FAQ

In the Farmer Platform, the farmer is given primary importance as the end user of the products collected in the project and it is often more difficult to involve them. However, all groups that want to contribute or receive information in the field of nutrient recovery are welcome to join the NUTRIMAN project.

Is important to the extent that a higher ammonia saturation in the air leads to faster draining: during chemical air washing, the EC-value increases faster and thus the limit is reached just before the (automatic) draining of the washing water. No further difference.

This is understandable reasoning, but nevertheless not a correct price comparison: farmers sometimes already have a spreading machine and not yet a sprayer or a spoked wheel fertilizer, etc., and then compare the zero cost for the application of e.g. KAS (or at most the depreciation cost) with the labour cost of drainage water fertilization per ha. This in itself is not a correct comparison: you have to compare fertilization cost/ha between drainage water and KAS or urean on the same basis, i.e. both administered via a contractor or both via their own machine (with specific investment and therefore depreciation cost/ha).

Yes discharge water from chemical air scrubbers ('artificial fertilizer') - and from biological air scrubbers ('other manure') - can be used on derogation plots under conditions

A piece of nitrogen was still released into the soil itself - through decomposition of organic matter. Even with relatively low OC levels in sandy soils, for example, a relatively large amount of organic nitrogen can be mineralized and - together with drainage water - provide more than enough nitrate. Fertilization as carefully as possible according to fertilization advice, i.e. always recommended.

Leaching in spring is very limited (ammoniacal N must first be converted to nitrate before it could be leached) and moreover, chemical spray water is quite acidic so once administered the ammonia will not evaporate just like that, but when administered by spraying machine (e.g. leaf treatment) and through slit caps under high pressure, some N loss can occur due to volatilization, especially when the weather is dry and windy. So only in case of non-optimal and possibly excessive administration (N-NH4) and bad weather conditions there may be some volatilization.

In terms of fertilization advice, the average sulphur requirement for wheat is 80 kg SO4/ha, potatoes 60 kg SO4/ha and e.g. sugar beet 30 kg SO4/ha. Time depends on the fastest growth, so generally speaking, administration in April/May is most relevant.

Dust particles (see previous question) can be an issue if there is no sedimentation (natural/via flocculants) and if there is a lot of dust in the air supply (e.g. poultry houses) and therefore depend on the farm to farm. In any case, it is very important that the product is pure for the farmer/worker, because otherwise you might get probes when administering it - e.g. spraying.

Usually there is a difference between wastewater from (chemical) air scrubbers in pig houses and air scrubbers during e.g. digestate dehydration - where prior fermentation has mineralized nitrogen.  4% N for the drainage water from pig houses seems representative, whereas in previous (international) projects 6 to 7% N in ammonium sulphate is often mentioned in product sheets of ammonium sulphate from air scrubbers for manure treatment.

With Biogas Bree there has also been a learning curve - where the first analysis results were around 7% N and the nitrogen content in the wastewater climbed to almost 9% as the air scrubber operation was perfected and the wastewater circulated once more to a first stage in the washer - to capture extra N/dust. This also gave slightly higher final pH values between 4 and 5.

In the demo greenhouse-field trials carried out in Italy the Ashdec® was used in different kind of soils and peat and that there have never been problems. Soil pH is not affecting the product, because the P is released by root exudates.

Some of them (ID:192-280-270) are available for organic farming, while ID:397-250-208-210 aren’t available at now, but maybe in the future.

For AshDec® production, sewage sludge ashes from sewage sludge incineration plants are used. Only sludges from urban waste water treatment plants are used in these incineration plants.

For a not optimised plant are needed 700-900 kWh/t of product: this number could be greatly reduced by using a heat recovery system.

After the European regulation, the producer who wants to put their product on the market will have to have the conformity of these products evaluated in relation to its specification which is included in the regulation. As far as product certification is concerned, this is relatively clear because the European regulation presents a set of descriptive elements. Compared to CMC the category of constituent materials is not really described according to the specification name but rather referenced to other codes and texts. It is not easy to see just where the producer should go with his specification description. Culturally this must be a concern because we do not have a mandatory equivalent throughout the country.

