Tuesday, December 08, 2009

Air cooled wok to reduce water use

Single Burner Luus Waterless WokDiagram showing heat shield around the wok ring and air gap, eliminating the need for water coolingCSIRO has developed an air cooled wok for commercial kitchens to reduce water use. Usually water is used to cool the wok. This saves about 5,000 litres of water a day, per stove. The unit has a heat shield around the burner and an air gap, reducing transfer of heat to the stove top and removing the need for water cooling. While the units are described as "waterless" they still use some water, but have features such as a timer to automatically turn off the water so the operator can't leave it running. An example is the Luus Waterless Wok range.
CSIRO Food Sciences, supported by Sydney Water, has developed an air-cooled wok burner with a user-activated spout, which not only reduces water consumption by 90% but also halves gas consumption. It is understood that Sydney Water is working to make the design commercially available. All models commercially available at present are of the conventional water-cooled type. ...

From: Switch on Gas - Revised Work Plan for 2007 to 2007/08, Report No: 2006/11, DRAFT DISCUSSION PAPER, EQUIPMENT ENERGY EFFICIENCY GAS PROGRAMME, E3 Gas Secretariat, Australian Greenhouse Office, October 2006

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Saturday, August 08, 2009

Low cost water filters for developing nations

Stuart Forsyth talked about Abundant Water at the Engineers Without Borders Canberra meeting in Canberra on Thursday. AbundantWater.org is a non-profit organisation developing a system using low cost clay pot water filters for developing nations.

The water filters are made from local clay mixed with organic material to make pots using traditional local craft techniques. When fired, the organic material burns away leaving fine pores in the clay which filer out bacteria.

The filters are claimed to have been developed by materials scientist Mr Tony Flynn of the Australian National University. There is a step-by-step guide (PDF 169k) to making the filters.

However, while Mr. Flynn may have researched how to make an effective filter, it is too much to claim to have invented the clay pot filter. Potters have known since the discovery of fired clay, that if you mix some organic material with the clay you end up with a porous pot.

The key to the Abundant Water project seems to be to transfer the technology to the local communities. The local existing potting techniques can be used and local staff employed.

While Abundant Water appears to be a worthwhile project by sincere people the way the project is promoted could be improved. In this case the presenter told a stories about family planning and corruption, which was inappropriate and insulting to people in developing nations.

One part of the talk claimed that Abundant Water used a tertiary model of technology transfer, with a partnership between the first world educator and the third world learner. However, it was still assumed that the people of the first world are needed to teach and the people in the developing nation are doing the learning.

The talk also diverted into a factually incorrect analogy to open source. The claim was made that Open Office.com started out as a European open source project. This is not correct: OpenOffice.com started as a closed source product: StarOffice. This product was purchased by Sun Microsystems and only then became an open source project.

The Abundant Water approach to development seems to be for trained engineers and other professionals from developed nations to go to developing nations to tell them what to do. This is a slow and expensive process. In the Internet age it would seem more efficient and effective to put the information and education online, so that those already in these nations could apply the technology. This could be done by providing a mobile phone compatible training course. Engineers and other professionals can be educated in place in developing nations in place. As an example of this, staff at the ANU and CSIRO work online with students in Indonesia.

Another problem with Abundant Water seems to be its charity business model. It is assumed that all the funding for the work will come from donations from the first world and be directed to projects in the third world. This may well perpetuate the poverty such projects are supposed to be working against. Abundant Water should look at business models which will make the project self supporting and allow the project to expand without donations.

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Thursday, August 06, 2009

Atlas of the Global Water Cycle

An Atlas of the Global Water Cycle An Atlas of the Global Water Cycle by Wee Ho Lim and Michael L. Roderick is available free online from ANU ePress. This has maps of estimated rainfall, evaporation and runoff for the 20th century and predictions for the 21st century. There are maps for the globe and more detailed ones for Australia.

The book is available for free in PDF format chapter by chapter, as one large PDF file or can be ordered as a paperback. The data files used can also be downloaded.

Unfortunately the PDF is difficult to read having been formatted for print publication, not for on-line viewing. The text is in multiple columns, making it difficult to read on screen and the maps are small and blurry. However, this is a useful publication.

An Atlas of the Global Water Cycle

Based on the IPCC AR4 Climate Models

Wee Ho Lim and Michael L. Roderick

ISBN 9781921536885 (Print version) $95.00 (GST inclusive)
ISBN 9781921536892 (Online)
Published July 2009

- Whole Book (8.7 MB)

What do climate models predict for the rainfall where you live? What about evaporation or runoff? Should your local community consider constructing new dams or do the existing water storages appear adequate? What about the availability of water for irrigation farming? Do the predictions differ between different climate models or do all the models basically predict the same changes in water availability where you live?

These are all simple questions but it is surprisingly hard for an individual, whether they be a farmer, water resources engineer, teacher or interested citizen, to answer them. As researchers active in the field we could not answer the questions either. In fact, we had never seen a compilation of the rainfall, evaporation and runoff predictions made by all the different climate models.

The Atlas contains maps and tables that document model predictions contributed by international climate modelling groups to the 2007 4th Assessment Report of the Intergovernmental Panel on Climate Change. The predictions are made available here via the wonders of the internet and ongoing cooperation by the international climate modelling community who routinely archive their results.

The maps and tables in the Atlas document rainfall, evaporation and runoff estimates for the 20th century along with predictions of the same quantities at the end of the 21st century. Whatever your interest, we hope you find the Atlas as helpful as we do.

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Friday, May 22, 2009

Waterless Video Urinal

The award for the most eye-catching product at the DesignBUILD 2009 exhibition would have to be Urimat's Waterless Video Urinal. This is a waterless urinal, much like others used to save water in public buildings but with a flat area at the top facing the user. This flat area can be used to fit a 7 inch, wide format video screen for advertising or information messages. This is one of the more imaginative forms of digital signage I have seen.

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Sunday, May 17, 2009

Modular Water Tanks

Diagram of a wall built from of Modtank modular water tanksModTank is a system of plastic water tanks which stack like children's building blocks. The tanks are 600 x 550 x 300mm, hold 77 litres each and cost about $60 each. This makes them about the same price per litre as other plastic water tanks. The tanks can be stacked as a wall, as a cube, or around corners. They can be stacked four (2050mm) high. One catch is that there are four connections for each tank, to allow water to flow to the adjacent tanks, making for a lot of places for potential leaks and the installation instructions look a little complex.

