Decentralized processing of liquid manure
Research project with the Münster University of Applied Sciences
In this research project, the influence of slurry aging and separation efficiencies on dense central processing was investigated. Fresh pig slurry, cattle slurry and NaWaRo digestate were separated at the company Bioenergie Beerlage GmbH & Co.KG in Billerbeck and separated in two different settings with the Klass spiral filter. A nutrient analysis (N, P, K, MgO, CaO) was carried out and the biogas yields (according to VDI 4630 in a batch experiment) and a sum parameter (pH, conductivity, redox potentials) were investigated.
- the biogas yield from raw manure halved after only 7 days of storage
- The biogas yield of separated solids from pig slurry is independent of the age of the slurry
- Phosphorus separation increases with slurry age and almost reaches the separation efficiency of a centrifuge with small size and power consumption (2.5 kWh/t raw slurry)
- The biogas yield from raw manure is halved after only 7 days of storage
- The biogas yield of the separated solids decreases with cattle slurry even with the age of slurry
- Cattle manure should be separated as freshly as possible
- Separation of nutrients is more difficult to achieve with cattle manure digestates
- The separation of digestate is primarily used for dewatering
- Different degrees of humidity produce different types of infestation (beetles or fungi)
- It is possible that the degree of degradation of the organic mass will increase (test results are still pending)
Influence of the TS content in the solid matter of pig slurry on the separation efficiency of nitrogen and phosphor as well as on methane gas production when using the Klass spiral filter
Research project with the Münster University of Applied Sciences
In this research project the Klass spiral filter was tested for the purpose of separating manure and fermentation residues. The main focus was on the relief of the area through a high degree of separation of nutrients, such as phosphorus and the achievable biogas yield from separated pig
manure. For this purpose, a comprehensive series of studies with scientific support was carried out. In the first step, manure with different settings was separated on an agricultural pig fattening farm with the aim of a maximum phosphorus separation. In addition, fermentation tests were carried out to determine the possible biogas yield of the separated phases and compare it with the raw manure.
- A setting could be found that provided promising nutrient separation rates.
- It could be shown that high dry matter contents in the solid phase only make limited sense, since the electricity consumption increases with the dry matter content, while the throughput decreases. The separation efficiencies for the nutrients phosphorus, potassium and nitrogen also decrease. By means of an optimum curve, sensible and optimum settings can be found for the use of the solid phase in the biogas plant.
- 7 to 3 parts of separated pig manure can replace one part of silage maize.
- The advantage of the Klass spiral filter is its flexibility and the associated good adaptability to the substrate to be separated. In addition, the Klass spiral filter provides impressive parameters for throughput and power consumption.
Separation techniques: key for processing digestate and slurry
Research project with the Münster University of Applied Sciences
In this research project, various possible process techniques were investigated with regard to the separation of liquid manure for direct use in biogas plants with regard to continuous operation, the recording of separation performance and the influence of liquid manure ageing on nutrient
separation.
- Separation with the Klass spiral filter generates electricity costs of approx. 0.40 €/t per slurry used
- Throughputs of approx. 400 kg/h are achievable for fermentation residues. Here approx. 55% phosphorus can be separated and a solid with approx. 18 % dry matter can be achieved
- Throughputs of approx. 600 kg/h can be achieved for cattle manure. Here approx. 50% phosphorus can be separated and a solid with approx. 17% DM can be achieved
- Specific nutrient separation is more difficult to achieve with cattle manure
- Throughputs of up to 2,000 kg/h can be achieved for pig manure. Here approx. 19% phosphorus can be separated and a solid with approx. 20% dry matter can be achieved
- Phosphorus separation increases with slurry age and almost reaches the separation efficiency of a centrifuge with small size and power consumption (max. 2.5 kWh/t raw slurry)
Farm fertilizer as silo maize substitute for biogas plants
Research project with the Münster University of Applied Sciences
In this research project, the solid/liquid separation in the field of slurry and fermentation residue treatment was investigated in order to develop a solution that on the one hand increases the energetic use of manure and on the other hand separates valuable nutrient resources such as phosphorus, potassium and magnesium under economic conditions and makes them available for other regions with nutrient deficiencies as mineral fertilizer substitutes. Using the Klass spiral filter and organic precipitation and flocculation aids, an optimal and economic separation of
manure and fermentation residues was investigated. Two research objectives were in focus:
Firstly, the increased use of separated liquid manure in biogas plants, the determination of biogas yields and the increase in energy production from manure as a silage maize substitute and secondly, maximum mineral separation (phosphorus, magnesium, potassium). The aim of these
research series was to develop a technical and economic assessment of when and under what conditions farmyard fertilizers are an interesting substrate option for biogas plants and which separation potentials can be achieved with regard to minerals. The separation tactics in
connection with precipitation and flocculation aids were investigated and optimized for these applications, so that a technical further development in this subject area is achieved and thus contributes to sustainable development in rural areas.
- The animal excreta must be processed as continuously as possible, as otherwise high losses are caused by the storage of the raw manure. This can be avoided by processing and storing the produced solids.
- The storage of raw manure records losses of up to 50% already after one week of storage and losses of 90% after 8 weeks.
- In contrast, the separation and storage of the produced solids preserves the achievable biogas potential. Losses of only around 10% can be found here over a total storage period of 8 weeks.
- Potential for substituting silage maize with processed manure. Thus, at the same cost and yield, around 14% of the silage maize to be used can be substituted by processed manure. The additional transport costs are offset by the higher efficiency.
- The filtrates from the separation can be used directly on the farm and are characterized by higher fertilizer quality and simpler handling.