The “poop factory” of Aboutengue camp

Aboutengue camp in eastern Chad hosts approximately 45,000 Sudanese refugees. When Médecins Sans Frontières / Doctors Without Borders (MSF) teams constructed a faecal sludge treatment site, it soon became known as the “poop factory” among camp residents.

The site processes waste from 932 latrines built by MSF, improving sanitation and helping to prevent the spread of infectious diseases during emergencies.

An innovative solution to treat and safely dispose of sludge from latrines, this process also works sustainably with the environment, and even involves the growing of safe-to-eat bananas.

Charlotte Maupu, former MSF deputy water and sanitation coordinator in the camp, explains how the treatment site works and its impact. 

Why does MSF need to build sewage treatment?

“When latrines are full, we either close them permanently or desludge them. Desludging involves pumping out the waste, digging a hole, dumping the waste inside, adding lime, and sealing it off. However, this traditional method risks polluting the soil and groundwater, which can harm both the environment and people’s health. 

To address this, we built this dedicated faecal sludge treatment site on the outskirts of the camp. The site is far enough from residential areas to avoid disturbing the camp. At the moment, the treatment site covers 3,600 square metres.

It’s important to clarify that this isn’t a traditional water purification station. Instead, our goal is to neutralise harmful bacteria and pathogens in the waste—a process known as “hygienisation”.”

How does the treatment process work?

“The process begins with pumping waste from the latrines. When trucks can’t access certain areas, especially where informal shelters are built, we use portable pumps. The waste is then transferred to a deposit tank, where we add lime—one part lime for every five parts waste. 

Using a pump system, we circulate and mix the lime with the waste, which raises the pH – a measure of how acidic or basic a substance is – to 12, making the environment too basic for most bacteria and pathogens to survive. We let this mixture sit for 48-72 hours. 

During this resting period, the waste separates into layers: water rises to the top, and denser sludge settles at the bottom. We then treat each layer separately. 

For the water output, we drain it into another tank where it rests for several days until the pH returns to neutral. From there, it flows into infiltration trenches lined with gravel and stones to help it filter into the soil. 

To prevent waterlogging, we’ve planted banana trees around the site, which absorb up to 200 liters of water daily. These trees will soon produce bananas that are safe to eat. 

For the sludge, we focus on drying it out through a two-step process. First, we spread the sludge on drying beds made of sand and gravel, which allow water to drain out by gravity. Once the sludge is semi-dry, we transfer it to a second concrete drying bed to remove any remaining moisture. 

Lastly, we’re testing a third step: incineration. Burning the dried sludge ensures that any remaining pathogens, especially intestinal parasites (helminths), are destroyed. 

The incinerator is built over a pit, allowing us to easily dispose of the ash. Once the pit is full, we can either empty and bury the ash elsewhere or move the incinerator to a new location.”