Efficient logistics – fertilizer production

The Fliegl RondoDry offers a new drying process

Why stocking up on water and carrying it as ballast when it’s actually about the manure and its valuable substances? Fliegl’s slurry and drying experts have developed the RondoDry, a system which extracts water from separated manure through a special process, so that storage and transport capacities can be used more economically. As a result of the drying process, the machine supplies high-quality fertilizer (ammonium sulphate solution).


A drum fitted with grates is rotating inside the RondoDry. During rotation, the grates – a total of around 400 square meters grid surface – are continually immersed in the separated manure which is pumped into the RondoDry, take up liquid and transport it upward. Highly efficient fans create hot air via a water-air heat exchanger which then flows onto the grates wetted with manure. Thereby, liquid and ammonia are removed from the manure – the RondoDry then blows the enriched air into an air scrubber. With the addition of sulfuric acid, 99% of the ammonia is dissolved from the air and collected in an ammonia sulphate solution (ASS) that can be specifically used as mineral fertilizer with excellent properties. On the field, the liquid substance runs through the stalks and directly reaches the roots - nutrients do not evaporate and there is no fertilizer carpet, such as when dropping manure (apart from ground-level application or injection).

The dewatering proportionally increases the dry matter content in the manure. The operator defines the amount of water to be evaporated, depending on the spreading technology that he uses. The manure must remain pumpable in order to be able to remove and spread it. By using an embedded Fliegl weighing system, the evaporation mass is determined and the process is continuously monitored. "We prefer separated manure with a dry matter content of about 3%", says Hinterholzner. "If half of the water evaporates, the ratio between dry matter and water content doubles. For example, from 3000 incoming liters with a dry matter content of 3 %, 1500 liters with a dry matter content of 6% remain." Besides storage capacities, this mass reduction also relieves transport capacities - evaporated water does not have to be transported in a tank trailer on the road.

The new Fliegl RondoDry only requires a hot water supply and a power connection, with the power consumption of the fans and the drum drive being less than 1 kW / h. Anton Hinterholzner: "An intelligent heat management software developed by Fliegl flexibly responds to changing scenarios. For instance, if the operator wants to use the heat produced by a cogeneration unit to supply upstream consumers, the RondoDry system switches off and back on if necessary. Thus, the entire thermal energy can be reasonably exploited - whether it’s 100 or 500 kW."

With its EcoDry, Fliegl has already established a product which dries separated fermentation residues and makes them storable. The RondoDry now also treats the liquid phase containing ammonia, which is intended to go onto the field, but on the other hand impairs the 170 N/ha balance. Anton Hinterholzner would like to emphasize three advantages: "Our customers in Germany benefit from the CHP bonus, they increase their storage and transport efficiency and produce high-quality fertilizer – all this at manageable acquisition costs and low operational costs."