I think that it will have the possibility to have several categories of CMC because if you take for example the product of compost from seaweed file compost the seaweeds are rather part of the category of vegetable CMC 2 a whole part and you will have the file that itself would rather be part of the category of animal by-products. If it is already composted it would be in the compost category. So anyway, at any given moment occurs in these products that can be assembled from different materials. Any way of organic product that is often opposed as an assembly of raw materials of different origin you risk at any given time finding PHS that are given as fertilizer as several CMC's appear.

This fertilizer can be applied using conventional injection equipment for grassland of arable land. An ideal product to apply with drag hose equipment on grain or grassland. The use of low emission application techniques is compulsory to prevent ammonia volatilization.

The product can be applied before sowing or planting of the crops with the same machines which are now being used for spreading slurry or liquid manure. During the cultivation of the crops the product can be applied with precision fertilising equipment. The use of low emission application techniques is compulsory to prevent ammonia volatilization.

The product contains urea and ammonium nitrogen. Average content varies due to the natural origin of the product: N 5,0-6,5; P₂O₅ 0,0-0,1; K₂O 6,0-9,0 kg/ton. It can be used for grassland, potatoes, maize, grain, arable crops and horticulture

It contains following nutrients: N: 4,3 g/kg; P₂O₅: 0,1 g/kg; K₂O: 9,6 g/kg. It is recommended for grassland, arable crops and horticulture.

The composting process has to be monitored the whole time on critical process factor such as temperature, time, moist, etc. More specifically, based on the hygienisation threshold of one of the most robust pathogens a minimum set of weeks at certain temperatures needs to be achieved and proved to Vlaco (Belgium) for certifying the compost. A Vlaco (Belgium) certified compost is in other words, at the end of the composting cycle, fully hygienised. In other words no weed seeds nor pathogens –  contrary to (stable) manure, slurries and other waste streams which have not had the quality certification.

This is a pretty stable value between 8 and 9 and averaging around 8,5 – 8,9

It can be delivered by the composter to the farmer OR picked up at the composting site by the farmer – more particulary through the system of ‘erkend verzender’ (in Belgium) implying presence of ‘verzenddocumenten’ (in Belgium). Equally as with all types of fertiliser it can be delivered to the farmer by a ‘erkend mestvoerder’ (with GPS-system and ‘mestafzetdocumenten’ (MADs).

There is no big difference. The average amount of compost (~= organic carbon) per year applied, is what counts most. Notwithstanding a more regular application of organic material may be more beneficial for stimulating micro- and macro organisms in the soil. On the other hand a (higher) dosage once every couple of years may be (economically) easier for farmers.

Compost is regarded as a slow working fertilizer (with N efficiency of around 15% and P efficiency of around 50%). As a ‘type 1 fertiliser’ (Flanders) it can be applied from 15th of January  until the end of October, equal to the allowed time for spreading type 3 (artificial-like) fertilisers and longer than the allowed time for spreading type 2 fertilisers. Late in the year or early in the next year would be the most traditional times for applying a soil improver with slowly mineralizing nutrients (such as compost)!

The effective organic matter content of straw is about 520 kg C/ha. If you calculate per ton straw (3 to 4 ton/ha) -> 130 to 170 kg C/ton straw. From compost it varies from 110 to 132 kg C/ton. So this is a bit lower. But the price from straw (75 – 100 euro/ton) is much higher than those from compost.

Various long term tests with compost and digestate show no higher risks of nitrate leaching if composts and digestates are applied according to correct fertilizing advice. Many of the composts and digestates have a N efficiency of only 15, 30 or 60% so not all N is available/should be taken into account. Of course with a precision fertilization with artificial fertilisers the risk of leaching is theoretically lower but on the other hand this is not sustainable on many other levels and doesn’t support soil fertility in general. A balance should be struck where organic soil improvers and fertilisers such as digestate and compost are more part of the yearly farmer routine.

Compost prices vary according to the amount ordered (bulk), to the cost structure of the composter, and to the composting site being a private entity or an intermunicipality. In Flanders compost prices vary between more or less 2€/ton to 12€/ton but for large uptakes/bulk the price will be towards the lower part of this price range.