Modtank modular water tanks in a uteOne advantage is that the couplings allow the tank to be flexible. One applicaiton is for carrying water in a ute, truck or trailer.

These tanks could have industrial and military application, where water is needed in remote locations. The tanks could form part of the protective wall of a military building. The tanks could be used in a building to form a thermal mass to keep it warm in winter and cool in summer. This would also provide some protection in a military application.

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Monday, August 25, 2008

Point-of-Use Electric Water Heaters

Delving into the issue of how to avoid wasting cold water while waiting for the hot to arrive, I found there are small "Point of use" indoor electric water heaters. There are
tankless models and ones with tanks. The tank less models are rated by their flow (in litres or gallons per minute) and the ones with tanks by the tank capacity.

The tank less ("instant") units have the advantage that they can heat water continuously, but require more power to do this than is available from a normal power point (they have to be specially wired). The units with tanks can be plugged into a normal power point, but only supply a limited about of water.

The units are designed to be used on their own, or placed at the end of a long line from a larger hot water system. For this purpose the smallest units (2 gallons, or about 8 Litres) would seem suitable. In my case the point of use hot water system would supply the first 4 Litres of hot water, at which point hot water would arrive from the main system and the unit's thermostat would cut out. The unit would not need to heat the remaining water arriving and would have its supply of hot water replenished. But it would use power keeping the 8 Litres of water hot, when the tap was not used for extended periods.

US Model point of use water heaters:
  1. Point of use water heaters
  2. water heater point of use tankless
  3. water heater point of use with tank

ps: Some bloggers have suggested turning the thermostat down or hot water system off when not needed to save power. It should be noted that authorities in Australia require a minimum temperature of 60°C to inhibit the growth of legionella bacteria. Also some of the POU heaters are designed for use with one tap and cannot be plumbed to several, nor connected to a shower.

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Sunday, August 24, 2008

Electric Trace Heating For Domestic Hot Water Pipes?

Hot Water Temperature Maintenance Self-Regulating Heating CableMy apartment shares a central gas boosted solar hot water system with the rest of the block at "City Edge" in Canberra's Inner North. This results in low hot water bills and minimal green house gas production, but wastes water. Perhaps I should install Electric Trace Heating, which would increase the energy use, but lower the water waste.

Water is heated by a large solar collector on the roof and when the sun is not shining by a large gas burner in the basement. The water is continuously pumped throughout the building, so it is hot when it gets to my apartment. But then there are several metres of pipe between where it arrives at the apartment and the taps. About 4 Litres of cold water has to come out of the internal plumbing before the hot water reaches the shower.

My efficient Australian made "Ecoshower" shower head uses only about 7.5 litres a minute, or 22.5 Litres for a three minute shower. So the cold water wasted is increasing the shower water consumption by 18%. In the kitchen this is a bigger problem with many litres of cold water going down the drain before the hot arrives.

By the way, a
s a subtle reminder to only have short showers, I have set the bathroom "tastic" heater to turn off after three minutes. So you see the light dim slightly to remind you you have been in too long. This is done using a motion sensor/timer, so the heater comes back on automatically when you step out of the shower.

As well as wasting water, the cold water is increasing my hot water bill. There is a meter on the hot water pipe and I am charged for a share of the building gas bill, according to how much water is used. So I am charged gas use for the cold water coming out of the pipe, before the hot water arrives. In my case this might be as much as 50% of the cost.

Electric Trace Heating (also known as Heat Tape and Pipe Heating Cable ) uses a fat flat electrical cable with a resistive element built in, which gets warm when current is put through it. A length of the cable is taped along the hot water pipe, between the normal hot water supply and the tap. Insulation is then wrapped around the pipe, and the cable plugged into an ordinary power point. A few watts of electricity is used to warm the pipe (about 14 Watts per metre). The cable is manufactured from a material which automatically regulates the temperature, so having its own built in thermostat and is designed for a set temperature.

I saw Thermon’s Warmtrace System on display at the 2006 Canberra Spring Home and Leisure Show , but haven't seen it mentioned elsewhere. Presumably the element only draws maximum power when the water in the pipe is cold, so it would not add much to the heating bill (or greenhouse effect).

Heat Tape seems to be common in the USA for preventing pipes from freezing. Amazon.com has Heat Tape for about $4 per meter. But note that the anti-freezing tape may heat to a lower temperature than that needed for domestic hot water. Also the USA uses a lower voltage than Australia and US tape can't be used in Australia. Also many of the tapes do not appear to be self regulating: they have a thermostat installed somewhere along the pipe, which would be less able to regulate the temperature.

There are also some practical problems with the heat tape: you have to run it along the length of the pipes and so need to be able to get to them where they run through the walls. The tape needs to be carefully installed, following detailed procedures. Also there has to be a power point handy somewhere to plug the tape into.

So the questions I have are:
  1. Is heat tape used for domestic hot water in Australia?
  2. Is the saving in water worth the increase in energy use?
  3. How much energy does the heat tape use in actual conditions?
Another option would be to install small electric water heaters near the taps. These would heat the first few litres of water.

Of course this all assumes that there is a reasonable charging system is used for the cost of the gas used for hot water. At present most of the bill I get is not for the cost of the gas used, but a fixed minimum charge. As a result there is little financial incentive to reduce energy use. It would be more cost effective to disconnect the solar and gas system and replace it with a conventional electric heater. This would be bad for the environment, but cheaper to run, as there would be no separate gas bill with its high minimum charge.

One interesting possibility would be to replace the complex pumping system and gas booster of the central solar system with the heat tape. At present water has to be continuously circulated with a pump to have hot water available. The pumps do not use much electricity, but when the sun is not shining, it is gas heated water which is being circulated. If the tape was installed on the pipes, that would remove the need for the pumps. It may also remove the need for the gas booster. Electricity is more expensive and less greenhouse friendly than gas, but this is only needed as a supplement and might make solar systems more practical.

See also:

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Thursday, July 10, 2008

Solving the global sanitation crisis

The Last Taboo: Opening the Door on the Global Sanitation Crisis by Maggie Black and Ben Fawcett  (Book Cover)"The Last Taboo" (Maggie Black and Ben Fawcett, Earthscan, 2008) tackles the little mentioned, but important problem of sanitation in the developing world. The authors point out that this problem was largely solved in western countries more than a hundred years ago with the flushing toilet, but that system is not economically or environmentally feasable for most of the world. They also point out that most attention and resources about water-related diseases go to providing clean water, when it is the failure to correctly dispose of human excrement which causes the problem.

