Belgrade is Europe's largest city without a subway. Unfortunately, it is also Europe's largest city without a wastewater treatment plant and a proper sewage system. In Belgrade, the feces of 1.7 million people and all kinds of industrial effluents reach the Danube untreated.
In April 2022, the German Andreas Fath started an experiment. He wanted to swim down the Danube, (almost) from the source in Germany to the mouth in Romania. 2857 kilometers. (Apart from the first few kilometers, as there the Danube is too shallow for swimming). Fath was not the first to do this, and yet his attempt was something special. He is not only an enthusiastic swimmer, but also a professor of chemistry at the Furtwangen University in Germany. His area of special expertise: water pollution. Fath didn't swim alone. After he set off from the German town of Sigmaringen in April 2002, he was joined by a research vessel a little bit further downstream. The scientists on that vessel regularly took water samples from the Danube for various detailed analyses. Everything went fine in beginning.
In the second half of April 2022, Fath swam through the German part of the Danube. He reached Linz in Austria on May 2nd, and Vienna on May 6th. On the next day, he was already in Bratislava, the capital of Slovakia. A week later, Budapest came into view, and another seven days later Vukovar in Croatia. On May 24th, Fath was about to reach Belgrade, the capital of Serbia. But this is when things took a turn Fath had not expected. Because in Belgrade, he had to interrupt his project. A Serbian biologist had already warned Fath a day's swimming journey upriver: “If I were you, I wouldn't swim in Belgrade. The last person who was in the water there for a longer of time had to be taken to hospital.” And indeed, the Danube near Belgrade can be life-threatening – because it is literally a sewer. The closer he swam to Belgrade, the more clearly he felt how the Danube was changing. Literally. The water became warmer. It smelled different (and definitely not better). Fath noticed dark crests of foam and greasy films on the surface of the water. “You can also notice the change in the color. The water is becoming more and more like of a brownish broth”, Fath says. He feared for his health and his project. So he got out of the water. Fath spontaneously explained to the documentary filmmaker who accompanied his project why he did so: “I'm not going swimming, no way. Nobody wants to go swimming here. 1.7 million people pipe their poop (in the Danube) here.” (Trailer "Bis ins Meer", 2024) The results of the water samples taken in Belgrade confirmed his decision: “Many results from Belgrade were the worst in the entire Danube. They were close to a critical limit – if this limit is reached, the water will collapse,” Fath says. Collapse? What does that even mean?
Basically, the Danube is its own sewage treatment plant and breaks down discharged pollutants, like any large river, says Fath. “But in this process, oxygen is consumed – and if there is too little of it in the water, the consequences are fatal.” “Then anaerobic processes set in and toxic gases such as ammonia, hydrogen sulfide or methane are produced. This is toxic for all kinds of living beings.” In the summer of 2022, the Danube in Belgrade was on the verge of entering into such a process, Fath claims. “The limit at which toxic gases are produced is four milligrams of oxygen per liter of water. In Belgrade we measured just five milligrams,” says Fath. And Belgrade is growing. Which means: More and more poop is being pumped in the Danube every day. Exposure to X-ray contrast agents, antibiotics and all sorts of drug residues can also be found in higher concentrations in the Belgrade section of the Danube than anywhere else along the river, as the wastewater from Belgrade´s hospitals also reaches the water untreated.
The situation is bad. "No big city in Europe commits such a crime towards its rivers," Serbia´s infrastructure minister Goran Vesic famously said in 2020, when he was still Deputy Mayor of Belgrade (Sovilj, M. 2020). Then why is nothing done about this? Well, it is. There are plans. There are first local treatment plants. But a comprehensive solution is not anywhere near. Because this is where the story gets complicated. And expensive (Novosti, 2023). It is a story about political will and spending priorities, about the “China Machinery Engineering Corporation” and Western financial institutions unwilling to pay for Chinese contractors, plus many other factors & actors (The Government of the Republic of Serbia, 2023).
Trailer "Bis ins Meer" (2024) (Andreas Fath & Shane Thomas McMillan) - Version 2.0 https://www.youtube.com/watch?v=DaTuC66jYo8
Martens, M. (2024) “An der schönen braunen Donau” https://zeitung.faz.net/fas/politik/2024-04-21/an-der-schoenen-braunen-donau/1018089.html
Sovilj, M. (2020) “Brown Danube: How Belgrade’s sewers taint Europe’s famous river” https://phys.org/news/2020-09-brown-danube-belgrade-sewers-taint.html
Novosti (2023) “First of Five Waste Water Treatment Facilities in Belgrade to Cover Needs of 1.3 Million Residents” https://www.ekapija.com/en/news/3978059/first-of-five-waste-water-treatment-facilities-in-belgrade-to-cover-needs
The Government of the Republic of Serbia (2023) “First industrial biological plant for wastewater treatment opens” https://www.srbija.gov.rs/vest/en/213348/first-industrial-biological-plant-for-wastewater-treatment-opens.php
Sofiyskavoda.bg (2021) “SOFIYSKA VODA COMMISSIONED A NEW DIGESTER AT THE WASTEWATER TREATMENT PLANT” https://www.sofiyskavoda.bg/en/news/sofiyska-voda-commissioned-a-new-digester-at-the-wastewater-treatment-plant