Rain delays play

The base for tank #1 is too wet to finish levelling and compacting the crusher dust. The site for tank #2 is a sticky, muddy quagmire that's very easy to dig but too soft for reliable border building.

The "Walk Against Warming" march was supposed to be ironic with everybody holding aloft their umbrellas in the sunshine. That point's going to be a bit lost in the present conditions.

On the positive side, I've discovered that I have another six months before I'm required to finish the installation of these tanks and still qualify for $850 worth of Brisbane City Council rebates. We have to register our application by the end of September but don't have to complete it all until the end of March next year.

Colin knows what you want

Now here's a story which might convince people environmentally-friendly living is actually something they want to do. No Impact Man touts the benefits he and his wife have experienced as a result of their experiment - including a cure for dandruff and no more period pains.

That's a pitch which might change a few behaviours!

Tell me what you want, what you really really want

This is something I've been struggling to write for a couple of weeks now. I'm not entirely happy with it but it's hopefully better than nothing. With the caveat that I'm not trained in psychology or sociology or anything like that, let's dive right in...

The basic idea is this: all of the greenies, the conservationists, the environmentalists, the reduce/reuse/recyclers, the peak oilers, everybody who wants everybody else to voluntarily change their behaviour in some way, has to understand that their struggle is not primarily with behaviours but with values.

Value decisions drive behaviours. I wrote this about six weeks ago:

It seems to me that the primary driver for personal behaviour must surely be personal values. If so, that would imply that my failure to change behaviour in personal matters (such as limiting my Ice Break consumption as I had committed to do) comes down to a question of my own values. That I value the experience of drinking coffee-flavoured milk more highly than the environmental benefits gained by reducing my consumption. And that would probably be because the benefits of drinking it are personal, immediate and known whereas the benefits of reducing consumption are dispersed, delayed and unknown.

There's a famous TV psychologist who nailed the issue with his often-repeated question, "What's in it for you?" People don't just do random things. They tend do the things which they believe will meet the needs or desires which are most pressing within them.

Needs and desires is a tricky subject. Another famous guy by the name of Jeremiah is purported to have written, "The heart is deceitful above all things... who can understand it?" Well, a bloke called Maslov took a good stab at it with A Theory Of Human Motivation (here) from which is derived his Hierarchy of Needs (here with illustration).

We get even more complicated when we consider that we can, with varying degrees of effectiveness, redefine and reprioritise our needs and desires by adopting just about any other moral, ethical or value principle you could possibly conceive of.

The majority of these are older than we are and are imparted to us through our family, friends and broader society. Sometimes a new or derivative principle comes along, like the famous "land rights for gay whales" slogan, which we might see fit to adopt.

Some of these ideas - especially religious ones - become almost as deeply ingrained as the needs which Maslov described, and can take such a high priority that people are literally willing to die for a cause.

Let's get visual here for all you right-brainers with a diagram I just whipped up...

I hope that's making some kind of sense. People do stuff because of what they care about. If you want people to do different stuff you need to either get them to care about the same things you do, or convince them that what you want them to do is somehow aligned with their own most pressing needs and desires.

Now to bring this all back into context and finish up...

I started with a statement about attempts to bring about voluntary changes in behaviour. That's really directed at anybody (myself included) who wishes to inspire "grassroots" or community-based action regarding climate change or sustainability. It's a really tough job and we need to be clear what we're up against.

The other aspect to bringing about widespread change is the use of the law. The law is (supposed to be) a codification of the agreed values of a society and has a couple of unique strengths in regarding to upholding values:
- laws can be designed to counteract our bias towards personal, immediate and known benefits
- any value written into law is reinforced by Maslov's safety needs which incline most people towards civil obedience

Changing laws in a democratic society is generally achieved by demonstrating that a certain set of values is held in common by a majority (or an influential minority) of the people. It's a different fight.