The authors detail and critique several designs of low cost and water saving toilets (pour flush pit toilet, double vault composting toilet,VIP Toilet, sanplat) and the programs developed to supply them. They are critical of projects which do not plan for maintenance of the systems and do not involve local people. They also advocate looking first to low cost solutions, based on behavior, not technology. As an example in rural areas they advocate an approach where people are educated to use a designated piece of land away from housing and simply bury their waste (in a "cat scratch").

I have one quibble with the book. At one point they discuss the benefits of separating urine from feces. They point out that urine contains much of the nutrients of the waste, while being almost free of pathogens and suggest its separate collection for use on crops. But they then point out that toilets designed to collect the urine separately are difficult to make, especially for females.

The Scandals of Clochemerle by Gabriel Chevallier (Book Cover)However, they don't suggest an obvious and simple solution: provide a urinal for males. Urinals are simple to make and maintain.They need not be complex waterless urinals which have been designed to look like a flush unit (some also require to be refilled with Sealing Liquid).

A urinal cab be as simple as a designated patch of ground, or a funnel and pipe. Males in many cultures are happy to use them, as satirized in the novel "Clochemerle". A urinal would divert about half the urine at minimal cost. In a communal facility it could also greatly increase capacity.

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Thursday, January 17, 2008

How to fix a dishwasher using the Web

dishwasherAfter several years of having to manually advance the dishwasher through the cycle, I thought it was time to fix it. The web turned out to be a useful resource to do this. Apart from the inconvenience, I was using more water having to use more water to rewash partly washed dishes. To find out how to fix just about anything, try typing into a search engine "how to fix a ...".

One danger is that how to instructions can get you to attempt repairs you should not really try. In this case the Dishwasher Troubleshooting Tool proved most useful. The symptom was " Dishwasher cycle does not complete" and the suggested checks were: Unfortunately these are generic instructions not specific to a particular model. But after testing the timer motor and heating element, I tried the thermostat. There turned out to be a small press button on the thermostat. I pressed this and it stayed pressed. The dishwasher then worked. This seems to be an overload cutout, but was not mentioned in any of the instructions.

Fisher Paykel Double DishDrawer dishwasherOf course, a replacement smaller countertop dishwasher, or a drawer unit would use less water and be more convenient for small loads. The Fisher Paykel Dual DishDrawer units look very attractive, with the ability to fill one drawer, while the other is washing. But as my unit is now working there is no point in replacing it.

ps: Another part of the dishwasher which may need replacing is the cutlery basket. There are some replacements ones sold, but these can be flimsy plastic. A better alternative might be a bit of the stainless steel security fly screen mesh used in windows. Offcuts are available from suppliers, such as Alucom in Canberra. Aluminum mesh is not suitable, as the harsh dishwasher detergent tends to dissolve it.

See also:

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Sunday, December 16, 2007

Pressure Washer to Save Water?

Pressure WasherVisiting a friend I tried out their new pressure washer to clean the balcony and tho cars. These units use an electric pump to spray high pressure water through a nozzle. We found the unit would work okay from a rainwater tank, without the need for a separate booster pump on the tank. This might be useful for people who want to save the cost of a pump on the rainwater tank, using the water by gravity for the garden, but occasionally want to use the water for washing a car, house or path.

The pressure pump uses about one third as much water as a mains pressure garden hose (5 versus 15 litres per minute) for much the same washing effect. But you need to be careful not to point the high pressure spray at anything delicate, especially people and pets. Also it will still use a lot more water than a bucket and brush. You still need a brush or a broom for some cleaning (such as getting down wasp nests from buildings).

See also:


Sunday, November 04, 2007

The most complicated tap in Canberra

Sign on library tapThe public library I complained about in February seems to have fixed their water wasting urinal by installing an infrared movement detector which activates when someone is present. But another problem in the same toilet is the bizarrely complex hand basin tap. The sign on the tap reads: "To turn on tap pull lever out. Turn Level to the Left for hot. Turn lever to the right for cold.". The problem is that an elegant but difficult to use tap has been installed which is not suitable for a public facility. The library should replace the tap with one which is easy to use and remove the sign.

The Design of Everyday Things   The Design of Everyday Things By Donald A. NormanDonald Norman discussed the design of tap handles in his book "The Design of Everyday Things". The technical details may be complex, but the idea is simple: the tap handle should work the way the user of it expects.

Justyna Chrome Proteus Wall FaucetIn this case the tap handle looks like a round knob with a bar sticking out, much like the "Justyna" model depicted here. The usual way this would be expected to work is you turn it to get more water. Even when you read the instruction to "pull lever out", it is not clear what the lever is ( there is a thin round bar, which does not look like a lever).

It may be difficult for the library to retrofit two conventional taps in place of the mixer (they would have to drill another hole through the stone facing). A simpler option would be to install a conventional knob which you turn for cold water only. If the cold supply is at too low a temperature to be comfortable, then hot water could be automatically mixed or a small water heater installed.

ps: Better than the infrared flush urinal would be a waterless urinal, or a single flush per day system, as used in the six star rated Australian Ethical Investments building.

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Tuesday, July 10, 2007

Saving water is counter intuitive

Toilet Sink LidThere are plenty of books, TV programs, and government information campaigns on how to save water. But the message does not seem to be effective. Recently I visited family friends who wanted to help the environment by saving water, so they installed a rainwater tank but found it did not help.

They had just finished showing me their very expensive tank, with electric pump when they opened the mail to find a letter from the water board. Their water consumption was above average and the authorities were threating to take action unless consumption was reduced. They said: "but we got a water tank, it cost thousands of dollars, why didn't it work?".

When I checked the tank I found it the pump had not yet been connected to the power and so could not be used for watering the garden. In any case this would only save a minimal amount of water, as most of the water was being used in the house and the tank was not connected to that. Even if the tank was connected, it could not save much water as there was a drought.

When I asked what water saving had been done, they explained that they had, as per regulations, been using a bucket to water the garden. Unfortunately they had been doing this very diligently and probably using as much water as if a hose had been used (using a bucket does not actually save water, just makes it harder to use a lot of water).

