yes,
the intended reuse of human excreta (urine and faeces) determines the level of treatment required, specifically with regard to removal of contaminants (pathogens and toxins).

Thus, the service chains and treatment have to be planned from the end: what do we want to reuse the human excreta for: then we can plan how to contain, recover, transport and treat them.

And, VT seems to be one appropriate technology to adjust treatment level by adding additional vermifilter stages, removing contaminants and adding nutrients.

ciao Hajo

By surface irrigation I also mean subsurface drip lines. By subsurface soakage fields I mean permanent soakage fields. These are expensive because they need to retain the soakage over time without contaminating groundwater, so use large quantities of drainage media (e.g. scoria) and pvc pipes which are accurately levelled. Primary treated effluent requires a much higher quality system of disposal because the risk is greater.  So Hajo you are correct, once the effluent is secondary or tertiary treated the reuse scope widens, even to flood irrigation. By modularising the vt plants you simply add modules till you achieve your required level of treatment. 
Cheers 
Dean 

Hello Chris,

thank you for this very valuable contribution. It is interesting to see to which advanced stage subsurface drip irrigation (SDI) has been developed. Although I wonder how they will tackle the problem with the rodents eating the pipes away. You may need a water meter or pressure gauge on every drip pipe if you want to find the possible location of damage. Like district water meter and leak detection equipment on a drinking water supply reducing non-revenue water (NRW).

But SDI does not rule out at all the use of irrigation water from a vermitechnology plant. Instead of pumping water from a well and feeding it with industrial fertiliser, the farmer can also be provided with irrigation water from a VT plant which is treating faecal sludge (from latrine pits or septic tanks) and/or sewage.

Whereas this scenario belongs more in a developed country where farmers are used to such sophisticated irrigation systems. In your and my current country, flood or overhead irrigation is probably more used by small and middle scale farmers and then the water must be treated to a level that it does not pose a risk for farmer or consumer. Vermitechnology will be able to provide this but which has still to be researched and proven beyond doubt to be accepted.

ciao
Hajo

Hi,

Just a quick note.

With subsurface irrigation, via perforated hoses or drip irrigation hoses, any risk of odors or pathogens is eliminated and we can still give back productive plants, like fruit trees, although the technology is now there for using tractors to lay dripline into the soil of, for example, corn fields and continue to till them.




Subsurface irrigation is also much more efficient, as loss to evaporation is eliminated and the hoses are protected against mechanical and solar damage. There is also less contamination of groundwater and less runoff to and contamination of surface waters.

Best wishes,
Chris

Dean, I understand your anger and your disappointment that vermitechnology does not (yet) attract the attention it deserves.

Therefore I wanted the topic under 'Resource Recovery', so that it is not seen as 'another' type of sanitation doing away with human excreta as cheap and eco-friendly as possible. Under the sub-category 'Resource Recovery' I want VermiTechnology being discussed as a sanitation technology which AIMS at the use of its products, i.e. humus and nutritious irrigation water.

For this use the products have to be safe, for the worker who handles them, for the farmer who applies them and for the consumer who eats the farmer's produce. Heiner, in another topic, voices his doubt that the products can be 100% safe. I object, I think we can make them as safe as possible as they need to be. Prof. Rajiv Sinha has started some research on the removal of pathogens and toxins by worms from human excreta. I am just discussing with Elisabeth, how we find out whether other researches have been in that direction. If not so, it has to be done.

Dean, you are further critical of Tiger Toilets and the 'worm-based septic tanks' in AUS and NZ. I think they are a small step in the right direction because they make the users accept that nature provides more sustainable technologies (worms!) for treating human excreta than industries: they are cheaper, they don't smell, they do not produce GHG, they produce humus instead of sludge, they produce a nutritious effluent, they reduce landfills. If we can promote more Tiger Toilets and more Worm Farm septic tanks and make public and decision makers aware of that development, we are going in the right direction.

And yes, the effluent is too valuable to be wasted into a soakaway, whether vertical or horizontal. We have to show and to prove that the second (or third) stage vermifiltration can make the effluent safe for any possible irrigation application. And then vermifiltration and transport systems have to be developed enabling the economically use of the irrigation water from Tiger Toilets, Worm Farm septic tanks, faecal sludge treatment works and WWTP. Stakeholders have to understand that all these processes aim at the reuse of the effluent as irrigation water and the infrastructure should be planned accordingly NOT at rivers BUT at farms.

Dean, I hope you see that we are on the right way even with Tiger Toilets and Worm Farm septic tanks. It just goes a bit slower than you want it go.

ciao
Hajo

Like I have said multiple times on this forum and even in the Wikipedia article on vermifiltration, the technology is used in both Australia and New Zealand abundantly... but mostly as a primary treatment system, with subsurface discharge to soakage fields. Much like a septic tank, but produces humus instead of sludge, and like Hajo said, doesn't generate greenhouse gases. Cheaper to construct than a septic tank also. Primary treatment digester "tiger worm toilets" are also gaining traction all over the world.

