Hi Florian,

In France in dry public toilets, urine is infiltrate in nearly all the cases. We use for it the technical specification defined for infiltration of used water in houses. I send you a picture with the drain cut (in french but easy to anderstand; terre = earth, gravier = gravel; lavé = watch). The pipe in diameter 100 mm is perforated with holes; rectangulare dimension 10mmx100mm. The pipe inclination is 5° and the length is 8 to 12 m.
It is working very well for more than 10 years.

charlesthibodeau2030 wrote: Just want to add one point: how is the legislation about animal slurry/manure in Moldovia? If a farmer wants free human urine as fertilizer, who will be against that? And how is it working with WWTP sludge?

We are not yet totally clear about legal situation but basically it seems there are no legal objections against farmers using human urine, or that work-arounds should be feasible. Our main worry is rather that no one is really interested in using the urine and that the schools will have a problem with full urine tanks. As uddt school toilets are otherwise very succesfull, at the moment the unsolved urine reuse/disposal is the main obstacle to make them a fully sustainable solution.

As for the legal situation in Moldova in general, that's quite a headake. Most technical legislation dates from the Soviet time and is little adapted to todays reality. Authorities insist in compliance with absurd standards which nobody enforces. One example is the issue disccused above: It would be legally ok to propose dumping the urine (or fecal sludge) in the wwtp of the next district capital, even if this plant is not operational any more since 20 years.

Hello everyone,

Just want to add one point: how is the legislation about animal slurry/manure in Moldovia? If a farmer wants free human urine as fertilizer, who will be against that? And how is it working with WWTP sludge?

In Quebec (Eastern Canada), I know that we can ask a one-year permit (extendible each year) to spread "fertilizing residual matter" on agriculture lands that has not been certified by a normalisation organisation yet.

Ciao ciao from Montreal,

Charles

Hi Stefan,
thanks for your comments and corrections.

For projects, seems I got the wrong list in my comments above. Indeed project 194 is ours (started with SDC / Thierry Umbehr) and now continued by Skat (in 1998, SDC tendered the next phase of the project and Skat won the contract). The project 195 was done by the NGOs mentionned by you (which are also involved in our project). For the current status of our project 194, see the numbers in my post above.

First experiences with urine use on fields are encouraging, so we certainly will put more efforts into this. But we also want to think about an option B, in case urine reuse does not work well.

What you propose (dumping urine to the next wastewater plant) is exactly what we get recommended by our local engineers, as this is the easiest way to get accepted legally. However techncially and environmentally, it does not make much sense to dump a truck load of urine into a non-working treatment plant (as it is in fact). So infiltrating the urine locally would be still better than dumping the urine in surface waters (via the wttp).
But I am certainly not yet convinced that this idea of infiltrating (and partly fertilizing plants) is a good one, so I am really happy about any comments on this.

As for the quantities of urine, we don't have more than 1 m3 per year in each school, not that much actually.

Cheers,
Florian

PS: you were involved with Thierry in designing the toilets, were you?

Hi Florian and all,
I guess the school-UDDTs you mention are the ones that are listed with no. 194 and 195 in the project-list Elisabeth posted. The first ones were constructed by Thierry Umber from SDC in co-operation with wecf. Local partner-NGOs (Wisdom, Ecotox, others followed) made the awareness-raising, training of pupils, teachers and caretakers. When skat was founded they took over the work from SDC and continued to construct further school-toilets with more or less the same design and principle of implementation. As far as I know all of the School-UDDTs in Moldova use 2 chamber GRP-tanks or PE-tanks that allow storage of the urine for min. 6 months (bigger tanks for longer storage are preferable!).
I still think that in Europe collecting the urine in tanks as big as possible is the best solution. If there are problems with the reuse (acceptance, legislative as in Moldova), the urine can still be pumped out and brought to the next treatment-plant if absolutely no other users can be found. We always recommend setting up demo-gardens in the school-yard where at least parts of the urine can be reused. Usually there are also enough trees, ornamental plants, hedges etc. near the schools where (at least part of) the urine can be reused without the risk of polluting the groundwater. I can hardly imagine a gravity-fed infiltration-trench that can distribute several tons of urine per year without infiltration into the GW or killing the plants. Since the plants do not take up nutrients during winter, there should be storage of the urine anyhow.

Against clogging I recommend citric acid or vinegar and proper education of the users.

Greets from Hamburg
stefan

Florian,

Our experience with struvite is that that the crystals are very small, so I quess that if you use 2 mm holes, as Chris suggests, they will just flow out of the holes and into the soil. My guess is the main trick will be to make sure the holes do not get blocked by soil particles and by sand, dirt, insects, hair and other stuff that ends up in toilets (it is amazing what one finds in urine ). So a filter is definitely needed.

I think you should have a small tank in which the urine and water are mixed before it goes into the ground. It may be an idea to have a plug in the bottom of the mixing tank so that you can drain out all the crystals and other stuff that stays behind in the mixing tank. If the outlet to the drain-pipes is about 10 cm above the bottom that will help trap sand and other larger particles so that they do not go into the lines.

If you need to bury the pipes deep to avoid freezing I do have to wonder how many nutrients will actually be used by plants, even trees. Also you will not be able to check your system. That may be the reason why this option is only for warm places, where the pipes buried very shallow.

rgds

Marijn

Hi all,
thanks for further input to my question. I will visit our team this week, and we will certainly discuss this issue. So I will probably come back with more questions...

