When waste is valuable
Vogelsang and BiogasTec (Belgium)
Positive experience of cooperation ensures environmentally compatible and resourcesaving energy and materials. To be successful in the biogas sector, you had to work intensively with biology, on the one hand, and technology, on the other.
Unnoticed by most, one of the biggest biogas plants that converts waste into valuable resources, went into operation in 2019. In Albertstroom, about 25 km east of Antwerp in Belgium, biowaste and residualmaterials are the basic material for producing valuable resources: energy, fertilizer and process water. BiogasTec specializes in precisely this form of sustainable waste utilization. The company is responsible for the planning, construction and operation of the plant. The focus at BiogasTec is on closed cycles and sustainable processes, as well as the highest possible efficiency. The company also relies on cooperation with Vogelsang.
It all started in the early 2000s. Student Wouter Platteau was following the development of biogas technology with interest. He believed that generating energy from waste using biogas technology conserved resources and was environmentally friendly, and felt that the actions of the early biogas players were very responsible and prudent with regard to the environment and resources. He was also fascinated by the diversity of the subject. To be successful in the biogas sector, you had to work intensively with biology, on the one hand, and technology, on the other. At the same time, it was necessary to develop economical solutions and to win people over for what, at the time, were highly unusual projects. A purely theoretical consideration of the topic was therefore ruled out from the beginning.
Instead, Platteau wanted to achieve something practical. And so he joined Trevi, a company specializing in environmental technology and consultancy in this field. Trevi focuses on solutions that help to conserve resources by making optimum use of them and by recycling and reusing them as far as possible. Ideally this is done using biological processes. Solutions include concepts for environmentally friendly painting processes in the automotive industry, specially designed sewage treatment plants in the food industry and plants for exhaust air treatment in the chemical industry. Trevi makes use of its know-how, gathered in many areas, nand applies and adapts it to other applications. The 180 employees can look back on over 300 successful projects. They include numerous plants for the treatment and processing of liquid manure from livestock farming. So it is not surprising that the company also plans, builds and often operates biogas plants itself.
Complex solutions thanks to team spirit
Trevi’s subsidiary BiogasTec has specialized in recycling of waste and residual materials. The objective of the first biogas plant designed was still relatively simple: the efficient treatment of liquid manure. To save resources, the waste and residual materials are fermented in a digester. This generates energy. Today, the concepts developed and implemented by Managing Director Wouter Platteau and his team are far more complex. Wouter Platteau is convinced that this can only succeed if everyone sees themselves as a team. Therefore, a healthy work-life balance is also important to him. Growth and success is essential for the company to invest in new projects. But he is careful not to neglect his own private life and that of his employees. Therefore, a realistically achievable project volume is another important element of his company philosophy. In order to be able to implement the complex projects successfully in the long term, from planning and approval to plant construction, BiogasTec only deals with a limited number of projects at any one time.
The high efficiency of the overall system and closed circuits are key requirements for completing a project. A prime example of this is a project that was completed in close cooperation with a manufacturer of frozen vegetables. The project was so successful for both parties that the capacity of the jointly operated plant was doubled in 2016. Production waste accounts for 77 percent of the input materials. The dewatered sewage sludge from the company’s own sewage treatment plant, which biologically treats the production wastewater, makes up a further 13 percent of the solid matter used. This is supplemented by a small amount of energy crops. The Vogelsang solid matter feeder mashes everything into a homogeneous suspension and the digesters are fed with substrates that have been treated for bacteria. They ferment in the digesters and post-digesters in the biogas plant, producing biogas, among other things. This is used in the plant’s two combined heat and power (CHP) units to generate 3 MWel of electricity and 3.4 MWth of thermal energy. Both are consumed by the two partners directly on-site and are significantly cheaper than the previous sources of supply.
