What Does Sanitation Look Like in Africa? Part 2 - Wet Systems

In the last post we looked at the types of dry toilet facilities, how they work, and the costs and benefits associated with their use. This included open defecation and multiple variations of latrine.This time round we will look at the facilities which do require water to function, wet systems.

A quick thing to note is that, as these facilities are all based on pits, there is the possibility for leakage into groundwater sources if too close.

Pour Flush Toilet

A pour flush toilet is a very similar concept to the toilets that we see in our homes in the UK, cistern toilets, except that the water is poured in manually to flush (SSWIM, 2018). The flushed out sewage then goes into a secondary pit away from the toilet to decomposes (figure 1). These toilets use on average 1-3 litres per flush, compared to the 13.6 litres (Home Water Works, 2018) used in the average cistern toilet and 6 litres if it is low flow.

Figure 1. Pour Flush Toilet (Image Source) 

The advantages of using this facility are that it is easy to construct, maintain and use, and it is also relatively low-cost. Pour-flush latrines wash away faecal matter from the site of defecation, reducing the presence of the bacteria which cause these diseases. The waste collected from the pit can also be used as fertiliser after it has undergone decomposition.

On the other hand, if there are any damages or blockages due to improper use or poor maintenance, piping parts may be difficult to locate and costly to repair. A frequent cause of blockages is the use of bulky materials for anal cleansing (wiping). There is also the issue of disposing of the waste from the pit. Whilst it may decompose after some time, it is not safe to dispose of until at least a year after final-use due to the time required for pathogen destruction. In the meantime, other sanitation methods will have to be used.

Similar to the double VIP latrine, in the previous post, the pour flush method can also have two pits, known as the double pit toilet. In this case the sewer pipe splits off into two different pits, with only one in use at a time. This system is advantageous as it allows for the same toilet to be used whilst one pit is left to decompose. The main issues with this toilet are that there potential for the second pit to fill before the already-filled pit is available to use and there may be leakage between pits if they are at too close a proximity, creating interruptions to decomposition.

Water Closet (WC) and Septic Tank Toilet

Figure 2. Water closet with septic tank (Image Source) 

This toilet uses a septic tank, a water-tight box that is split into two sections (NESC, 2018). After use, waste is flushed into the first section of the tank, in which separation of solids and liquids occurs. Solids remain in the first section in the form of a sludge pile, which the bacteria naturally found in the wastewater decompose. The liquids flow into the second section of the tank, leading into a 'soak away', allowing them to drain into the soil (UNICEF).

This toilet is hygienic to use as, before the next user arrives, waste is flushed away. As seen in figure 2, this toilet also has an inspection chamber, preventing against blockages that may be caused by cleansing materials. This allows for continuous, safe use of the toilet without the issue of harmful, pathogen-containing fecal matter backing-up into the vicinity of the user.

As this toilet is more complex, it comes with higher costs for construction and repair. It also relies on a connection to household water, in order to use the flushing mechanism. As the sludge needs to be emptied from the tank, it can only be built in areas with access to the emptying service. Therefore, this is only viable in communities established with these services.

Aqua Privy

Figure 3. Aqua Privy (Image Source) 

A simplified version of the septic tank, an aqua privy collects waste directly from the toilet and stores it for up to 5 years (SSWIM, 2018). The privy is filled with enough water so that the waste is completely submerged, preventing flies and mosquitoes from entering or escaping and concealing any smell.

This is less expensive than a septic tank as it is less complex and does not require piped water. This makes it relatively easy to construct. As waste flows directly into the storage area, materials for sanitation and cleansing cannot be put into the system. A restraint on this facility is that a sufficient amount of water is required to seal the waste and eventually the sludge must be carefully removed.

In all of these examples, the facilities are communally shared. This makes room for the spread of diarrhoeal diseases between those using the facilities. Although the wet systems flush away the fecal matter containing the harmful, disease-inducing bacteria, improper upkeep of the facilities, such as the toilet seat, will cause the facilities to become unhygienic and harvest these bacteria.

As these last two posts have made clear, there are a variety of sanitation systems within societies across Africa. Each of which with their own associated costs and benefits, and varying complexity. These facilities are by no means readily available to all who require them nor are they fairly distributed. The how and why of this is something that will be explored in future posts.

What Does Sanitation Look Like in Africa? Part 1 - Dry Systems

It would be nonsensical to believe that the quality and type of sanitation in Africa is uniform across all 54 nations. Nevertheless, figure 1 portrays an image that most of us are probably used to seeing when sanitation facilities in Africa are discussed. Despite what the media tends to depict, the reality of sanitation in Africa is not limited to only a simple hole dug into the ground, it ranges across many types of facilities, from intermediate technologies to those that are more advanced.

