August 25, 2008

Sewage - an exercise in futility

Every time you use the toilet you flush down from 10-15 liters of clean potable water which probably traveled many miles through a myriad network of holding tanks , pipes and what-not . And the act of flushing gets rid of the waste and all is forgotten to most of us . We all know that it goes down the sewage system but beyond that we don't care. I say we must because every pipe has two ends , flushing away your refuse just transfers it to the other end . So at the other end we create another system of settling tanks , aeration systems where this refuse is brought to a state where it is deemed harmless to be released into the waterways . The price is that the whole process is very energy and resource intensive . And it doesn't always work . Over time as the amount of sewage increases there is a need for more and more facilities or else as it happens all over the world , raw sewage is dumped into the waterways creating a serious health hazard . To illustrate
Take Delhi, as a typical instance. Yamuna is Delhi's main sewage drain. Yamuna enters Delhi at
Wazirabad - where the city draws its water supply - and after this an estimated 1,800 million
litres per day (mld) of untreated sewage flows through 18 drains into the river. In the last four
decades, the total sewage output has increased rapidly. Untreated sewage has grown even
faster. In 1999, the Central Pollution Control Board estimated that Delhi produces over 2,547
mld of sewage of which only 885 mld is collected through the sewage network for treatment
and the bulk - over 75 per cent flows into stormwater drains and then into the river. By late
2000, treated sewage had increased to 1,333 mld as had the quantity of sewage - still over 50
per cent of the city sewage was dumped into the river. By 2005, Delhi plans to triple its present
sewage treatment capacity at a cost of Rs 750 crore. But this will still be less than what is
needed. Paradoxical chase It is an ironic situation. Even if Delhi builds all the sewage treatment
plants, it will still not have the sewage to treat. Why? The city's sewage drains are choked and
silted. The government admits that the present capacity of the sewage treatment plants is not
being utilised and when it builds new treatment facilities, sewage never reaches these plants.
From Down to Earth

So we create a gargantuan system to get clean water , shit in it and then make an even larger system so that we get the shit out of it so that we can get clean water again . Sounds a bit crazy to me .
"Anyone starting out from scratch to plan a civilization would hardly have designed such a monster as our collective sewage system. Its existence gives additional point to the sometimes asked question, Is there any evidence of intelligent life on the planet Earth?"
G. R. Stewart

Wouldn't it be better to create a system where human refuse is handled at the source with minimal use of water , especially potable water when a really small fraction of the developing world has access to clean , potable water ? Wouldn't it be better to reuse the nutrients , give back the soil the nutrients that would otherwise be chemically synthesized ? I am talking Humanure but that is another story .

1 comment:

Anonymous said...

The Humanure Handbook 3rd Edition + How to video + photodocs
All the content from this torrent ( is on the website, however, it is compiled in to a convenient directory listing. Help seed this, show your support for the tipping point.