Here comes an answer to the posting of Detlef Schwager above (15 May) which was sent to me by e-mail:
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Detlef had asked:

"The unit can be linked to flush or pour-flush toilets,..." This makes me a bit alerted on the "travelling" of the possible liquids involved! I understand, all liquids passing trough an active layer near the surface, where solid waste get digested and then enters a filtration bed where the liquid waste is further treated by aerobic bacteria.

After that, do the treated liquids pass direct through the soil around the pit? Or is the possible pit maybe lined and "you" try to discharge from that aerobic filtration bed by gravity via a biological more active topsoil and vegetation filtration first, before treated water is entering ground water or surface water?

Answer by Claire:

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Dear Elisabeth,

I am a co-worker of Walters who designed and ran the trails on the Tiger latrine. I have answered your questions below.

If theres is a enough distance between the bottom of the system and the water table the liquids and the infiltration rates rea ok the effluent is directly infiltrated into the soil, we have done this in Wales and Ethiopia.

If the water table is high or the infiltration rates are to low then the bottom of the system is sealed and the liquid can be diverted into a planted systems or beds infiltration wells.

The effluent will not be directly discharged into surface water.

I hope this answers your questions.

Claire

Claire Furlong Ph.D C.WEM


Find out more about me and my work at www.clairefurlong.com

Thanks Walter!
From my perspective the most attractive solution would be to find ways to reuse the liquid effluent, since it should be potent as a fertilizer; for example using a drip-irrigation system, which reduce exposure risk if the levels of pathogen are not satisfactory (see www.who.int/water_sanitation_health/wastewater/gsuww/en/).

Regarding your question on recommendations of effluent levels of COD, I have seen values from guidelines in Sweden of 70mg/l for sanitation systems >25 pers. This could be compared to your levels that are between 500-1200 mg/l. Hence, if reuse cannot be achieved then it may be necessary to install a soil infiltration system, to ensure appropriate treatment. If you want to achieve acceptable discharge levels, I guess it is not recommended to have the septic tank as a reference since this should be considered as a pretreatment system.

Best regards,
Kim

I received this answer by Walter Gibson by e-mail on 21 May 2013 (Walter is one of the researchers of this grant):

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My thanks to Kim for the question about effluent quality from the Tiger system. Just to answer his specific point about the prototype filter - yes, the one at CAT uses the same type of filtration bed as we used in the pilot tests.
This may change in the systems we hope to field test later this year.

We're not aware of any recognised standards as far as COD and pathogen levels in effluents from such small systems but if Kim has any information or references that would be useful. The levels of COD and pathogen reduction we have observed are greater than the published data on septic tanks which is our main reference point.

Kind regards

Walter

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I also just wanted to highlight that some work on the Black Soldier Fly Larvae, which is also part of this grant, is now being discussed in a separate thread here:
forum.susana.org/forum/categories/91-pro...mit=12&start=12#4542

Dear Jeroen,

In regard to this by M&B Gates funded project, I found the stated project approach on "Global Access and Intellectual Property" most refreshing, so much different to what we all know about Microsoft, making sure all people receiving the "key" and not only some.

I am not very sure about, the USA might have a clear government policy, that all public funded research results have to be fully accessible by the public. Maybe someone from USA can correct me on that nice policy? Is this real reality in USA?

Beside this refreshing discovery on the "key", I have a more technical question to you, to understand better technical targets behind.

"The unit can be linked to flush or pour-flush toilets,..." This makes me a bit alerted on the "travelling" of the possible liquids involved! I understand, all liquids passing trough an active layer near the surface, where solid waste get digested and then enters a filtration bed where the liquid waste is further treated by aerobic bacteria.

After that, do the treated liquids pass direct through the soil around the pit? Or is the possible pit maybe lined and "you" try to discharge from that aerobic filtration bed by gravity via a biological more active topsoil and vegetation filtration first, before treated water is entering ground water or surface water?

Thanks in advance.

Good Luck and Best Regards,

Detlef SCHWAGER

Dear Jeroen,
Thanks for your reply and for sharing the project report.

I think I still have some doubts regarding the liquid effluent that you will infiltrate to soil (from your vermi-compost system connected to a flush toilet). According to the result of the effluent quality analyses in your report, the levels of COD and bacteria are still high; hence uncontrolled infiltration could have negative impacts on groundwater quality. However, it is not clear if the test of the prototype in the report includes the filtration bed that you mention on the homepage. Would be good to get some more details on this matter.

Best regards,
Kim Andersson

Dear Kim,

Sorry for the belated reply to answer your questions

I can see that you have partners in different countries; are you setting up pilots in communities in various socio-economic contexts?

