DIG-L: Re: Anaerobic Digestion

[doelle <doelle@ozemail.com.au>]

>>>> 
> Date: Mon, 21 Feb 2000 07:38:19 +1000
> To: "Chuck Steiner" <h2osmart@ix.netcom.com>
> From: doelle <doelle@ozemail.com.au>
> Subject: Re: Anaerobic Digestion
> In-Reply-To: <000e01bf7bc3$f3baad80$61a38ad1@chuckste>
>
> Dear Chuck,
> I still cannot understand your believe that I am against thermophilic anaerobic digestion. I am not as I had it in my teaching program. I am very well aware of the one-stage and two-stage development.
>
> All I am saying and I hope you get it right please, that your system has its place and the mesophilic system has its place. It all depends what you want and how much money you got and how much waste you got.
>
> That nearly 90% of all anaerobic digesters are mesophilic simply means that they work in their environment as yours works in your environment. This has absolutely nothing to do with ignorance of people, but rather with choice of technology.
>
> You simply cannot build a thermophilic digester for US$ 50-1oo. Here in SEAsia, most protein for human consumption comes from fish protein. If the liquid effluent from a 20 m3 anaerobic mesophilic digester has enough food for the production of 8-9 tons of fish, that is real progress.
>
> If I am in a city with massive human and animal waste production, then I may agree with your system, as there is no area for aquaculture or farming.
>
> I can fully understand that you want to sell your system. Good Luck to you, but please do not try to tell us that everything is obsolete exept what you want to sell. THAT IS TOTALLY UNACCEPTABLE. We scientists know that you are not correct in your statements.
>
> I hope that solves our so-called differences, which are not really differences in technology, but in the interpretation and philosophy of technoloyg transfer and use.
> Horst Doelle
> At 10:59 20/02/00 -0600, you wrote: 
> >>>>
> > 1.20.00
> >   
> > Dear Dr. Doelle:
> >   
> > I can appreciate your protection of a subject you taught for 30 years.
> > However, you may still have a few things to learn and appreciate.
> > For example, methanogenic bacteria do not need either acidogenic
> > or fermentative bacteria present for hydrogen transfer.  The Institute
> > of Gas Technology proved this about 10-12 years ago.  Their 2nd
> > phase had an ORP of -425mV.  Additionally, one cannot deny that
> > single phase digestion at any temperature can accomplish much
> > more than 50% VS destruction at common HRTs whereas two-phase
> > can easily hit 95%, possibly higher.  Twice the destruction means 
> > twice the methane.  As for cost, we routine compete against the likes
> > of Biothane and others with marketplace quotes around 50% of theirs.
> > My two-phase thermophilic advocacy is pointed toward efficient
> > digestion for the benefit of all.  Two-phase thermophilic doesn't belong 
> > to us as the good Lord invented it for both you and me to use if we 
> > appreciate it enough.  I'm talking organic loadings of well over 
> > 100 kg COD/m3/d with HRT's of but hours (depending on strength)
> > rather than days.  And one can't beat the dewaterability of  thermophilic
> > sludge nor its pathogen count.  As for pH control, the first phase with
> > but initial slight human intervention controls its own pH thereafter.  The
> > second phase requires constant, but slight, pH control due to the
> > beneficial continuous release of alkalinity.  Generally, pH control is
> > very easy to accomplish.  As for C:N ratios, it's easy to add NH3-N
> > if necessary,  Since this nutrient is produced by the process, its
> > addition is but rarely necessary.  However, it would still be extremely
> > easy to add.  Chemical feed and feeders do not represent a 
> > compromise of nature's technology, only a recognition of its
> > process demands.
> >   
> > We are also interested in the production of very valuable organic 
> > acids in the first phase.  Acetic acid, for example, has a far greater
> > economic value than its methane or electricity equivalent.  The larger acids
> > may also be of far greater value.  They are easily separated by fractional
> > distillation.  Additionally, the first stage, with proper selection of
> > bacteria, can produce as much as 25% H2 and we believe this product
> > can more efficiently be produced biologically than the standard commercial
> > methods.  As we continue our efforts this potential will be further investigated. 
> >   
> > I'm not out to bash mesophilic, single-phase, suspended growth anaerobic
> > treatment.  Make no mistake, however, that this dated technology cannot 
> > possibly compete against thermophilic, two-stage, fixed growth  treatment
> > any way you want to slice it.   You're more than welcome to think otherwise
> > if you like.  Regards-Chuck Steiner 
> >   
> >      
> >   
> <<<<
<<<<


Horst W.Doelle, D.Sc., D.Sc. [h.c.]
Chairman, IOBB
Director, MIRCEN-Biotechnology
FAX: +617-38783230
Email: doelle@ozemail.com.au DIGESTION List Sponsors, Archive and Information http://www.crest.org/renewables/digestion-list-archive http://www.crest.org/renewables/biomass-info/ Beginners Tour of Biogas http://WWW.roseworthy.adelaide.edu.au/~pharris/biogas/beginners