On-site sanitation and groundwater contamination

 By Naledi Msiya and Annah Ndeketeya

Sanitation is a vital part of our lives because of its direct impact on public and environmental health. The sustainable development goal (SDG) 6 calls for ‘‘clean water and sanitation’’. However, many developing countries are still lacking in the provision of decent sanitation. The dire sanitation situation is exacerbated by exogenous factors such as rapid urbanization and population growth, leading to many underserviced areas.

One common form of sanitation implemented in African countries is on-site sanitation, which includes facilities such as pit latrines and flush toilets connected to septic tanks. Often, the people in these areas also rely on groundwater for household uses and drinking purposes. Most of these toilets do not meet the design guidelines, and in some cases, community members are not aware of the requirements, such as keeping a safe distance between the septic tank and the groundwater source.

                                                    A picture of a self-made pit latrine in Loskop, Kwazulu-Natal.

 

Without following proper siting and design procedures, the risk to public health is very high because there is a high likelihood of faecal matter and bacteria contaminating the groundwater. Poor water quality can result in water-borne diseases such as typhoid, cholera, dysentery, and diarrhoea. For example, the City of Harare experienced an outbreak of cholera due to water contamination in 2018, and multiple fatality cases were reported (WHO, 2018). Similarly, Zambia also suffered from child fatalities caused by drinking contaminated groundwater (Banda, 2015).

Therefore, proper guidelines must be made available to communities and followed at all times to ensure public safety. Moreover, governments and private entities should invest more in this topic by providing safe water sources and faecal sludge management, frequent monitoring and testing of groundwater quality, and training communities on affordable ways to clean their water before use. In addition to the technical support, more funding should be injected towards affordable sanitation solutions that address location-specific problems.

 

General guidelines for siting and building sanitation facilities

·         On-site sanitation facilities can be used in:

o   Thick soils such as clay layers and soils should have a high organic content to encourage natural denitrification.

o    Climatic conditions should be dry, as wet conditions may support the infiltration of contaminants.

o   On-site sanitation facilities should be located down-slope from the water source

o    Locations with deep aquifers that have very minimal fissures.

•         The recommended minimum distance between the toilet and groundwater source is 15-30 m (Graham, Matthew & Polizzotto, 2013).
•        Pit latrines can be constructed at an elevated area or lined to reduce the chances of contamination (Graham et al., 2013). Residents can also get support and information from local WASH non-governmental organisations (NGOs) and International development organisations such as WHO.

The current threat of Covid-19 on groundwater resources

Recent studies have shown that the coronavirus (Covid-19) can remain present in human faeces for up to 33 days (Huo et al., 2021). However, no evidence has been submitted so far for faecal−oral transmission of the COVID-19 virus. On the other hand, the best way of preventing Covid-19 is through frequent washing of hands. Of course, this requires access to clean water, which might not be available in these vulnerable communities. Hence, urgent measures are needed to help such communities cope with the pandemic and have clean water available for clean washing.

·         Some of the affordable water purification solutions to consider include:

•       Boiling the water before drinking
•          Treatment by Chlorination using chlorine tablets or bleach
•           Biosand Filtration
•          Ceramic filters
•      Solar sterilization and solar distillation