Hi Florian,
Thanks for your comments again.
I'll keep you posted on how the project develops.
Bests,
Anthony.

Anthony wrote: The filling and pouring would be the operational requirements of the users, and my objective is to reduce the operational requirements as much as possible. Also, how would you control the volume of pour-flush water entering the system? And how would you avoid water wastage?

Hi Anthony,

ok, if you considered that already, my suggestion may not help much.

Anyway some comments to your concerns:

If or not the effort to fill a bucket and pour it after use is worth the benefit of no smell and better esthetics, depends of course what your users are accustomed to. This only you (or better your users) can answer.

As for limiting the water consumption, one option would be to require users to fetch water first outside the toilet cubicle and take it with them. Water consumtion will then be limited to the volume of a bucket. It adds the need for some logistics of course. The permanent (or at least frequent) presence of a operator would be helpful for this, but this is true for any type of public toilet to ensure cleanliness. Ensuring regular cleaning is the most important point to make sure that a public toilet is hygienic and attractive.

Best, Florian

Thank you Florian,
I had thought about pour flush toilets, but this would require a bucket of water in each cubicle to be filled and poured after each use.
The filling and pouring would be the operational requirements of the users, and my objective is to reduce the operational requirements as much as possible. Also, how would you control the volume of pour-flush water entering the system? And how would you avoid water wastage?
Regards,
Anthony.

Dear Anthony,

welcome to this forum!

Interesting toilet solution, I've not yet come across this. I would see the same disadvantages as you list here.

Pour-flush toilets could be a better alteranative. These can be made as ceramic squatting pans, have a water seal and are flushed with a bucket. They also would have no flushing device, so low maintenance and low risk of vandalism.
Water consumption would be higher than in your system, but is generally lower than in WCs. Pour-flush toilets would offer a clearly better user comfort (smell, flies, esthetics).

Some examples of simple pour-flush toilets
http://www.flickr.com/photos/wateradvocates/3041068367/
http://www.flickr.com/photos/wateradvocates/3041068367/
http://www.flickr.com/photos/wateradvocates/3041068367/
http://www.flickr.com/photos/wateradvocates/3041068367/

Regards, Florian

Dear Susana Members,

My name is Anthony Kilbride. I am a Civil Engineer who has been working on Sustainable Sanitation projects in Haiti since the 12th January 2010 earthquake.
I am faced with a problem in the evacuation of human wastes from a toilet block. The solution I wish to explore is what I call a 'combined flush' system, whereby human waste is collected from a channel beneath a row of toilets, and flushed away all-together by a known volume of flushwater. This system is fairly common in institutional toilets (schools and hospitals) in Haiti.

The specifics of my case are:

1. 10 toilets (ceramic, sitting type) installed in a toilet block.
2. A 1' (one foot) dia. plastic halfpipe built into the floor slab to collect the waste.
3. A 15 gallon (57 litres) flush volume installed at 2m elevation above the upstream channel inlet.
4. A gradient of 2% on the plastic halfpipe channel.
5. 7 flushes planned each school day (to be monitored).

The expected benefits of this system are:

A. Less flush water use because amount of water is controlled by toilet manager and not individual users.
B. Known volume of water enters into on-site DEWATS (ABR), so process characteristics may be better determined.
C. Lower O&M requirement for flushing mechanism.
D. Lower risk of vandalism of toilets.

Some of the foreseen risks are:

X. Smell and flies for the period between flushes.
Y. Aesthetic problems associated with users seeing other users waste in the channel below.
Z. Hydraulic overloading of downstream pipes and manholes after each flush.

I attach 2 sketches showing the proposed design, and I would be very interested in hearing about other experiences with this type of flushing system, as well as receiving any critical feedback on my sketches.

Many thanks,
Anthony.