The Water Page: Ecological Sanitation

Time 2020-12-22 12:03:18

Web Name: The Water Page: Ecological Sanitation

WebSite: http://www.thewaterpage.com

ID:142584

Keywords:

Water,The,Page,

Description:

Most families in the North make use of 'flush and discharge' systems - the regular waterborne sewerage toilet. These are designed on the premise that human excreta are a waste, suitable only for disposal. This approach also assumes that the environment has an infinite capacity to absorb and assimilate these wastes. On average, 15,000 litres of treated, safe, drinking water is used to flush 35 kilograms of faeces and 500 litres of urine per person every year. This conversion of cleanwater into 'blackwater' is a massive waste of water for arid regions. In developing countries 90 percent of this sewage is flushed into surface waters, polluting rivers, lakes and coastal areas. This can contribute to the spread of disease, as well as lowering the oxygen content of the water bodies, leading to increased algae growth and eutrophication. In developing countries the most common sanitation system is the pit latrine, based on the 'drop and store' principle. Although this uses much less water than flush systems it also has its drawbacks. Due to the large volume of the underground pit needed it is not suitable for densely populated urban areas. If the groundwater table is high, or the ground is very hard it is not possible to construct these toilets. In areas where they are used there is the risk that the surrounding groundwater will be contaminated from seepage or from water flowing in during floods. This has implications for health as pathogens can contaminate drinking water supplies. Due to the high humidity levels in the pits disease vectors breed rapidly, producing diseases such as filariasis, yellow fever and cholera. As mentioned above, all linear systems have the other major disadvantage that nutrients and organic matter are wasted. Nutrients, such as nitrogen, phosphorous and potassium are plentiful in urine and faeces provide carbon and condition the soil. Advantages Removal of pathogens from the domestic environment. Elimination of foul odours - if properly constructed. Convenient & easy to use. Hormones & antibiotics enter the drinking water system. Very costly to construct and maintain effective sewerage network. The energy contained in the organic carbon from faeces is lost. Pit latrines can't be used in high density areas. Pit latrines can't be constructed in areas with hard ground or high water tables. Ecological sanitation is a safe method of recovering nutrients from human excreta, then recycling them back into the environment and productive systems. A human being produces exactly the amount of nutrients that is needed for growing his or her food (measured in crops) – 7.5 kg of nitrate, phosphorus and potassium for 250 kg of crops. Urine hardly contributes at all to the spread of diseases (e.g. bilharziasis) and contains approximately 88% of the nitrogen, 67% of the phosphorus and 71% of the potassium carried in domestic wastewater. Faeces contain 12% of the nitrogen, 33% of the phosphorus, 29% of the potassium and also 46% of the organic carbon, as well as most of the pathogens. If separated, urine can easily serve as a fertiliser after it has been diluted with water. After faeces have been dessicated (dried-out), they are free from pathogens, diseases and odour. They can then serve as a soil conditioner for agriculture, returning a significant part of the nutrients and trace elements to the soil. The remaining treated greywater may be used for irrigation and also for recharging the local aquifer. This closes local cycle, helping to improve food security and to conserve soil fertility. At the same time, human health is improved due to the removal of disease sources from the domestic environment. Advantages Removal of pathogens from the domestic environment. Elimination of foul odours - if properly constructed. Diseases are destroyed, not just contained. No potential to contaminate other water sources. Use very little, or no water. Nutrients and organic matter is recovered. Very cheap to build and operate, with very few components which can malfunction. Users do need to be taught how to use them properly. Faeces need to be treated in the correct manner, otherwise they pose a health risk. High density urban areas don't always have the capacity to use the byproducts produced. © 2000 - 2012 Water Policy International Ltd - Materials may be used with consent and acknowledgement.

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