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Biogas Additives Improving Digester Biology in Anaerobic Digestion Plants

Image shows intro to 7 Digester Additives article and video.
Watch our video introduction to this subject!

In this article we provide a summary of Biogas Additives which are offered to AD Plant operators. This is all about improving Digester Biology in Anaerobic Digestion Plants for higher biogas yield and greater digester resilience against loss of biogas production when the anaerobic digestion process becomes stressed.

There are a large number of products which are available for operating biogas plants to be used for stabilising and improving digester biology, and compensating for deficits in trace elements.

The formation of biogas from biomass is a complex process with a multitude of variable process parameters.

The effectiveness of any biogas additive will vary from biogas digester to biogas digester. Generally, it is necessary to conduct some live trials to find out whether biogas additives such as the ones we refer to here, will be useful in raising biogas plant performance. Remember that even if performance gains are found, it is necessary to check that the benefit will outweigh the cost of dosing a biogas additive.

Many biogas experts agree that the stability of biogas production, and production rate, can indeed be greatly improved by keeping these parameters close to their optimum. One possibility to achieve this is by use of additives.

In Germany alone there currently are over 250 additives on the market which demonstrates the demand for optimisation of biogas plants. The effects of these additives are hardly investigated and can only be evaluated by costly, time consuming tests (e.g. continuous anaerobic digestion experiments).

Examination of commercial additives for biogas production (PDF Download Available). Available via Examination of commercial additives for biogas production

A Company Called “Biogas Additives” Offers Biogas Additives to Maximise Performance at AD Plants

Assuming for a moment that you accept the hypothesis that the performance efficiency of your biogas plant is closely dependent on the fermenter biology which can be improved by using biogas additives. The highest possible yield can only be achieved through establishing a close to perfect fermentation process, with the best culture of bacteria species, and other micro-organisms. Now, biogas additives can help, in the words of

Agri Flex Trace elements for greater biogas yield

Image which shows: Trace elements additive for greater gas yield .
Image attributions are shown at end of video.

Agri Flex is a custom-made additive, containing trace elements and micro-nutrients which can improve methane yield by up to 30 per cent. After analysing the contents of your fermenter (usually every three months) they offer to design and formulate a specific mixture tailored to the particular needs of your own biogas plant. This additive, available as a powder. It, according to the supplier, stabilises the anaerobic biological processes so acidification is avoided. When this occurs, less substrate is needed for a given amount of biogas production. Gas output is improved thereby maximising profit.

Agri SOS  First aid for your biogas plant

Image which shows: First Aid Additive for biogas plants.Agri SOS, available as a powder, is their first aid for your biogas plant. It contains all the required trace elements to ensure a reduction in high acidity. Its use will avoid a rapid collapse in biogas production and will save you the costly task of restarting the plant. For long-term stabilisation of the biological processes they recommend their individual trace element mixture, Agri Flex.

Agri Visco

With the use of Agri Visco the biogas can rise more easily through the substrate and the substrate digestion is also improved.

  • Reduces substrata viscosity
  • Cuts energy consumption
  • Easier mixing and pumping
  • Better release of biogas

Optimises viscosity in your fermenter

Image which shows: Viscosity reducing biogas additive.Agri Visco is a selected combination of different enzymes which can reduce the viscosity of the substrate in your digester. Some raw materials contain high levels of carbohydrates, such as starch, protein and polymer substrate fibres. These materials withhold water, increasing the viscosity in the fermenter thus causing mixing and pumping problems. High viscosity also results in higher energy consumption for mixing, resulting in methane having greater difficulty in passing through the substrate.

Agri Combi – A bespoke combination of trace elements and enzymes to suit your fermenter

Low microbiological activity can threaten stable processing and lead to significant reductions in production and yield. Agri Combi helps maintain an optimum supply of micro-nutrients because we individually tailor a combination of trace elements and enzymes to the needs of your fermenter. Agri Combi allows faster and more complete digestion of fibre-rich substrate components while the use of enzymes optimises the fermentation process increasing gas yield. A concomitant reduction in viscosity significantly reduces the energy needed to operate the agitators and pumps. via Biogas Additives | Renewable Energy Additives

Performance enhancement by using additives, especially the trace element supplementation from BioGAS+

Beyond the use of machinery, the use of additives is the alternative – or complementary – way of optimising an anaerobic digestion process.

The use of additives has become an important topic due to their capacity to increase reactors performance in terms of process stability, biogas production and treatment capacity. Research experiences also showed that additives could lead to inhibitory phenomena.

Regarding inorganic additives, Co, Fe and Ni are the most investigated nutrients. Other reported inorganic additives comprise substances able to mitigate ammonia nitrogen inhibition and/or to immobilise anaerobic biomass.