In the house they had asked the children to take shorter showers but that had little effect. When I asked if they had installed dual flush toilets they explained the rebate for this was much less than for a water tank and they were waiting to renovate. Similarly they had not installed low flow shower heads or tap aerators. The fact that these measures would be much simpler and cheaper (even without a rebate) than the water thank and save much more water, had not occurred to them.

These were not stupid people (both have PHDs) and this indicates the current water saving strategies by government are seriously flawed. The policies send two different messages: the water pricing policy sends the message that water is cheap (and therefore must be plentiful), but the water conservation policy says it is in short supply. The rebates on water saving devices favor some devices, such as water tanks, over others. This mixed message makes it hard for people to make good choices.

It would be more effective if the water saving target per household was aligned to the water pricing: if the household uses too much water it gets charged more. There would then be a clear incentive to save water and the household could sensibly budget for water saving devices.

The measures I suggested they take were, in order of ease, cost and effectiveness:
  1. Low Flow ShowerLow Flow Shower: I have the Australian made "Ecoshower Sapphire" shower head (from Queensland company E-Co Shower) in my bathroom. This only uses 6.8 litres a minute, but creates tiny bubbles of water so it looks and feels like more. The Oxygenics range of showerheads are claimed to work on a similar principle. CSIRO claim to have invented a better one, but it may be years before they are available. There are many other low flow showers.
  2. Water Saving AeratorWater Saving Aerator: E-Co Shower also sell a "Sink Hand Shower" which fits in place of a tap aerator. This is the same mechanism as used for the shower. This is expensive for an aerator (there are cheaper options), but might be worthwhile.
  3. Washing MachineWater Efficient Washing Machine: Front load washing machines tend to use less water than top loaders. For those who want a top loader, Fisher & Paykel make the AquaSmart, which claims to provide the water saving of a front loader in a top load model.
  4. Dual Flush Toilet:Dual Flush Toilet: Caroma's Smartflush toilets use 4.5/3 litre on their dual flush (typical dual flush toilets use 6l for a full flush). But they can't be installed in all situations. Otherwise you could just buy a standard dual flush tank which can be fitted in a few minutes (two pipes to connect).

    If you really want something to show you are saving the planet, you could get
    Caroma's Integrated Hand Basin. This has a handbasin built into the top of water cistern. When you push the button water flows through the spout allowing you to wash your hands. That water is then collected in the tank to flush the toilet. Caroma claim this meets plumbing standards. There is a similar "toilet sink lid" offered on Amazon, which is intended to be retrofitted to a cistern, but I do not know if it meets Australian regulations.
Another tip, which I was not game to tell them was to stop watering the garden. Those plants which were not capable of surviving could be replaced with others which would. They could also stop using a garbage grinder, which consumes water and wastes organic matter, and instead compost the scraps in the garden. This would improve the soil and allow it to retain more moisture.

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Sunday, June 24, 2007

Carbon Cops

Carbon Cops LogoABC TV's new environment show "Carbon Cops" starts Tuesday June 26 at 8.00pm. It has a very similar format to SBS TV's "Ecohouse Challenge". Experts visit a typical family and conduct an energy and water use audit, then the family is set the task of reducing use.

These programs are useful for educating the community about enviornmental issues in an entertaining way. But they may give the wrong message: SBS's show first cut off water and power to the households and documented the suffering of the families. At the end they rewarded the families with low water and energy appliances to restore their lifestyle. But many people would not have lasted to the end of the show. The message many people would have got is that energy and water saving is not feasible, rather than seeing that only a small investment and a few changes were needed.

ps: To see how computers and the internet can save the planet, join the new ICT Environmental Sustainability Group.

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Monday, April 16, 2007

Economics of Rainwater Tanks in Australia

Oxygenics Water-Saving ShowerheadA report on "The economics of rainwater tanks and alternative water supply options" suggests tanks could delay the need for water desalination plants, particular when the energy costs of such plants are considered. The report was prepared by economics consultants, Marsden Jacob Associates for the Australian Conservation Foundation, Environment Victoria and the Nature Conservation Council of NSW.

One shock in store for house holders is that water from a rainwater tank costs at least $2.15 per kilolitre and possibly much more, taking into account the cost of the tank. But then the bigger shock will be that water from desalination plants costs around this as well. State politicians seem reluctant to tell voters that water is going to have to at least double in cost in the next few years.

The only flaw I can find from a quick skim of the report is that demand management measures are not given more weight. The report points out that saving water is cheaper than water tanks or desalination plants, but does not seem to go on to quantify this. This confusion seems to extend to the general community, where people are considering thousands of dollars on water tanks, before they have spent hundreds on a dual flush toilet and low flow shower.

The full text of the report is available online, but it is a large (1Mbyte) PDF document. The issue is an important one and the authors should take the trouble to produce an easier to access version of the document. They could at provide the Executive Summary in a separate PDF file, which would take a few mouse clicks to produce, or better still as a web page, which would take a few minutes work.

Here is the Table of Contents of the report:
Executive Summary 4
1. Introduction 8
2. The relative cost of rainwater tanks 9
2.1. Rainwater Tank yields 9
2.2. Cost of rainwater tanks 11
2.2.1. .Rainwater tank costs 12
2.3. Cost of alternative water sources 12
2.3.1. .Case Studies: Sydney and SEQ 14
2.3.2. .Summary 15
2.4. Other potential impacts 16
2.4.1. .Water mains 16
2.4.2. .Stormwater systems 17
3. Adding environmental costs to levelised costs 19
3.1. The cost of carbon 20
4. Deferring alternative water sources with rainwater tanks 22
5. Cost of rolling out rainwater tanks 31
6. References 33
Some excerpts from the Executive Summary:
Marsden Jacob Associates (MJA) has been commissioned by the Nature Conservation Council of NSW, Environment Victoria and the Australian Conservation Foundation to conduct research into the impact of a targeted rainwater tank roll-out in Sydney, Melbourne and South East Queensland (SEQ).

For individual property owners, the cost effectiveness of rainwater tanks is typically determined by comparing the cost of installing and operating a rainwater tank against savings from household water bills plus the impact of garden water restrictions. However, considering the benefits only from the perspective of the property owner does not recognise the broader cost savings to the community such as deferred water infrastructure, savings to stormwater infrastructure, and environmental externalities such as the cost of greenhouse gas emissions.

