Ib Group 4 Project

Alex, Joe, Jonathan, Willard, Kevin, and Jacob

Purpose Our IB Class wet to Rottnest for 3 days to research sustainability from the four parts of IB Group 4 subjects, which consists of Biology, Physics, Chemistry and Design & Technology.

Sustainability Sustainability is the ability to sustain life. We researched into how Rottnest is able to sustain life, as in waste management, power and water. We also took into account how Rottnest would cope with future growth.

Power Usage Power at Rottnest is divided between Wind Power and Diesel Generators. Rottnest has an annual power requirement of 4,650,000 Kilowatt Hours. 50% of this power is used solely for businesses. About 35% of the power generated at Rottnest is from Wind Power.

Power (Continued) On the island there are 7 Diesel Generators, 4 main and 3 back-up generators. The island uses over $1 million worth of diesel a year. That is on average 2,150 litres of diesel a day! Generators have a maximum output of 1,100 Kilowatts

Power (Continued) In 2004 the Wind Turbine was built. Since then it has saved approximately 1.6 million litres of diesel and it can operate in wind speeds ranging from 7 km/h to 130 km/h! The turbine is expected to save $400,000 and 1,100 tons of green house gasses, 40% Rottnest’s green house gas output!

Power (Continued) The cost per Kilowatt hour on Rottnest is $0.33, in comparison, the price in Perth is $0.139 per Kilowatt hour. Most of this is due to energy lost in low-voltage transmission of power. Businesses have introduced power saving measures such as solar power, water heaters, and smart building designs.

Power (Continued) Wind measurements reached speeds of 13.65 m/s, which is 49.15 km/h.

Waste Management A problem for sustainable life is waste management, what can we do with it? Up until 1995, Rottnest housed a landfill, but it had started to outgrow its size. Today, Rottnest has systems in place to deal with Waste Water, Recyclable Garbage, and General Garbage.

Waste Management (Continued) Waste water is processed using a Cyclic Activated Sludge System (CASS). It is automated, so there is only one employee who only needs to check the site 3-times a week. Using this system, raw sewage can be converted to water suitable for drinking within hours. Each Year, it can handle 100,000 Kilolitres enters the waste water management plant. This is 800 Kilolitres per day, and on New Years Eve (the day with most inflow), there is 650 Kilolitres of waste water produced.

Waste Management (Continued) The CASS presses sludge out of the dirty water to separate the waste from the water and then the remaining waste is transferred to the waste management program. The water that is left is either evaporated or sent into tanks where it is chlorinated. All deadly bacteria is wiped out in this process. None of this water is used for drinking, it is used for other things, such as watering the oval.

Waste Management (Continued) In 1996, Rottnest introduced a recycling program and a organic material composting program. In 2006, $1.5 million was dedicated to expand and improve the waste management program, in a step to make it more sustainable for the future. Before this 97% of garbage at the landfill was recyclable!

Waste Management (Continued) 1.8 cubic metres of general garbage (nonrecyclable) is shipped on a barge to the main-land every second day in summer, and every second week in winter. This waste is taken to Canningvale. This greatly reduces the amount of waste taken to the landfill.

Desalination

75% of the drinking water at Rottnest comes from desalination. Water is pumped up from shallow bores and then it is filtered to remove sand and other fine material. The water is out under highpressure for reverse osmosis. Salt gets rejected when the water is passed through a membrane. For the future, they have considered digging for fresh water, but it is expensive, and salt water has started leaking into the underground water system.

Rottnest Wildlife The human settlement on Rottnest has had a profound effect on the wildlife. Early settlers burned native bush to make room for farming and houses, destroying significant parts of the islands ecosystem. Quokkas used to be a commonly hunted animal, replacing the effect of natural predators wiped out by human habitation, and the stopping of this practice has led to the explosion of the quokka population.

Rottnest Wildlife (continued) Despite the impact of human settlement, the ecosystem has recovered under the protection of a extensive national park protected status. Only recreational fishing is allowed, and strict guidelines are placed on this. Large amounts of unsettled land are considered national park as well.

Rottnest Wildlife (Continued)

One of the most important parts of the island is the salt lakes in the centre of the island. The shallow salt lakes support large plankton populations, are as a result are a important food source for most of Rottnest’s birds, and other wildlife. Many of the birds migrate to Rottnest to breed, and as a result these breeding areas are heavily protected. This fragile ecosystem needs to be protected from dangers such as lowering of the water table, caused by boring and large scale desalination , as the affect the salinity of the lakes with affects up through

Conclusion

Rottnest is sustainable for the near future and can sustain growth. There are options to increase power and improve the waste management systems, such as the proposed additional desalination plant as well as another wind turbine.

Thank you for listening!