Promote VERMIFILTRATION Technology for WASTEWATER PURIFICATION by EARTHWORMS to produce clean water

  • hajo
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  • Director of catWASH: consultancy, advice, training in WASH. Late but not too late I have founded my own consultancy hoping to provide useful advice and training in construction, O&M, management and governance of water and sanitation in Rwanda and in the region.
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Re: Reply: Promote VERMIFILTRATION Technology for WASTEWATER PURIFICATION by EARTHWORMS to produce clean water

Hi Harry, welcome to the club!

Hi Dean,

Thanks for taking your time proposing another design for the upscaled vermi-filter. We currently look at three different designs: the stacks of fruit crates, the upright HDPE culvert pipes and the concrete/block box with the drainage cell panels (your last post).

If we plan designing a (scalable) VC filter for community use, I feel the fruit crates are still the best solution. Let me try to summarise the pros and cons:

Fruit crates:
• The filter structure only requires the crates, windbreak cloth, media, wall sheathing and roof;
• The structure is easily set up, adjusted in size or set-up, and easily maintained;
• Looks professional;
• Fruit crates may not be easily available and may be expensive (compared to second-hand DIY material but not compared to ‘state of the art’ standard designs).

HDPE culverts:
• 600mm culvert with slotted pipes inside provides only 0.15m2 effective filter area, thus, many more culverts are needed than fruit crates providing the required filter area;
• Culverts can only be filled with media once they are in position and I wonder how the media can eventually be maintained/exchanged if necessary;
• Setting up multiple culverts with slotted pipes inside, plastic mesh and windbreak cloth inside a 3m long, 600mm culvert is not as easy as the fruit crates with windbreak cloth inside only.

Box with drainage panels (described in Dean’s last posting):
• Once it is built it cannot be adjusted in size if found necessary;
• As for culverts, the fixing of the panels covered with windbreak cloth to a depth of 3 (or 4) m and at 60cm distance will not be easy;
• As for culverts, the maintenance and exchange of media will be difficult (if not impossible) unless the whole inside structure of the box is removed;
• The costs of this alternative are mostly in the outside wall structure which makes it not necessarily economical.

As said, I still tend to the fruit crates if we can get them in Rwanda. They may not be the cheapest solution (of the 3), but I rather look for functionality, including adaptability and maintenance as well as ‘looks’. Because I assume that any of above solution will be cheaper than the ‘state of the art’ standard design, we must choose the most ‘professional’ solution convincing partner and financier.

I know, Dean, this is not what you are aiming at but please consider that (at this stage) we are not designing household facilities but community size infrastructure which must be appreciated by water & sanitation administrators and be financed by international development banks. And I need your professional input designing them right.

We will come to designing household facilities, those to be financed by banks and those to be built by the users… 😊

Dean, what do you pay for the fruit crates in NZ?

Ciao
Hajo

We can't solve problems by using the same kind of thinking we used when we created them.
Albert Einstein
Any intelligent fool can make things bigger and more complex... It takes a touch of a genius - and a lot of courage to move in the opposite direction.
E.F. Schumacher
Everything should be made as simple as possible, but not simpler. :-)
Albert Einstein
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  • hajo
  • hajo's Avatar
  • Director of catWASH: consultancy, advice, training in WASH. Late but not too late I have founded my own consultancy hoping to provide useful advice and training in construction, O&M, management and governance of water and sanitation in Rwanda and in the region.
  • Posts: 209
  • Karma: 14
  • Likes received: 89

Re: Reply: Promote VERMIFILTRATION Technology for WASTEWATER PURIFICATION by EARTHWORMS to produce clean water

Hi all,

In a parallel thread discussion about compost toilets, Geoff Hill presents two research papers which look at the destruction of ascaris in VC digesters . The result of this research is that vermi-digestion does not destruct ascaris, which is in contradiction to other researches done earlier by Eastman and Boxmann and which are quoted in these two papers.

If this research by Hill et al. is proved correct, it means that humus from VC digesters cannot be used without restrictions or without further treatment. For the time being we must assume this.

I have also contacted Prof. Sinha (see author of this thread) because his research indicated that the humus from VC treatment would be fully safe. He now concedes that the humus may require additional treatment getting rid of the ascaris.

Because I anticipate that under our conditions multi-barrier approaches (use of humus only for fruit trees, windrowing of humus before further use) may not be observed, the humus leaving the VC TP must be safe! Here I agree with Joe who voiced similar concerns in the above mentioned thread.

Which is the most economical treatment destructing the ascaris in the humus? I read about urea and ash treatment, which would require additional input materials. Another possibility can be heating the humus to above 40C or higher for a given time (the hotter, the shorter, sun drying?). Any comments on these two alternatives? Or any other proposal? Don’t forget that we discuss about ‘central’ community VC TP not about household applications!

Ciao
Hajo

We can't solve problems by using the same kind of thinking we used when we created them.
Albert Einstein
Any intelligent fool can make things bigger and more complex... It takes a touch of a genius - and a lot of courage to move in the opposite direction.
E.F. Schumacher
Everything should be made as simple as possible, but not simpler. :-)
Albert Einstein
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