed filter assimilates and evapo-transpires the effluent as it flows through the subsurface root system where impurities are removed by combining microbial, chemical and physical processes.
Bucket latrine A laborer replaces the bucket with a clean one, empties the excreta into a larger container, and takes it to a composting site: Water must be available so the laborer can wash the containers and buckets. Composting can be done with no odour, flies or disease. The compost is then used to fertilize crops. The bucket holds excreta (faeces & urine) and added covering materials it must be emptied every 1–3 days, preferrably every day. The bucket is made of rubber, enamel, galvanized metal, or lacquered wood it is placed under the slab, in the compartment created by the platform also more simple constructions are possible
Biogas generation Modern biogas technology constitutes a widely disseminated branch of technology with a history of over 30 years. The technology is efficient, well demonstrated and provides a cost-effective method of disposing organic wastes and producing fuel and fertilizers. Anaerobic bacteria degrade organic materials in the absence of oxygen. Methane and CO 2 are produced. The methane component can be used as an alternative energy source. A reduction of total bio-solids volume of up to % can be realized. The final waste sludge is biologically stable and can serve as a rich humus for agriculture. The excreta of 25 people produce an average of about 1 m³ of biogas per day (40 l per person and day), representing the approximate cooking energy demand of one household. In institutions with 500 or more attendants (schools, prisons, religious centres, public facilities like markets) the produced biogas may supply sufficient energy for a canteen. Anaerobic treatment processes are suitable in tropical conditions because anaerobic treatment functions well in temperatures exceeding 20ºC.
Some books The Composting Toilet System Book –235 pages –April 1999 –ISBN: –CEPP (Center for Ecological Pollution Prevention) The Humanure Handbook: A Guide to Composting Human Manure. –302 pages –Juli 1999 –ISBN: –2.nd edition - Jenkins Publishing (PA)
Some organizations SANDEC (Sanitation in Dev. Countries department of EAWAG (Swiss)) SIDA (Swedish International Development Assistance) WSP (UNDP & World Bank: Water and Sanitation Programme) WSSCC (Water Supply and Sanitation Collaborative Council) IETC (UNEP Intl. Environmental Technology Centre (Japan)) WEDC (Water Engineering and Development Centre (UK)) CAWST (Centre for Affordable Water and Sanitation Technology (Canada))
...some more organizations CEPP (Centre for Ecological Pollution Prevention) IRC (International Water and Sanitation Centre (Netherlands)) IDRC (International Development Research Center (Canada)) GARNET (Global Applied Research Network in Water Supply and San. (UK)) AIT (Asian Institute of Technology (Thailand)) Sanitation Connection Ecological Engineering Group
Some webpages Ecological Sanitation – an introduction by Steven A. Esrey –http://www.thewaterpage.com/ecosan_esrey_intro.htmhttp://www.thewaterpage.com/ecosan_esrey_intro.htm The Water Page – Ecological Sanitation –http://www.thewaterpage.com/ecosan_main.htmhttp://www.thewaterpage.com/ecosan_main.htm News on the „2003 World Toilet Summit“ in Taipei (Taiwan) –http://taipeitimes.com/News/taiwan/archives/2003/10/12/ http://taipeitimes.com/News/taiwan/archives/2003/10/12/ SSHE (IRC & UNICEF) news from Aug –http://www2.irc.nl/sshe/nn/nn0208.htmlhttp://www2.irc.nl/sshe/nn/nn0208.html
...however, application of this revolutionary approach, and understanding of its implications for public health, agricultural gain, economic benefits, and institutional requirements - especially in modern urban settings - are still in their infancy... (from the 1st International Conference on Ecological Sanitation 2001) THE END...OR THE BEGINNING?