Hey Sahej,

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.

Hi Namita,

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

Appreciate the details and your feedback, Christoph!

We periodically test the effluent water, will share the test results of the latest round as soon as i receive.
The bio-digester has been used by Indian defence for a fairly long time for soldiers stationed faraway at borders and high altitudes with sub-optimal temperatures. We have in-licensed the technology 3 years ago and have installed in various states in India urban/rural everything, and very notably in Indian trains for waste treatment on-board.

Don't know what's being promoted in Brazil or elsewhere but the system that we use has come out of Indian defence R&D of many years.

Sanjay Banka

++++++++

Note by moderator: A related thread about the DRPO biotoilets that Banka BioLoo is marketing is here:
forum.susana.org/forum/categories/35-bio...-constructed-wetland

Dear Banka,

I appreciate your enthusiasm for sanitation and apparently you are doing well in India with the system you are promoting. I have to admit that your system is against many of the scientific rules I learned at university and in practice – so I am not very convinced. But also I have to admit, that in warm climates I have "felt" - not proven - that some aspects are very much different from colder climates. But I am not able to say if that is due to lack of a continuous sampling or really a scientifically different aspect which has not been proven yet.

So please take my questions and observations as open questions, I am interested in the system but suspicious.

The effluent is fairly ok, slightly pale to white, and is odor-free and harmless.
The effluent water is pathogen-free

Could you elaborate a bit on these statements? Maybe post some general data of effluent quality and elimination rates? Or maybe I understood something wrong? What is discharged into the environment? Water course or infiltration? You state pathogen free. How could that be only after an anaerobic process? That is totally different from all other anaerobic systems and even with special bacteria in my understanding not possible. When you use it for gardening it should be at least bathing water quality in terms of coliforms, not to speak of helminth eggs. I don’t have the impression (would need some data of detention time – could you give us an idea about that?) that detention time is sufficient for retention of helminth eggs.

The advantage is that there's no sludge formation. No further treatment is required.

Always there is a good percentage of inorganic material = non degradable material n the wastewater – that means EVERY system which retains solids has a sludge build up. So I would understand if you say very slow sludge build up, but no sludge formation is impossible! So apparently you had no need to desludge up to now. What is the oldest system you have in operation?

And just one more question – could you give a rough number of how many systems are in operation – 10,100,1000? Just to get a better impression about the range of experiences, as sometimes with a very few – new systems the conclusions may be different from larger numbers.

Sorry for being so critical, but here in Brazil I am dealing quite often with "wonder" systems – ex. just a series of septic tanks and the inventor states “odor free, no coliforms and no sludge”. In reality we have been asked to operate such a system, as there was odor, coliforms and sludge in the effluent (we declined as it is impossible for us to solve the problems for the client). People get attracted by the statement because the system is cheap and needs no energy.
So it would be nice to get some data in order to understand better the process.

Thank you.

Christoph

A very happy new year, Mr Mughal,

We have been in-licensees of the bio-digester technology for the last 2 and a half years. Never had such an occasion of getting struck-up.

Dear Sanjay,

Congratulations on being featured on the Green Industry Platform. That is a great honor!
Your biodigestor is interesting. Just one query - What do you do, if the biogestor gets struck-up, biologically?

Happy New Year,

F H Mughal

Well researched, Chris!

Some more responses, and many thanks for all the suggestions. We attempt to put some in practice depending on resource availability at our end, and the desire/budget of the client.

-- Is there some reason that these bacteria cannot get out of the biodigester in the effluent?
The biodigester is a packed container or tank, hence these are not supposed to come out. The digestion process is anaerobic (absence of oxygen).

-- Can they survive in the open environment?
Don't know, not tried but they come in contact with open air when we pour in container or tank.

-- Can these bacteria survive in the human gut? What would they do to us? Has anyone ever gotten sick from contact with these?
Never came across a case but the bacteria aren't harmful.

-- Are these bacteria available in other countries or only in India?
No, inoculated here so far.

-- Has the effluent been tested for pharmaceutical chemicals?
We haven't done, didn't ask the DRDO. The effluent water is tested by us regularly.

-- Does your organization ever build Urine-diverting Dry Toilets (which also have lots of advantages)?
We currently focus on the bio-digester toilets. Have heard and read a lot about UDDT but didn't implement. Could think of sometime in future.

-- Why have we not heard of this type of Bio-Toilet/Biodigester before here on the SuSanA Forum?
We have shared few things, though never got discussed in such detail. Thanks to you, we have built a small repository on the Forum. Members, once back from holidays, should find it useful.

Thank you,
Sanjay

Dear Sanjay,

Thank you for your quick response. This is very impressive.

Several webpages, including this one from the Down To Earth Magazine in India, state that the Indian Army collected these bacteria in Antartica. DTE also states: '' The tank made of cement had sheets with bacteria embedded in it and free-floating bacteria. The bacteria cannot move out of the sheets but can multiply.'' It is very interesting if the bacteria cannot leave the biodigester, but what about the ''free-floating bacteria''?
www.downtoearth.org.in/content/next-gen-toilets

-- Is there some reason that these bacteria cannot get out of the biodigester in the effluent? Can they survive in the open environment?
-- Can these bacteria survive in the human gut? What would they do to us? Has anyone ever gotten sick from contact with these?
-- Are these bacteria available in other countries or only in India?
-- Has the effluent been tested for pharmaceutical chemicals?

