Cutting leaky drain to size

Each year in Chippendale we save over 4 million litres of water to irrigate our road gardens.  We built the drains for this ourselves at a once-off cost of $300.  The story is here.

An ice house in Iran - Image from Gardens of Persia, Penelope Hobhouse, photo by Jerry Harpur, published by Floriligium (yes, the same wonderful gardening bookshop in Glebe)

Four hundred or so years ago Persian engineers made ice without electricity.

Ice houses (yakhchal in Farsi, or icehouse) kept ice in the burning heat of the Iran plateau.  They’re rarely used today.

They’re up to 20 metres high and 6 or so metres below ground.  A single door is insulated with thick, dry grass.  Thick walls, 2 metres at the base, and their shape – an inverted funnel  which allows cooling wind to spiral down the exterior – keep the ice frozen for the summer.  The walls are made of sand, clay, egg white, lime, ash and goat hair. During the winter there are shallow ponds with high walls on the sunny side which are filled with water which becomes ice.  Thus, Persian wealthier classes ate ice cream several centuries ago without electricity.

Thanks to the author of this book for the text: Two wings of a nightingale – Persian soul, Islamic heart by Jill Worrall, on the road in Iran, Exiles Publishing 2011 P 68

‘Mike,
On  recent tour of your house with Ryde TAFE college, you told me the septic tank did not give off methane because of the anarobic bacteria. You asked me to ask the question on your blogg. Being an old fart, I do not know how to use these wiz bang electronic garbbage, so in search of knowledge, I am contacting you directly. My knowledge on septic tanks is limited to the anarobic bacteria break down the liquids; while airobic bacteria breaks down the crust which forms on top. Chemical are not used for fear of killing these little criters. If the bacteria are killed the whole tank must be emptied and the tank walls scrubbed before the tank is allowed to be refilled and the bacteria begins to form again. My understanding/ mis-understanding is while the bacteria is breaking down the solids/liquids they release methane gas.
One thing I was please to hear from you is “search for the truth and do not accept anything less”, those inspiring words has me at you door step. If the answer does help others please feel free to transfer my question to your blogg.

Regards
FL’

FL, the sewage system here works like this:

• raw sewage goes into a tank at one end where it sits for about a day or two while more and more sewage is added
• when that first tank gets full a pump transfers the top couple of hundred litres from the top of that tank to another two connected tanks in which air is continually blown into the sewage there by a 60 watt pump at 60 litres of air a minute
• if those two connected tanks are full then, when the pump transfers sewage from the first tank, that transferred sewage displaces water from them to a final tank where the water is held until it’s pumped to flush the toilet, wash the clothes or hose the garden
• all the tanks are ventilated with inflowing air naturally entering them and being drawn across the sewage to a vent pipe at one end which rises above the house roof

So air is pumped into about half of the stored sewage.  This is aerobic.  That is, it’s full of air.

About half of the sewage has only the air that is in the water or passes across it as it is drawn up to the vent pipe. This is slightly anerobic.

Some observations:

• frogs live in the tanks and I hear them calling out.  As far as I can tell, they’re not saying, “Help, I’m full of it, get me out of here”.  Judging by the little ones I disturb when I inspect the tanks they’re happy in there
• some slight odour is detectable when sewage is transferred from one tank to the other

As the system doesn’t smell I think its almost entirely aerobic; it’s easy to tell when something’s anerobic because there’s a smell.

So the process doesn’t produce a significant amount of methane but it does produce some.  My research suggests the amount is minor.

There are sewage systems in India and other countries where the gases are harvested to cook with and they have methane, but they are different to mine.

Great to have your question, thanks,

M

‘What is it now?”, you ask?

The circular through my door today, announces “Night works in Abercrombie Street from Irving to Broadway”.

For the next six months + – yes, ’ 6 – 7’ – the diggers, trucks, sludge, shouts, groans and tra la la-ing will happen seven night a week there.  It’s about 100 metres of Abercrombie that’s to be dug up for this super drain.

The explanation makes me curious:  ”The installation of this stormwater pipe is an essential part of the construction works for the public park at the centre of the future ‘Central Park’ precinct.”

That sounds unbelievable because:

• that’s a hell of a pipe to take away stormwater
• such a pipe would carry more than the water to fall on and be wasted from the little park to be created in the project
• the amount of stormwater to be wasted through such a large pipe that will take six months to dig for a length of about 100 meters – or 20 metres a month to dig it on average - must be a very large amount of water
• trumpets, international architects, slideshows, Ministerial proclamations, dancing girls, marching bands, green gurus, web pages and wizards – all these and more said this Broadway project was to be a sustainable project where rainwater would be harvested and reused on the greenest precinct Sydney would have.

Could it be that what all the hullaballoo amounts to is the usual greenwash hocus pocus?

Could it be that rainwater is in fact to be mostly wasted and treated as a waste product here?

Who to ask in this leaderless town where all in authority spend most of their time and money on spin?

Let’s just ask ourselves, use our eyes, ears and cameras over the six months period of open heart surgery to be conducted on yet another part of Chippo that’s to be dug up for drains to waste precious water.

No doubt we’ll be blessed with telephone calls after it all to ask how much fun it was and what problems we may have.  With all responses fed into the spin doctors kitchen whence it will come back at us with press releases, spin and life will go on as usual, drain after drain.

Did you see this week the announcement by the wise government in Brazil, which is presiding over the collapse of flows of the mighty Amazon river, diverting so much water to industry and so much rainforest (which once generated rain for the river) to farming, will now build a dam to make electricity?

Could be worse; we could live there, I guess, where they’re about to flood the folks and critters who live where the dam waters will go.

Or, we could live as a fish in the waters of Blackwattle Bay which are copping all the silt streaming out of our ‘raingardens’ and off the site entries to the Frasers site.  The fish must be chuffed these last few days; check out the tonnes of silt running out of the Frasers site – you know, the sustainable one on Broadway.

May the raindrops stay where they fall,

Michael