THE QUESTION: What is 'Appropriate technology'??
EWB NSW set out to answer some of these questions through an Appropriate technology Showcase Day held on the Sunday, 2/04/06. NSW showcased four such technological productions, which proved how a small idea could become a practical action in managing technical change.
The Aim: To Demonstrate there is more to engineering than what meets the eye![edit | edit source]
1. The briquette press presented by Adrian Vandenbergh[edit | edit source]
A Magnificent wooden structure, like the Trojan horse was to Helen, the Briquette Press was to lost Ewbers in Centennial Park. The Briquette press was a good indicator of where to meet, given its stature atop a small black car driving around Centennial Park Although minor structural damage was suffered during pre-show tests, the presentation and the producing of briquettes gave attendees a good understanding of how the device works. A history of the briquette press, along with where the device has been used and could be used, also gave members a deeper understanding of the word "appropriate". The main goal was clear - to reduce the time taken searching for combustible fuel, and reducing a community's impact on forests.
A great outcome from the day were suggestions from Peter and Rob, both biomed engineers, who's understanding of mechanics led to possible improvements on the design, minimising the stress placed on the wood. Stay tuned for updates on the Press MKII!
2. Solar Oven presented by Nishan Disanayake[edit | edit source]
The solar oven display enjoyed favourable conditions, with the Sunday sun in full beam. Though further improvements could have been made, such as having an oven large enough to cook a meal for the attendants, the oven was a valuable way of encouraging engineers to consider the importance of the social impact of their engineering work
3. UV DISINFECTION Presented by Tana Tan[edit | edit source]
Tana Proved how a 1.5L Coke bottle could save lives and prevent mass epidemics! Although there is little information available about solar water-disinfection, the information shared with attendees explained how a simple technology can create powerful changes for society.
The UV disinfectant bottle proved to be quite a thought provoker. Here are an array of Questions asked and answered on the day.
- Do PET bottles leach toxins in to the water when it is heated in the sun? YES it does, but according to SANDEC, the levels are no greater than that found in tap water in major cities in the developed countries.
- Has this technology been applied on a larger scale? NO, however a known group in Adelaide is trying it out.
- What happens if you don't drink the water immediately, does the bacteria count increase? YES it will. Solar watar-disinfection is disinfects water - that is, it reduces the amount of bacteria to a safe/controllable level (down to 0 in some cases). Sterilisation is the process of completely killing the bacteria. For example Sydney water is disinfected water rather than sterile water. Even bottled water has a use-by date on it.
- Has solar water-disinfection been used on a larger scale? YES, UV light has been used in disinfecting has been used in commercial applications and to treat sewerage effluent in the USA since 1916. This was introduced to replace older chemical treatment methods as they are being increasingly considered as environmentally unacceptable and also because of their potential carcinogenic effects.
- How can you distinguish PET bottles from other types of plastics used in bottles? PET bottles will burn and produce a sweet smelling scent, although we DO NOT encourage this. PET bottles will also burn with a different colour of smoke.
- Can you use glass instead of plastic? YES, ONLY if the glass blocks out UV-A. Quarts and similar glass can be used as they allow penetration of UV-A.
4. WATER FILTRATION presented by Susan Conyers[edit | edit source]
The water filter displayed, consisted simply of layers of sand and gravel. It demonstrated how successful it could be at removing turbidity, faecal coli forms, harmful heavy metals, organic matter and viruses. A cheap technology which does not require power, the filter can often be constructed using local materials, requires little technical know-how and can be implemented at a household level – making this technology appropriate for many developing communities.
Susan presented a slow sand water filter, consisting of merely a plastic bottle, sand, gravel and some filthy water to filter. Except for having to explain why the water still looked dirty (basically the water only works properly if it is subject to a continual water flow over several days, creating a layer of bacteria on top which eats up 'yucky stuff') the presentation was well received. Chris, an attendee, even pitched in with some information about an alternative method of maintaining slow sand water filters – in order not to lose the layer of good bacteria on top of the sand (which needs to happen periodically so the filter doesn't become too slow) the sand is churned up with a tractor, causing the bacteria to move further into the sand instead of being destroyed – and enabling the filter to do its work even better! (Links describing this maintenance technique are at Wikipedia:Slow sand filter)
CONCLUSION[edit | edit source]
Technical change drives wider changes in economic, social, cultural and political life. The current era of 'globalisation' is strongly driven by progress in technologies such as those of information and communication and the life sciences.
A successful Day in Centennial Park had people talking, thinking and wanting to act to make a change!