As I think about the year 2050 and what kind of civilisation I hope we will have, I see a society in which the core values associated with environmentally sustainable (or even beneficial!) human society are broadly accepted and expressed in law so as to guide individuals as well as commerce and industry in behaviours which will meet our most important needs not only today but for the very long term.


And maybe a world in which I never ever ever quote the Spice Girls again.

Hard yakka in the rain. Glorious!

Since about lunch time today we've had fairly constant light rain. The BOM says about 10mm has fallen since 9AM. If I had my tanks installed that'd be about two thousand litres captured.

They're not installed yet, of course, but I'm working on it. Yesterday I ordered some crusher dust to use in completing the base for my tanks. I did some calculations and worked out I needed just a touch over one cubic meter of the stuff to form the base and ordered one and a half since it's better to have too much than too little in this kind of situation.

Today it arrived, all two tonnes or so of it dumped in our front yard. Caitlin (my almost-six year old daughter) and I spent a good couple of hours working in the rain to shift nearly half of it down to the end of the house and into the excavated area. We added more water using the hose (the rain was really very light) and I compacted it using a very simple but distinctly heavy tool borrowed from a neighbour. Square bit of metal with a long metal rod sticking up from the centre of it, lift it up, bang it down, hundreds of times.

It's so different to the kind of "work" I do during the week that I'm thoroughly enjoying myself... and thoroughly stuffed tonight. I can't show you a pic of the result because I didn't want to get the camera wet. But I'm very proud of the effort and of having persisted with it even in the rain. Not that I'm complaining about the rain of course.

In the next couple of days I'm hoping to do a final level and compact at that end of the house and finally get that tank into place where it's meant to be. Have a niggling concern that what with all the geometry changes due to choosing and siting the border bricks it's going to be a fraction too small. But hey... it's only more work to do.

Don't OVERFEED the worms

I might have mentioned it previously, but I've been wondering why the worm farm instructions make such a big point of not overfeeding the worms without explaining why it's a concern or how you know when you're giving them too much food.

You might have realised this before now but sometimes I'm not very smart. Especially when the answer is a really simple one.

If you give worms too much food... they don't eat it all and it goes bad. Humans and worms both want to stay away when this happens.

I'm quite happily forgiving myself for not getting this right on the first go. There's no sign that any worms have suffered as a result. Hopefully all that's necessary is to dump out the bad stuff and try again with smaller amounts - which is what I've done.

Learned a number of small things along the way too...
- carrot tops can sprout when kept in a dark, moist, nutrient-rich environment
- compost worms don't appear to be able to bite raw carrot very well
- a few vinegar flies is not a problem, but lots of them indicates a problem
- compost worms prefer food that has been really finely chopped, but not blended
- the little critters can move surprisingly quick when they want to

Action stations!

Mr S sent me a link to the Big Switch campaign website the other day. It's an initiative of Greenpeace with support from quite a number of conservation groups and a couple of business organisations. It aims to promote grass-roots community action on climate change and use that as leverage to pressure individual federal politicians into ratifying Kyoto, committing to significant emissions reductions by 2020, committing to significant renewable energy production by 2020 and establishing a national emissions trading scheme.

I gave it some thought and decided to participate. My details are registered and I've sent an email to my local member of parliament. But I was most interested in the community group aspect of the campaign.

My electorate (called "Petrie" even though it does not include the actual suburb of the same name) is bizarrely-shaped with the northern and southern halves having almost nothing to do with each other. Through the Big Switch site I discovered that there's a Redcliffe Climate Action Group but I have no intention of driving all the way up there to be part of it.

Thankfully there's another group based in the adjacent electorate of Lilley, going by the (possibly temporary) name of the Brisbane North Climate Action Group. This looked like a much better fit.

So Mr S and I went along - car pooling - to a meeting of the BNCAG this evening. What a fascinating bunch of people they (we) are. A dozen in total, a handful of whom started getting together about two months ago. Highly informal, friendly, and motivated to actually do something about reducing our community's impact on the Earth, and in particular on the climate.