The present study compares the yield and levelised cost (i.e. the cost per kilolitre supplied) of various long term water source options in Sydney, Melbourne and SEQ against the potential yield and cost of rainwater tanks. Previous research by MJA for the National Water Commission indicates that both the yield and the cost of tanks varies significantly based on individual household variables - in particular the size of the roof collection area. This study compares the cost of rainwater tanks with other water infrastructure such as dams and desalination plants. Levelised cost (the cost per kilolitre of water supplied) is a factor of water yield from a particular technology and the cost of supplying it. Yield from a 5 kilolitre tank for a small (50m2 ) and large (200m2) roof collection area was shown to vary from around 47 kL to 105 kL in Sydney, 24 kL to 86 kL in Melbourne and 41 kL to 99 kL per year in Brisbane (airport sites only).


In addition, the key findings of this report include:

rainwater tanks will be widely installed in new housing developments due to regulations imposed by both the Queensland and NSW governments. While new dwellings can be designed to be 'rainwater tank-friendly', a growing proportion of future dwellings are expected to be in high density unit blocks which are mostly unsuitable for rainwater tanks (although the majority of new dwellings since 2001 have been detached 'rainwater tank-friendly' dwellings). However there is also significant potential for take-up of rainwater tanks in existing dwellings. The majority of existing dwellings, particularly in SEQ, are detached houses, making them suitable in theory for rainwater tanks. Many may not accommodate a tank due to limited land area or plumbing constraints. There are currently around 1.1 million houses potentially suitable for rainwater tanks (i.e. detached and semi-detached houses)1 in Sydney and 0.9 million in SEQ.


Water sources could potentially be deferred by more than the indicated time if demand management initiatives reduce future demand, or may be deferred by less than the time indicated due to other factors such as the need for emergency water supplies or specific regional growth requirements. The deferral of water sources will be cost effective only to the extent that rainwater tanks are less expensive than alternative water sources ..

Similar results would be expected for Melbourne depending on the growth in the number of dwellings and the impact of demand management initiatives. Additional demand management initiatives could potentially defer the need for water infrastructure even further. ...

research indicates that rainwater tanks are more than five times as energy efficient as desalination plants per kilolitre of water produced (rainwater tanks requiring around 1 MWh/ML compared with a typical desalination plant requirement of 5 MWh/ML); ...

See also my:

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Sunday, April 15, 2007

Self Watering Pots

Self Watering PlanterMy smart apartment balcony is a harsh environment for plants. The Canberra sun can dry out plants quickly. One way around this is to use a self watering pot. These have a water reservoir in the bottom.

The pots are usually made of plastic and do not look as good as more natural materials. So I fitted the self watering pots into glazed ceramic ones. The air gap between the ceramic and plastic pots provides some insulation, reducing the heat in summer.

Plastic self watering pot being fitted with a plastic sleeveOne plastic pot did not fit, so I cut the top off with a small saw. The pot then fitted, but did not quite come up to the top of the ceramic pot and there was a gap between the two. So cut a piece out of the off-cut top of the plastic pot to make an adjustable sleeve. This I inserted into the top of the pot to cover the gap to the ceramic one. The springy plastic held it firmly in place until the soil was added to cover it.

Keep in mind that some plants do not benefit from the constant water supplied from the pot and may need to be left dry some times. Also the water could harbor mosquitoes other pests in some areas.

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Thursday, April 12, 2007

Folding Bicycle in Echohouse

The first episode of SBS's Eco House Challenge TV show went reasonably well. The idea is that two families try to get along with limited water, energy, rubbish removal and no private cars.

In the first episode we are introduced to the two families and watch their worry as the water and electricity are disconnected from their homes. The families are given a kit of portable alternative energy and water gadgets to help them get along. In later episodes the houses will be provided with low energy and water saving devices to make them more livable.

One of the gadgets provided was a small folding bicycle. I am a folding bicycle enthusiast. These can be used on their own for short trips, or combined with a car or public transport. You can put the bicycle in the boot of a small car, or take it on a bus, train or aircraft. This makes it much easier to minimize car use.

The EchoHouse challenge is useful is showing how dependent we are on energy and supplied water. But those who watch the first episode my get the idea that energy saving results in a drastic drop in the comfort of life. In fact with the right investment a home can be very livable while using minim of energy and water. Hopefully that message will come through in later episodes.

See also my:

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Saturday, March 31, 2007

Ecohouse Challenge Update

SBS TV have released more details of their "Ecohouse Challenge". It starts Wednesdays, 7.30pm from April 11. Two families try to along with limited water, energy, rubbish removal and no private cars. There is also a viewer competition.

The idea of the show might sound trivial to committed environmentalists, but is a good way to get people interested. The prizes look suitably green: Electrolux appliances, Air-Cell insulation, Solectair Heat Transfer System, Solahart hot water systems, SunPower photoelectric solar panels and a Toyota Prius hybrid car.

Solectair Solar Ducted Heating System WITH ducted evaporative airconditioning systemThe Solectair Heat Transfer System is an interesting new Australian invention. Instead of a heater, ducts in a house are connected to fans which draw hot air from the roof cavity to warm the house in winter. This is similar in concept to the system in the new green office building in Canberra, but on a domestic scale.

See also my:

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Monday, March 26, 2007

Ecohouse Challenge

Oxygenics Water-Saving ShowerheadSBS TV are advertising an "Ecohouse Challenge", to begin in April. The idea is to see how two average families got along with limited water, energy, rubbish removal and no private cars. According to The Age, as well as Eco house Challenge there will be a series from ABC TV called "Carbon Cops".

On Friday Senator Bob Brown opened a green office building in Canberra. Perhaps there will be a spin-off of the TV shows, with business executives having to shrink their ecological footprint in the office.

Canberra also had a "Eco-living Exhibition" of environmentally sensitive display homes. These make living green a lot easier, with solar panels and water recycling built in. Even CSIRO have got in on the act with a bubble shower to save water.

In 2004, there was a UK based "International student ecohouse challenge. Architectural Press and Elsevier Publishers, with Teachers in Architecture and Circle 33 Housing Group:
Architecture students with green design ideas should get ready for the 2004 Design Competition For An Ecohouse, sponsored by Architectural Press and Elsevier Publishers, with Teachers in Architecture and Circle 33 Housing Group.

