🌬️ Energo-Zelena and the air we breathe: what actually happens when the smell arrives
The animal waste processing plant near Inđija has for years been linked to foul odours across the municipality. A clear explainer: how the plant works, which compounds cause the stench, why wind and still evenings make it worse, and what the authorities do and do not measure.
When the smell suddenly arrives in Krčedin, usually in the evening or at night, the conversation in the yard always follows the same order: where is it from tonight, how long will it last, and why does nobody do anything. The name mentioned most often is Energo-Zelena, the animal waste processing plant on the edge of Inđija, some ten kilometres from us. This article tries to break the story into parts anyone can understand: what the plant does, how the odour is created, why it comes and goes, and what the authorities actually measure.
What Energo-Zelena is and what it does
Energo-Zelena d.o.o. is located at Zeleni zaselak 1 in Inđija. On its own website the company describes itself as an animal waste processing plant owned by the Republic of Serbia and as the only modern facility for the safe processing of hazardous animal waste in Serbia and the Balkans, with the exception of Croatia. It states a capacity of 150,000 tonnes of hazardous animal waste and an initial investment of 21.5 million euros.
Behind the factory lies a long business and legal story. The Belgian owner launched international arbitration against the Republic of Serbia at ICSID in Washington in order to protect the 21.5 million euro investment. The head of the Veterinary Directorate, Dejan Bugarski, said at the time that the plant's capacity was 250,000 tonnes while the total amount of animal waste in Serbia was around 150,000 tonnes, that three other rendering plants operate in the country, and that the company had asked for subsidies and for permission to import waste from neighbouring countries. The state later became the owner, and in August 2024 the Ministry of Economy issued a public call for the sale of the company's capital: the starting price was around 10 million euros, the sellers being the Republic of Serbia (87.23 per cent) and the Autonomous Province of Vojvodina (12.77 per cent), with bids to be opened on 28 August. Media reports recall that the state had paid around 48 million euros in compensation determined by arbitration, meaning it is now being sold for a fraction of what was paid.
How the smell is created, step by step
Rendering works in much the same way everywhere. The raw material, meaning fallen animals and slaughterhouse residues, arrives by truck and is unloaded in the reception hall. It is then ground and thermally treated under pressure at high temperature to destroy pathogens. Fat and a dry residue are separated from the cooked mass, and the residue is milled into meal.
The key to the odour is that every one of these steps releases vapours. The raw material smells in the trucks and in reception, the cooking steam smells, the dryers and storage smell. That is why a serious plant must operate indoors, with negative pressure in the halls (so air flows in, not out) and with exhaust air treatment through condensers, chemical scrubbers and a biofilter, before anything reaches the stack. The smell usually escapes when something in that chain fails: a ventilation breakdown, an overloaded or dried biofilter, an open door, raw material standing too long before processing or already decomposing, an overfilled reception area on hot days.
What exactly the smell is, and which compounds cause it
It is not one smell but a mixture. The decomposition of proteins and fats produces:
- hydrogen sulphide, rotten eggs, detectable at extremely low concentrations
- mercaptans and sulphides, cabbage, onion, a note of leaking gas
- ammonia, sharp and irritating
- amines, above all trimethylamine, rotting fish
- fatty acids such as butyric acid, rancid butter and vomit
- aldehydes and ketones from heated fats, a heavy, sweetish cooked note
That is why people describe the same night differently: for one it is „rotten fish", for another „boiled bones", for a third „sewage". And this matters: most of these compounds are detectable by the nose at concentrations thousands of times lower than those that would be acutely harmful. So „no limit values were exceeded" and „the stench is unbearable" can both be true at the same time, and that gap is the main source of public distrust.
Why in the evening, and why not every day
Odour does not travel evenly. Three things decide.
First, wind direction. The Srem plain has no obstacles, so an odour plume can travel for kilometres in a narrow band. With a southwesterly wind, Krčedin is downwind of Inđija; when the košava blows from the southeast, the same plume goes the other way and people in the village smell nothing and assume someone is exaggerating.
Second, wind speed. Strong wind dilutes, weak wind carries the plume concentrated. The worst case is a breeze of barely one or two metres per second.
Third, and most important for our summer nights, temperature inversion. After sunset the ground cools quickly, a layer of cold air forms near the surface and the warmer air above acts as a lid. Fumes cannot rise, so they spread out in a thin layer exactly where we breathe. That is why the smell typically starts after ten in the evening, lasts until dawn, and is gone by midday.
What residents and institutions say
In June 2026 an unpleasant, intense smell lasted for several evenings into the early morning hours and was noticed across the municipality. The local authority responded with a short statement on social media saying that a prompt intervention by the municipal environmental inspection had established that the odours came from the company Energo-Zelena, which handles the removal of waste of animal origin. According to the IN Medija portal, the statement contained no air quality data, no readings from monitoring stations and no concrete next steps; the municipal inspection forwarded the case to the provincial inspector because the plant holds an integrated permit, while the ministry passed responsibility on to the provincial and veterinary inspections.
“The company Energo-zelena has been doing enormous damage for years by spreading stench and polluting the environment. (from a reaction published by IN Medija, June 2026)”
The same source notes that last year Inđija was among 28 municipalities in Serbia to receive a new automatic air quality monitoring station under an EU supported project.
Monitoring that does not measure what bothers us
This is the heart of the problem. Automatic stations as a rule track PM10 and PM2.5 particles, sulphur dioxide, nitrogen oxides, carbon monoxide and ozone. None of those parameters is odour. Odour concentration is measured by a separate method, dynamic olfactometry, in odour units per cubic metre, and it requires field sampling and a trained panel of people. Until that is done systematically and the results are public, every debate stays a matter of one word against another.
What residents can do is keep their own record: the date and exact start and end time, intensity on a scale of 1 to 5, a short description of the smell and, if possible, the wind direction. Complaints go to the municipal environmental inspection and to the provincial inspection. Ten such records from a single street are worth more than a hundred comments online, because they become a document.
If you keep notes like this in Krčedin, get in touch, we will publish a summary by month and by wind direction.