Found an article at Sustainable Design Update (the site seems to have disappeared) about Sintex Industries making a prefabricated biogas digester which turns waste and garbage into cooking fuel. Nothing new about the technology but constructing a tank has always been the biggest headache. Now, you can just get it ready-made and install it. According to some reports, it costs about Rs. 17,000 for a tank that’s 1m³ in size which is enough for a family of 4 and the payback period is 2 years.

Interestingly, most references to Sintex call it a “plastics and textiles manufacturer”. I didn’t know they did textiles. Here in Bombay, Sintex is to tanks what Xerox is to photocopiers. In the meanwhile, not a single Indian newspaper or website had picked up on this. Yet…

The Sintex website makes no mention of this product and it’s still probably a pilot project because only 100 have been installed as of date. They do plan to increase production tenfold but 1000 tanks is still merely a drop in the ocean. If other manufacturers copy this design with as much alacrity as they did the Sintex loft and overhead tanks, then we might get somewhere.

Edit: Since this was written, Sintex has updated their website and you can see septic tanks listed as one of their products.

Edit #2: The page itself has disappeared so, for the moment, the link above points to an archived version on Wayback Machine.

Researchers at IIT Kanpur are working on a toilet design that will reuse water. The design is still under development but, if it works as advertised, it’ll be a good thing because the amount of fresh water flushed down the drain is dramatically reduced. The article at Down To Earth may disappear in the next few days because access to archives requires subscription. From what I understand of the system, a vortex is created to clean the pan and then, further, to separate the solid from the liquid matter. The liquid is then being pumped back for reuse. In places where there is little or no power, hand-pumps can be used a couple of times a day.

What you are left with is dry waste which can be composted and reused liquid which contains a lot of urine. They’ll have to work on the smell angle because… well… have you ever been to a urinal at a train station? The smell is so strong, methinks it would almost be commercially viable to bottle the ammonia!

I’m also left wondering if at least a small amount of electrical power would be required to help with this mini centrifuge work better. Indian Railways have approved the design and they’re going to test it out on one particular route. It remains to be seen if the centrifugal force which is running on gravity is strong enough to override the rock and roll effect of a railway carriage running at high speed.

Finally, even if the system doesn’t work for reusing the water, I still think it’s a good idea to separate the solid and liquid components because dry composting is far more efficient.

Edit: The original article at Down To Earth Magazine has been removed.