Assuming we obtain the required funding we will be testing in urban, rural and humanitarian relief settings (Possible field sites are in India, Uganda and Ethiopia)

What is the general design and function of your system? What are the main components (type of toilet model, collection tank, etc.)? If you could share a photo of your system it would be great.

Detailed descriptions of the systems can be found online described in a report you can find at www.sanitationventures.com/_pdf/Mileston...vation-Final-Web.pdf

What are the requirements when it comes to operation and maintenance?

We don't know exactly yet but we anticipate it will not be high - removal of some vermicompost occasionally

Do you have any results regarding volume reduction of the material to estimate the frequency for emptying?

These are presented in the report above

Since your system is connected to a flush toilet; how do you manage excess water from the system after it passes the filtration bed? Do you promote reuse?

Not planning to at the moment, just allow it to infiltrate the soil

How do the tiger or earth worms cope with the high humidity in the biofilter?

So long as the drainage is good from their bedding layer they should be fine

best regards
Jeroen

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Note by moderators: This post was made by a former user with the login name jensink who is no longer a member of this discussion forum.

Dear all,

I obtained some further information from one of the researchers of this grant, Walter Gibson.
He told me that only the BioCycle has been progressed since Sep. 2012. The work is being done near Cape Town, at the AgriProtein experimental facilities.

Website: www.thebiocycle.com

The website contains some interesting videos, see e.g. this one which explains the idea behind using the Black Solider Fly (Using Black Soldier Flies to convert human waste to valuable commodities):



He also told me that they are are awaiting funding to do the field trials for the Tiger system. If they get it this will be done in India, Ethiopia and Uganda.
There is no work going on to his knowledge on the BSF toilet idea (within this grant). [BSF = Black Soldier Fly]

I have added some documents on results for this project here in the SuSanA library:
susana.org/lang-en/library/library?view=...eitem&type=2&id=1743
You can find:
1 - Literature review (May 2010)
2 - Poster by Ian Banks from Stockholm World Water Week in 2012 on black soldier fly
3 - Report on progress (Aug. 2012)
4 - Presentation on pit latrine fill; key lessons learnt (Sept. 2012)

Regards,
Elisabeth

P.S. Note: further discussions about the Black Solider Fly research that is part of this grant is now in this separate thread:
forum.susana.org/forum/categories/91-pro...h-africa-agriprotein

Some more information about our research project (Kim, your questions have not been ignored, we will get to that soon):

Current state of affairs:
Currently we are in the process of analysing the data from our detailed microbial analysis, and are looking for associations with with management and use practices. We have come up with definitions on what we consider good and poor performing latrines when it comes to fill-up rates. We are further in the process of field testing our tiger and black soldier fly toilets.

Biggest successes so far:
The interest from outsiders in our new toilet designs, but also the fact that it is clear from our initial analysis that good performance of latrines is associated with particular microbial communities but also management practices.

Main challenges / frustration:
The main challenges in the project has been a variety, selecting good and bad performing latrines and measuring use and performance was a challenge, followed by collecting indisturbed samples from different layers. Most of the analysis we conducted on the samples were too complicated to be done on site so samples had to be shipped under the right conditions to the UK and the Netherlands, while in Tanzania we faced long power cuts and a lack of electricity. The 454 sequencing done at the Sanger Institute is in high demand and as a result we had to wait quite some time for the results to come back to us.

Regards,
Jeroen

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Note by moderators: This post was made by a former user with the login name jensink who is no longer a member of this discussion forum.

Dear Jeroen,

Thanks for introducing your project to the Forum. It is an interesting idea to combine biofilters with worms and low-flush toilets. I would appreciate a lot if you could share some more insights about the current status of your research and what are the main lessons so far.

Here are some more specific questions to get a better understanding of your innovative project.
- I can see that you have partners in different countries; are you setting up pilots in communities in various socio-economic contexts?
- What is the general design and function of your system? What are the main components (type of toilet model, collection tank, etc.)? If you could share a photo of your system it would be great.
- What are the requirements when it comes to operation and maintenance?
- Do you have any results regarding volume reduction of the material to estimate the frequency for emptying?
- Since your system is connected to a flush toilet; how do you manage excess water from the system after it passes the filtration bed? Do you promote reuse?
- How do the tiger or earth worms cope with the high humidity in the biofilter?

I am looking forward to hear more about your exciting project.

Thanks and best regards,
Kim Andersson

I hereby would like to introduce our grant 'New concepts for on-site sanitation based on bio-additives and pit design' which was started in August 2009 and is held by the LSHTM (Walter Gibson and Steven Sugden used to be the project director and principle investigator, while I led the two work streams focusing on factors affecting decomposition within pit latrines and took over as PI about a year ago when the grant was extended).

