Cattle farmer Jacob Bjerrum invested in a sand separation system from Mavasol in the autumn of 2025. The system was ready for use in October last year. He has been very pleased with it ever since.At Lundbjerggård near Hobro, Jacob Bjerrum runs a cattle operation with 800 cows. Much has changed since he bought the farm 24 years ago, when he had 200 cows. The business continues to evolve. His latest investment is a sand separation system from Mavasol. "We have to keep developing our operation continuously. Environmental considerations have also become increasingly important. That led us to look at ways of reusing our sand, as we consume large quantities of it," he explains.
Separating sand from slurry
Jacob Bjerrum chose to invest in a sand separation system from the Dutch company Mavasol, where Klaus Bruun has been a permanent employee since the turn of the year. He has been involved in developing and designing the containerised sand separation systems, which are available in different sizes depending on the size of the operation.
The smallest systems cater to farms with as few as 250 cows, while systems are also available for farms with more than 1,000 cows. All systems work by allowing sand to settle in the chambers of the unit, after which it is conveyed out using an auger.
"That way, nothing operates under pressure and on the outside there are nozzles using clean water to wash off the remaining sand. In the end, we recycle around 95 percent of the sand," Klaus Bruun explains. He continues:
"At the same time, the system produces sand-free slurry for biogas production, with a dry matter content of 7% to 9%. The entire system is designed to keep sand away from pumps and valves. We have focused on simplicity and ease of maintenance throughout the design process."
For Jacob Bjerrum, the sand separation system means he can easily separate sand from slurry, which can then be sent directly to the biogas plant without first having to remove sand from the slurry tank. "The slurry goes directly from the sand washer to the biogas plant. The recovered sand can be reused in the barns. Overall, it has been a good investment," says the cattle farmer.
A significant saving
The harsh start to 2026, marked by snow and temperatures as low as -24°C, made Jacob Bjerrum wonder whether the system could continue operating under such extreme conditions.
"That's when we really got to know the installation.We even considered shutting it down temporarily. In the end, we decided to keep it running. It handled the conditions without any problems. The only maintenance required during the winter was removing snow and ice. Over the past two months, with milder weather, I haven't had to pay any attention to it. It simply keeps running," he says.
The sand separation system does more than simply separate slurry and sand. It has also had a major financial impact for Jacob Bjerrum.
"We used to spend 500,000 to 600,000 kroner a year on sand, but since we got the system, we've stopped completely. Being able to recycle the sand in the barns has saved us a lot of money," he explains. He adds:
"After it has gone through the system, it needs to sit for 3–4 weeks before we can bring it back into the barn. The quality of the recycled sand has been excellent. Before we started reusing sand, our herd's somatic cell count was around 100,000. It remains at the same level today."
Good service
The Danish farmer has nothing but praise for Mavasol's service and support. The company is easy to reach and carries out maintenance on the system several times a year. "Our experience with Mavasol has been excellent from the start. That applies to the installation process, day-to-day operation, and ongoing service and maintenance. It's much like a milking parlour. If something needs adjusting, there's always someone available to help. I'm very satisfied with that," he says.
Klaus Bruun explains that Mavasol offers two types of service agreements. Farmers can choose quarterly visits from a technician or opt for a monthly subscription that provides full service coverage. "After each visit, the farmer receives a service report detailing the work that has been carried out on the system," says Klaus Bruun.
A clearrecommendation
Jacob Bjerrum is quick to recommend a sand separation system from Mavasol to other dairy farmers.
"Any concerns I had about wear and tear have completely disappeared. Seeing how little sand reaches the pumps has given me a great deal of confidence in the system. There's no need to worry about whether it can cope with a harsh winter either. It handles those conditions without any problems. I can wholeheartedly recommend it to other farmers," he says.
