Optimization through biomass return filter in combination with ultrasonic technology
Wavebox with ultrasonic technology
Returgant Direct for biogas and sewage treatment plants.
The unique combination of the Returgant Direkt biomass return filter and ultrasonic technology makes it possible to shred unfermented and previously undegraded fibers. This achieves an even higher gas yield!
The problem & the solution
Between 8% and 15% of the fermentation residue produced are fibers that have not yet been fermented or decomposed during filtering. Despite current techniques, it is not possible to completely shred the fibers.
By cleverly integrating a biomass return filter in combination with ultrasound technology into the existing system of the biogas plant, it is possible to break down the fibers even better and faster and to dissolve the organic matter. By breaking down the fibers, a faster degradation rate is achieved. This allows more power to be extracted from the same container system.
Increase your biogas yield of up to 20 % possible*.
- Avoidance of emissions from separation system
- Increasing the gas formation potential of the input materials
- Reduction of the residual gas potential in the digestate
- Normal BGA: Degradation of organics 75%
- BGA with Sepogant-Direkt and WaveBox: Degradation of organics 90%
*Returgant Direct – biomass return filter in combination with ultrasonic wavebox.
The process
This variant removes substrate from the fermenter or secondary fermenter and, after filtering, feeds it directly back into the fermenter/secondary fermenter as a thickened phase with the not yet fully fermented fibrous materials. Even substances that are difficult to break down, such as GPS (straw, manure), can be broken down using this process.
The WaveBox ultrasonic technology makes it possible to break down the material to the maximum, as the ultrasonic waves create air bubbles in the substrate and cause them to implode. This cavitation means that a higher proportion of the organic dry matter can release gas due to the disintegration of fibers.
The repeated feeding process saves input materials. This means that the entire gas potential of the fed substrates is utilized.
In addition, agitators and their agitation times in the fermentation residue store are saved, as the tanks contain a homogeneous mass with a uniform structure that does not segregate again. In addition, the volume of input materials is saved during feeding, which results in a lower load (energy and wear) on the feeding technology.
In a conventionally operated biogas plant, 75% of the organic matter is broken down. As soon as a biomass recirculation filter is used in conjunction with ultrasonic technology, the degradation of organic matter increases to approx. 90 %. In this way, an increase in biogas of up to 20 % can be achieved from the original substrate fed to the biogas plant.
Design example
- Fermentation approx. 40m³/ d
- NawaRo substrate mix with grass/GPS content
- Dwell time: 60 days
- Room load approx. 8 kg oTS/ m³*d
- WaveBox 4-sonotrodes approx. 3.5 kW
- Increase in biogas production by approx. 14
Note: The samples originate from the BGA Isny (Baden-Württemberg) – May 2021
Technological aspects of the combination
Increased efficiency of the ultrasonic system through
- the treatment of the thickened organics
- Arrangement of the probes – max immersion depth
- Optimum gas dissipation
- No deposits
Effects for ultrasonic technology
- Increasing the efficiency of the WaveBox
- Significant reduction of the TS content in the overall system – thereby reducing operating costs
- Savings effects due to increased organic degradation
- Better stirring ability due to reduced shear forces
Ecological aspects of the combination
- emissions are avoided
- Increasing the gas formation potential of the input materials
- Reduction of the residual gas potential in the digestate
- conventional BGA: degradation of organics 75%
- BGA with Returgant Direct and Wavebox: Degradation of organics 90%
- Up to 20% more biogas from original substance
Wavebox - Application area biogas plants - Frequently asked questions (FAQ)
The WaveBox uses ultrasonic waves to break down fibrous substrates in a targeted manner. A pump transports the substrate through the WaveBox, where sonotrodes generate ultrasonic waves. These sound waves form microscopic air bubbles that implode in the substrate. This cavitation effect breaks up the fibers in the substrate, allowing microorganisms to break down the organic matter more quickly and efficiently.
The Wave-Box offers numerous advantages for biogas plants:
- It can be retrofitted to existing systems.
- The decomposition of organic dry matter can be increased by up to 20%, which increases the biogas yield.
- The agitation times in the fermentation residue store are shortened, which can reduce the energy requirement for the agitator.
- Foaming can be prevented, which stabilizes system operation.
The WaveBox’s intelligent control system enables flexible adaptation to the respective operating conditions. The flow rate, pressure and energy input can be individually adjusted via the control unit to ensure optimum processing of the substrate. This ensures that the system runs efficiently and trouble-free.
Wavebox - Application area sewage treatment plants - Frequently asked questions (FAQ)
The WaveBox uses ultrasonic waves to break down sludge more efficiently. As a result, the organic components in the sewage sludge are broken down better, which increases methane production in digesters and reduces disposal costs.
By breaking down the cell structures in the sewage sludge, biological utilization is improved. This leads to better sludge stability and reduced odor formation.
The optimized cell disintegration leads to faster and more complete fermentation of the organic material. As a result, the biogas yield can be increased by up to 20%, which improves the efficiency of the wastewater treatment plant.
Yes, the WaveBox is designed for simple retrofitting and can be easily integrated into existing wastewater treatment plants. It is integrated into the sludge cycle and can be flexibly adapted.
As the digested sludge is easier to pump, the energy required for agitators and pumps can be reduced. At the same time, the volume of biogas obtained increases, and with it the energy yield.
Yes, the improved sludge structure can reduce foam formation in digesters and secondary clarifiers. This leads to more stable operation and minimizes operational disruptions.
In a nutshell
The combination of the biomass return filter, the retention of not yet fully fermented fibers and the treatment of the biomass by ultrasound is currently the only functioning process to get the best out of the substrate. This means that no gas potential is wasted, as energy-rich feed does not remain unused, regardless of the dwell times.
When feeding the system, the volume of input materials is reduced, which reduces the load (energy and wear) on the feeding technology.
The effective decomposition of the fibers of the substrate means that an increase in gas yield of up to 20% can be achieved.
