1. The Hidden Power of Sewage St. Paul’s Co-educational College Lo Ka Shun, Parco Tsang Tin Ki, Angela Wong Ho Gan, Albert Poon Wing Yiu, Sarah

2. How much sewage we Hong Kong people produce each day?

3. 2.6 million cubic metres!! X 1400

4. Working Principle. Utilize kinetic energy of running sewage Sewage rushes down along the pipes outside buildings Large kinetic energy spin a watermill A dynamo changes kinetic energy to electricity

5. Preliminary Model 1.5 metres long plastic PVC water pipe plastic box with a watermill

6. Preliminary Model  Drawbacks Some water escapes without spinning watermill Some water rebounds back onto the watermill –hinder the rotation.

7. Advanced Model 1.top and bottom each have a hole for the entry and exit of water 2.Slightly tilted plane 3.An arc is craved for the watermill to tuck in 4.space below the watermill is enlarged

8. Advanced Model

9. Output Power Measuring Setup: –An electronic water pump –Amount of water pumped to our model is kept at a constant Water velocity =0.4516 m/s² –AC-DC transformer in our advanced model

10. Procedures: –Substituted the resistor and –re-measure the current and voltages –calculate output power Output voltage is very stable ~5 batteries X 5 Output Power

11. Applications Widely used, especially in big cities like Hong Kong modified and installed in underground pipes to generate electricity

12. Further Improvement Further Investigation on –How many of our device is to be installed in a pipe outside a building –What interval between devices can achieve the maximum electrical output Further develop: –Use lighter material to make the watermill –Use a more corrosion resistance material

13. Conclusion clean, inexpensive energy resource. easy to build applying this alternative energy resource in a large scale, the reliance on burning fossil fuels for energy environmental damage, e.g. global warming

14. Thank You!