Link correction

http://wte-ltd.co.uk/reed_bed_sewage_treatment.html

Hi Xavier. I'm a little confused by your question. If you're going to be storing all the cleaned water for irrigation rather than using soakaways/greenfilters, then I don't understand why you're asking about soakaways?!

Storing the water this way in your climate makes me feel very nervous though, especially given that you have charge of children. Putting the water through the primary vermicomposting chambers cleans upwards of 90% of all pollutants when the system is working as it should be, but that still leaves around 10% remaining to be treated. And what about potential contamination if something goes wrong (eg. a chamber outlet gets blocked)?  I would not consider storing the water until it's been treated (at least) a second time by a vermicomposting ecosystem, whether that's in a 'greenfilter' situation, or a secondary chamber after the first. And for preference I wouldn't store the water at all - I would take it straight to the gardens. It's much safer being used straight away. You really want to avoid anaerobic environments altogether where sewage is concerned. It's difficult enough to store clean water in tanks and keep it healthy and, in tropical temperatures especially, it would be easy for pathogens to proliferate. If you must store the water, then I would separate your grey water from your black water and only store the grey water. That means having separate vermicomposting chambers for your grey water and black water (assuming you want to clean the grey water before storage).

How many people are going to be using your system? I'm wondering if the 3 vermicomposting chambers will be sufficient for what they have to handle, especially the number of toilets.

Assuming you ARE going to be using soakaways ...

This article about reed beds in the UK: the beds failed because of low temperatures. So the man was handling raw sewage. He got it in a reed cut, so he had a bad infection. It's a completely different situation to a vermicomposting soakaway/greenfilter. Firstly, the soakaways/greenfilters do not handle raw sewage. The water is cleaned of upwards of 90% of pollutants by the time it reaches the soakaway. Secondly, a reed bed is a predominantly anaerobic treatment system - an environment where pathogenic bacteria can proliferate. A vermicomposting system is aerobic and should be kept that way at all times. The soakaway should therefore be sized so there is no possibility of standing water accumulating at any time.

If there's no standing water in the soakaway at any time, then the question about mosquitoes is redundant. Mosquitoes only breed in standing water.

I don't know about Thai snakes. The snakes here are not venomous, so are not a concern, and I've never seen any in and around the greenfilters.

I hope that helps.

Hi and thanks for your answer.

Well let me clear a point that we plan a second stage as a reeds beds to clear the water but maybe it s not enough.

We will not follow that project and find another solution because of the climate: 5/6 months in the year we have rain everyday so we need to adjust our watering pattern. This explain the storage.

We can divert grey and black water we have toilet with diverter. 

Doing dry toilet is not in Asian culture as people clean themself with water and not wipe.

I m a bit confusing now. Maybe we use conventional sceptical tank for black water and treat / store greywater.

What's your tought?

OK. Now I understand better. Thanks for clearing that up. I wouldn't recommend using reed beds as a second stage. Use another container (or a soakaway) with a vermicomposting ecosystem. This keeps everything aerobic (as it should be) and therefore free of pathogens and problems associated with standing water (mosquitoes, etc). Reed beds may be a proven treatment method but they're still not treating sewage in the way nature designed it to be dealt with! Keep it aerobic! You reduce your potential problems tenfold by doing so.

I wouldn't use a septic tank! It doesn't treat the water at all and once again it's an anaerobic system which invites all manner of problems. You're much better off using this vermicomposting system to treat the black water.

So ... what I would recommend for your situation where you're needing to store water for irrigation in dry periods, is to either ...

i) separate your grey water and black water. Treat both with separate vermicomposting ecosystems. Store the grey water. Take the black water straight to the gardens to irrigate trees, banana circles or to a vermicomposting 'greenfilter' soakaway.

or ...

ii) Treat your grey and black water together in vermicomposting ecosystems and take it straight to the gardens to irrigate trees, banana circles  or to a vermicomposting 'greenfilter' soakaway. Capture rainwater off all of your roofs and store that.

The vermicomposting ecosystem is an enormously flexible tool which can be used in all sorts of ways to clean water and deal with wastes. It's much better than any anaerobic system - it's much faster, it's odour-free and it's pretty much pathogen-free.

Hi Thanks for your precious answers and your time.

We will follow this advise and do point i).

As I m doing worm composting from 7 years now I love and I'm convinced by the power of worms.

We will update you and post pictures.

Thanks again