South Sudan's City of the Dispossessed

An earth bank, topped in some places with a coil of razor wire, surrounds the United Nations peacekeeping base outside Bentiu in South Sudan. There are also watchtowers and armed peacekeepers.

Inside the 6.5 kilometer (four mile) perimeter fortifications live 118,000 people, some of the 2.2 million uprooted by civil war since December 2013.

Around 195,000 people live inside six U.N. Mission in South Sudan (UNMISS) bases after the unusual step of allowing civilians refuge alongside peacekeepers was taken when fighting broke out, first in the capital Juba, and then in other parts of the country.

Bentiu is by far the biggest of these, with survival a struggle for its dispossessed residents and a challenge for the aid workers seeking to make their lives liveable.

"By any measure the humanitarian situation in South Sudan is as bad, or worse than, anywhere else in the world," said Simon Mansfield of the European Commission's Humanitarian Aid and Civil Protection department (ECHO) in Juba.

In Bentiu there are, "extraordinarily high rates of starvation" and "emergency levels of mortality among children," Mansfield said. "We have to do more but it's very difficult."

Conditions are appalling inside what the U.N. and aid workers call "the PoC" -- standing for "Protection of Civilians" site -- but they are a big improvement on a year ago when the camp would fill up like a paddling pool each time it rained, leaving the 40,000 people then living there wading through filthy water full of faeces and rubbish.

A medical worker said that drowned children were found "every day".

An $18 million (16 million euro) extension and redevelopment was begun to stop the flooding and reduce congestion by more than doubling the space available for civilians.

The site was expanded and drainage canals dug, a grid system for housing was carved out of the forests, and 8,000 stick-framed dwellings were planned for the population. Ten water boreholes were sunk and 1,710 latrines dug.

"It was an amazing project, against the odds. We transformed swamp and mud into a town," said Andrea Paiato of the International Organization for Migration (IOM), which oversaw the construction.

South Sudan's abysmal infrastructure makes doing anything difficult and expensive. The journey from Juba to Bentiu takes between three days and two weeks depending on the weather.

During the rainy season the dirt road is unusable so everything has to be flown in.

John Paul Mugo Mwaniki, a water and sanitation expert at the charity Concern Worldwide, says 10 flights a month are used to bring in bars of soap for the camp's population.

"And this is just soap!" he said. "Then we need timber, plastic sheeting, metal sheets..."

For now, there is no night lighting in the camp, making a trip to the communal toilets dangerous for women and girls, who risk rape and sexual assault in the darkness.

The reason, explains Gilbert Ogeto of the Danish Refugee Council (DRC) -- the charity tasked with managing the camp -- is that the nearest place to get sand and gravel to fix the lighting poles in the mud is the town of Wau, and the road is impassable.

Before the extension work had even finished a brutal, scorched-earth government offensive, from April to July, drove an influx of people that trebled the population.

"We planned to rehouse 40,000 people, and now the population is 120,000," said Ogeto. So 11 people are cramming into shelters meant for five, and more arrive everyday.

Paiato says it could have been much worse: "Imagine what would have happened without the expansion, with 120,000 people? It would have been disgraceful."

Still, conditions are awful. A recent outbreak of malaria spread fast through a crowded, weakened population surrounded by standing water where mosquitoes breed.

Five of George Duop's eight children have contracted malaria since he and his family arrived in the camp in June. His two-year old daughter Nyakiem has had it twice and is being treated at a hospital run by medical charity Doctors Without Borders (MSF).

"We never got sick like this at home," said the 55-year old, who fled his hometown of Koch when government troops attacked. "I'm not happy here as the children just get sick, time and again, one after another."

Twice a day a Land Cruiser station wagon arrives to collect the plastic-wrapped dead from a makeshift morgue by the hospital gate.

They are taken to a graveyard a short distance outside the base where the bodies are interred in a cratered and waterlogged patch of swamp. By mid-September, 623 people had been buried there this year, their mass graves gouged out of the sucking soil by a tractor.

"The relatives of the dead feel awful about the process, but there's nothing we can do," said Bentiu's gravedigger, Simon, a 46-year old former businessman. "This is what the war has done."

"I feel so bad because people are dying every day, every day. It never stops," he said.