P07401: EPA Water Disinfection Project

Function and Performance Summary

Metric # Need #'s Metric Imp. Units Marginal Value Ideal Value Obtained Value Spec Met
1 1.6, 1.6a, 1.6b, 1.6c Cost per unit to manufacture 9 $ 60 25 42.59 (w/o feed water) 73.98 (w/ feed water) no
2 1.1, 1.1a '# of parts imported 9 # 5 0 2 yes
3 1.1, 1.1a % of total cost for imported parts 9 % 30 0 26.93% (w/o feed water)

15.50% (w/ feed water)

4 1.2, 1.1, 1.1a Local fabrication possible 9 % of component type 80 100 100 yes
5 1.3, 1.4, 1.5 Use of chlorine, wood as fuel source, electricity 3 y/n n n n yes
6 2.1, 2.2, 2.5, 3.1 Total coliform reduction 9 log 4 5 98% reduction no
7 2.1, 2.2, 2.5, 3.1 Change in temperature between ambient & fluid in pasteurization section 9 delta deg. C. 40 40+ 40+ yes
8 2.1, 2.2, 2.5, 3.1 Reached Safety Zone* 9 y/n y y n no
9 1.7, 2.1, 2.3, 3.1 Handle sediments 3 y/n n y y yes
10 1.7, 4.1, 4.2 Output before expected failure** 9 L 7300 36500 phase II n/a
11 1.7, 4.1, 4.2 Average time for preventive maintenance 1 min 1.5 3 2.3 yes
12 2.4 Leak proof 1 y/n y y y yes
13 1.7 Thermal cycling until failure** 3 # cycles 2000 4000 phase II n/a
14 3.1, 3.2, 3.3, 3.4 Average daily potable output for typical Venezuelan climate 3 L/day 20 40 23 yes
15 4.2 Usability of setup 9 1-7 rating 4.2 5.6+ 5.4 yes
16 1.7, 4.1 '# of moving parts 3 # 2 0 1 yes
'*Equivalent safety zone is a reference safety zone curve shifted by an applicable delta deg. C that fits test conditions

'**Due to required completion date of April 6th, testing will not get done

Engineering Metrics Defined

1. Cost per unit to manufacture - the following assumptions were made in the mass production analysis:

(a) Processing cost reduced since processing time has been reduced (welding not needed)

(b) Metal components are average raw material prices

(c) The rest of the components follow the commercialized prices

2. # of parts imported - parts imported consist of air vent valve and SOLKOTE (TM) selective coating. The air vent valve has a probability of being available in Venezuela.

3. % of total cost for imported parts - total cost of imported parts divided by total cost of pasteurizer multiplied by 100

4. Local fabrication possible - the 100% value results from the assumption that the equipment and processes used were entirely available in Venezuela. Mills, lathes, and band saws are basic machining tools in any industrialized nation. The assumption is that Venezuela, a large exporter of oil and aluminum and industrialized nation, has these basic tools for fabrication.

5. Use of chlorine, wood as fuel source, electricity - the pasteurizer does not utilize any chlorine, fuel wood, or require electricity during operation.

6. Total coliform reduction - log 5 reduction entails a 99.9% reduction of contaminants initially present in the water. Lab test results showed no trace of coliforms (the presence of which is an indication of bacteria and viruses such as E-coli and Hepatitis A being present).

7. Change in temperature between ambient and fluid in pasteurization section - after the initial warm up period, the SPIHX remained 40+ deg. C. higher than ambient temperatures.

8. Reached Safety Zone - by analyzing temperatures along the plates and the flow rate of water, the actual time-temperature curve were compared against the safety zone curve.

9. Handle sediments - the funnel fitted with a filter attached to the inlet of the water bucket handles sedimentation. The team did not focus too much on this aspect of the design but future phases of the project should address this issue in more detail.

10. Output before expected failure - testing to be performed as part of future work.

11. Average time for preventive maintenance - a 'usability' test was conducted in which students and faculty members were asked to perform basic maintenance checks while the unit was operating. The times were recorded and averaged.

12. Leak proof - leaks must be nonexistent within the heat exchanger plates as well as past the thermostat valve to ensure that no contaminated water passes through without getting pasteurized. Pressure testing was conducted to verify that the pasteurizer is leak proof.

13. Thermal cycling until failure - testing to be performed as part of future work.

14. Average daily potable output for typical Venezuelan climate -

15. Usability of setup - a standardized 'usability' test was conducted to see how easy or hard it was for the end user to perform the initial set up procedure of the SPIHX. Students and faculty were asked to perform the set up and times were recorded. The way in which the test was standardized can be found in the test methods section.

16. # of moving parts - the only moving part of the SPIHX is the auto thermostat valve.