Waste not, want not

By Ian Douglas, 20 April 2016

Ian Douglas is a retired expat living in a small village in Thailand. Here he muses about the cyclical system of food and human waste.

As my friends know, I regularly feed the wild birds in my village. Four handfuls of rice a day gives me a regular clientèle of sparrows, zebra doves and collared doves, sometimes mynahs – although they don’t seem partial to rice unless cooked.

There is another bird which has a very long-winded name, the oriental magpie robin. Now “oriental” I can accept, “magpie” also (it looks like a scaled-down magpie, sparrow-sized), but why “robin” I have no idea other than that it is quite bold around humans.

Anyway, this bird is an insectivore and in this present drought insects are in short supply. But the bird is very adaptable; it has learnt to hop inside the street drains in search of prey. Whereas its normal prey is a one-gulp type of insect, cockroaches are a different proposition. They fight back and have to be dismembered before they can be swallowed.

On the topic of drought, a visitor to the village might wonder why the mango trees that line both sides of the road are luxuriant with leaf and also heavy with mangoes. The reason is simple: the trees are all planted directly above the street rain sewer system (the same one the mini-magpies hunt in) which no doubt is penetrated by their root systems.

But with no rain for months, why is there still water in these drains? This is where it gets interesting.

When I first moved here I made a point of having my two sewage tanks emptied every six months. Then I gradually realised that no one else ever did.

A quick investigation revealed why. When full, the tanks overflow into the street drains. So the street drain is also the main sewer fed by every house and thus never runs dry.

This benefits the trees, the cockroaches and now the mini-magpies. But it does not stop there. The village sewers empty into a small canal which a local farmer uses to irrigate his paddy fields. The paddy field is home to molluscs, fish, frogs, snakes, rats and wading birds, all of which feature in the village diet.

The small canal in turn empties into a large canal which apart from many fish also has several flocks of semi-domesticated ducks, which also of course feed into the local food supply.

So in summary the entire system is cyclical. Human shit and waste goes in, protein and fruit comes out. I think to pump out my cess tank would be anti-social.
However, I do wonder what pathogens also enjoy this cyclical system.