It's very early days. Almost embryonic, you might say. But I'm hoping that this might be the opportunity I've been looking for to get involved and make a meaningful contribution to the future of civilisation.

Next meeting in a fortnight. I'll keep you posted.

Progress on the tanks

This weekend I finally got the second and third sides of the in-ground brick border done for the first of my two tanks. The third side is visibly straighter and more level than the second, which in turn looks positively professional compared to the first. Oh well. They'll do the job. That is, if I ever get it all finished - which at this rate is a bit of a concern.

There were a couple of interesting things that came out of today's work. First, I now not only know what a cold chisel is but have purchased and used one so that a brick can butt up smoothly against the concrete apron around the house. And second, I'm now aware that when a brick company describes bricks as being 400mm wide and 200mm high, that includes 10mm of non-brick (ie, empty air) in each dimension to allow for the concrete which typically is found in between each brick. Of course my brickwork includes no concrete and so the result is not quite what I had expected it to be.

Am pleased to note that the advertised width of the brick includes no non-brick components.

What's the vision?

Something I've been asking myself for some time now is why 2050vision.blogspot.com is so devoid of any clear vision about what a sustainable civilisation might (or should) look like in 43 years time. I don't even have a "vision" label defined yet to apply to a new post. Either I need to come up with something or I need to change the name of the blog.

I guess to date I've been trying to understand some of the issues the world is facing, exploring some of the possible responses and finding out from my own experience what are some of the barriers to change. I've focused largely on energy-related concerns and discovered how easy it is to reduce electricity consumption but how hard it is to break the chains of oil dependence for transport. I've become horrified by our society's concept of "waste" and "waste management". And, at the age of thirty, have just started to learn the language of soil, plants and living systems which was second nature to countless generations of humanity before me.

It's probably a good time to start bringing ideas from all those areas together and forming some kind of picture of a desirable future. I say only "desirable" because it would be foolish to declare something "likely" or even "possible" based on my limited study and the uncertainties surrounding those big issues of peak oil and climate change. But I'm going to try and work on some thoughts of my own as well as link to other people's ideas for the future.

For the next post, though, I will have to revisit some ideas which I'm told I did a bloody poor job of communicating in my first attempt: the subject of human motivation, or why we do anything at all.

Stats update (with comments)

The latest figures are for 9 days from 21st to 30th July:
- General electricity 5.36kWh per day (average 6.65 this quarter vs 7.98 last quarter)
- Electricity for water heating 7.01kWh per day (average 7.33 this quarter vs 5.60 last quarter)
- Water consumption 301 litres per day (average 333 this quarter)

We were away on Saturday night so the figures are slightly skewed in our favour but they're still not bad. Our water use is holding steady at about 330L per day even without the tanks installed yet. The government's high-profile target is 140L per person per day. Our kids are young but even if you considered the three of them as equivalent to one person we'd still be 90L under the target.

I'm baffled as to how other households can use as much water as they do. We use our dishwasher, we wash our clothes (lots of them with the three kids), we water our fledgling vege plants, we are pretty lax about shower times. Our conservation efforts could largely be summed up like this:
- use the "water saver" options on the dishwasher and washing machine
- don't be obviously wasteful with washing hands or brushing teeth
- keep the water pressure low in the shower
- and the big one... don't flush the toilet for every little wee

Julie pointed out just recently that using less electricity can also contribute to reduced water consumption. (Though that's not true of wind, wave or solar photovoltaic systems, it is the case for the vast majority of electricity generated in Australia.) So I'll get on to electricity now.

Obviously we use more energy heating water in winter than we do in summer. That's why there's an obvious seasonal variation in the graphs I've previously shared. So although this quarter's figure of 7.33 is up against last quarter, it's significantly better than the 9.0 we consumed during the same quarter last year. And I reckon this winter is actually colder!

The water/electricity relationship goes both ways here: by using less hot water in the shower we're reducing our energy demand.

