Bron article: https://effektivtlandbrug.landbrugnet.dk/artikler/kvaeg/107117/stjernholm-og-mavasol-anlaeg-virker.aspx
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Introduction by an Expert
During a recent themed event on sand separation, organized by Agillix and Seges Innovation, more than 80 participants gathered at the Messecenter Vesthimmerland. The objective? To learn about the benefits and challenges of sand separation in cattle barns. Carsten Aarup, environmental and strategic advisor at Agillix, opened the day with an important message: "Transporting manure to biogas plants is one of the most proven methods to reduce climate impact." However, he also warned: "If sand is present in the manure, no biogas plant will accept it."
Sand is Good for Cows but Comes with Challenges
Rasmus Kjeldsmark Nielsen from Byggeri & Teknik, who has been interested in the use of sand for 20 years, initiated the discussion. He emphasized that while sand is the best material for cows, its use comes with obstacles. "The sand we have available is becoming increasingly scarce. With a sand separation system, we reuse a valuable resource. This story is not only good for the media but also results in CO2 savings and access to biogas, which is the major incentive."
Sand separation involves extracting sand from manure, reusing it in cubicles, and preparing the manure for biogas production.
Different Types of Sand
In Denmark, fine sand is traditionally used in cubicles because it is easier to process in conventional manure systems. However, coarser sand is easier to separate in sand separation systems. Nielsen advised farmers to explore different grain sizes with their peers and assess what is practically feasible. "The sand content in manure after separation must not exceed that of manure from farms that do not use sand," he stated.
Two Systems Available on the Danish Market
Currently, two systems are available in Denmark that meet these standards: one from the Danish company Stjernholm and another from the American manufacturer DARITECH Inc., sold by Agri Teknik under the name MAVASOL.
- Stjernholm: Operates five installations in Denmark, with a sixth under construction.
- Mavasol: Operates nine systems in Denmark, with five more under construction. Globally, Daritech has over 200 systems in use.
Both systems are effective, but they have differences. Stjernholm offers a basic model suitable for 500–600 cows, which can be easily scaled for larger herds. The Mavasol system is standard for 1,000 cows but requires higher costs to scale.
Costs and Efficiency
The sand recovery rates for both systems range between 90% and 97%. Stjernholm often achieves slightly higher rates, but the installation and maintenance costs of this system are also higher. This is due to the use of pressurized manure, which causes more wear and tear. Mavasol, on the other hand, is considered more sensitive to irregularities, such as water supply issues.
Individual Choice
Nielsen emphasized that both systems are justified, and the choice depends on the size and needs of the farm. "Both systems perform well, but their success heavily depends on what is fed into them."
Final Products: Sand and Manure
The sand must be clean enough to be reused without the risk of contamination. According to Nielsen, it is essential for recycled sand to rest for three weeks before being returned to the cubicles to minimize bacterial risks. In addition to sand, a separation system produces fibers and liquid manure. These can be used for biogas production or directly applied to the land, depending on the farmer's strategy.
Conclusion
Sand separation provides a sustainable solution to sand scarcity and optimizes manure for biogas production. At Mavasol, we believe in customized solutions tailored to the unique needs of each dairy farm. Our system combines efficiency with reliability, supporting farmers in making their operations more sustainable. Recycled sand not only tells a strong environmental story but also serves as a vital building block for a future-proof dairy sector. Together, we are moving towards a sustainable and circular industry.
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