Dear All,

My name is Xiao and my master thesis is about proposing sanitation systems in urban slums in Kenya. The study area is one of the biggest informal settlements in Kisumu.The traditional pit latrines are still the dominant types of excreta disposal.The pit latrines are in a bad condition and the whole system is without proper management.
I have taken four sanitation systems into consideration, two commual blocks two household size:
1.Bio-centre; 2.Safi Sana; 3.Dehydration toilet; 4.UDDT+composting site
Bio-centre has already implemented in Nairobi but Safi Sana is quite a new project. No.3 and 4 are two common types of ecosan.

Firstly, I estimated the potential amounts of energy and nutrients which can be recovered from the systems.Secondly,I compared these systems with regard to five aspects including technical, environmental, human health, economic and social culture.

Of course, each system has its own advantages and disadvantages.As I realize, the communal santation blocks have more than one function such as water kiosk, bathroom, office/meeting.The community can make profit from activities. Safi Sana adds organic waste into the anaerobic digester, it produces more biogas. It can also reduce the solid waste problems.Ecosan are simple and people would prefer household facility to communal one especially for women.

During writing my thesis, I found this topic quite interesting but at the same time it is very complex.I am new to this area and hope to continue it in the future.

You are welcomed to share your ideas and experiences on this issue.Thanks a lot for your interest and I am looking forwards to your reply.

Best regards
Xiao

The biogas based communal sanitation system is the most sustainable and environmentally beneficial since it generates biogas and avoids that the methane (CH4) is entering the atmosphere. As indicated, the biogas system allows the deposition of soft kitchen and food waste, which in turn will improve gas production, and reduces fly population. Additional starch and sugary material will further increase gas production, but this needs to be controlled (measured). Woodfibre based toilet paper for dry anal cleaning can easily deposited into the biogas installation as it helps balancing the C/N ratio. Because of the combination of CH4 burning and social benefits large amounts of CERs can be obtained which co-finances part of the installation.
The project in India (SCOPE) has a working communal dry composting toilet system, and has added a sanitary towel incinerator. This is a need also for other UDT and UDDT systems.
Apart from the technical aspects, the community organisational and financial aspects are most interesting to compare and evaluate, and should be a key element in your study.
All airated composting processes of faeces will leak methane into the atmosphere and are environmentally less beneficial than biogas based systems. An interesting theme of your study is to compare the GHG effects of each sanitation system (whole cycle including plant fertilization) and post this on this site.
The biogas based systems exist in several countries, while city sewerage can be treated with a UASB system to substract the biogas, but cleaning and botteling costs are needed and the resulting (city) sludge cannot be easily disposed of because of chemical, medicine, plastic, rubbe and heavy metal wastages in the effluent.
The most biogas domes from biogas reactors are single and do not have an extended flow pattern that assures a long term retention period of all intake material. Measurements in small rural biogas reactors in Nepal indicated that 20%-30% biogas loss occurred from these installations. The attached sketch gives the working principle of the Low Leakage Urban Biogas Reactor (LLUBR, from a more extensive document) on how to assure a longer retention period and a higher gas production. The cross section of both round reactor domes assures and S flow, while in the first reactor a stainless steel mixer is located.
If I recall my Swahili, Safi Sana means nothing more than a clean toilet, which all toilets should be.

Dear Sjoerd

Thanks a lot for your reply. I agree that using biogas from sanitation system is a great advantage. As I know, the bio-centre in Nairobi connects the pit latrines directly to the anaerobic digester without adding other waste.The sludge in the digester should be transported outside when it is full and then furthur treated. Safi Sana (safisana.org/)has just started a pilot project in Ghana which tries to integrate sanitation,waste,energy and fertilizer all these aspects. The sludge is treated on site and the final product coming out will be fertilizer.

The biogas based system in Asia is mainly of small size in rural area. The communal block in African slums is supposed to serve 500-1000 people per day. I am not sure how big the difference will be under different settings. I did not find much information on the biogas based system in Afica, so I would like to know more.