The challenge is to design an environmentally friendly house, that's comfortable in both summer and winter, and able to function without relying heavily on fossil fuels. ...

From: "International student ecohouse challenge" in Upfront with Building!, 2004.
The results of the 2003 Ecohouse Design Competition are also available, as is the companion book "Ecohouse 2" by Sue Roaf (her "Ecohouse 3" is due out 30 July).

The SBS series is directed by Russell Vines and the ABC series is produced Tarni James. But as useful as the TV shows will be in educating people in an entertaining way, try living in a house in rural India, to see how the lack of clean water and reliable power can effect your life.

See also my:

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Friday, March 16, 2007

Report on the ACS Canberra Branch Conference 2007

The ACS Canberra Branch Conference 2007 was on Thursday 15 March. This was an exceptional conference. We had the announcement of a Ministerial policy, an insight to secure Customs systems, police on e-crime and details of how a high tech executive runs a family online. Some highlights:


Phil Argy said that simple word was needed to describe what ICT people do. His suggestion was "technologist" with a selectable adjectives in front of it, such as "software".

He then went on to talk about regulation of the ICT profession. He used the example of programing a robot for safety and argued this is an application where professionalism is clearly needed. He suggested that Asimov's "Three Laws of Robotics" influenced the movie "2001 a Space Odyssey" with the fictional HAL 9000 computer. They are explicitly quoted in the later film "I Robot", which is loosely based on Asimov's stories. Roger Clarke wrote a two part paper on the application of the laws to computing.

Phil when on to use an analogy with the push for environmental sensitivity in business, arguing employing a professional will show your business is supporting ethical business. Environmental issues in ICT turned out to be a theme which several speakers raised during the conference. Perhaps the ACS should be supporting environmental concerns in the ICT business. Computers and telecommunications (and the air conditioning for them) use a significant amount of energy in business. Routers, broadband modems, and computer in the home are also consuming more electricity. We might even earn some carbon credits from energy reduction moves. ;-)

Phil's quick definition of ethics is: "Doing the right thing even when no one looking". He used the example of including a secret code in software to stop it if the customer does not pay.

His third argument for professionalism was that ICT professionals are needed to support Australian exports. He argued that in three to five years time India and China will need to import ICT expertise and Australians were welcome. He gave the example of China getting10M new mobile phones a month (I saw this first hand on a visit to Beijing. This of course assumes that the Chinese economy does not collapse later this year, as predicted by George Friedman. ;-)


The Minister mentioned his former career as a professional surveyor and made parallels with the ICT profession He said how that profession had regulation for 100 years, with reciprocal licensing across all Australian states and NZ.

The Minister has responsibility for AGIMO. He said he has had a battle with other minsters to get their departments to use the central government web site run by AGIMO for their advertising campaigns. AGIMO mentioned this initiative at a Web Standards Group meeting some months ago. Instead of each agency using a different web address in advertising campaigns, the one standard address is used, with the campaign acronym on the end.

The Minister said the Australian Government Entry Point has 400,000 people a month visiting (which sounds low to me).

The Minister gave the FunnelBack search engine a plug (spinoff from CSIRO). He mentioned a geo-spatial test on the web site. I gave the service a quick try and it seems to work okay. It gives you a map of government services:
"We would appreciate your comments regarding the usefulness or accuracy of the map content; map features you would like to see; how easy it is to use the maps; or any other aspect of the Service Locator Trial. You can complete the Service Locator Trial Survey to provide your feedback."
The Minister said that geo-spatial data sets need to be coordinated to help with environment issues, particularly water conservation. This issue came up in Dr Markus Buchhorn's talk later in the day at the ANU. He should chat with the Minister on how to use the technology for water conservation in the Eden-Monaro. ;-)

The Minister mentioned the "single signon" for online government services. This was demonstrated at a WSG meeting some time ago. It would be useful and raises some significant technical and security issues, but far fewer than the Access Card.

The Minister mentioned the shortage of ICT people in the public service and the 75 apprentices in nine agencies. This is a good scheme, provided the apprentices do actually go on to get education and are not lured into just full time work due to the skills shortage.

At the end of his talk the Minister surprised the audience by announcing eight principles for ICT-enabled citizen engagement. There was no media release or document with the announcement, but I gleaned some details from the AGIMO web site.

There was then a question time:

Pat Barrett, Senior Fellow at the ANU and former Australian auditor-general, asked about retention of the apprentices in the public sector, and what would stop them getting jobs in companies after they were trained. The Minister replied this was being considering it, but skilled staff would benefit Australia, even if they were lost to the public sector.

I then asked: "Minister, there is a limited trial of electronic voting planned for the next election. So I set the ethics of this as an assignment for my computer students at the ANU. In the process I noticed that the Australian Electoral Commission does not appear to have made much progress setting up for the trial. Are you confident they are giving the project sufficient priority?"

The Minister replied there were to be two trials: one for Defence personnel, working via a Defence secure network and one for disabled people at 30 booths around Australia. He emphasized these are no Internet voting trails. He said it better be ready as he is the responsible minister. The AEC is aiming to be ready by 4 August, which is the earliest plausible election date.

Someone then asked about the public's confidence in the security of single signon. He replied that education was needed, as the security of the online systems was in many cases much higher than current paper based systems and much better than commercial ones.

The minister did a very credible job, showing a grasp of the topics and willingness to answer some tricky questions and answer them well.


Murray Harrison started his talk by demonstrating the security of his password protected Windows Visa Laptop and flash drive. He showed how the new customs system will allow secure access for officers around Australia.

I was a little skeptical of the demonstration and would not put that level of faith in this technology. He gave as a example using the system in a QANTAS airport lounge. I laughed at this point and he asked why, so I asked him if staff were going to be trained in keeping their information secure, given a senior military officer suffered embarrassment after leaving sensitive information in an airport lounge. He said this was being done in conjunction with system introduction. Perhaps Customs need to make a bulk purchase of lanyards to secure their electronic security tags. ;-)

Murray talked about what Customs were planning to do with ICT in the future, but did not go into detail. This contrasts with his presentation to the 2004 conference, when he discussed the "Implementing the Customs Cargo Management Reengineering System" in detail. That project now seems to be largey over the criticism it suffered.