Here are two videos on these bio-toilets and bacteria, with scientists from DRDO:



It would be great if the biogas produced in these bio-toilets in trains could be burned in the motors of these trains, even if it only amounts to a small percentage of the total.

I still consider that it would be optimal to recycle the effluent to flush these same toilets, esp. in toilets on the trains and other mobile toilets, thus new water would only be needed for washing hands and anuses and there would be no concern about bacteria or pharmaceuticals going into rivers or groundwater. The cost of water would be almost entirely eliminated and water could be pumped with treadle pumps that are like exercise equipment (see video linked in the thread on this recycling).

-- Does your organization ever build Urine-diverting Dry Toilets (which also have lots of advantages)?

-- Why have we not heard of this type of Bio-Toilet/Biodigester before here on the SuSanA Forum?

Thank you for this discussion.

Best wishes,
Chris Canaday

Responses below:

-- Who designed this biodigestor? (I see that you have listed as a technical partner the Defense Research and Development Organization. Did they provide the design? Are they part of the Indian Army?)
Yes, the Indian defence R&D arm, DRDO, designed and developed the biodigester. We have in-licensed the technology and improvize/innovate as per user need and surrounding.

-- What are the advantages of having the pipes different from those of an ABR?
Guess, the system's functioning is that way, nothing to compare with ABR. Biodigester follows the displacement method.

-- Where do the microbes come from? Are they diverse natural microbes from the bottom of a lake or other wetland, or were they cultured in a laboratory, or both?
The bacterial culture was developed in a lab, using varying strains. We inoculate the same at our plant for mass production.

-- What are the dimensions of this biodigestor? How deep it it? Is there a formula for calculating the dimensions according to the number of users?
Yes, the volume of the biodigester tank varies on the number of users.

-- How are the production and use of the biogas?
Biogas is produced as a byproduct, usage can be for heating/cooking etc. through piped connection.

-- How many have you built?
Wouldn't know the precise numbers but user-base comprises households, schools-universities, construction companies and factories, plantations, and most notably the Indian trains.

-- How transparent and odor-free is the effluent? Can you imagine using it to flush toilets again and again, in a never-ending loop that does not discharge into the environment, like we are discussing in the following thread?
The effluent is fairly ok, slightly pale to white, and is odor-free and harmless. It is discharged into the environment, seeps into the ground or used for gardening. We can have the option to use the water for flushing again and again. So far, no one has opted for that. There would be an additional cost associated.

-- With soak pits, there would be a risk of groundwater contamination, esp. if people consume well water not very far away. I suggest it would be better to have extensive leach fields (perforated pipes, buried not very deep) among fruit trees and banana plants.
As stated earlier, the effluent water is pathogen-free and harmless and left to the ground. We conduct regular water tests.

Hi Sanjay,

This is spectacular. Please allow me to ask some questions.

-- Who designed this biodigestor? (I see that you have listed as a technical partner the Defense Research and Development Organization. Did they provide the design? Are they part of the Indian Army?)
-- What are the advantages of having the pipes different from those of an ABR?
-- Where do the microbes come from? Are they diverse natural microbes from the bottom of a lake or other wetland, or were they cultured in a laboratory, or both?
-- What are the dimensions of this biodigestor? How deep it it? Is there a formula for calculating the dimensions according to the number of users?
-- How are the production and use of the biogas?
-- How many have you built?
-- How transparent and odor-free is the effluent? Can you imagine using it to flush toilets again and again, in a never-ending loop that does not discharge into the environment, like we are discussing in the following thread?
forum.susana.org/forum/categories/40-gre...ructed-wetland#11393
-- With soak pits, there would be a risk of groundwater contamination, esp. if people consume well water not very far away. I suggest it would be better to have extensive leach fields (perforated pipes, buried not very deep) among fruit trees and banana plants.

I look forward to hearing back from you.

Best wishes for the New Year,
Chris Canaday

Hey Chris,

Greetings of the season!

Our system is called "bio-digester", and comprises bacteria that are placed in the multi-chambered bio-tank. These bacteria eat away the human waste, releasing effluent water and biogas. Both are usable.
Yes, in terms of structure, the bio-digester is similar to an ABR - multiple chambers.
The advantage is that there's no sludge formation. No further treatment is required. And, all this is one-time affair, no emptying of tank for cleaning or replenishing of bacteria needed.

Hope this helps,
Sanjay Banka

Dear Namita,

Congratulations on being featured ... and especially on your important work.

From your webpage
www.bankabio.com/bio-digester-tank-system.html
it seems your biodigestor is very similar to an ABR (Anaerobic Baffled Reactor) but the pipes are located differently. What is your system called and what are its advantages?

Best wishes,
Chris Canaday