Regarding biological additives, results clearly indicate that bio-augmentation might be a useful tool to improve digester performance: especially when the digester is subjected to stress conditions (e.g. start-up, inhibitory concentrations). However, its application in full-scale plants is still scarce due to its economic uncertainties and risks.” via Additives – BioGAS+

The nanotechnology solution offered by BioGAS+

In this context, the effect of nano biogas additives can improve the anaerobic digestion process and consequently on the biogas yield is an active area of research and the most promising

The pioneering biogas additives solution from nanotechnology is BioGAS+ by Applied Nanoparticles.

There was a clear need for a unified, standard and efficient solution for the optimisation of anaerobic digestion. Applied Nanoparticles offers the trace element supplementation BioGAS+, a nanotechnology-based innovation that obtains the highest ever-reported improvement of biogas production. BioGAS+ claims that they can triple the biogas yield and offers all this other benefits for process optimisation:  via Additives – BioGAS+

Zorg Biogas AG – Sells Enzymes for biogas

A mixture of enzymes is offered by a well-known and well-established biogas company called Zorg Biogas AG. Their product is based on probiotics and microelements, we are told. It is an additive used for biogas yield increase. Zorg says that additives achieve considerable results at low cost. The main advantages of enzymes application are the increase of biogas yield from 25 to 40% without any changes in plant design, stability of the process and increase of methane content in the biogas.

Thanks to enzymes it is possible to get almost all the biogas out of the main digesters without a post-digesting stage. Biogas plant [construction] size/ cost can be halved with the additive. The Enzyme additive has been applied already for 4 years in 100 biogas plants and gives guaranteed increases of biogas yield from 10 to 40%. An example of this is a biogas plant where the biogas yield is 260 m3/t of corn silage is reached, that is 45% yield increase. The saily consumption for 1 MW biogas plant is 1 to 2 kg. via Zorg Biogas AG

Silage Additives from Biogas | ADDCON – Green Chemistry

Stable maize silage with high energy content is the foundation for success.

During the preparation of silages for biogas, it is vital to preserve nutrients. This means that the aim is to have lowest possible preservation losses, and a perfect hygienic condition of the end product. Nutrients, that are lost between silo and fermenter, have cost money during the cultivation and harvesting period already. Preserving these nutrients saves money and justifies technological effort. via Biogas | ADDCON – Green Chemistry

For biogas plants fed with purpose grown crops making good silage is vital to their profitability. More biogas per tonne of material and minimised storage losses increases efficiency per hectare.

Firstly you need to select the right seed variety to suit your location and requirements. We can offer an extensive range of seeds through our Forage and Arable division.

Once the crop is grown you need to ensure it is preserved correctly to minimise energy losses. That's where biogas additives are used.

FM BioEnergy recommend the use of Silasil Energy, a biogas specific silage additive manufactured by Schaumann BioEnergy. Silasil Energy has been approved by the DLG (German Agricultural Society) as increasing methane yield and improving aerobic stability. via Silage Additives | ForFarmers UK

Biogas – Antifoams – Schill + Seilacher “Struktol” GmbH

Antifoam additives have been used throughout the wastewater treatment industry when needed, for probably at least the last 50 years.

Foaming can occur whenever biogas is produced during the anaerobic digestion of organic material. It is normally seen when the fermentation process is not running well, and the fermentation organisms are stressed. The need to dose should be short-lived if the plant operator finds and corrects for the chemical imbalance that causes foaming. Substrates are specifically grown energy plants like maize, previously unused parts of plants, liquid manure, wastewater sludge and other bio-waste. The organic material is biodegraded by microorganisms into biogas. In many cases the organic material also contains foam-active substances like proteins which are involved in foam production.

During digestion disturbing foam can occur. It happens if the process in not correctly driven and “foam active” substances (biogas additives) are present: inside the digester, during the isolation of the biogas from the digestion substrate, during the digestate evaporation etc.

Struktol antifoaming agents are well-balanced between destruction of already built foam, and the prevention of more foam and the degassing of high viscous digester content. Biogas additives via Biogas – Antifoams

Tailor-made additives to optimise bioreactor environments from

Biogas from anaerobic digestion (AD) with enhancing biogas additives, is rising in popularity. The AD industry is hoping biogas additives will help by holding a key-role, in the responsible management of the world’s limited resources.

EGx by – High purity tailor-made additives, which optimise bioreactor environments:

  • Remove Hydrogen Sulphides
  • Increase Biogas and Methane Yields
  • Reduce Odour Formation
  • Address Struvite Formation
  • Adhere to National Fertiliser Regulations.

EGx by [allegedly] incorporates the latest research in the field, with the focus to substrate-independently raise the biogas volume and its methane concentration. assists AD-plants in the implementation of a sustainable desulphurisation process, minimising their environmental footprint. via

Raise Biogas Plant Efficiency with Lukeneder Iron Additive Dosing

Deuto-Clear® Sulfo removes hydrogen sulphide and ammonia gas from the substrate and adds biogas additives with nutritious trace elements and minerals to produce a healthy and productive environment for anaerobic bacteria.

