This system provides domestic wastewater treatment to an exceptionally high level at low cost, requires no external power supply and is reliable. There is no sludge to deal with and nutrients are all recycled to growing plants. Seems to me like a win-win opportunity for the global sanitation community. Any further comments?

Hi Bara,

Not sure what you mean by "net area"? Surface area is more important in the primary treatment digester, which is 1 square metre. The secondary and tertiary vermifilters have basket volumes of approximately 80-100 litres each and surface areas of 0.1 m².

Worms are introduced a couple of weeks after commissioning and rapidly build up in numbers. I've consistently observed there are more in the secondary vermifilter than the tertiary vermifilter, suggesting their numbers depend on the treatment level (BOD) of the wastewater recirculating.

We use cleaning products, detergents and disinfectants in our household, but don't use them excessively, and we certainly don't coddle the worms. In my experience once the worms are established they are resilient and not easy to kill off, so provided disinfectant use is not excessive they'll be fine.

Cheers
Dean

Dear Geoco,

Thank you for sharing the post,

What is the net area of the digester ? How many worms do you have there ?

How do you overcome the challenge of the chemicals in the wastewater?

Best, Bara

Some of you may know I've been working on a low cost wastewater treatment system in my spare time for the last decade. The system is for all household wastewater (blackwater + greywater) and treats to a level suitable for irrigation to the soil surface and agriculture.

I thought I'd share the latest development, where I've been running a full domestic tertiary treatment plant for a couple of years using two small solar panels to run the whole system. It's completely off-grid, reliable, and can be constructed at low cost. Treated wastewater is pumped uphill to surface irrigation. Being aerobic the wastewater is rich in plant nutrients. Information is available about the system at  www.vermifilter.com

Happy for feedback, I've designed this to help people in poorer regions of the world to achieve the level of sanitation we all require. I live in a privileged country where we've broken the helminth cycle by eliminating open defecation. Yet we haven't closed the nutrient cycle:

• Standard practice sewage treatment is centralised and discharges to water bodies. 
• Domestic systems at best discharge secondary-treated effluent to unproductive effluent fields that use ornamental plants. 
• Agricultural fertiliser is almost exclusively artificial. 

Solutions are required.

Here is a video:

Find out more about the system at www.vermifilter.com