I agree the organizational and financial aspects are very interesting. Due to the limitations,I did not carry out the stakeholder analysis which it might be anothoer thesis topic. I only discuss the institutional aspect within some pages. With regard to the costs and benefits, I would like to ask for your ideas. It strongly depends on the local conditions and the design of systems. Of course the cost of one unit of communal block is much more expensive than one unit of ecosan. It is not easy to compare directly.


With kind regards

Dear Xiao,

I am also interested in sustainable sanitation for urban slums, but more from the social and cultural perspectives. I also studied one case in Kenya... Maybe if we put our works together we may have almost a phd thesis! hehe. Then, only the financial/economic aspects will be missing...

Did I get you right? Did you finish already your work?

So, since I don't have the engineer background, it's hard for me to talk about technologies, but I can suggest you to have a look at the program of 'The faecal sludge management Conference' in Durban', you may have useful insights there.

Best,
Cecília.

In the cost and benefit aspects you need to distinguish several elements.
1. The building or installation cost of the equipment, whether for individual households or for housing clusters. Many people are looking too much at the building cost in the decision making process.
2. The maintenance cost of the system. Sometimes higher building costs can reduce substantially the cleaning cost. When you can clean the toilets with a high pressure water yet, maintenance costs can be low, but this has consequences in the design.
3. The individual operational costs include the anal cleaning agents. In many countries no suitable toilet paper for dry cleaning is available; when it is available it has high recurrent costs. Fitting a suitable water spray is increasing the building cost but lowers the user expenses. These costs have to be projected over the lifetime of the installation.
4. The municipal or city level costs for eventual sewerage, transport of gas, effluent, treatment, etc. In the end the population has to pay somwhere, while endless (cross)subsidy systems are not advisable.
5. The municipal and environmental costs for water supply (depletion) or sewage of alternative systems.
6. The environmental costs in terms of CH4 emissions or reductions.
7. The country cost for importing fertilizers with other sanitation systems.
8. The agricultural costs of buying imported or locally produced fertilizers.
All these costing aspects need to be taken into consideration.

Dear Cecilia,

Thanks for your reply. My work is not 100% finished yet. I have the full draft and now I am waiting for the comments.

I am also very interested in your topic. Could you please tell me more about it? What is your focus, user acceptance/behavior or stakeholder participation ect.? Maybe you can recommend some reports or articles on this topic.

best

Dear Xiao,

My topic was stakeholders' involvement. I analysed how civil society, private and public sector participate in the different stages of planning and implementing a sanitation project.

I can think about some literature to recommend you. Which aspects would you be more interested? When do you have to turn in your paper?

Best,
Cecília.

You can have a look on these two websites about Kenyan sanitation projects:

“Up-scaling Basic Sanitation for the Urban Poor”

and

Ecosan Kenya Blog

Best,
Cecília.

Dear Xiao,

How is your research doing? Are you finished already? I hope eveything fine with your project.
I remember that you showed some interest in my master's thesis topic, so in case you still want to have a look on it, it was recently uploaded to SuSanA Library, here is the link: www.susana.org/lang-en/library?view=ccbk...p;type=2&id=1615

Comments and remarks are very welcome!

Best,
Cecília.

Thank you very much!
I finished my thesis as well. I will read your thesis these days.

Thanks again~

best regards

xiao

Dear Xiao,
I would like to read your thesis and see what solutions did you manage to find for informal areas in Kenya. My current research involves finding a technical sanitation solution for informal areas, so believe that what you've done is good; but want to know/understand how did you find the solution? and what solution in your view is suitable?

Let talk

Chris This e-mail address is being protected from spambots. You need JavaScript enabled to view it

Dear all,

I think it is important to also look into the Peepoo launch in Kibera that has been ongoing since end of 2010. The Peepoo is a mobile toilet, a home toilet but also part of a sanitation system with collection and resuse. For more information please see www.peepoople.com.

One of the biggest challenges in informal settlements is space. And shared toilets are great if clean and taken care of. Problem is most cant be reached due to the insecurity problems during night time (closed between about 8 pm - 6 am).

Warm regards

Camilla