Suspected or confirmed Ebola cases should be provided with separate flush toilets or latrines that are not used by other individuals. If flush toilets are used it is important that standard procedures for wastewater treatment are followed, including at a minimum, on-site septic tank treatment with later controlled removal for further treatment (WHO, 2002). Containing the wastewater for a period of time prior to secondary biological treatment, will allow for natural die-off of the Ebola virus and will significantly reduce the concentration of Ebola virus along, with other pathogens, that may be found in the wastewater. If health care facilities are connected to sewers, a risk assessment should be conducted to confirm that wastewater is contained within the system (i.e. does not leak) prior to its arrival at a functioning treatment and/or disposal site. Risks pertaining to the adequacy of the collection system, or to treatment and disposal methods, should be assessed according to a “safety planning” approach, with critical control points prioritized for mitigation.
For smaller facilities, if space and local conditions allow, pit latrines may be the preferred option. Standard precautions should be taken to prevent contamination of the environment by faeces and urine. These precautions include ensuring that, at least, 1.5 metres exist between the bottom of the pit and the groundwater table (more in coarse sands, gravels and fissured formations), and that the latrine(s) are located at least 30 metres horizontally from any groundwater source (including both shallow wells and boreholes) (WHO 2008). Given what is known about the virus and its die-off in the environment such recommendations are applicable in the specific case of Ebola. If there is a high groundwater table and/or lack of space to dig pits, excreta (faeces and urine) should be retained in impermeable storage containers and left as long as is feasibly possible to allow for reduction in virus levels before moving such waste off-site for additional treatment and/or safe disposal. However, consideration of Ebola virus characteristics and evidence on the fate of other viruses in sewage offers important insights. For example, in settled sewage at 25 C, approximately 99% of a similar structured virus (enveloped), coronavirus, was removed in 7 days. Ebola is likely to inactivate significantly faster in the environment than enteric viruses with known waterborne transmission (e.g., norovirus, Hepatitis A).
Two tank systems with parallel tanks would help to facilitate this, as one tank could be used until full, then allowed to sit while the next tank is being filled.
Source: WHO & UNICEF (Reviewed by MSF, CDC, and Tufts 2014) Ebola Virus Disease (EVD) Key questions and answers concerning water, sanitation and hygiene
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