Every digestate is based on a different specific set of inputs (digesters differ in what they take into their digester. Also every digester post-treats their digestate according to its own specific separation, drying, concentration, backmixing, etc processes. That’s why it is best to ask for and base fertilization on the last available N- and P-analysis – which every digestate has to have done at least every 3 months.

Various long term tests with compost and digestate show no higher risks of nitrate leaching if composts and digestates are applied according to correct fertilizing advice. Many of the composts and digestates have a N efficiency of only 15, 30 or 60% so not all N is available/should be taken into account. Of course with a precision fertilization with artificial fertilisers the risk of leaching is theoretically lower but on the other hand this is not sustainable on many other levels and doesn’t support soil fertility in general. A balance should be struck where organic soil improvers and fertilisers such as digestate and compost are more part of the yearly farmer routine.

For now in Flanders digestate are not allowed yet for organic agriculture but Vlaco has been discussing the topic with Department of Agriculture to find agreement on which inputs precisely would be allowed according to the EU regulation 889/2008

• STEP 1 volatilization of the ammoniac by increasing pH
• STEP 2 Scrubbing of the NH3-containing air either with nitric acid or sulfuric acid to produce an ammonium nitrate or ammonium sulfate liquid fertilizer

N-recovery process: Energy for heating the liquid fraction up till 40°C - 70°C; energy for pumping.

EC is preparing the RENURE legislation in order to establish criteria for recovered fertilizers.

The fact that these products have a lower concentration than the chemical fertilizers is a real disadvantage. It entails practical problems, for example application has to be repeated, meaning a higher frequency of application machines on the field with risk for soil damage. Also if more than 1 application is needed, this is time consuming.

Yes. Most farmers are equipped to be able to apply liquid fertilizers.

There is no clear answer for this. It was decided to harvest because the plants had dried out. There were no fully-grown corn cobs and about 90 % of the stems even didn’t have any cob at all, this was similar for all objects. So dry matter is lower than normal.

There will be less risk for volatilization (compared to NH₄NO₃) since NH₄-concentrations are lower. So application by drag-hose is an option.

The N-concentration in the produced product depends on the system settings. It is difficult to produce higher concentrations. Also, production risk increases with higher concentrations.

At the moment of sowing.

Most compost producers can bring it to you legally.

Only green compost, digestate not yet but there are things going on (with restrictions on the feedstocks).

Compost is slowly acting so low risk for leaching. But there are restrictions in regulations.

This does not make much difference.

You do not need a liquid proof floor, you can hire or share a turner, you can compost together with other farms or companies, you can supply enough or excess brown material in order to limit the monitoring and turning (static composting).

Not at this moment since there are problems with crystallisation.

pH is 6.

Yes. This is positive since most farmers can apply this to their fields.

On the Planet Earth naturally high concentrated Phosphorus can only be found in one unique mineral and that is the apatite, which has two natural forms:

1. MINED MINERAL APATITE is a mineral phosphate rock that is non-renewable (formed over millions of years) critical raw material and naturally containing high levels of cadmium, uranium and other toxic chemicals. Today the mined phosphate rock is the only significant commercial source of phosphorus used to manufacture chemosynthetic fertiliser. The process to convert the ore into a phosphorus fertiliser product is done via chemical extraction with an acid. Phosphorus fertilisers produced from phosphate rock poses a risk to human health and environment.
2. BONE BASED-APATITE which is an unexploited and renewable biomass raw material with high dicalcium phosphate content. The food grade cattle bones are pure and free from organic and inorganic contaminations and available in economically interesting industrial scale. The 3R zero emission pyrolysis technology treats the food grade cattle bone grist at as high as 850ºC material core temperatures in absence of oxygen. The end-product is the Bio-Phosphate (animal bone char) which is pure and environmental safe recovered fertiliser product.

As both materials are same apatite group substances the standard high P concentration is >30% - 36% P₂O₅ in both cases. All Phosphate products are critical raw materials as of COM/2020/474 final.

40-50% green materials, 50-60% brown materials 

This depends on the measurements of oxygen and temperature.

Legislation is not ready yet, but this will be 3 farms (Flanders).