But, alas, combined primary and secondary treatment systems using "vermitechnology" haven't yet taken hold. These are the ones of real interest because they can use surface irrigation, because the effluent is treated to a secondary level. Surface irrigation is the way to go, it can be moved around and the nutrient-rich water used to irrigate useful plant crops.
cheers
Dean

hi Elisabeth,

I understand the "eco-friendly septic tank with worm technology" by Worm Farm Waste Systems as follows:

• different from septic tanks, they also add organic kitchen and garden waste;
• thus, the digester takes grey water, black water and organic waste;
• different from septic tanks, the digester contains worms and aerobic bacteria, NOT anaerobic bacteria;
• a vent pipe with fan keeps the processes aerated;
• thus, the processes are aerobic, do not stink and do not produce greenhouse gases (which we always forget to mention!);
• the effluent also carries wormcast (and eggs) away which makes the effluent even more nutritious;
• the effluent is never soaked away down but always distributed via subsurface pipes feeding lawns or garden produce;
• and (they say) the wormcast (from all the digested solids in the waste) has never to be removed from the septic tank.

Still, I also have some questions regarding the processes. I have asked Worm Farm Waste System to join the forum, so that we can discuss their technology approach on the forum.

Nevertheless, I find it fascinating that VT has already reached such spread of use in Australia and I hope we learn more about its practical use from the company.

"Septic tanks with worm technology" I would not call an alternative 'term' for vermitechnology but would define it as a subset of VT, like vermidigester, vermifiltration, vermicomposting, ...

ciao
Hajo

I’m hoping to interview them for the podcast as we have mutual friends. Let me know what you want to know and I’ll ask the questions....

I had a quick look at the mentioned website ( www.wormfarm.com.au/ ). As usual, and understandably, it's full of sales talk with very few hard facts. They call their system "eco-friendly septic tank with worm technology" and praise all its advantages but without showing any details of the technology. I do understand that, as their website is for selling their products. Maybe if you, Hajo, contact them, they'd be willing to talk to us here on the discussion forum? That could be interesting. The number of example projects, including industrial sites, does look impressive!

So here is an alternative term for vermitechnology: "Septic tanks with worm technology"...
Regards,
Elisabeth

Good day Pete,

thank you for alerting me on this. I was aware that quite some research has been done at Griffith University in Brisbane on vermitechnology and I also read about this being applied by some councils for converting sewage sludge to humus for sale instead of taking the sludge on a costly landfill.
But this household application of VF in Australia was new to me and I definitely will follow up on it, because every application has its peculiarities from which we learn something new.

ciao
Hajo

Hi Hajo,

One of my podcast guests in Australia told me that worm-based systems that handle both grey and black water are quite common in his neighbourhood. He sent me this link. Are you aware of this?

www.wormfarm.com.au 

Dear all,

In developed countries current state-of-the-art wastewater technologies reduce BOD and COD to a level at which the effluent does not pose too much harm to the receiving surface waters. In developing countries WWTP are either not of such high standard or do not function properly. Thus, the danger of water pollution is even higher.

And why do we pour more or less treated wastewater back into rivers, where downstream users are then struggling to give drinking water quality to the raw water which they draw from the river…  only to put it into the toilet and their treated wastewater back into the river again?

Already in 1993 the WSSCC (WaterSupply and Sanitation Collaborative Council), WHO and UN asked, why we divert nutrients contained in the excreta away from land, adding artificial fertiliser instead which pollutes groundwater and requiring additional treatment making it potable again. The authors are asking for another way where the ‘waste’ is used as a resource.



Vermitechnology can be the answer. But it will require a completely new thinking and new designs. Water and sanitation and environmental engineers will have to learn again. With VT all sorts of organic waste (and especially human excreta) will be converted to humus and irrigation water, both dearly needed in organic farming. Besides learning to design VT treatment plants (VTTP) for all sorts of waste streams (sewage sludge from WWTP, faecal sludge from pit latrines, septage from septic tanks, sewage from sewers) and at different sizes, they also have to re-think that the effluent is not a waste, going to the nearest river, but VTTP have to be placed above arable land where the treated effluent will be used. And it will not be used because we must get rid of it, but because it is needed for better
yields and healthier environment.

Not all details of all these plants exist already, but also today’s conventional WWTP have been developed over the last 150 years. If we believe in this new technology and concentrate resources on its development, in 10 years a reasonable number of VTTP can have been built instead of conventional WWTP. I see especially use for this technology in developing countries, where it can help saving infrastructure and O&M costs, reduce waste products (sludge, wastewater) and increase reusable products (humus, irrigation water).

Ciao
Hajo