Non-waste biogas plant
The biogas plant makes it possible to process organic waste into biogas, which can be converted into electricity or biomethane, solid organic and mineral fertilizers, carbon dioxide and clean water.
1. Every day, substrate is collected in a well. Before it is moved to the bioreactor, the substrate can be crushed and mixed with recycled material until it reaches a pumpable state.
2. The substrate enters the anaerobic fermenter. The bioreactor works on the flow principle. This means that fresh substrate can be prepared by using an anaerobic pump (up to 12 times per day). The fermenter works in either the mesophilic (38-40°C) or thermofilic temperature range (50-55°C). A heating system ensures the right process temperature is automatically controlled. The contents of the fermenter are agitated regularly using an embedded churning device.
3. Material formed during gas fermentation accumulates in the gas tank. The gas pressure is regulated by an inbuilt relief valve and can accumulated gas for several hours.
4. The biogas obtained after drying enters a block cogeneration plant that produces electricity and heat. About 10% of electricity and 30% of heat (in winter) are required to operate the installation. An alternative method to using biogas is its purification to biomethane and a compression unit, for further use as a motor fuel.
5. After leaving the biogas plant, the processed substrate is fed to the separator. The system performs the mechanical separation of fermentation residues into solid and liquid fractions. The solid fraction of the substrate is 3-5% and represents vermicompost containing crude protein (20%) and a large amount of organic substances (80%), including the hard constituents of degradable fibres.
6. The liquid fraction separated in the production process of the separators is sent to a UASB fermenter, where the fermentation process takes place in an upward liquid flow through a layer of anaerobic sludge - a self-created granular biomass consisting of methanogenic microbial materials. The main advantages of UASB fermenters are the high rate of COD (chemical oxygen demand) removal, high load on biomass, low production of excess sludge, process stability and high-level production of biogas (energy recovery), and the shortening of liquid fraction fermentation from 25-45 days to 6-8 hours.
7. After the UASB process, the liquid fraction becomes slurry made of soluble mineral compounds, and is directed to the LANDCO module, where it is concentrated, with excess water (85%) removed. The resulting concentrate is a complex fertilizer liquid which contains the full set of macro-and micronutrients needed for plant growth: nitrogen, phosphorus, potassium, sulphur, calcium and magnesium.
To obtain microbiological complex fertilizer, these derived components (vermicompost and concentrate) is mixed and subjected to superfine grinding in which the raw material is mechanically activated. Available as either crystallized or pelletized complex fertilizers, in this case, it amounts to no more than 2% of the total fermented liquid fraction received by the LANDCO module. 85% of this volume is pure water (with salinity of less than 10 mg per litre), which can be diverted to reservoirs and used for irrigation purposes or for technical needs.
Biogas plant operation is continuous: the fermenter is constantly supplied with fresh substrate and blends fermented material. The biogas formation cycle, depending on the type of substrate and type of fermenter, takes from several hours to one month. The whole plant is regulated automatically. The number of employees at biogas plants typically does not exceed two individuals.
The output of biogas plants offered by our company ranges from 1 to 150 million cubic metres of biogas per year, and between 200 kW to 40 MW in terms of electric power. Russian plants are still more profitable with a capacity of more than 1 MW and 4 million cubic metres per year. While every biogas plant project is different, each is created using standard solutions.
Diagram of non-waste biogas station: