SuSanA - Forum Kunena Site Syndication http://forum.susana.org/ Mon, 31 Aug 2015 06:41:55 +0000 Kunena 1.6 http://forum.susana.org/components/com_kunena/template/default/images/icons/rss.png SuSanA - Forum http://forum.susana.org/ en-gb Re: Are there any issues with anaerobic digestion of faecal sludge? - by: vishwanathdalvi http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/13172-are-there-any-issues-with-anaerobic-digestion-of-faecal-sludge-disposal-of-the-concentrated-fecesurine-question-from-mumbai-india#14526 http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/13172-are-there-any-issues-with-anaerobic-digestion-of-faecal-sludge-disposal-of-the-concentrated-fecesurine-question-from-mumbai-india#14526
Thank you for your reply. It is helpful to know that some urine entering the digestor is ok. It was especially important to know that the effluent of the anaerobic digestor is not strictly safe for environmental disposal.

We have had a look at Flycatcher's digestor. They claim to get good rates for kitchen wastes: something like 2 kg/day of waste treated in a 250 litre vessel. Their effluent is a low viscosity liquid that does not have a repulsive odour: which can be used as fertilizer for flower beds. This unit seems good for treating the fecal matter of a family of 5 (assuming 250 gms/day of fecal matter produced per person).

We are developing a unit that uses air to flush. The fecal matter is sequestered from the environment by allowing it to sink through a bed of particles and is removed from the bottom. The problem was what to do with this fecal matter and how to recover the particles that are lost with the fecal matter.

The anaerobic digestor seems to address both problems. By dumping the fecal+particle mix into the digestor, the particles (which are hydrophobic and lighter than water) will separate from the fecal matter: which will degrade. The particles can be collected from the overflow of the digestor and dried (basically to destroy the liquid bridges that make them clump) and recycled to the "flush" system.

A readily apparent problem with Flycatcher's systems are that the digestor gets upset without warning. Once it is down, it needs something like 30 litres of inoculum to get going again.

Another problem is what happens if there is a sudden spike in toilet use (guests coming to stay) or a drop (family goes on vacation). Anaerobic systems go belly up in such cases. Is there a solution?

Could an aerobic system be preferred in this case: we will forego the methane in exchange for reliability?

Really appreciate your inputs.

Vishwanath]]>
Biogas sanitation systems and DEWATS Sun, 16 Aug 2015 14:07:18 +0000
Re: More compact DEWATS technology? - by: AquaVerde http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/6407-more-compact-dewats-technology?limit=12&start=24#14108 http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/6407-more-compact-dewats-technology?limit=12&start=24#14108 VORTEX:

www.blueeconomy.eu/blog/the-power-of-the-vortex/

Vortexes can clean water, as their rotational speed is higher at the bottom than at the top. In this way, particles are sucked down the vortex and can leave the water by a vacuum created at the end. Furthermore, the water is set into a chaotic state. The constant swirl presses air out of the water and sucks it back in, so that microorganisms are stimulated or die.


This technology is not to be confused with expensive vortexes that dubious websites promote to customers, propagating that they would “harmonize”, “revitalize” or bring back the water to a “virgin state”. On the internet one can read the most bizarre promises about vortexes. These attempts of fraud should however not discourage people to realize the real potential the physical use of vortexes has.
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Biogas sanitation systems and DEWATS Wed, 08 Jul 2015 15:25:09 +0000
Re: More compact DEWATS technology? - by: jgoyani http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/6407-more-compact-dewats-technology?limit=12&start=24#14101 http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/6407-more-compact-dewats-technology?limit=12&start=24#14101 Biogas sanitation systems and DEWATS Wed, 08 Jul 2015 11:47:22 +0000 Re: Are there any issues with anaerobic digestion of faecal sludge? - by: muench http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/13172-are-there-any-issues-with-anaerobic-digestion-of-faecal-sludge-disposal-of-the-concentrated-fecesurine-question-from-mumbai-india#13847 http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/13172-are-there-any-issues-with-anaerobic-digestion-of-faecal-sludge-disposal-of-the-concentrated-fecesurine-question-from-mumbai-india#13847
Your question was rather broad. What would be your treatment objectives with the anaerobic digester technology?
I had a quick look at the "Flycatcher" website link. The website looks quite snazzy but without much details. It seems to me that they have only used organic solid waste as in input but not fecal matter.

Anaerobic digestion will not destroy the pathogens in the faeces, so therefore the question is what do you plan to do with the digestate? Using it as fertilizer could be an option but safety precautions would apply.
Adding the urine is not a problem as such but it won't give you any additional biogas and will instead shorten the hydraulic retention time which is a disadvantage.

These are just some pointers. Maybe you could tell us more about your project and plans?

