Dear Bertin

Please kindly find the attached two documents which could be useful for your study. Sorry for the delay in response.

All the best!
Bipin.

[attachment:1]C:\fakepath\Onsite latrines literature review Belen2010.pdf[/attachment]

Dear Christoph
100 to 200 kg TS/ m²/ year loading rate is based on the literature. I don't have experience with such loading rate. However, for unplanted drying beds there should not be any problem with such loading rate. In this case there is higher slope (1:10) in the bottom of the bed and drain. Therefore most of the water part is filtered out. Drain of the bed should be covered with perforated sheet, that crates partial vacuum and hence high filtration rate.
In case of planted beds slope is much lower. In such case overloading may result in creation of anaerobic condition and foul smell. Although rhizomes of macrophytes help create aerobic condition to some extent.
In planted as well as unplanted drying beds, no. of beds is important. For a 20 cum per day septage I have prepared 6 no. of beds each having size of 5 m x 12 m. No. of such beds depends on local climatic conditions and rain fall. In Brazil, rainfall is good enough and you may require more number of beds.
regards
pawan

Dear Pawan,
I do my bed design here (Brazil) with a max of 100 kg TS/m²,a. And normally actual loading is well below that. Do you have experience with loadings on a medium load of 200 kg/m²,a? I fear that this will turn the bed anaerobic.
Concerning heavy metals that would not be my doubt. The key is not to load the beds with a frequency that the upper layer can not dry up (and drain) so a 1-3 times loading should be followed by a resting period. How do you manage that?
We do normally at least 4 beds.

Yours
Christoph

Dear All
There is not much information available on full scale operation of PDB based septage management and design criteria based on characteristics of septage. The design consideration is only for total solid loading rate. It is taken as 100-200 kg TS /m2/ year. Frequency of loading is taken as 1-3 times as week.
Design of PDBs for different characteristics of septage in terms of heavy meals BOD, COD, N, P are not taken into account. FS from sewage treatment plants may have high heavy metals and affect growth of macrophytes in a PDB. However, septage from a septic tank or a pit is not supposed to have high concentration of heavy metals. Hence such metals are not the limiting factors for PDBs based FSM from such sources.
Due to rhizomes, Macrophytes have ability to grow under diverse conditions and can tolerate extremes of pH and salinity. Therefore, differences in characteristics of septage will have least effect on system of PDBs provided heavy metals in such septage are within the tolerance limits.
Best
Pawan

Thank you so much for your participation on my question.
THanks once again to Elisabeth for keeping us updated and so much information she gives to us.
In addition to that, it is nice to hear that you have been here at UNESCO-IHE.
To Bipin, I have read your thesis and it is nice. It was about the co-treatment of Feacal sludge in wastewater treatment plant. I have seen also that you have done a lot of literature on characterisation of faecal sludge which will be useful in my results analysis. (meanwhile here is my e-mail : harel1@unesco-ihe.org,beritini@gmail.com for you to send me those documents)
Briefly, in my research i am doing characterisation of fecal matter and urine from the field testing of eSOS toilet.
Any document found relevant please send. My dream is to contribute something important to sanitation especially in emergency.
Thanks once again.

--
Bertin HARELIMANA
MSc Participant in Sanitary Engineering
UNESCO - IHE, Institute for Water Education
Delft, the Netherlands
e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Mobile:+31(0)685275180

OK, great. About your thesis from UNESCO-IHE, just for your information we already have quite a few MSc theses from UNESCO-IHE here in the SuSanA library (put UNESCO-IHE in the search field and you find these 20 entries):
www.susana.org/en/resources/library?search=unesco-ihe

I worked there at UNESCO-IHE in Delft from 2004-2008 by the way - great place with awesome alumni all over the world!

Dear Elisabeth:

Thank you very much for the suggestions and useful instructions. I am relatively new user for SuSanA forum, so don't have much idea.

Ok sure, I will share useful data and documents to the post shortly. Regarding adding my thesis to the library, I need to get consent from my institute.

Thank you again!
Bipin.

Dear Bipin,

If you have useful data and documents to share on the topic of design parameters for planted drying beds (or faecal sludge characterisation) why not just attach dem directly to a post rather than e-mailing the documents to individual people (unless there are copyright protection issues)? We could add your thesis also to the SuSanA library:
www.susana.org/library

And about getting Bertin's e-mail address. I think many people still haven't noticed it but there is actually a blue envelope button to the left of all the posts. When you click on there you can send any other user a short e-mail message (e.g. to ask for his or her e-mail address).
Therefore, there is no need to ask for an e-mail address in someone's post. (just as a reminder for everyone, as it doesn't seem to be well known)

Regards,
Elisabeth

Dear Bertin:

I am Bipin Dangol and I have done my MSc. from UNSECO-IHE from 2011-13. I think we have met in UNESCO-IHE sometime ago. I have done my MSc. thesis on FS characterization as well and I am sure you have a copy of my thesis. Please pass on your email and I can send you some useful data and documents.

All the best!
Bipin.

Dear Elisabeth,
Thanks for this nice information. Actually i am working on characterisation of faecal sludge therefore, i needed the most important information required from Faecal sludge to be treated by drying beds.
Regards
Bertin

Welcome to the forum, Bertin.

You might also find some useful answers to your research questions in this thread on the forum:
forum.susana.org/forum/categories/53-fae...r-septage-management

It was called: "Rate of filtration of septage through sand filter beds and technology for septage management".

Let us know how you get on and if you have further questions.

And how about this thread, it could also be useful (nobody has replied in it yet):
"Simple Solar Sludge Drying During the Monsoon (experience in Bangladesh)"
forum.susana.org/forum/categories/53-fae...rience-in-bangladesh


Regards,
Elisabeth

Did you have a close look at the PDB chapter in the FSM book already?
www.eawag.ch/forschung/sandec/publikationen/ewm/dl/fsm_8.pdf

While I am really not an expert on these systems, it seems to me like the construction design parameters are not possible to establish very well given the high impact of climatic conditions and the likely not very uniform sludge characteristics, i.e. yes the latter should have an effect on the design, but rarely are you dealing with a very uniform source and thus you will need to have a design that can deal with most sludges.

Typical sludge water content (and frequency of loading) might be an issue though, as you would want to prevent the beds from drying so much that the plants die. The above manual suggests an adjustable leachate outlet to control moisture content.