One last comment on these figures. With our continuing downwards trend in general electrical consumption, this is the first quarter in nearly two years of data where we're using less energy for lights, cooking, computers etc than we are for heating water.

The cat's away...

... and the mice are playing in the compost again.

The compost bin comeback

Found another surprise in the compost bin today... a pleasant one this time.

As happy as I am about my first thousand worms, they aren't eating a lot of kitchen scraps yet. I'm guessing that's partly because they're so (relatively) few in number and partly because they still have lots of other food to consume in their initial bedding material. Most of what I provided for them on Saturday is still there and our little bucket in the kitchen was full. Well the scraps had to go somewhere and it sure wasn't going to be landfill, so out to the compost bin I went.

Sometime in the past couple of weeks I had decided the compost pile was too dry. I started experimenting with a new formula: one bucket of kitchen scraps spread out, a layer of dried grass clippings and finally one kitchen bucket's worth of water on top. After making this contribution again this afternoon it seemed like I should aerate the pile a bit and make sure it's not going nasty in the middle.

Well! Far from being nasty, what I found in the middle of the pile looked suspiciously like the stuff I'd seen on the glossy front cover photograph of my neighbour's composting book. It was dark, moist, spongy, inhabited by tiny bugs and earthworms, and it gave off a noticeable amount of heat. No visible rodents, either.

Perhaps I should have left it alone, but I used my garden fork to try and mix things up. There's plenty of material still to be decomposed and I'm hoping that introducing some air and those additional nutrients into the core will help it rather than hinder. This coming weekend I'll turn the whole pile again and see what I find.

If that kind of result is repeatable, and the mice stay away, I may keep the bin going in addition to the worm farm.

Worms: not dead yet

Peeked under the layer of wet newspaper which is on top of the food in the upper tray and found a few adventurous worms munching away. They slithered away to the tray below in a hurry.

Lifting off the top tray to the full bedding tray below, the kids were delighted to see scores of worms all over the top. Startled to be exposed all of a sudden they practically sprinted for cover down their holes. Didn't know they could move quite that quick.

Seems to be pretty straightforward so far, except that I've got a whole lot of scraps in the kitchen - far more than these worms seem ready to eat. Will have to use the compost bin as well for a while I think.

I have worms

Funny thing: you buy a "Can-O-Worms" but the worms are sold separately. But anyway, as of yesterday I have one of the first and around a thousand of the second, and a hundred and ten fewer dollars in my bank account. That's eleven cents per worm.

The worm farm itself deserves a bit of a plug, I think. For starters it appears to be a really good design. It has legs, a fluid collection base with tap, three "working trays" and a lid. The theory is that when the top tray gets full the bottom tray will contain heaps of fertiliser and very few worms so you just empty the bottom one and then place it at the top. As you add food to the top the worms come up through the holes and begin creating more fertiliser there. Round and round it goes.

It is made of plastic, but it's made of 100% post-consumer recycled plastic. As with my decision to use concrete blocks as part of the base for my water tanks, I think it's an appropriate use of materials. It's hard to imagine something like this being made from anything other than plastic or metal - of which plastic seems like the less wasteful choice. We do have an enormous amount of existing plastic which would otherwise be headed for a landfill. And unlike many other plastic products this one's designed to perform a valuable function over a long period of time.

Moreover, it's made in Australia and there's very little packaging to be "disposed of" after the purchase. You can check out the model I bought here.

Worms are sold separately, as I mentioned. I grabbed a box of a thousand from the shelf right next to the Can-O-Worms. Good thing, too - it turns out that a thousand worms is the minimum recommended number for starting a worm farm. The worms aren't loose in the box, they're buried in a lump of moist, compost-y black stuff which you just place as-is into the worm farm. Once they've eaten through all the tasty parts of that they will, I understand, squirm up through the holes into the next tray in search of the food scraps I've laid out for them.

For the time being they seem content to stay in the bottom tray in their black stuff. Just to prove I'm not making all this up, here's a pic I snapped late this afternoon.

