FAQ

N varies from 4 to 7%; S from 12 to 18%; pH is between 1.5 and 6.5. These are variabilities between different plants. However, a low pH of 1.5 is rare. The variability of 1 and the same installation will of course be lower. Only at the start there can be some variation, but once the installation is running smoothly, the composition should be constant.

The ratio deviates somewhat from the stoichiometric (NH₄)₂SO₄ because there is an excess of H₂SO₄ in the scrubber water.

Struvite's exposure to organic and inorganic impurities is classified as very low and is well below the legal limit values.

Although the water-soluble portion of the nutrients is low, the fertilizing effect of struvite has been determined in tests to be as good as mineral P-fertilizers.

In principle, this technology can be used for all sewage treatment plants.

The process control ensures that undesirable substances such as organic pollutants or heavy metals are eliminated. This means that all valid limit values are observed in the product.

The good availability of the ash fertilizer to plants has been proven in many tests. In the trials, it was comparable to water-soluble mineral P fertilizers. The good effectiveness could currently be confirmed in the demonstration tests within the framework of the NUTRIMAN project.

With the REGENIS technology all kinds of liquid organic materials can be dewatered and treated.

There is currently no legal basis for its use in Germany. The new European fertilizer regulation EU 2019/1009 will shortly regulate the possibility of using biochar.

That is depending on the mass flow. The process can be good combined with a biogas plant.

Struvite is a salt of magnesium, phosphorus and ammonium; this must be taken into account because, depending on the needs of the crop in which it is applied, it can be applied as it is or it can be mixed with another type of fertilizer to make a blending, a fertilizer designed to suit the crop.

No, it isn’t. There is the technical possibility but it is not economically and agronomically correct to produce compost with less than 40% of humidity.No, it isn’t. There is the technical possibility but it is not economically and agronomically correct to produce compost with less than 40% of humidity.

Probably not but the new regulation should allow bio-based fertilisers from other EU member states to enter on the national market.

Indeed, the nitrogen value of the poultry droppings depends on the mineralization of the organic nitrogen i. the soil temperature and moisture. That is why local tests and experiments at field are needed to be gathered to advice seriously farmers.

The producers have to do a conformity assessment either by themselves or by an notified body. This processus let verify the respect of the criteria set up for the PFCs described in the regulation. The guarantee level is therefore defined straight away by the criteria and their thresholds in the regulation.

Composts are organic soil improvers: they increase soil fertility, but they don’t bring a lot of nutriments for the crop just after spreading.

[The sewage sludge recycled as fertilisers is cosnidered in France as a case study for bio-based fertilisers]. No, the EU regulation does not consider currently the sewage sludges but works are on going to include them in a close future.

Yes, any type of digestate can be used as long as it contains a relevant amount of nutrients (N and P) and does not contain contaminants that could impurify the struvite crystal (such as PTEs).

Solid algae-based fertiliser should be stored in a closed container in a dry, unlit place at room temperature.

The organic-mineral fertiliser has been tested on short-cycle barley crops with excellent results.

Yes, as long as it does not contain undesirable components for algae growth and subsequent application.

The growth of algae from the ALGAECAN process is independent of the time of year and the climate of the place where the plant is installed. This is because the algae do not need light to grow and because the algae growing conditions can be directly controlled.

Struvite has low water solubility, which gives it slow-release fertiliser properties and prevents leaching and eutrophication.

By carrying out anaerobic digestion in two phases, the growth of specific bacteria in each phase (methanogenic and acidogenic) is promoted, obtaining a greater yield of biogas globally than in single-phase anaerobic digestion systems and therefore increasing the economic profitability of the process.

Struvite should be stored in a closed container in a dry and unlit place at room temperature.

The algae-based product is not soluble in water and therefore cannot be used for fertigation.

Struvite has been tested on grass growth and is currently being tested on other crops such as lettuce, tomatoes, etc. In all cases, better results have been obtained than when a mineral fertiliser has been used.

Yes, of course. But it’s needed to wait 16 July 2022 and the entry into force of the new EU Regulation.

The compost (including ID:280) is exported to the nearest countries like France and The Netherlands.