Sheryle talked about AIIA initiatives with industry and government, including those to address the skills shortage. She mentioned the CSIRO water saving shower which "hollows out the water". She also she mentioned energy use by computers as an environmental issue and NICTA's work on water management technology.

On the topic of the skills shortage, Sheryle pointed out that there are few statistics on how many students have a second degree in IT.

On the topic of globalism,
Sheryle said that AIIA are having a Borderless World Conference:
Built on collaborative innovation, integrated production and outsourcing to specialists, the new model corporation bases its services where the expertise and skills lie, disregarding geographic borders.
  • How do these borderless enterprises reshape geopolitics, trade, leadership, workforces and education?
  • What is Australia’s place in a borderless world?
  • How does this new model affect the Australian SME?
  • How do SMEs and MNCs collaborate in this new world?
  • What is Australia’s innovation value proposition?
On a less serious note, Sheryle mentioned the high rate of use of communications in modern families, with spouses e-mailing, phoning and SMSing to remind their forgetful partners of tasks. I have arranged for Sheryle to talk at ANU next week. A team of students is programming a GPS smart phone, so perhaps they target it at family applications:
"... the built in phone would refuse to take any calls while your car was in motion. The automated voice response system would say on your behalf "Yes dear, I am on his way to pick up the kids, ETA is 2 minutes. I have parking slot 3 reserved in the school queuing system. Press 1 if you want me to get some milk on the way home, press 2 for bread ...". ;-)

From: <http://mailman.anu.edu.au/pipermail/link/2006-June/067002.html>

Nigel gave the most entertaining talk of the morning, with diagrams generated by the intelligence analysis software used by crime investigators to track online attacks. He talked about the risks of criminality online, including to children in services such as Second Life. He mentioned the use of money transfer services by terrorists. One comment was the problem with jurisdictions where Spam laws are "opt out" unlike Australia's "Opt In" laws.

About then the batter started to go in my laptop and I decided to sit back and enjoy the event.

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Wednesday, March 14, 2007

Water prices not rising enough to reward conservation

In "Australian cities have no drinking water shortage" I suggested the price of water should be doubled over five years to reward those who conserve it. Unfortunately this has proved politically unpalatable in Queensland:
THE Queensland Government has been forced to limit its wholesale water price rises to placate angry residents while also pressuring councils to allow a takeover of water infrastructure in southeast Queensland.

After the Queensland Water Commission last week called for $9billion in new water infrastructure to be fully funded out ofhigher charges, Deputy Premier Anna Bligh acknowledged yesterday that it was "too much, too soon".

... "Instead of price rises doubling within five years, going from $350 to more than $700, we will see them rise by about $175 over that five-year period," Ms Bligh said of the 50 per cent wholesale price rise. ...

From Limits on rises in water prices, Sean Parnell, The Australian, March 14, 2007

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Sunday, March 11, 2007

Bubble shower saves water

Oxygenics Water-Saving ShowerheadCSIRO announced they had developed a device for saving water by introducing bubbles into shower heads. But the technology is not new as claimed; such products have been available for years and even the wording of the media release appears to not be original.

The CSIRO described their work in a media release:
While the general concept of using an aerated showerhead to save water is not new, the technology behind the CSIRO's device is novel.

Developed by a team led by Dr Jie Wu, the aeration device is a small nozzle that fits inside a standard showerhead. The nozzle uses a small Venturi tube - a tube for which the diameter varies, creating a difference in pressure and fluid speed. Air is sucked into the Venturi tube as a result of the partial vacuum created, causing air and water to mix, forming tiny bubbles within the water stream.

From: 'Air shower' set to cut water use by 30 per cent, Media Release 06/223, CSIRO, 9 November 2006
In 2005 I bought an aerating shower head from the Australian business E-Co Shower. As CSIRO describes, the unit sucks in air, and mixes it with the water to give you a shower of bubbles.

As pointed out on PhysOrgForum, what CSIRO announced appears to be very similar to the existing E-Co shower. Even some of the wording of the the CSIRO media release appears similar to the wording of the E-Co web site from 2003:
  1. E-CO : "air and water mixing together causes bubbles"
  2. CSIRO: "air and water to mix, forming tiny bubbles"
Leaving aside the question of who invented what (and who wrote what), such devices work very well. It is difficult to tell the E-Co shower in my bathroom from a normal one. There is a slight tingling sensation, which is pleasant. As well as saving water I suspect the system uses less hot water and keeps the bathroom dryer. This is because there is not the very fine mist you get from many low flow shower heads.

Previously I tried a water saving shower head. When on the high setting this produced a narrow jet of water. I had to move around it the shower to get my whole body wet and the force of the water was almost painful. On low setting it produced a fine mist which did not seem to wet the body. Either way it was not a pleasant result.

The E-Co units seem to be particularly popular with institutions. There is a vandal resistant model which just has a small hole for the water to come out of, instead of the usual rose pattern. The unit is only about 20mm wide and 40mm long and can be securely connected to the pipe coming from the wall. As a result there is little for anyone to vandalize.

Also there is the Oxygenics shower head. I am not sure I believe the health claims for the "oxygenated" spray, but it seems to operate on the same principle as the E-Co and CSIRO units and they have a clever animation showing how it works.

Diagram of of Oxygenics showerhead

The innovative technology behind Oxygenics® is based on the Venturi Principle. As water enters the base of the showerhead, it is propelled through an accelerator fin to increase the velocity of the water flow. It is then directed through a channel where oxygen is injected into water. The result? Phenomenal coverage and a continuous range of sensations - from a soft relaxing spray to a deep, therapeutic massage to everything in between. Are you ready to be wowed? Get ready for a healthy, powerful, oxygenated spray!

From: Oxygenics, 2007

The only innovation in the CSIRO approach seems to be that it is an adapter designed to be added to a normal shower head whereas E-Co make a complete shower head. E-Co make an adapter for hand-held showers and basins. E-Co include testimonials from Canberra residents and from the Department of Defence, so it it difficult to believe that CSIRO didn't know of it.

There is also a US Patent for such a device from 1978, complete with diagram:
The passage of water from conduit 17 and through the chamber within the shower head establishes, in accordance with the Bernoulli, or venturi principle, a low pressure environment within the shower head. The low pressure environment tends to draw ambient air through outlets 20 and 21. The drawn air mixes with the water within the shower head due to the turbulent nature of the flow therein and is ultimately ejected through nozzles 31.