Bricks it is, then.

Besser blocks model 15.01, to be precise. 40cm long, 15cm wide, 20cm high. Six of them to a side on three sides, the fourth side being the edge of the concrete apron around the house. 18 per tank site, 36 blocks in all, delivered for $156.20. About the same price as the equivalent quantity of pine sleepers soaked in copper, chrome and arsenic.

They were delivered late yesterday and today I spent a few hours sculpting the trench in which the first six of them now sit. I say "sculpting" because below the turf in my back yard is a whole lot of very dense clay. Using my 150mm spade and a mini-mattock I carved out a surprisingly neat rectangular slot. The blocks went in with a little clay soil packed into the slight gaps along the long sides. The goal is to build a nice rigid wall that will hold a base of crusher dust firmly in place beneath a five tonne water tank. The clay is so solid I'll probably not use any additional concrete to bed the blocks as I had planned.



If it takes a few hours to get one side done, I have an awful lot of hard work remaining. It would have been so much easier just to pour two slabs of concrete - and probably cheaper given that I have a builder, an underground cable layer and a concreter as neighbours. Why the heck am I spending my weekends scratching about in the clay?

The primary environmental concern with concrete is the energy used in manufacturing cement. I read somewhere yesterday that 8% of the world's anthropogenic (man-made) greenhouse gas emissions result directly from the production and use of cement. Scary, if it it's true. But concrete is such a practical building material I can understand its appeal: even mixing by hand I could have poured two slabs in an afternoon, and they would easily outlast the tanks they'd be supporting.

In the end I compromised. I needed something heavy, strong and durable for the border; needed to prevent termite damage to my home; wasn't keen on the copper-chrome-arsenic approach. Pre-formed concrete bricks are going to do the job nicely, are non-toxic, and would probably be re-usable in the future if I ever had reason to take them out of the ground. I think it's an acceptable use of resources.

As added bonuses, I've had my kids out "working" with me, I've performed some much-needed physical exercise, and so long as it turns out OK I'll have the satisfaction of knowing I did it with my own hands.

I declare the Weekend of the Worm

Some things were just meant to be. After my mice-infested compost disaster last weekend I've been exchanging comments with Crazy Mumma (her blog here) about the idea of using worms to process kitchen scraps instead of putting them outside where they become food for vermin instead of plants.

CM gave me a link to some instructions on building your own worm farm on the cheap, and now Colin (aka No Impact Man) has just posted his own DIY worm farm tips as well! There's absolutely no excuse left now.

This weekend I'm getting worms. I dare you to join me! (That means you, CM!)

Vaguely like eBay, but free!

I love it when I have an idea and then discover it's already a reality. Not only does it mean the idea was probably a decent one, but it means I can enjoy it without having to put in the effort of making it happen.

Case in point: Freecycle.

"The Freecycle Network™ is made up of many individual groups across the globe. It's a grassroots and entirely nonprofit movement of people who are giving (& getting) stuff for free in their own towns... When you want to find a new home for something -- whether it's a chair, a fax machine, piano, or an old door -- you simply send an e-mail offering it to members of the local Freecycle group. Or, maybe you're looking to acquire something yourself. Simply respond to a member's offer, and you just might get it."

This kind of voluntary community-based recycling via the internet is something I've been idly thinking about over the past couple of weeks. There's a group with 300+ members based in Strathpine (the suburb immediately to the west of where I live) so I've just sent an email off to join up. Hopefully I'll be able to reduce some of the clutter around my place by simply finding better homes for things, and avoid creating "waste" in the process.

Spark and Splash Stats for you to use

Spur of the moment thing here. I've been using the free online spreadsheet service at Google Docs for a number of things including tracking my electrical and water consumption. I find it simple and useful and it occurred to me that maybe it's worth sharing.

So I've created a template which you can either download as an Excel file or use online like I do. There are two parts to this.

