Founded in the early 2000s, the Koster company quickly established itself as a benchmark in the organic waste management industry. Originally started as a family business in agriculture and animal husbandry, Koster has used its expertise in organic waste management to evolve over time, expanding into waste treatment. This transformation has enabled the company to become a benchmark for organic waste treatment in the province of Novara, serving a catchment area of about 500,000 inhabitants.
As of today, Koster operates two composting plants, one in San Nazzaro Sesia in the province of Novara and one in Gallarate in the province of Varese, where compost is produced from lingo-cellulosic waste from separate collection. The San Nazzaro Sesia plant, on the other hand, in addition to mowing, also treats organic waste and produces about 35,000 t/y of compost.
Koster is not only a company committed to composting, but also represents excellence in the panorama of biomethane production plants, thanks to a project that began with the expansion of facilities in 2018-2019 and recently started. The construction of the biomethane plant involved collaboration with technology partner Cesaro Mac Import, a trusted supplier with whom Koster has worked for more than two decades.
THE BIOMETHANE PRODUCTION PROCESS
Koster’s biomethane plant is an example of innovation in the field of organic waste treatment. Designed and developed in collaboration with Cesaro Mac Import, the plant is designed to transform about 50,000-60,000 tons of waste per year into biomethane, thanks to an anaerobic digestion system that takes place inside two digesters of 2,100 m³ each.
The biomethane production process at the Koster plant is developed in several stages.
Waste collection and delivery Organic waste, from separate collection and green waste, is delivered to the facility from Monday to Saturday.
The trucks transport waste directly from the served territory, without the need for intermediaries. A system that allows waste to remain in the territory by optimizing travel and thus reducing emissions, consumption and consequently costs.
Pretreatment. Once the waste arrives at the plant, it is pretreated through an initial coarse shredding stage followed by screening to remove the bags.
Anaerobic digestion. The mixture is then sent to digesters with Plug&Flow technology, where it undergoes the process of anaerobic digestion, a biological treatment that takes place in the absence of oxygen. At this stage, microorganisms transform the organic matter into biogas, composed mainly of methane and carbon dioxide.
Mixing. At the end of digestion, the extracted material (digestate) is started to a UM320 Cesaro Mac Import mixer and mixed with the recirculation surplus from the composting stage and shredded green waste in order to obtain a homogeneous and sufficiently porous and aerated mixture for the next composting stage.
Aerobic phase in biotunnels. After mixing, the material is transferred to biotunnels using Il Girasole Tunnel Composting technology, where it undergoes an additional aerobic phase to stabilize the remaining organic matter.
Screening and curing. The stabilized material then goes through a screening process to separate the woody parts. Next, the resulting compost is matured for about 90 to 100 days to a finished product suitable for use in agriculture.
Upgrading of biogas to biomethane. The biogas produced during anaerobic digestion is purified through an upgrading system that removes impurities and carbon dioxide, transforming it into high-quality biomethane (99.8 percent purity) ready for feeding into the grid.
FROM PRODUCTION TO DISTRIBUTION
In addition to biomethane production, the Koster plant integrates a distribution system that allows biomethane to be delivered directly to citizens. This public distributor, owned by the company, represents one of the few realities in Italy where the biomethane produced can be directly used as a sustainable vehicle fuel. Koster’s goal is to create a virtuous cycle, from waste treatment to clean energy production and distribution.
TECHNOLOGIES AND TRUST
The choice of Cesaro Mac Import as the technology partner for the biomethane plant was no accident. After more than two decades of collaboration, Koster decided to rely again on Cesaro Mac Import’s technology, which is considered one of the best on the market for biogas production. During the planning phase, the company visited several plants built by Cesaro, both in Italy and abroad, seeing for itself the effectiveness of the proposed solutions.
The Koster plant is equipped with a number of advanced machinery supplied by Cesaro Mac Import, including Doppstadt shredders and screeners, Sennebogen loaders which enable efficient and safe waste management during all stages of the process, as well as the UM320 mixer built by Cesaro MacImport.
The overall investment for the construction of the biomethane plant exceeded 25 million euros, a figure that demonstrates Koster’s commitment to promoting sustainable solutions for waste management. The company continues to grow thanks to a solid family structure and a team of over 100 collaborators distributed across the various operating sectors, from agriculture to transport to waste management. With the biomethane plant, Koster not only contributes to reducing greenhouse gas emissions, but offers a concrete response to the growing demand for renewable energy, confirming itself as a model of innovation and sustainability in the waste sector.
