Archaeologists are discovering new insights into how the Romans lived in Herculaneum 2,000 years ago by what they left behind - in the ancient city's sewers.

View of Herculaneum [Credit: Herculaneum Conservation Project]

Herculaneum, which lies on the Bay of Naples in southern Italy, was buried by the eruption of Mount Vesuvius that destroyed Pompeii, Stabiae and other nearby towns in 79 AD.

Specialists involved in the Herculaneum Conservation Project have excavated the ancient sewers of the city and uncovered the largest deposit of organic material ever found in the Roman world.

Layers of excrement that lay buried by volcanic mud for centuries are giving experts new clues about the diet and health of the city's ancient inhabitants.

Project manager Jane Thompson told ANSA the team has recovered some 750 large sacks of human excrement.

"Studying this waste and linking it to the inhabitants or workers in the buildings above is allowing us to learn more about their lives, the types of food people ate and the work they did," Thompson said. "This is even more unusual because it emerged from a conservation project".

Herculaneum Sewer [Credit: Herculaneum Conservation Project]

When Vesuvius erupted the Roman city had an efficient system of water drainage with subterranean sewers that flowed beneath several roads that ran on a north-south axis in the city. One of the channels is only 60 cm wide and a metre high and is believed to have served the town's main public baths and several houses, and a second channel with similar dimensions.

Both ran through the town to the shoreline.

"We cleaned out the two principal Roman sewers that ran to the shoreline," Thompson said. "The sewer under the Cardio III road was cleaned out with a high pressure pump and it is immaculate.

But it was the third of Herculaneum's north-south roads that revealed the biggest surprise - a large tunnel measuring 3.6 metres high that runs under Cardo V street along an entire city block.

"The sewer we found under the Cardo V road in the lower stage of the city is so large and spectacular we could use human beings instead of pressure hoses," Thompson said.

"This was crucial because it has never been completely excavated and we found a half-metre deposit of organic waste along its entirety." The 86-metre tunnel is linked to chutes that flowed from the latrines and kitchens of the homes and shops above. Instead of draining into the sea, this sewer was more like a giant septic tank that collected human waste, food scraps and discarded objects.

Food remains from a latrine pit: grape pips, fig pips, fish bones, sea urchin shell [Credit: University of Oxford]

Apart from 170 crates of artefacts including pottery,a lamp and 60 coins, the excavation team has recovered bone pins, necklace beads and a gold ring with a decorative gemstone from the sewers. But it is the organic deposits that may provide the most innovative research - giving researchers an unprecedented insight into the diet and health of the Roman inhabitants.

Early analysis confirmed that the human faeces were rich in vegetable fibres and one sample showed a high white blood cell count, which according to researchers, indicated a bacterial infection.