Title of grant: New concepts for on-site sanitation based on bio-additives and pit design
Subtitle: Sanitation Ventures (www.sanitationventures.com/)

Name of lead organization: London School of Hygiene and Tropical Medicine
Primary contact at lead organization: Jeroen Ensink
Grantee location: London, UK
Developing country where the research is being or will be tested: Tanzania, South Africa and Vietnam

Short description of the project:
The project assesses the potential of modern biotechnology to deliver effective bio-additives which can accelerate decomposition processes and extend the lifetime of pit latrines. It will also build a sound scientific understanding of the key factors influencing decomposition processes, including the potential of pit design to improve fill rates and longevity. At the same time, research will be undertaken to build a deeper understanding of the current user experience, needs and aspirations of on-site sanitation that can be used to inspire improved, lower cost on-site sanitation options for the poor.

Goals:
To improve the lives of those with access to poor or insufficient sanitation by (i) delivering deeper knowledge of excreta decomposition, user needs and aspirations, and application of biotechnology and (ii) developing innovative, compelling concepts for non-piped sanitation

Objectives:

1. To identify scientific advances from a variety of fields that could improve pit latrine performance, for example by accelerating faeces decomposition, or decontaminating faeces
2. To understand decomposition processes and the influence of on-site sanitation design factors on performance to support bio-additive and/or pit latrine product development.
3. To assess the current/potential market and understand consumer needs/aspirations for on-site sanitation, so any new products/designs will be adopted and used
4. To generate new on-site sanitation concepts for further development and commercialization, that may lead to a step change in performance, cost-effectiveness, and user adoption, use and maintenance of on-site sanitation (workstreams 5 and 6)
5. To create a platform for future research and development based on key insights and potential partnerships to further accelerate improved on-site sanitation for the poor.

Start and end date: Start 01/09/2009 End date 31/05/2014 (extended until June 2016)
Grant type: Other
Funding for this research currently ongoing: Yes

Research or implementation partners:

• Ifakara Health Institute (Tanzania)
• Sanger Institute (UK)
• Institute of Environmental Science and Engineering (Hanoi, Vietnam)
• Glasgow University (UK)
• Imperial College (UK)
• LeAF Wageningen (NL)
• Wageningen University (NL)
• AgriProtein (SA) (see also this thread: forum.susana.org/forum/categories/91-pro...h-africa-agriprotein), Centre for Alternative Technology (UK)

Links, further readings – results to date:

• www.sanitationventures.com/
• The Tiger toilet is also discussed further here: forum.susana.org/forum/categories/206-ve...itu-vermi-composting

Best regards
Jeroen

P.S. This page on our website might be particular relevant for you because the term "Tiger toilet" is perhaps something you heard of already:
www.sanitationventures.com/innovation-project-tiger.htm

Of all the ideas we reviewed, we have chosen to focus on biofilter technology as our lead approach to addressing people’s concerns about the filling of pit latrines. As well as being effective, it’s the closest to being commercially viable, so we believe it can make a real difference to people’s lives.

Biofilters are contained units typically consisting of an active layer near the surface, where worms (often tiger worms) and other organisms digest the solid waste as it enters the system. Beneath this is a filtration bed where the liquid waste is further treated by aerobic bacteria, resulting in a highly treated effluent which can be safely discharged into the environment. The unit can be linked to flush or pour-flush toilets, so there’s the immediate benefit of waste being removed from sight, unlike a latrine.

Our biofilter design and development activity is integrated and market-led. We call it Project Tiger. The project team of scientists, market researchers and design experts is applying known biofilter technology to develop systems which digest and treat faecal solids effectively, while producing low residual waste, using small amounts of water, taking less space than a septic tank and remaining affordable to purchase and maintain.

Such systems have been quite extensively studied and are already in commercial production in developed world contexts. We believe our product will be attractive to people in developing countries who aspire to upgrade to a septic tank but can’t afford it. They form a massive potential market.
Our user-centred design approach includes:

• Reviewing existing knowledge of biofilters
• Building a target-user profile
• Pilot lab work to assess key parameters affecting performance
• Designing and evaluating concepts
• Developing and testing prototypes
• Exploring business models
• Evaluating market demand.

Project Tiger aims to:

• Design a biofilter system to meet people’s needs and aspirations, which is foolproof to install and maintain
• Demonstrate performance and demand, and estimate potential social, economic, environmental and health impacts
• Provide a knowledge platform and engage with partners to develop ventures to bring our biofilter to market (by the end of 2011).

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Note by moderators: This post was made by a former user with the login name jensink who is no longer a member of this discussion forum.