Anaerobic Digesters Waste

Anaerobic digesters are attracting interest among Australian dairy farmers. However, research to date suggests they are unlikely to be viable for pasture-based dairy systems.

Biogas technology does not have to be complex or difficult to operate, but it does need to be tailored to the specific needs of the farm in terms of farm management, waste characteristics and biogas use.

This fact sheet outlines whether an anaerobic digester is the right choice for a farm.

Since 2012, almost 1,400 dairy shed energy assessments have been conducted in all dairy regions across Australia as part of the national Dairy Australia project Smarter energy use on Australian dairy farms, funded by the Department of Industry and Science as part of the Energy Efficiency Information Grants Program. During the project, the potential for implementation of biogas technology for specific situations on dairy farms was raised. This fact sheet summarises information on the feasibility of this technology for the dairy industry.

Research to date suggests they are unlikely to be viable for pasture based dairy systems unless the operation has a larger herd spending a significant amount of time on a flood-washed feedpad.

Anaerobic digestion research

Below are some links to research happening around the world on anaerobic digestion on dairy farms.

A combination anaerobic digestion scheme for biogas production from dairy effluent — CSTR and ABR, and biogas upgrading.

By Lars Jürgensen, Ehiaze Augustine Ehimen, Jens Born, Jens Bo Holm-Nielsen

Highlights

• CSTR and ABR in series are able to treat low strength dairy waste water.
• The system is shock-load resistant according to high fluctuating dairy effluent.
• The CSTR acts as hydrolysis stage and buffer tank ensuring stable operation.
• COD removal and biogas production takes places in the ABR.
• The produced biogas can be used as CO2 source for energy storage.

Read the abstract.

Determination of kinetic constants from the co-digestion of dairy cow slurry and municipal food waste at increasing organic loading rates.

By John Morken, Magnus Gjetmundsen, Kristian Fjørtoft

Highlights

• Anaerobic digestion of dairy cow slurry (DCS) and municipal food waste (MFW).
• Methane production increased by 479% when 32.2% MFW was added.
• The kinetics of the process was investigated.
• A model was developed based on the kinetic constants found in the experiment.

Read the abstract.

The effect of bacterial and archaeal populations on anaerobic process fed with mozzarella cheese whey and buttermilk. 

By Giorgia Pagliano, Valeria Ventorino, Antonio Panico, Ida Romano, Alessandro Robertiello, Francesco Pirozzi, Olimpia Pepe

Highlights

• The key archaeal species involved in H2 and CH4 production were identified.
• Dairy wastes are suitable byproducts for being valorised in a biorefinery process.
• Inoculum significantly influenced microbial dynamics and process performance.
• Microbial dynamic and biochemical intermediate were considered and related.
• Higher inoculum amount increased methanogens concentration of 1 log CFU/mL.

Read the abstract.

Semi-continuous anaerobic co-digestion of dairy manure, meat and bone meal and crude glycerol: Process performance and digestate valorization.

By Fetra J. Andriamanohiarisoamanana, Aya Saikawa, Guangdou Qi, Zhifei Pan, Takaki Yamashiro, Masahiro Iwasaki, Ikko Ihara, Takehiro Nishida, Kazutaka Umetsu

Highlights

• Anaerobic co-digestion of dairy manure, meat and bone meal and crude glycerol at 37 °C.
• Crude glycerol boosted methane yield while meat and bone meal improved fertiliser value.
• Ammonium nitrogen increased with the increase of meat and bone meal.
• Phosphorus concentration was not affected by the co-digestion process.
• Nutrient recovery and water recycling are the best alternative to sustain biogas plant.

Read the abstract.

Anaerobic co-digestion of end-of-life dairy products with agro-industrial wastes in a mesophilic pilot-scale two-stage system: Assessment of system’s performance.

By Alexandros Kopsahelis, Konstantinos Stavropoulos, Constantina Zafiri, Michael Kornaros

Highlights

• End-of-life dairy products can be efficiently co-digested with agro-industrial wastes at about 20% (w/w) of overall feedstock.
• Pilot-scale co-digestion of end-of-life dairy products with agro-industrial wastes was demonstrated in a two-stage system.
• Acidification of end-of-life dairy products alone should precede their co-digestion with agro-industrial wastes.
• Two-stage co-digestion produces 50% more methane (0.51 L/LR/d) than single-stage.
• 1.84 m3 H2 gas and 29.53 m3 CH4 may be produced per m3 EoL-DPs.

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Valorizing waste iron powder in biogas production: Hydrogen sulfide control and process performances.

By Fetra J. Andriamanohiarisoamanana, Tomoya Shirai, Takaki Yamashiro, Seiichi Yasui, Masahiro Iwasaki, Ikko Ihara, Takehiro Nishida, Suchon Tangtaweewipat, Kazutaka Umetsu

Highlights

• Waste iron powder was used to control hydrogen sulfide in biogas production.
• In batch experiments, there was a reduction of 93% of H2S at waste iron powder of 2.0 g/L.
• Total sulfide concentration in the digester increased together with waste iron powder.
• Waste iron powder did not affect methane yield in batch and continuous experiments.
• In continuous experiments, H2S was reduced by 50% at waste iron powder of 1.0 g/L.

Read the abstract.