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Drinking from the swamp | Engineering a sanitary water supply in South Sudan

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Former civil engineering consultant and hydrogeologist from north east Wales Peter Roberts, 31, spent two months from March to May 2015 at the Bentiu Protection of Civilians Camp in South Sudan.

Working as a Water and Sanitation Engineer with Medecins Sans Frontieres/Doctors Without Borders (MSF), Roberts describes daily life and the engineering challenge in providing clean, safe water.

I’d spent the morning marking out locations for new toilets in the hospital and had just sat down for lunch, when my radio crackled into action: “Pete for Be, Pete for Be, Move Two, Move Two, there’s a problem at the SWAT”.

I left my beans and rice, grabbed my hat and sunglasses, and headed out into the 44°C sun.

South Sudan became the world’s youngest country after gaining independence from Sudan in July 2011. But, in December 2013, the landlocked country in eastern central Africa – home to more than 12 million people – was plunged back into chaos following the outbreak of civil war.

Until civil war broke out in 2013, Be, a 19-year-old South Sudanese from Bentiu, enjoyed studying maths at school. Instead, he found himself fleeing for his life when government forces attacked his town. He escaped, along with tens of thousands of others.

What had initially been thought of as a temporary living situation – a patch of swampland behind a UN peacekeeping building – became a permanent camp for about 70,000 internally displaced people. These people have to live in makeshift shelters, endure horrendous floods, survive on food rations and frequently die of diseases which I thought only existed in Medieval Europe.

I jumped in a Land Cruiser and headed out of the 170-bed tent hospital which MSF has built in the middle of the camp. I passed a hectic mishmash of plastic sheeting, sackcloth and tree branch shelters on one side and tall barbed wire fences on the other. Kids played in the road and everyone waved and smiled at me.

Why MSF?

A few years previously, after studying Hydrogeology and working for a year for a civil engineering consultancy in Bristol, I’d quit my job after being offered some work on an exploration drilling rig in Ethiopia. For a long time, I’d wanted to work overseas, and especially in the aid sector. So, for two years, I went to Ethiopia, then to siting boreholes in Uganda and running pump-tests in Zambia.

While MSF are most well-known for providing medical aid to those who need it most, what many people don’t realise is that the teams are also comprised of water and sanitation experts (WatSans), logisticians, field communications specialists and project coordinators. In August 2014, I carried out my first MSF mission as a WatSan in Ethiopia, which was soon followed by South Sudan.

Drinking from the swamps

In Bentiu camp there was a real problem with drinking water. The Humanitarian Charter and Minimum Standards in Humanitarian Response states that average water use (drinking, cooking and washing), should be 15 litres per person, per day. Drop below this and the number of people getting ill increases dramatically. When I arrived in Bentiu there was, on average, six litres of water available per person, per day.

At the end of the rainy season, huge swamps full of stagnant water were to be found dotted around the camp. These became the focus for MSF to use as part of its Surface Water Treatment Plant (SWAT), in order to increase the amount of drinking water available.

The SWAT in Bentiu is a beautiful process in my eyes - when it’s working that is. It operates for 12 hours a day, seven days a week and turns 180 000 litres of raw swamp water each day into potable chlorinated drinking water. Without this vital resource, the daily amount of water available would be even lower than the already dangerously low six litres per person a day.




The ‘Onion Tanks’ within Benitiu camp’s Surface Water Treatment Plant (SWAT)

How it works

1. Raw water is pumped from any nearby ditch or swamp into sedimentation tanks: three self-supporting 20,000 litre open sedimentation tanks (known as Onion Tanks due to their appearance).

2. Aluminium Sulphate powder is added to the tanks which acts as a coagulant and binds with water particles to create ‘flocs’ (think snowflakes) that grow in size with gentle agitation. Over a three-to-four hour period, these flocs grow in size, become denser and settle to the bottom of the tank.

3. Once settling has finished, the turbidity is checked. If it’s below 5 NTU, (down from 1,000 NTU as raw water only a few hours ago) the water is pumped out of the sedimentation tanks and into two 20,000 litre ‘bladders’, huge yellow collapsible water containers. Great care must be taken not to disturb the sediment now lying on the bottom of the onion tanks.

4. During the filling of the bladders, the water is chlorinated by adding a concentrated solution of a chlorine generating project – Sodium DiChloro-isoCyanurate (NaDCC). This oxidises any remaining organic compounds, in effect killing any bacteria, parasites or viruses which remain. Careful calculation of the amount of chlorine added means that there is some chlorine residual left unused so should recontamination occur – say from a dirty jerry can when filling up a tap stand – a small amount of chlorine will still be active.

5. The NaDCC needs 30 minutes of contact time before all the organic compounds have been deactivated. After 30 minutes the residual chorine levels are checked using the same simple equipment that is used on swimming pools back in the UK. If all is good, the clean water is pumped out to tap stands in the camp, where queues of women and children wait with their plastic jerry cans.



Be Gadet Lam adds coagulant Aluminium Sulphate to swamp water before it is pumped to the Surface Water Treatment Plant (SWAT)

I reached Be and we walked over the earth bank (which the UN built to protect the camp from stray gunfire) and towards the swamp in question. The team had been using this particular swamp for a few weeks but it was clear its days were numbered due to its decreasing water level. We fixed the problem by moving the pump intake but we knew that ultimately, we’d have to find a new swamp.

Unfortunately, the new swamp was more than 1.5 km away, next to a dirt road used by government troops on their way to fight the rebels in the north. This posed a risk, but without the SWAT, people in the camp faced a desperate situation to access clean drinking water. We had no choice.

It took two days to set up the new SWAT and in that time, the queues at the other boreholes become extremely long, tensions rose and even fighting broke out. It was a relief when it was finally operational.

Seeing the children run and dance as word got out that the SWAT was operational again was wonderful – a great way to end a day.

To find out more about working with MSF, visit or call 020 7404 4466.

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