Figure 1. Hand flushed sanitation pit (Image Source)

In the case of figure 1, this toilet is a simple open pit, which could be ambitiously classed as a latrine. This would be deemed an unimproved sanitation facility by the World Health Organisation (WHO) and the United Nations International Children’s Emergency Fund (UNICEF). Unimproved and improved sanitation facilities will be discussed in a later post but for now we will be looking at the types of sanitation facilities across Africa, how they work, and the costs and benefits associated with their use. This post will focus on dry toilets, facilities without the need for water (Unicef), with the next looking at wet.

Open Defecation

Whilst open defecation is not strictly a sanitation facility, it is the lack there of which results in this method of defecation. Described as 'the greatest nightmare of Africa' (Face2Face Africa, 2016), open defecation is, put quite simply and intuitively, the act of defecating in open spaces such as bushes, bodies of water and forests.

The obvious benefits to this method of excretion are that it is easy and cost-free, at least monetarily, however the health costs associated with open defecation are fatal.

This practice aids the transmission of diarrhoeal diseases, such as cholera and e.coli, which are one of the key causes of child mortality. As the waste is not contained, diseases spread easily through contamination of water sources. Defecation carried out upstream will travel downstream and tarnish water supplies which may be for drinking or irrigation. Additionally, rain water may become laced with fecal matter once it generates surface runoff, distributing contaminated water wherever it flows.

Latrines 

Figure 2. A group of girls on their way to use the pit latrines (Image Source)

There are multiple variations of latrines, a simple pit latrine (figure 2), is the simplest method of creating a sanitation solution (WEDC). It is a hand dug pit, usually several feet deep, covered by a platform with an opening to excrete through. The structure is enclosed for shelter from the elements and privacy (figure 2). Once defecation has taken place, the excrement decomposes aerobically with older matter decomposing anaerobically.

The benefits of implementing simple pit latrines are that they are low cost, can be built by the locals, and are easy to maintain. Additionally, the conditions of the pit do not sustain pathogen survival, killing the organisms that cause disease. An overarching positive aspect of all dry toilet facilities is that no input of water is required and so they can be used in times of water scarcity or allow for water sources to be utilised in a different feature of the community.

Whilst latrines are an appropriate technology,  they posses a contested reputation due to the costs associated with them. As the faeces is left to decompose, rather than being removed, latrines can have a foul odour and it is very common for flies, mosquitoes and even cockroaches to be abundant within and around latrines. Despite being a nuisance in general, mosquitoes and cockroaches can carry diseases, posing a threat to sanitation of latrines. Moreover, it is not easy to empty these pits and most often they are abandoned and a new latrine is built, occupying space. A further issue is that, if not lined properly, the faecal matter can seep into groundwater supplies. It is also possible that, if misused or not constructed properly, people may fall into the pit and potentially drown.

Ventilated Improved Pit Latrines (VIP) are fundamentally the same as simple pit latrines, however they are fitted with a vent pipe and a fly trap/screen (figure 3). The pipe allows for continuous airflow, to fuel decomposition of faeces and removal of odours. The fly screen/trap prevents the nuisance of flies and their spread of diseases. Whilst theses factors show the advantage of using a VIP, the advancement in equipment required for VIPs makes them more challenging and costly to maintain, as specific parts are required. Shared with the simple pits, VIPs also have the risk of potential injury in the pit and also the possibility of leakage into groundwater supplies.

Figure 3. How a pit latrine works (Image Source)

Pit latrines can be improved even further with the use of dual-pits, a.k.a the double pit VIP (SSWIM, 2018). This is when two pits are built adjacent to each other, with one pit in use at a time. Once one is almost full, it is covered and the secondary pit can be used. As this happens, the contents of the first pit will decompose and drain, making removal of content easier. 

A clear benefit of using a dual-pit facility is that, although it is initially expensive to build a larger facility, they are easily reused and fewer pits will need to be built, saving greatly on costs. On the other hand, with two pits comes double the risk of groundwater contamination and injury by falling into the pits. 

It is evident that there are a range of costs and benefits associated with the use of dry toilet facilities. With the next post, I will be looking into the methods behind and costs and benefits associated with wet systems. 

An Introduction to Water and Sanitation in Africa

Welcome to my first blog post on Water and Sanitation in Africa!

I thought that I would start by sharing a short video, produced by WaterAid in 2010, that I initially watched as a naive 12/13 year old. I remember one of my main thoughts about it being 'how can diarrhoea kill you?'. In the UK, we are privileged enough to see diarrhoea as an inconvenience and often make jokes out of it. Others are not as lucky.

Diarrhoea is caused largely by lack of access to safe water and poor sanitation. It was documented by the World Health Organisation (WHO, 2017) that, each year, diarrhoea kills more than 500,000 children. This number is far too high for an illness that can be treated with a sachet of Oral Rehydration Therapy (ORT) and a glass of water.

In this blog I will aim to explore a range of issues surrounding the quality and abundance of water and sanitation facilities in Africa - including their causes, impacts, and possible solutions. Please do follow the evolution of this blog as I try to create an understanding, for myself and you readers, of the relationship between water and sanitation and the way that they affect the continent of Africa.