In Valencia, they no longer just look anxiously at the sky. Now they’re doing it at their feet, too, where the sewer network, still affected by the sludge from October 29’s DANA, faces a second challenge: new rains. With more than 200 warnings of sewer blockages in flood-affected areas and abundant rainfall forecast, many questions arise: How will the network react? Are there real risks? What should be done with the accumulated mud, which poses both a logistical and health challenge?

From those showers… According to Aemet, this sludge represents a major problem, the worst in a century in the areas affected by DANA two weeks ago. This mixture of water and soil is so formidable that on Sunday the Emergency Coordination Center (Cecopi) realized that its removal was at the top of its task list. “These actions are a priority and have been implemented to prevent the emergence of a real public health problem,” explained Fire Prevention general manager Rosa Tourís: “This is an extremely complex task because the water table remains high.”

Precisely to facilitate the repair of the supply, sanitation and treatment network, the Council of Ministers this week gave the green light to spending 500 million euros. President Pedro Sánchez used a clarifying phrase when presenting the initiative: It is, in his words, “a plan against mud.” “We want to lift it as soon as possible to return to normality,” the leader explained: “The task is huge.”

Why is it so important? For various reasons. First, the amount of sludge and its impact on sewage. Following the DANA conducted two weeks ago, most of the sludge taken from houses and streets mixed into the sewer network. And this is a real challenge. Sludge accumulates, solidifies and becomes clogged. Daily Levant 200 reports of sewer blockages in areas affected by heavy rains are being reported today. Ecological Passage goes further and mentions that approximately thirty municipalities have serious problems with their sewers. To meet this challenge, the fleet of unblocking trucks currently in operation is expected to be reinforced with twenty machines coordinated by Cecopi.

“When mud loses its water, it turns into a very plastic structure, almost like plasticine or potter’s clay, and because it is so heavy, it is very difficult to move. It is very invasive, and once it dries, it turns into a very hard stone structure, so all pipes and pipes can become clogged,” he warns. 20 minutes Adrián Barbero is professor and director of the Global Change Research Institute.

A complicated war. In order to fully avoid the risk of collapse in the sewer network, the Massanassa City Council in the L’Horta Sud district, which was fined by DANA at the end of October, launched a few days ago several tips on how to handle the sludge. Even then he warned of the risks that poor management could pose. “You have to make sure it doesn’t dry out completely,” he insisted in a video posted online.

“If the water had been allowed to remain inside the buildings and settle with the mud, it could have moved more easily and quickly.” Predicting what will happen, the town of Valencia warned of “one of the main problems” that the towns most affected by the 29th flood are at risk: “The collapse of our sewage network, which cannot function due to serious health problems.

It matters how much… And it matters what it is. If the sludge that accumulated after the first DANA became one of Cecopi’s biggest headaches, it’s not just its volume. The content of that mud is equally, if not more, relevant. And the risks. This is also pointed out by Barbero himself, who, after focusing on the “physical” problem represented by the mud, shifts his focus to the composition of the mud.

“The sludge acts as a kind of collector for all kinds of dispersed substances, which can become a very complex problem,” warns the IICG expert. “All this sludge traps toxic molecules that may be present in the water. It traps all the microparticles, so their chemical toxicity becomes very high, and this leaves It leaves a toxic sludge and after it dries it begins to break down into particles that begin to rise into the atmosphere and these can be very polluting.

There are also concerns about salmonella, E.coli or leptospira and how they might affect people who come into contact with the sludge. In fact, a few days ago the Ministry of Health reported its suspicions that two volunteers in one of the DANA-affected areas of Valencia were infected with this latest bacterium. Regional president Carlos Mazón expressed concern about the risk of epidemics, focusing specifically on tetanus. CSIC has already been asked to analyze the sludge to know exactly “what the sludge is made of” and decide where it needs to be extracted.

And new rains are coming. In this environment, the Valencian Community saw how complex the problem had become. The reason: new rains. Among other problems, there are concerns about how the collectors and the sewer system will react, which have collapsed due to the mud accumulated following the cleaning works carried out in recent days, causing the cleaning efforts to intensify.

The response of pipes in some homes is also concerning. “If the collectors are clogged with mud, straw and plastic, perhaps there are downpipes that do not have the capacity to drain dirty water. These will rise again,” he warns. Levant Enrique Cabrera, International Water Association.

“The population is in a vulnerable situation,” the expert adds. “Municipalities’ historical solution has been to pave everything, and asphalt doesn’t penetrate, so an underground network was created that would normally mix rainwater with wastewater. In many points, that network stopped working.” On Monday, Cecopi estimated that more than a hundred unblocking trucks would be needed for sewers. At that time they numbered around thirty. More are expected to arrive today.

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