[Digestion] 5000 dairy cow AD system

Mon Jan 9 10:08:52 CST 2012

Dear Rex,

I would suggest contacting Burdens who is distributing the "Portagester"
system in the UK and that could be useful for your intended use and scale.

Their web is www.bioplex.co.uk/*portagester*.shtml<http://www.bioplex.co.uk/portagester.shtml>

Best regards,
Pablo.

2012/1/9 Alexander Eaton <alex at sistemabiobolsa.com>

> I concur on Paul's preference for smaller systems.  I have seen a handful
> of proposals based on trucking waste from a number of small to medium farms
> where they have tried to show energy balance (all the trucks are methane
> powered, etc.), but the numbers never add up.  Specifically, de-watering
> this waste requires relatively well developed systems at each site, and
> likely still leaves you with a serious amount of waste water treatment for
> each site to achieve healthy discharge levels (in Mexico it is the water,
> not the solids that is the treatment challenge).  The management system is
> also more complex and requires a high level of coordination.  The
> alternative de-centralized option will likely have similar initial capital
> costs, but you can make a better case for farmer investment as they will
> reap the benefits.  You then have much smaller long-term operating costs,
> and all that energy for trucking can go to good use (or maybe still
> trucking some effluent fertilizer to local fields).  As Paul mentioned, the
> option to eventually pipe gas a larger distance for centralized use is an
> option that may make sense (but I have not seen it outside of the European
> context or large landfill gas context yet).
>
> Cheers
>
> A
>
>
>
>  On Sun, Jan 8, 2012 at 10:51 PM, Paul Harris <paul.harris at adelaide.edu.au
> > wrote:
>
>>   G’day Rex,****
>>
>> ** **
>>
>> Apparently a lot of the biogas comes from the fines/solutes in the liquid
>> – I noticed that with piggery effluent the raw effluent was almost
>> impermeable to water (it would hold puddles for quite a while) but after
>> treatment the solids were pretty free draining (water disappeared in
>> minutes).****
>>
>> ** **
>>
>> I will also raise my usual point in favour of distributed systems – why
>> not put smaller (cheaper!) digesters at each farm and if necessary pipe the
>> biogas to a central generator (depending on distance)? You will be spending
>> a lot of energy on trucking waste in and then you have to truck the
>> digestate out from the central facility again. The total capital cost may
>> be higher, with more units to maintain, but you can start with one or two
>> and spread the finances out a bit as well as helping local employment (I
>> guess people will be working on digesters instead of driving trucks!).***
>> *
>>
>> ** **
>>
>> Happy digesting,****
>>
>> HOOROO****
>>
>> -- ****
>>
>> Mr. Paul Harris, Room 202, Charles Hawker Building ****
>>
>> Faculty of Sciences, The  University of Adelaide, Waite Campus, ****
>>
>> PMB 1, Glen Osmond SA 5064****
>>
>> Ph    : +61 8 8303 7880      Fax   : +61 8 8303 4386****
>>
>> mailto:paul.harris at adelaide.edu.au <paul.harris at adelaide.edu.au>****
>>
>> http://www.adelaide.edu.au/directory/paul.harris****
>>
>> ** **
>>
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>>
>> *From:* digestion-bounces at lists.bioenergylists.org [mailto:
>> digestion-bounces at lists.bioenergylists.org] *On Behalf Of *REX
>> *Sent:* Sunday, 8 January 2012 5:26 PM
>> *To:* digestion at lists.bioenergylists.org
>> *Subject:* [Digestion] 5000 dairy cow AD system****
>>
>> ** **
>>
>> Hi All,****
>>
>>  ****
>>
>> I have been approached to put together a proposal for a centralised AD
>> using the manure from 5000 dairy cows. The intention is to pre-concentrate
>> the dairy manure slurry and to truck the solids to a central processing
>> unit. As silage and grass is extensively used as feed, we would be able to
>> co-digest this with the manure to increase the gas output. Furthermore, it
>> is intended to use the exhaust gas and the AD liquor to grow macro algae or
>> a plant such as hyacinth (an indigenous variety that is not likely to
>> become an invader should it get out) which can be shredded and added back
>> to digestion. We aim to use the gas for power generation and to use the
>> heat to keep the digester(s) warm.****
>>
>>  ****
>>
>> Questions:****
>>
>> 1. By leaving the water behind, do we lose most/all/some of the FFA? What
>> impact would it have on gas production?****
>>
>> 2. Can anyone recommend a supplier of technology for this size of plant?*
>> ***
>>
>> 3. 5000 cows is an arbitrary amount at this stage - 10 farms of 500 cows
>> each. Is there a better/more economical size?****
>>
>>  ****
>>
>> Kind regards****
>>
>> Rex Zietsman****
>>
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>> for more information about digestion, see
>> Beginner's Guide to Biogas
>> http://www.adelaide.edu.au/biogas/
>> and the Biogas Wiki http://biogas.wikispaces.com/
>>
>>
>>
>
>
> --
> Alexander Eaton
> Sistema Biobolsa
> IRRI-Mexico
> RedBioLAC
>
> Mex cel: (55) 11522786
> US cel: 970 275 4505
>
> alex at irrimexico.org
> alex at sistemabiobolsa.com
>
> sistemabiobolsa.com
> www.irrimexico.org
> www.redbiolac.org
>
>
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>
> for more information about digestion, see
> Beginner's Guide to Biogas
> http://www.adelaide.edu.au/biogas/
> and the Biogas Wiki http://biogas.wikispaces.com/
>
>
>
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