  • Fertiliser quality produced from the digestate, is improved by biogas additives and ammonium and sulphuric compounds are bound in the digestate.
  • No longer necessary to dose fermenter with oxygen to convert H2S.

Protects Biogas Plant Equipment with Lower Maintenance Costs

By removing hydrogen sulphide from the raw biogas, Deuto-Clear® Sulfo avoids corrosion from oxidation of the engine and the exhaust gas heat-exchanger of a power plant, making it a better alternative to using oxygen to convert H2S.

You can therefore prolong the intervals between oil and filter changes without violating the operating conditions of the manufacturers.

Installing expensive physical and chemical scrubbing systems is avoided because Deuto-Clear® Sulfo eliminates sulphur.

The product also reduces ammonia in the raw biogas, thus preventing high temperatures in the engine and exhaust, avoiding wear and tear of the engine, and reducing NOx emissions.

Reduces Emissions and Improves the Fertiliser

Deuto-Clear® Sulfo is one of the Biogas Additives which boosts the nitrogen and sulphur content of the digestate – greatly improving agricultural productivity! The phosphoric content of the digestate also remains intact.

Furthermore, ammonia emissions are reduced when the fertiliser is spread on the fields, thus reducing total emissions of the biogas plant.

The improved homogeneity of the biogas additives dosed sludge reduces wear and tear of spreading machines and the fertiliser just flows off the leaves of the plants preventing damage. The product also supports Feeding Biogas into the Natural Gas Grid. via Improving Biogas Plant Efficiency

Biological additives

3 Biogas Additives Tested – The Research Result

Anaerobic digestion (AD) converts biomass to biogas and many say that this process can be aided by using biogas additives. However, its performance is often affected by the nutrient condition of AD substrate. In this study, a few substrate supplements were selected to promote the biogas production; MgO, FeCl3, and cellulase were selected based on the result from elemental analyses of the biomass. The potential impact of the additives on AD process was evaluated by performing a series of biochemical methane potential (BMP) tests.

BMP reactors with the substrate with one of the selected additives (i.e., MgO of 380 mg Mg L-1, FeCl3 of 88 mg Fe L-1 or cellulase of 25 mg L-1) exhibited higher microbial activity; 5–15% more biogas production was observed, compared to the blank. Microbial community analysis showed that different additives resulted in proliferation of different microbial species. Therefore, it was decided to add the mixture of the three additives to the biomass.

Addition of the mixed additive resulted in 22% more gas production. Anaerobic digestion (AD) converts biomass to biogas, however, its performance is often affected by the nutrient condition of AD substrate. In this study, a number of biogas additives were tested… via Effects of supplement additives on anaerobic biogas …

More Biogas Engine Additives!

OLOA® 46600 Landfill / Biomass / Digester Gas Additive

OLOA® 46600 high performance additive has been developed specifically for landfill/biomass/digester gas operations. It has received positive market feedback from OEMs, customers and end-users, even when tested in highly-loaded, late-model engines operating in severe landfill operations.

Gas engines working with renewable sources are very difficult to lubricate. Why?

  1. The gases differ in composition whether they are produced from sewage, agricultural waste, or sawmills (all landfills are different in composition)
  2. Biogas and landfill gases are essentially composed of methane and contain a lot of impurities like halogens, siloxane, and sulphur, which can harm gas engines. via OLOA® 46600 – Oronite

Not Sure About Biogas Additives – How About Training on “Essential operating materials and additives”?

Course objective:
After completing the course you will know which auxiliary operating substances are important for preventing deficiencies in the fermentation process and how to support and optimise the metabolic activity of micro-organisms.

Date: 14 March 2018, Schwandorf and 10 October 2018, Allendorf
Duration: 13.00 pm – 16.00 pm
Fee: 75€ for existing customers (Fit for Biogas or Methanos contract), 165€ for new customers

Language: German
Courses in English upon request.

via Essential Operating Materials and Additives

Biogas Additives Worth Looking at or Snake Oil? Conclusion

Anaerobic digestion is a worldwide technology for the treatment of organic waste streams with clear environmental benefits including generation of methane as renewable energy. However, the need to improve process feasibility of existing applications as well as to expand anaerobic digestion to a range of new substrates has raised interest on several intensification techniques.

Among the are the supplementation of inorganic and biological additives. This has shown good results at improving digesters performance. via The role of additives on anaerobic digestion: A review

So, we consider biogas additives are worth looking at. And, they do not deserve the “Snake Oil” description, if when fully tested at an AD plant, they are shown to work.

Additive dosing can be expensive and in a relatively new industry like the biogas industry, there is always the possibility that some treatments offered might as well be snake-oil and have no effect if not used in the right circumstances, at the right dosing rates, for the right reasons.


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    • December 4, 2018

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    • October 20, 2021

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