German biogas specialist Weltec Biopower has launched a solution for the processing of slurry and digestate by livestock owners or biogas plant operators.
Its automated Kumac system reduces the liquid manure and digestate volume by 50%. In a four-stage procedure, clear water, liquid fertiliser concentrate and valuable solid matter are extracted from the source material.
To separate the solid and liquid matter in the first step, flocculants are added to the liquid manure and digestate. This fixes certain nutrients and makes it easier to separate solids from the liquid with a belt filter press. The additives also alleviate odour emissions.
The drained solids have a dry matter content of about 30% and can be used as fertiliser, compost, litter or, in the case of slurry, as biogas feedstock.
The remaining liquid phase is passed through a flotation tank to separate further small particles and suspended matter using a fine filter. In the next step, the filtrate traverses a three-stage reverse osmosis process in order to concentrate salts and nutrients. The resulting liquid fertiliser is rich in nitrogen and accounts for one quarter of the original volume.
The major portion of the treatment products consists of clear water (50%), which can be introduced to the water cycle after being processed in an ion exchanger.
The scalable modular system can be used to treat 50,000 tonnes a year of slurry or digestate. If the processing needs to increase, several Kumac lines can be implemented.