(more details on your research project are available here but it is not saying anything about anerobic digestion there:
forum.susana.org/forum/categories/141-ot...the-toilet-challenge)

You might also find some pointers in the other threads here:
forum.susana.org/forum/categories/35-bio...n-systems-and-dewats

Regards,
Elisabeth]]>
Biogas sanitation systems and DEWATS Wed, 24 Jun 2015 21:22:34 +0000
Re: Implementation of DRDO Biotoilet through Public-Private model in India - such as Banka Bioloo - by: bankabio http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/11463-implementation-of-drdo-biotoilet-through-public-private-model-in-india-such-as-banka-bioloo?limit=12&start=12#13799 http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/11463-implementation-of-drdo-biotoilet-through-public-private-model-in-india-such-as-banka-bioloo?limit=12&start=12#13799
Responses:
Can a bio-digester accommodate used toilet paper? - to a very minor extent, may be ok - but not in larger quantities.
What happens if people throw in things like chewing gum, plastic wrappers, cigarette buds in the toilet. - these get collected and will need to be removed periodically. Ideally, people shouldn't throw.
Is there a filtration mechanism for such non degradable waste? - Not at this time, but we plan to develop soon.

Can the effluent water be used again in the flush tanks? - Yes
Is there any chemical filter used in the bio-digester? Not really, in the general sense. Though chemical filtration is used in certain cases.]]>
Biogas sanitation systems and DEWATS Mon, 22 Jun 2015 18:14:42 +0000
Re: Implementation of DRDO Biotoilet through Public-Private model in India - such as Banka Bioloo - by: Sahej http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/11463-implementation-of-drdo-biotoilet-through-public-private-model-in-india-such-as-banka-bioloo?limit=12&start=12#13794 http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/11463-implementation-of-drdo-biotoilet-through-public-private-model-in-india-such-as-banka-bioloo?limit=12&start=12#13794
Can you please answer these two questions for me?

1. Can a bio digester accommodate used toilet paper? What happens if people throw in things like chewing gum, plastic wrappers, cigarette buds in the toilet. Is there a filtration mechanism for such non degradable waste?

2. Can the effluent water be used again in the flush tanks? Is there any chemical filter used in the bio digester?

Thanks,
Sahej]]>
Biogas sanitation systems and DEWATS Mon, 22 Jun 2015 13:59:45 +0000
Are there any issues with anaerobic digestion of faecal sludge? - disposal of the concentrated feces+urine, question from Mumbai, India - by: vishwanathdalvi http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/13172-are-there-any-issues-with-anaerobic-digestion-of-faecal-sludge-disposal-of-the-concentrated-fecesurine-question-from-mumbai-india#13172 http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/13172-are-there-any-issues-with-anaerobic-digestion-of-faecal-sludge-disposal-of-the-concentrated-fecesurine-question-from-mumbai-india#13172
We are designing a waterless toilet at the Institute of Chemical Technology, Mumbai. An important consideration is disposal of the concentrated feces+urine.

We are seriously considering using an anaerobic digester using the Dedko digester technology developed by Flycatcher Technologies (flycatchertech.weebly.com/).

We would really appreciate any heads up about potential pitfalls of anaerobic digesters especially when urine is added straight to the digester.]]>
Biogas sanitation systems and DEWATS Sun, 03 May 2015 14:12:23 +0000
Re: ABR-CW quick sizing tool - by: dmrobbins10 http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/12962-abr-cw-quick-sizing-tool#13150 http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/12962-abr-cw-quick-sizing-tool#13150
The first is a simple Excel tool that provides some rough design ideas. In this tool the strength of the wastewater is adjusted by adjusting the storage factor (see instructions at the bottom of page 1 of the tool). It uses 1.35 for a storage factor for residential strength wastewater, 1.8 - 2.4 for medium strength wastewater typical of a public market or hospital, and 2.5 - 3.5 for high strength.

The second is a constructed wetlands toolkit developed some years ago by the Bohal Environmental Management Office (BEMO) in the Philippines. This one is modeled using Reeds method. Pay special attention to the hydraulic conductivity of the media, as this has a big impact upon the overall sizing.

To my knowledge both of these have not been vetted by "professional" engineers and should be used with caution, and for discussion only, and not as a substitute for real engineering. It would be good to know if you find these useful or at least interesting.

Best,

Dave Robbins
This e-mail address is being protected from spambots. You need JavaScript enabled to view it ]]>
Biogas sanitation systems and DEWATS Fri, 01 May 2015 06:29:11 +0000
Re: ABR-CW quick sizing tool - by: AquaVerde http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/12962-abr-cw-quick-sizing-tool#13106 http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/12962-abr-cw-quick-sizing-tool#13106
Keep your self on very conservative side, e.g. use average temperature of colder season of possible location to design an "improved pre-treatment" (ABR) in front of CW.
Keep Up-flow velocity in ALL ABR-cambers less them 1 m/h!!! Especial if you do your first ABR-trail, do not reduce 40% CW-m2 as recommended in a GIZ/GTZ-paper. You may start very conservative with max. 10% reduction... without "wishful thinking" .