Because the ejected jets of water are mixture of air and water, the spray striking a bather will not have the conventional sting of sharply defined jets of water. Instead, the spray will tend to be "softer" and produce a physiological massaging effect which is very pleasant. Aside from the physiological benefits, the amount of water seemingly necessary to provide the bather with a shower to which he has become accustomed to, consumes approximately one-half of the normal water useage. Thereby, aerator 15 can effect a water savings of approximately 50 percent and yet require no change in habits by the bather nor in any manner curtail or restrict the habits developed from a lifetime of showers."

From: Shower head aerator, Richard Harmony, United States Patent 4072270, February 7, 1978
There are only two things I have found wrong with the E-Co shower: is the price and the web site used to sell it. The price is very high compared to a cheap plastic water saving shower head. But the device is very well made, from solid metal and comparable in price to fashion shower heads. E-Co let the quality of the product down with a poor web site, which makes it hard to buy.

There is also another use for a Venturi in a shower: This is the "Venturi shower", where cold mains pressure water is used to draw hot water from a low pressure tank:

Diagram of venturi shower"High pressure mains cold water is used to "suck" tank pressure hot water through the special venturi valve inside the unit, so that the resulting mixed water comes out at a much greater rate than could be achieved using an electric shower or ordinary shower mixer valve. The venturi shower uses no electrical connections, it simply plumbs straight into the heating system."

From: Venturi Shower, tubz.co.uk, 2007 http://www.tubz.co.uk/venturi_shower.php

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Sunday, February 25, 2007

Saving Water in Public Buildings

Enware  Sensor Activated Flushing UrinalWith water restrictions in place in Australian cities one of the frustrations is to go into a public building and see water being wasted. While Australian governments are requiring private citizens to save water, their own agencies are wasting it.

As an example I have sent a quick note to one Canberra library suggesting they fix their toilets. Water is leaking from the cistern down the drain in one and the urinals self flush every minute or so. The result is thousands of liters of drinking water water wasted each day.

It would just take a few minutes for a plumber to fix or replace the leaking valve. At the same time they could adjust the urinals to flush less often. A Sensor Activated Flush could be installed which only works when someone is present (at least it would stop the flushing over night when the building is deserted).
The movement of a user at the urinal is detected by the detector & control module. After a delay of about 50 seconds the urinal is flushed by the water actuator. Once the urinal is flushed all user movements are ignored for 20 seconds to reduce unnecessary water wastage. The sensor reactivates and waits for another user.

Enware tapware range- Electronic hands free (Urinal flushing devices), Enware Australia Pty Limited
Waterless Urinal TrapBetter still would be a waterless urinal. Some of these use a cartridge filled with vegetable oil to form an air tight seal to stop smells. This needs maintenance. Other units use a flexible plastic seal:
  • Urine flows down the waste.
  • The silicone diaphragm opens, allowing liquid to pass through.
  • One urine has flow through the diaphragm, it closes.
  • When the diaphragm is closed, a positive seal is created, therefor trapping odors within the pipes and not in the atmosphere.
From: How does it work?, Britex
The Australian Government is handing out $200M in Community Water Grants for such water saving devices. Unfortunately federal government agencies can't apply for the grants. But local government can:
Improving Water Efficiency in Boroondara's Public Conveniences

$38,315.50 (+ GST)

Proponent: City of Boroondara, VIC

This project will save water by replacing 15 full flush toilets with dual flush toilets and 7 water flushing urinals with waterless urinals at four public facilities. This will save an estimated 789,000L of water per year. A community education program will be undertaken as a part of this project.

From: Details of Demonstration Round projects - Local government projects, Department of the Environment and Water Resources, 2006
See also:

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Wednesday, February 21, 2007

Community and Environmental Facility at White Street

This is a comment on Development Application: D/2007/31, 31 White St, Lilyfield NSW 2040: "$500,000 Alterations and additions to existing building".

This was previously described as the "Community and Environmental Facility at White Street", in the Leichhardt Municipal Council Media Release 19 January 2004:
"Concept plans for a new and unique multi-use community facility in Annandale ... The major focus of the project is to retain as much of the existing structure as possible whilst incorporating many innovative environmental features. The plans include composting toilets, on site waste water treatment, use of solar and wind power and community veggie gardens. ... The design of the centre incorporates meeting rooms, office space and an education centre. ..."
While the media release talks about "composting toilets, on site waste water treatment, use of solar and wind power", of these only a solar hot water system appears to be included in the plans submitted for the building. Composting toilets, on site waste water treatment, and wind power appear to have been dropped.

I suggest enhancing the water conservation features which are in the design by:
  1. Increasing the size of the proposed water tank and expanding its use,
  2. Increasing the water saving rating of fixtures from AAA to AAAA.
Also I suggest the council place all future plans, online for community consultation. By not providing the detailed plans online the council is excluding a large section of the community from consultation and is increasing the cost of the planning process.


The plans include a 5,000 l rainwater tank for watering the gardens. But the tank is too small and too limited in use to make a significant contribution to water savings. I suggest the tank be increased by six times to about 30,000 litres in capacity and the water be used for flushing the toilets as well as watering the garden. A larger tank would not take up significantly more space. nor significantly increase the cost of the project. It would provide much greater water savings.

Comparison of tank sizes:

Capacity (Litres) Height (m) Diameter (m) Cost Model
5,000 2.08 1.83 $1,190.00 1913
27,000 2.67 3.85 $3,793.00 2046

Tanks and prices from Irrigation Warehouse used for comparison.


The plans call for Water Services Association Australia (WSAA) AAA (3A) rated water fixtures. I suggest this be increased to the more efficient AAAA (4A) rating.


Local authorities, such as that of the ACT, publish the full details of development applications online. The Leichhardt Municipal Council does not appear to do this and instead just publishes a list of applications and then requires the community to obtain a paper copy of the plans.

In the case of the Facility at White Street, the consultants were required by the Council to provide their plans in an electronic format. It should therefore have not been difficult to provide these online.

Not providing the plans online reduces the ability of the community be consulted. It also increases the cost to the Council (and ultimately to the community) by having to produce and distribute more paper copies. I suggest the Council implement an online process.


* Technology for Energy and Water Efficient Houses
* Energy and Water Saving Books and Products

ps: If you are wondering why someone with a Canberra address is commenting on part of Sydney, I spend part of my time there:

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