For BiogasTec an important detail for the sustainability and success of the project is its almost complete use of the heat produced. It is mainly used to generate process steam, which is needed in the partner company’s production process. But the heat is also used in the company’s own wastewater treatment plant and the biogas plant itself. This includes processing of the fermentation residues. These are separated into a liquid and a solid fraction (approx. 20,000 tonnes per year). While the solid fraction is immediately suitable for use as fertilizer byagricultural suppliers, theliquid suspension undergoes further treatment in an evaporator. It is ultimately turned into demineralized, high-quality water that can be reused in the partner’s production. In addition, a liquid nutrient concentrate is obtained, which is added to the dry fraction and thus increases its nutrient content. All in all, a complete closed circuit.
Biogas plant in Albertstroom: The largest project to date
BiogasTec projects are characterized by automated processes and functional components with high efficiencies. Economical and sustainable operation of the company’s own six biogas plants operated with partners is guaranteed by just 17 of the total of 40 BiogasTec employees. As a planning office, plant manufacturer and operator, you know what is important. Numerous Vogelsang technologies support the operation: Rotary lobe pumps from the VX series, RotaCut macerators and solid matter feeders process and convey liquid manure, suspensions and digestates in the BiogasTec plants.
Vogelsang products are also of great importance at the Albertstroom biogas plant in Grobbendonk. Albertstroom is the seventh and, at almost 13 MWel, by far the largest project realized to date. The size played a subsidiary role for BiogasTec, as there were more important questions when developing the product, such as: Which residual materials and types of biowaste are available where and in what quantities? How can the energy generated be used and where can the digestates be used effectively?
In Albertstroom, around 250,000 tonnes of liquid manure and liquid organic waste are fermented annually, as well as a wide variety of residual materials and waste from the region. When the input materials are delivered, a sample is first taken from each batch and analyzed to avoid possible complications caused by undesirable constituents. Importantly, and typically for BiogasTec, the entire receiving area is housed in one building with several boxes and underground tanks. A ventilation system ensures a constant negative pressure and the entire exhaust air flow is treated by a biological air filter filled with wood chips. This reduces odor emissions to a minimum, which is extremely important, considering that abattoir waste and waste from the food industry and the catering trade are delivered there. This includes packaged foods that are no longer nsuitable for consumption. BiogasTec then unpacks them itself to ensure that they are absolutely free of plastic. For the solid matter feeding, five feed lines with different fittings have been installed in order to process each substrate as efficiently as possible. There is also a liquid feeding system from Vogelsang. In the digesters, the bacteria convert the supposed waste, which in reality is raw material, into 36,250,000 Nm³ of biogas per year. Four CHP units, each with a nominal power of 3 MW, are installed to provide the power supply. An ORC turbine generates a further 900 kW of electricity from the waste heat in the exhaust gases. Around 4.5 MW is reused by a company that manufactures plastic packaging.
Of course, the figure also covers the energy requirements of the plant itself. The remaining electricity is fed into the grid and covers the electricity needs of around 20,000 Belgian households. Eleven megawatts of the thermal energy generated is used by the neighboring concrete component manufacturer for drying parts. The water from the fermentation residue treatment is also reused here. Another part of the thermal energy is used in drying boxes directly on-site at the plant, e.g., for drying wood. In addition, 65,000 tonnes of organic fertilizer are produced, which contains 94 percent of the nutrients supplied with the input materials. Storage and collection is located right next to the receiving area; the exhaust air from this area is also passed through the biofilter, thus eliminating odor emissions.
Trusting and professional cooperation with Vogelsang
For realization of its projects, including Albertstroom, BiogasTec has relied on Vogelsang as a trustworthy partner for pumping, solids reduction and solid matter feed technology. Ten rotary lobe pumps from the VX series and four RotaCut cutters ensure effective treatment and pumping of the organic suspension at various points. Important selection criteria include reliability, easy and fast maintenance, and a rapid spare parts supply. In addition to the sophisticated Vogelsang technologies, BiogasTec also benefits from other Vogelsang services. Specifically they appreciate expert advice that would not be possible without the many years of experience at Vogelsang. This is precisely what BiogasTec considers to be a crucial criterion for a good supplier. It wants partners that are not stuck in a rut, and react flexibly to new challenges and develop individually tailored solutions with its customers. For BiogasTec, good and trusting cooperation such as that with Vogelsang is a very important criterion for a long term and mutually beneficial business relationship.