I have all different versions of BORDA's Excel used, I found them very cumbersome. They need further developments in my opinion. By the way, Prof. Otterpohl developed this "tropical"-Excel together with Mr. Sasse many years ago! E.g. in Moldavia one ABR for 30 m3/d been designed, I regret 1/2 the size necessary with BORDA's "tropical"-Excel without real practical ABR-experiences! I by my self ended up using just "common sense" & only pocket calculator for our cold climate conditions in Germany, just to keep on the save side...
see picture in German language:




Good luck
Detlef]]>
Biogas sanitation systems and DEWATS Wed, 29 Apr 2015 07:25:30 +0000
Re: ABR-CW quick sizing tool - by: Marijn Zandee http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/12962-abr-cw-quick-sizing-tool#13062 http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/12962-abr-cw-quick-sizing-tool#13062
Thanks, I was aware of the DEWATS booklet by Sasse, et al. I find a bit unfortunate that they presented the formulas used in the spreadsheets as EXCEL code, rather than as the formulas they used to base the Excel code on.

Probably, a lot of the formulas that were used for this booklet are still valid. Though for colder climates some parameters (such as up flow speed)may have to be adjusted.

Regards

Marijn]]>
Biogas sanitation systems and DEWATS Sat, 25 Apr 2015 03:36:47 +0000
Re: ABR-CW quick sizing tool - by: jankn http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/12962-abr-cw-quick-sizing-tool#13048 http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/12962-abr-cw-quick-sizing-tool#13048 Exactly, the formulas are there in the book, but the Excel files are not available for general use (as far as I know).
I have seen those Excel files being used by BORDA colleagues; but you are right, a word of caution might be advised. Given that the original book has been published nearly 20 years ago now, I am certain that these calculations have been updated based on more recent findings and regional experiences with different design parameters. However, they can still serve as a starting point (!) for dimensioning DEWATS modules (namely Settler, a modified septic tank or ST; Imhoff tanks, biogas settlers or BGS, ABR, AF, PGF, and polishing pond or PP - to add some more abbreviations to the list), but final design should be reviewed by experienced regional experts.
Best
/Jan]]>
Biogas sanitation systems and DEWATS Fri, 24 Apr 2015 09:56:46 +0000
Re: ABR-CW quick sizing tool - by: muench http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/12962-abr-cw-quick-sizing-tool#13047 http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/12962-abr-cw-quick-sizing-tool#13047 Just to answer your question from 19 April quickly: yes "hab." is the abbreviation for habitant or user. Let me add that to our list of abbreviations: en.wikipedia.org/wiki/Wikipedia:WikiProj...iations_and_acronyms


Hi Jan,
Are those Excel files available for general use? I guess not, as perhaps in the hands of non-experts they do more harm than they do good? (I think this was one of the reasons for BORDA in the past to not make such Excel files available). Just wondering.

Regards,
Elisabeth]]>
Biogas sanitation systems and DEWATS Fri, 24 Apr 2015 09:42:17 +0000
Re: ABR-CW quick sizing tool - by: jankn http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/12962-abr-cw-quick-sizing-tool#13046 http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/12962-abr-cw-quick-sizing-tool#13046
http://www.sswm.info/sites/default/files/reference_attachments/SASSE%201998%20DEWATS%20Decentralised%20Wastewater%20Treatment%20in%20Developing%20Coun]]>
Biogas sanitation systems and DEWATS Fri, 24 Apr 2015 09:09:06 +0000
Re: ABR-CW quick sizing tool - by: Marijn Zandee http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/12962-abr-cw-quick-sizing-tool#12973 http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/12962-abr-cw-quick-sizing-tool#12973
Thanks, this will give us some general idea to start a discussion.

Christoph,

The figure of 3m2/hab does this mean per inhabitant/user?

Regards

Marijn]]>
Biogas sanitation systems and DEWATS Sun, 19 Apr 2015 08:30:20 +0000
Re: ABR-CW quick sizing tool - by: christoph http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/12962-abr-cw-quick-sizing-tool#12968 http://forum.susana.org/forum/categories/35-biogas-sanitation-systems-and-dewats/12962-abr-cw-quick-sizing-tool#12968 ... just to have an idea about volume and space.
  • 12 h detention time for the ABR
  • 1,8 m²/hab. for a vertical flow sand filter wetland, 3m²/hab. horizontal flow.

correction. hab. = pe (person equivalent)

For warm climates
CP]]>
Biogas sanitation systems and DEWATS Sat, 18 Apr 2015 13:58:54 +0000