Elisabeth:
No it is not the project in your list. I don't know which project exactly is in your list (as no name of implementer) but I assume it is one of the local NGOs we are also cooperating with (WISDOM, SEAM) and the approach is very similar or the same as used in our project.

Our project is called ApaSan (Water Supply and Sanitation Project in Moldova) funded by the Swiss government and alrady active in Moldova since around 2000.
My company, Skat, is responsible for the project since 2008, and I myself am involved only since beginning of this year (so the achievments so far are not mine ).

So far, 12 school toilets based on UDDT have been built and are working rather well (around 4.500 users). However, reuse has only been started this summer, so limited experience with this so far.
Currently our focus is on geting the reuse working (or if it not works, find alternative solutions) and also aim at supporting household sanitation in the project villages.

My colleagues have already prepared a draft susana case study, which I will have to review yet before you'll get it (s.th. that will probably cause me some nostalgia, having done that many times during my time at gtz ). Also a newsletter entry is possible of course. You'll here from me on that.

Dear Florian,

we had a similar set-up in a school in Kenya. The urine from urinals and the 3 cubicles of the teachers UDDT were connected to a 150 liter tank. The handwash basin also drained into that tank. It had a tap for withdrawal (for research of the students, further storage etc. - since we were not sure if there will be an active urine reuse) and an overflow into an underground infiltration area. We had forseen the planting of fruit trees or similiar on top of this area to make use of the nutrients and water. We used a 2 inch PVC pipe, perforated it and placed it in a gravel bed about 1 foot deep. Unfortunately the teachers never really started to use the toilets for specific reasons, but the urinals were well used as well as the handwash basins. So urine and handwash water was always collected. The school was suppose to plant banana trees around the urine infiltration area but failed to do so even after many reminders (lack of ownership and lack of overall training activities).

Have a look at the pictures
www.flickr.com/photos/gtzecosan/sets/721...071/with/6086990592/

I think it is a good set up, however the risk of faecal cross-contamination of the urine makes the withdrawal from the tap abit questionable in terms of health risk.

Cheers
Christian

PS: you could also send an email to the SuSanA working group 5 on food security the link to this discussion for more input. send it to wg5.at.susana.org!

Hi Elisabeth,

I make the perforated hoses for distributing urine with the cheapest hose that is available here--black, recycled hose for electrical connections (about $0.12/m). I puncture it every 50 cm and insert a section of a lollipop stick, which are almost always tiny pipes. This makes the holes very uniform (around 2 cm diamter) and professional-looking.

Yes, my theory is that this only works in the Tropics, thanks to biodiversity and relatively constant temperatures. SOMEONE (I think on the EcoSanReg Yahoogroup) said that this has been tried in Europe and it did not work. I also think the plastic meshes are key, to keep sawdust out.

I think it is a great idea to put the hoses however deep is needed to avoid freezing, as long as this is still accessible to trees. The hoses could be surrounded by sand, gravel and/or shredded disposable PET bottles, to avoid plugging by clay. And they could also receive most kinds of greywater (maybe not from laundries, with all the chlorine bleach). People may also feel more comfortable about this kind of food recycling, as it involves passing the nutrients through wooden filters that are meters thick (the tree trunk from the perspective of filtering). The main problem would be if someone has a water well too close.

Best wishes,
Chris

Dear Florian,

Chris Canaday suggested some solutions against clogging in his first posting already. I am quite intrigued by his observation of insects and microorganisms feeding on the urine/struvite and keeping the holes clear (what size holes did you use, Chris, for your perforated pipes?).
But is your theory that this only works in tropical conditions and not for European soils and especially not in winter?

My other question is: you briefly mentioned your project in Moldova. How exactly are you involved in that project? Is it the same as project number 194 in our worldwide ecosan project list? (I attach the file - we will soon update it on our website as well, then it will be here and will replace the old version from February:
www.gtz.de/en/themen/umwelt-infrastruktur/wasser/30631.htm




And maybe it is time that we report about this project in our next ecosan newsletter (for September), how about it? See my other posting here on the forum about the material collection for the next newsletter.

Regards,
Elisabeth

Hello Florian,
To avoid struvite precipitation and clogging I don't really know. But you may try to contact a scientific that I met once that was really nice that works on urine management and potential ways to reuse it: www.eawag.ch/beratung/experten/detail/udertkai/index_EN
To avoid groundwater pollution in winter, maybe can you use constructed wetland for winter only? So about 80% of BOD, at least 50% of P and 50% of N would be trapped and treated. After lets's say 20 years you could reuse the wetland media as fertilizer. I'm not a wetlands specialist but I read a lot about them.
Ciao-ciao
Charles

Hi Chris and Charles,

thanks for your answers!

Luckily it's not as cold as Canada, but Eastern Europe also gets pretty cold in winter, water pipes are laid normally around 1 m below ground.

Good point with the hot water! We have no showers (school toilets) and also not large quantities of water to mix with the urine, but still some warm water for hand-washing, that might help to keep the freezing risk low.

So I see 2 main issues:
1) how to avoid clogging from urine precipitation? Dilution with hand-washing water may help, but perhaps not enough? Would a smaller urine settling tank that allows collecting precipitating struvite etc. work?
2) Due to the deeply buried pipes, urine could only be taken up by tree roots, and in winter it would be entirely lost. So we would have to accept that it is a mix of urine reuse and urine disposal to the groundwater...

Happy about any further comments!