It is the cows that give the Netherlands its ammonia problem, there is no doubt about that. There are more pigs than cows here, three times as many, but apparently there is something in pigs’ urine and faeces, or the combination of the two, that keeps their ammonia emissions down. The booklet released in 2021 Nitrogen – The creeping effects on nature and health didn’t have room to go into it, which is a real shame. However, you could find that cutting the heath never made sense. It backfired.

The cows stand one, the pigs two and the chickens three. Then there are some more residual items which are occupied by sheep and goats. Fish farms are not included, even though fish put their excess nitrogen directly into the water as ammonia. It won’t mean much though. Today’s nitrogen crisis is about an excess of ammonia in the air.

That ammonia is mainly released from the urea that is dissolved in the urine that cows and pigs let to walk so freely. Under natural conditions, the process only starts when the enzyme urease the so-called ‘hydrolysis’ of urea into ammonia (and carbon dioxide) can be accelerated and it is pre-eminently bacteria that can supply that enzyme. But urine from healthy mammals is low in bacteria, in the past it was even mistaken for sterile, which is why a lot of ammonia is only produced when faeces mix with urine. Because faeces are packed with bacteria with urease activity, this insight is almost a century old. Modern nitrogen policy advises to keep faeces and urine separate.

Metropolitan urinals can smell strongly of ammonia.

Photo ANP

Measured in numbers, the Dutch are well above the pigs and no one can fail to notice that the Dutch also mix urine and faeces. From a modernsource separation‘It hasn’t gotten very bad in the sanitary waste streams yet. Strangely enough, you never read anything about the contribution of the Dutchman to national ammonia emissions. It must be measurable because, for example, the nappy of an infant that has been changed too late can emanate a penetrating smell of ammonia. Also think of metropolitan urinals and toilets at pumping stations and overcrowded campsites.

How much ammonia does the Dutchman produce himself? The farmers want to know that too. An older Amsterdammer, name known to the editors, was willing to donate his morning water for research. He was even persuaded to stick a stout monster out of his morning excrement. The national colon cancer research had left him with a shovel and a certain dexterity.

An intriguing cloudy haze

Two portions of urine ended up as such in a jam jar, to a third some excrement and to a fourth some garden soil was added, because, according to a scientific source, soil material is also rich in bacteria with urease activity. Initially, the morning water was clear as Heineken, but within an hour and a half an intriguing cloudy turbidity developed that did not disappear. It was not clear what it was, nor did the microscope get a hold of it. Bacteria? They don’t grow that fast at a low temperature (it was 17 degrees). It must be a chemical conversion, even cold tea becomes cloudy if you leave it for too long. After about three or four days, all the urine gradually took on the color of the famous Old Brown, which was so popular with lactating women and gastronomes who ate game dishes.

In the meantime, little or nothing has changed in the smell of the urine. Not in the blanks and not in the supplemented samples. Only after a week did an ammonia smell hang over the jam jar with urine and the clump of excrement. Using pH paper, it was possible to show that the acidity had risen from about 6 to almost 9. The pure urine had not changed in pH even after two weeks. There was no trace of ammonia there.

Puzzling, because urease activity is a very common property of many bacteria and urease-active bacteria are, according to the literature everywhere present. So also on the glassware and in the air. Faeces don’t appear necessarily required for ammonia formation. Admittedly, urine is a meager, largely mineral nutrient medium, but for urease-active bacteria it contains almost everything necessary for growth. The ammonia formed acts as an energy and nitrogen source, the CO formed2 is a source of carbon and furthermore there is no lack of phosphate, sulfate and potassium. So why didn’t ammonia arrive?

Is hygiene the culprit?

It cannot be ruled out that the ever-increasing hygiene is the culprit and that there is no more spontaneous supply of urease at all. Beer leftovers no longer turn into vinegar because acetic acid bacteria have become rare. To investigate the hygiene influence, some urine from a glass in which a lot of ammonia had already been formed thanks to the faeces was inoculated into a glass of fresh urine. Like you use a starter culture to make yogurt yourself. But it didn’t work out and a temperature increase (to 22 degrees) didn’t help either. It must be the case that the faeces not only supply urease bacteria, but also essential nutritional components. Maybe it nickel that urease so needs.

On the other hand, in earlier centuries people never had any difficulty in starting and maintaining the described ammonia production. Converted urine (‘steel urine’) was used up big scale used to degrease and bleach wool and, in another process, to felt wool fabrics. You read about the intense stench of the activities but never about lack of ammonia. It was noticed that a group experimental archaeologists that wanted to felt wool in Eindhoven in 2004 in a medieval way, but preferred to use soft soap from Driehoek instead of converted urine. For example, today a new problem has been added to an existing problem.

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