Page 10 - Australian Pork Newspaper
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Pork CRC boosts biogas systems across Australia
MOST pork producers are now aware of the uptake of biogas capture and use systems across the industry over recent years.
There are currently 20 biogas systems operating at Australian piggeries, including 14 covered an- aerobic ponds, four mixed hybrid in-ground ponds (stirred and heated CAPs) and two above-ground mixed tank digesters.
About 13.5 percent of total Australian pork production is currently sourced from farms with biogas systems. Significant benefits
One of the aims of the Pork CRC Bioenergy Support Program is to promote the adoption of biogas systems across the industry.
Industry experience has
already shown significant financial benefits follow- ing biogas system instal- lation, resulting primar- ily from the reduction or elimination of external on-farm energy costs (electricity and heating).
Another major benefit is a substantial reduction (64 percent) in farm green- house gas emissions.
Producers who haven’t
previously investigated biogas system develop- ment may be interested in discovering just how much biogas their pigger- ies could potentially pro- duce and what options are available for productively using the available biogas.
While all piggeries are different in terms of their design and operation, a typical 500-sow farrow-
to-finish piggery (about 5000 SPU capacity) could be expected to produce 400 to 500cu m of biogas per day.
This biogas, which gen- erally contains 60-70 per- cent methane, could be burnt in a reciprocating engine driving a genera- tor, having an electrical output of 40-50kWe based on a typical electrical ef-
ficiency of 35 percent.
Powerful incentive
Industry experience suggests biogas systems at farrow-to-finish and grower piggeries often generate more electric- ity than the total on-farm energy consumption, de- pending on site-specific factors such as the opera- tion of on-farm feed mills and high-capacity effluent or irrigation pumps.
While some piggeries ex- port surplus electricity to the supply grid, the relative- ly low feed-in tariff, tech- nical and administrative complexity and significant capital investment involved in setting up this option may curtail its practical and economic viability.
In addition to generating electricity, combined heat and power systems may be used to provide on- farm heat energy.
The cooling systems and exhausts of engines driving CHP system gen- erators are fitted with heat exchangers that heat wa- ter for circulation through radiator-style heaters in weaner sheds and under- floor heating systems in farrowing sheds.
In this way, biogas heat- ing may be used to replace on-farm LPG consump- tion.
In assessing the viabil- ity of on-farm biogas sys- tems, it is important to be aware the following factors may influence pig- gery biogas production. Feed wastage
A recent APL-funded research project indicated a 5 percent increase in feed wastage can result in a 12 percent increase in methane potential.
However, the value of the
additional energy did not justify the additional feed costs associated with high- er levels of feed wastage. Diet
An earlier Australian Pork Limited-funded re- search project compared the methane potential of manure excreted by pigs fed four typical Austral- ian diets.
The results indicated a maximum 15 percent variation in methane po- tential between diets. Temperature
Biogas production from unheated CAPs may vary by up to 20 percent from the mean due to seasonal temperature fluctuations. Micro-organism health
The health of the distinct microbial communities responsible for breaking down and converting the organic matter to methane can be affected by chemi- cal inhibitors such as am- monia and sodium, par- ticularly following shock loadings of high-strength effluent.
Some disinfectants, animal health medica- tions and feed additives can also affect microbial performance in digesters and CAPs.
Excessive sludge deposi- tion in CAPs can encroach on their treatment capaci- ties.
Digester/CAP design
It is important to ensure the digester/CAP capacity is sufficient for the load- ing rate coming from the piggery sheds, and that it provides adequate contact time (hydraulic retention time) for the micro-or-
ganisms to function ef- fectively.
Piggery design and op- eration
To maximise methane production, the general rule is ‘the fresher, the better’ with regard to get- ting manure into the di- gester or CAP.
Consequently, the meth- ane potential associated with daily flushed manure management systems is likely to be higher than for pull-plug systems, where manure may be held for several weeks before trans- fer to the digester or CAP.
The effluent stream dis- charged from piggery sheds generally contains some coarse materials (such as grain husks and pig hair), which may form a floating crust under a pond cover.
Solids separation (screening) is generally recommended to remove the potentially problemat- ic coarse solids, however, some digestible organic matter is inevitably re- moved in the solids sepa- rator, resulting in reduced methanepotential.
CRC help
The Pork CRC Bioen- ergy Support Program can help pork producers assess the technical and economic feasibility of establishing on-farm bio- gas systems by preparing site-specific, preliminary biogas feasibility reports.
For further informa- tion, please contact me on 07 4529 4247 or email alan.skerman@daf.qld. at Department of Agriculture and Fisheries, Toowoomba, Queensland.
It,s a gas
by ALAN SKERMAN Leader, Pork CRC Bioenergy Support Program
Travel arrangements for the Christmas ham
THE pork on your plate this Christmas has made its last trip without a mandatory passport.
From February 1, 2018, all state and ter- ritory government will introduce mandatory reporting of all pig movements via Pig- Pass.
PigPass links pigs to a property of origin us- ing a Property Identifi- cation Code, registered pig identification (ear tags or tattoos) and pig movement documenta- tion.
PigPass is a traceabil- ity system that can be used to try to reduce the impact of a disease outbreak or food safety issue.
Australian Pork Lim- ited general manager Policy Deb Kerr said PigPass has been de- signed in consultation with stakeholders of the Australian pork in- dustry.
“We don’t have many of the diseases that threaten pork industries outside Australia, and we want to keep it that way,” Ms Kerr said.
“PigPass will help us to do this by keeping a record of all pig move- ments.
“That way, if there is a disease outbreak, the source can be almost immediately identified and pig owners in the affected area notified, giving the best chance of protecting animals and stopping the spread of disease.
“We need all pig own- ers to play their part in making sure our pigs stay the healthiest in the world.
“PigPass is a form you complete and hand to either the person transporting your pigs or the person buying your pigs.
“When transporting pigs off the property, the receiver needs to re- port via PigPass within two days.”
Pigs require a PigPass form whenever they are transported.
A pig may have a number of different types of journeys and several parts to that journey.
Pig movements to and from other farms, sale- yards, abattoirs and knackeries and shows must all be reported via PigPass.
See to register and for more information about how PigPass works.
To our valued clients and friends. Jefo thanks you for your
continued support and wishes you all a very merry Christmas and a safe 2018!
Page 10 – Australian Pork Newspaper, December 2017

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