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Functions of the dwelling
Published in Stephen Battersby, Véronique Ezratty, David Ormandy, Housing, Health and Well-Being, 2019
Stephen Battersby, Véronique Ezratty, David Ormandy
WC (water closet) basins should have smooth, impervious internal and external surfaces and be self-cleansing. They should be connected to a properly working, flushing cistern that is provided with a supply of water, and is also properly connected to a drainpipe capable of safely carrying the waste out of the dwelling and into the drainage system. The basin should be provided with a water seal to prevent foul air escaping from the system. It should be securely fixed and capable of carrying its own weight and that of the user. It should be fitted with a hinged seat. All the cisterns, basins, pipes and drains should be watertight. There are alternatives to WCs, such as chemical toilets and composting toilets. Chemical toilets retain the waste in a tank or cassette, which should be charged with a chemical to prevent decomposition and smells until the tank or cassette is emptied. Composting toilets usually use a dry material to cover the waste while allowing it to decompose, until the tank/container is emptied.
Green Buildings and Urban Space: A Water Soft Path Perspective
Published in David B. Brooks, Oliver M. Brandes, Stephen Gurman, Making the Most of the Water We Have: The Soft Path Approach to Water Management, 2009
Chemical extraction from concentrated wastewater, dry toilets and urine diversion are also promising techniques to capture resources (Jönsson, 2001; Johannson, 2004; Novaquatis, 2006). Currently, many commercially available composting toilets (Del Porto and Steinfeld, 2000; Jenkins, 2005) are designed for convenience and aesthetics, and they may consume more materials and energy than a low-flush toilet connected to municipal wastewater treatment. Not only are composting toilets larger appliances, but electricity is used in some models to evaporate excess moisture to avoid overflow (urine may provide more water than is required for composting or can be absorbed by the dry material) and to run a vent fan, which pulls conditioned air from buildings. These problems can be avoided by providing capacity to store all liquid and by integrating the toilet vent with the building exhaust and heat recovery ventilator. Future dry toilets may be receptacles from which material is extracted and taken to composting plants for later distribution to farmland. The composting plants would ensure pathogen elimination through high temperature using thermophilic (heat-loving) bacteria that thrive at 55–60°C, and would properly stabilize the material for one year following composting, tasks which are difficult to guarantee with small domestic composting toilets because of the small mass of material and the constant addition of new excrement. The infrastructure to service a large-scale switch to dry toilets does not currently exist and could only be justified by backcasting from a long-term goal.
Sewage Disposal Systems
Published in Herman Koren, Best Practices for Environmental Health, 2017
Composting toilets may be used in rural and suburban areas which do not have sewers. This system which processes feces, urine, toilet paper, and sometimes garbage, depends on aerobic bacteria to break down the waste in unsaturated conditions. The remnants must be removed by a professional sewage hauler or buried. These units are especially good for reducing the quantity and strength of the wastewater and the remnants can be buried. Problems include the maintenance of the units, disposal of the end product, lack of maintenance, and creation of odors, and most of the units require some source of power.
Case study for analyzing nutrient-management technologies at three scales within a sewershed
Published in Urban Water Journal, 2021
Kevin D. Orner, Seneshaw Tsegaye, Hélène Kassouf, Komal Rathore, Aydin Sunol, Jeffrey A. Cunningham
Based on the review of literature, the average annual cost per household (over an assumed 20-year lifetime) for composting toilets is 1,004 USD, biological nutrient removal is 502 USD, source-separating toilets is 107 USD, constructed wetlands is 55 USD, and ion exchange is 14 USD (Figure 3; cost details in Supplemental Material). The costs are broken down into CAPEX and OPEX in the Supplemental Material. Potential cost savings from implementing each technology are shown in Table 5; the savings range from 90 USD to 600 USD per day, which results in a yearly household benefit of 2 USD to 14 USD (Figure 3; cost details in Supplemental Material). The overall cost of composting toilets is higher than the other four technologies due to the 900 USD annual OPEX costs, resulting in the highest overall cost (Anand and Apul 2014). Based on the higher costs of composting toilets in comparison to other technologies, a more in-depth economic analysis is recommended and other less expensive technologies should also be considered. Municipalities can also consider progressive upgrading of nutrient management technologies upstream or at the WWTP to reduce immediate economic challenges and provide flexibility in treating wastewater with variable physical and chemical characteristics. For instance, municipalities may wish to consider decoupling of carbon, nitrogen, and phosphorus management to increase modularity and flexibility (Fernández-Arévalo et al. 2017).
Physicochemical and microbiological characterization of human faeces and urine from composting toilets in Abidjan, Côte d’Ivoire
Published in Environmental Technology, 2019
K. R. Effebi, G. T. Ballet, M. A. Seka, D. T. Baya, B. L. N’takpe
Composting toilet is a naturally occurring aerobic process, whereby native micro-organisms convert biodegradable organic matter into humus-like product [11]. The majority of pathogens (e.g. total coliforms; faecal coliforms; faecal streptococci, anaerobic sulphite reducers (ASRs), Ascaris lombricoïds and Trichuris trichiuras) can be found in the human faeces [11], and are major threats to soil and water quality. Sources separating dry sanitation systems offer an alternative to meet the sanitation requirement; while plant nutrient, sand and organic material from collected human excreta can be used for food production [12]. Separating faecal matter at the source would minimize the occurrence of Ascaris eggs in other wastewater fractions, such as sewage sludge and wastewater. However, it would increase the need for high energy-demanding sanitation methods for the faecal matter since it is no longer subjected to dilution. Nowadays, the most common treatment of source-separated faecal matter is low-temperature composting, i.e. long-term storage with little or no increase of ambient temperature. However, reliable pathogen inactivation is crucial for safe reuse of human excreta [13]. Pathogens and parasites found in human excreta are responsible for various diseases in developing countries [14,15]. Sossou et al. [16] mentioned that composting matrixes (sawdust, rice husk and charcoal) and the composting process did not significantly affect the inactivation rate of pathogenic bacteria. It did, however, impact their lethal capacity (namely when a pH increase is observed during composting).