One sheet lets you record your own meter readings. It shows you your average daily consumption over the period from the first to the last reading. With a little bit of copy and paste work you also get differential figures showing how your consumption changes from reading to reading.

The other sheet is designed to keep track over longer periods based on your utility bills. Enter the date of the bill and the average daily use over the period that bill covers, and you'll get a nice graph for your trouble. I've put two example entries in which you can delete and replace with your own data. As you add new data you'll need to tell the graph to incorporate that as well. It's not hard, but ping me in the comments if you want any help with that.

You need a (free) Google account to use this, and it works best in FireFox from what I can tell. Without any further ado... you can check it out here. You'll need to either export it as a file to your computer or copy it to your own Google account to use online before you're able to change any fields.

Comments and questions would be welcome.

Renovating for water-efficiency

We bought this place and moved in almost two years ago with the intention of staying for at least twenty. Location, size and price were the key criteria. Water and energy efficiency were not even on the list - if they were we might have chosen not to buy this one.

This post is a bit of a look at the physical attributes of our house in relation to water efficiency and the improvements we're in the process of installing.

The building is basically rectangular with the top edge in this image facing just slightly east of north. It's about 22m long with no eaves at the ends, and about 9m wide including the eaves along each side. Were it a complete rectangle it'd be almost exactly 200 square meters of catchment area.

The roof has a single centre line running the length of the building and falling away to the east and west. There are five downpipes for stormwater drainage - one at each of the corners along the long sides. It doesn't make sense to try and get the water to flow just to one end of the house so two tanks are needed if all the run-off is to be captured. Since I don't have room to install tanks half way up each side of the house, the only alternative is to put them at each end and install pipes to bring the water around the corners.

Siting the tanks was made more difficult by the 1m concrete apron which runs completely around the house. Early ideas involved a new concrete slab which partly overlapped the apron but my more recent preference towards using crushed rock for the base pushed them that meter away. That in turn had an impact on designs for the stormwater pipes which need to be high enough for people to walk safely underneath. In the end they'll be positioned as per the image: it's a compromise between the practical and aesthetic challenges of running the pipes as well as the limits on available space.

The tanks we chose are 5000L each, calculated to hold approximately one month's worth of rainfall in an "average" year. They're made of plastic with a ten year guarantee and I hope to extend their life as much as possible by shading them from direct sunlight. At 2.2m diameter they're only 1.6m tall in the centre and about 1.3m at the inlet. An internal first-flush diverter (it has a dedicated drainage outlet at the side of the tank) will reduce contamination from dust and debris and the inlet filter is designed to take the weight of a child without breaking.

Up until recently (when I was writing up a comment on another blog) I had envisaged using one tank solely for gardening and the other for washing clothes and flushing the toilet. But after realising that Julie's tank, half the size of mine and with comparable inflow expectations, would make available something like 160L/day just for the garden I had to reconsider that approach. Our block is flat so I'm now looking at installing a permanent hose between ground-level outlets on each tank: this will allow the two tanks to function as a single 10kL reservoir.

In order to supply the toilet (thankfully there is just one, dual-flush) and the washing machine the plan is to install a small electric pump and two new taps - one in the toilet, one in the laundry. We'll manually attach the hoses to those taps when there's water available in the tanks, and manually switch them over to the town water supply when the tanks are running low. Doing this should avoid any problems with backflow or pressure and makes a top-up valve unnecessary. Both rooms are on the western side roughly two-thirds up.

If the tanks do end up linked together it would probably make sense to install an external pump-powered tap at the northern end near the gardens. And a tap over the laundry sink might be smart as a way to access tank water for other internal uses like filling our gravity-fed water filter or even just mopping the floor.

So after all of that, our two remaining consumers of town water will be the kitchen with its dishwasher and the bath and shower. We'll still be drawing some water from the river systems but hopefully the rain that does fall on our heads will be put to some use instead of being channelled straight out to sea.