The GREEN COMPOST (ID:280) in Belgium costs 2-5€/t bulk ex-works. The DRIED DIGESTATE (ID:270) costs from 15-20€/t to 40-50€/t depending on the nitrogen content. Transport costs must also be considered.

 No. Now, the priority is to make this products available for conventional agriculture. But in the future it’s hoped that they will be available also for organic agriculture. In order to make struvite available for conventional agriculture the UE should approve the CMC12. When the delegated act will be available, the congruity of the struvite refers to input materials (Reg.848/18) will be verified. If a positive opinion will be found, the struvite will could be used also in organic agriculture.

It depends on the nutrients content and on how clean are the input materials.

Yes. But also other kinds of slurry and industrial waste can be used.

 About 10 kg/day in the pilots plant. But in the future it’s hoped that bigger plant will be installed in bigger cities.

We expect a price of about 200 €/tonne, however it will depends on the formulations and the final price distributors will do.

Because when we added urea to biofertilizers we added lower content of N just because all the biofertilizers contains N, with the exception of the Ashdec(ID:397). However, in this case, it hasn’t added mineral phosphorous. Ashdec’s P is not soluble in water, while the mineral P it is. The combination of the rapid availability of N and P of the mineral fertilization plan could be more dangerous than the only rapid availability of N.

Often, if the roots stretch excessively, it is believed that they don’t find the right nutritional conditions near the plant collar and that they then go deeper to search for nutrients, which is a bad parameter. However, in this case we considered the overall root development (not only the length) and it was noted that the plants that produced the most biomass were also those with the best root development index. In addition, the fertilizers were mixed thoroughly with the substrate prior to transplanting the lettuce. Therefore a large root development, in our case, means that the fertilizers were distributed correctly and that the plant was able to absorb the nutrients more efficiently.

The lettuce is a crop very susceptible to urea burns. And the composts contain microelements, organic matter and microorganisms compared to the  the mineral fertilizers which might have supported the plant development.

Because the lettuce is a crop very susceptible  to urea burns.

Some of them (ID:210-280) contain more N than P. So they were balanced starting from N in order to avoid the possibility to apply too N. In case of high P content, like Ashdec, it was not necessary to add any mineral P fertilizer.

No, they were not. These were demonstration trials for farmers and agricultural practitioners. We’ve only balanced the NPK macroelements.

No, because copper, zinc and others are not important or relevant in the trials we carried out (short term trials), while for sure NPK and other nutrients are much more important.

Yes. The demo greenhouse and field trials UNITO carried out in Italy were set up in different kind of soils: from peat (pH=7,5) to sandy-silty soils (pH=6,5). The pH did not influence the results obtained by using the product.

We are not allowed by the French regulation to test products  not already authorized in France and to ask for experiment permits would be too expensive and too long to get. But there are results of fertilising use for local digestates, especially in the neighboring departement of Deux-Sèvres.

Indeed, the nitrogen value of the poultry droppings depends on the mineralization of the organic nitrogen. The conditions of this mineralization are the soil temperature and moisture. That is why local tests and experiments at field are needed to be gathered to advice seriously farmers.

The shown effect on grassland growth is shown with a grass plate meter and converted into biomass production. It can be explained with combined potassium and phosphorus supply.

It is decided by every manufacturer by itself. He or she has to decide as the fertilizer products regulation is optional so if the manufactures want to have compost or digestate or another product marketed throughout Europe with the CE logo he can apply for the conformity assessment. If he doesn’t, he will anyhow continue to comply with the national rules.  So basically, is a case by case situation over the decision to apply the new regulations and have the CE logo or not.

Two revisions of the draft have already been made and the draft considers struvite and ashes from pyrolysis as biofertilizer products, but there is no specific date yet for the approval of this regulation.

Possibly the best option would be the incorporation of these bioproducts in a blending process to formulate biofertilisers with the appropriate nutrient composition.

The coordination of the NUTRIMAN project and the rest of the participants are very involved in the subject and are committed to keeping the platform active until 2030. However, it would be interesting to have the support of national and European institutions in order to maintain all the knowledge generated by the project.