Finally I ought to mention cost. A combination of Brisbane City Council and Queensland Government rebates worth $1,850 are applicable to this little project. The only expense so far has been the tanks themselves at about $2,600. I have another thousand dollars set aside to pay for materials, a pump, an electrician and a plumber... though I'm not entirely confident that's going to be enough.

Composting tragedy: a cautionary tale

This is going to be a difficult post to write. It has the potential to be quite disturbing to some people - you probably wouldn't let your kids read this. But it contains an important lesson for anybody interested in composting as a waste reduction strategy.

I wrote yesterday about a couple of different options for suburban composting. I described briefly the open-bottomed black plastic bin which I've been using in my first foray into managed decomposition.

Prompted into effort through the act of blogging (as I tend to be), late this afternoon I set about tending to the pile: turning it, then adding some new material and a bit of water. It's probably not the "right" way to go about things but I'm new to this.

The easiest way to turn a pile that's in a bin like mine is to lift the bin off the top, put it down next to the pile and start putting the pile back into it so that what was on the top ends up on the bottom and vise versa. So far, my compost pile is a mixed bag in terms of original material and current condition. Some of it looks really rich and vital, some is dry or woody. Not surprisingly the earth right at the bottom tends to be dark, moist and rich-looking. Since I'm transferring the pile between the same two locations each time I turn it, I have a habit of digging the shovel in a bit and moving some of that rich soil/compost into the active bin.

Today, that underlying soil was a lot more alive than I'd reckoned on. My shovel's blade went straight into a nest full of young mice.

I had read about the risk of mice or rats being attracted to compost bins. Prior to today I'd not seen any here, but while I was turning the top parts of the pile over two or three had dashed out to safety. I'd felt disappointed but somewhat resigned, and suddenly the neighbour's cat's recent tendency to camp out in this corner of my yard made a lot of sense. With those few out of the way I hadn't for a moment considered there'd be more beneath the ground.

Startled by a nest of vermin, and with some awful injuries already inflicted, my immediate reaction was to end the matter as quickly as possible. I don't know whether it was the right thing to do, and I'm not going to use this post to try and argue it either way, but I hated doing it and have felt sickened by it ever since.

The point of posting about it is to remind you of the obvious: human "wastes" are a rodent's "dinner", and wherever you find people you will also find rats and mice. Recycling our kitchen refuse in a compost bin is a brilliant idea in terms of resource utilisation and efficiency but we're not the only ones interested in those nutrients.

Maybe one of those fancy compost bins I linked to in my earlier post is not such an extravagant idea after all.

Copper, chrome and arsenic - oh my!

After going back and forth for ages I decided that the tanks would be installed on a bed of crushed rock instead of concrete. Cost was a factor, as was my disinclination to contribute even a few more square meters to the concrete jungle of a modern city. (Future archaeologists probably won't view this as the "information age" the way we romantically project. I think it's more likely to be known as the concrete or plastic age. But I digress...)

One disadvantage of the crushed rock option is that unless is it securely restrained it has a tendency to spread out or erode from the edges. The way I've seen people counter this is to construct a border out of sturdy wooden sleepers to contain the rock.

What I hadn't considered until I was exploring my options at the hardware ubermarket this arvo is that in order to prevent the wood from decaying - that is, being eaten by insects, fungus and bacteria the way all non-living wood naturally is - it has to be soaked in a toxic cocktail of copper, chrome and arsenic. That way the things which try and eat the wood will become sick and die, or if they're smart simply be repelled.

Now I'm having to re-think.

Partly I'm concerned about the potential for toxic effects on my family and I. The jury is officially out on whether there is a measurable risk to human health from the use of "treated" wood such as this, but remember I'm building a water supply which I intend to use on surrounding vegetable gardens. It just doesn't seem like a smart thing to do.

The other part of my concern arises from the "waste equals food" philosophy espoused in the book Cradle to Cradle. This book has had a huge influence on me and now it doesn't seem right to take a perfectly good piece of timber and turn it into something which has a short useful life and then becomes toxic waste.

I may end up pouring concrete after all.