1. CIVE 6900 Sustainability Science and Engineering Fall 2008
Identification of the Most Sustainable Alternative System for NE Toilets at UT: A comparative Study of Implementation of Rainwater Harvesting, Greywater Recycling, and Composting Toilets
CIVE 6900 Sustainability Science and Engineering
Fall 2008
Professor: Dr. Apul
Presenters: Akhil Kadiyala, Zheng Xue, Andrew E. Wright

2. Objectives Application of ‘EIOLCA’.
Indicator Analysis – Environmental Indicator.
– Natural Resource Consumption Indicator.
– Economic Indicator.
Sustainability Index and Performance.
Possibility of obtaining LEED Credits.

3. Data Collection
Floor plans, plumbing diagrams, and number of toilets – Maintenance Department.
Utility water usage (gal/flush) obtained from online websites based on manufacturing company.
NE water bill - $ for 1048 ccf (783,904 gallons).
Materials required, quantities, and costs requires for LCA are obtained from online web search and open literature.

4. No. of facilities in the room Company / Manufacturer
Data Collection
Room No
Type of Utility
No. of facilities in the room
Company / Manufacturer
Flow rate
1262
Faucets 3
Crane Plumbing NA
Urinals 2
Zurn
3.0 g/f
Toilets
1.6 g/f
1260
2014
Kohler
Sloan
2013 5
2053
2056
1012
1013
1055
1056
0520A
0600

5. Current Water Usage in Restrooms
Assumptions
No. of people = 2370
Usage of restroom = 1.5 times/day.
75% Male and 25% Female
30% of total water consumption is used by toilets.

6. Rainwater Harvesting Design Criteria:
Roof rainwater collected at a general point and sent to a tank.
Filtered via ground filter.
The rainwater is then pumped to a header tank .
Disinfection with UV.
Rainwater is distributed to the WCs via the header tank which incorporates the main water back up, riser connection and overflow.

7. Components and Cost Estimates for Rainwater Harvesting
Rainwater Harvesting Estimate
Quantity
Unit $
Total
Holding Tanks 2 ea
$113,783.00
$227,566.00
Pipe from downspouts to holding tank
300 lf
$14.50
$4,350.00
Pump-2 hp, 100 gpm 1
$965.00
Self Cleaning Tank inlet Filter
$750.00
$1,500.00
Floating tank filter
$220.00
$440.00
6000 Gallon Header tank
$4,611.17
2" pipe from holding tank to header tank 50
$11.50
$575.00
4" pipe back to toilets piping
700
$32.50
$22,750.00
$262,757.17
Activity
Cost
Labor Charges
$80
Power Consumption by Pumps
$42.34
Spare parts and Repairs
$800
Total O&M Charges
$922.34

8. Greywater Recycling Components : Greywater Source
Collection through plumbing
Treatment System
Storage
Greywater Reuse

9. Greywater Loading Rates
Hydraulic Loading Rates
gal/sq .ft /day – Fine media
3-10 gal/sq .ft/day – Recirculation
Organic Loading Rates
lbs BOD5/ft2/day to lbs BOD5/ft2/day - Fine media

10. Components and Cost Estimates for Greywater Recycling
Piping
$1,101.60
Equalization Tank
$11,108.12
Living Machine
$650,000
Disinfection System
$244,000
Pumps
$965
Storage Tanks
$ 4,939.04
Additional Charges
$39,172.34
Total Construction Charges
$950,321.10
Activity
Cost
Labor Charges
$1,040
Power Consumption by Living Machines
$205
Power Consumption by pump to lift water to storage tank $
Spare parts and Repairs
$5,222.98
Total O&M Charges
$10,506.92

11. Composting Toilets
Waterless or consume a minimum amount of flushing water.
Human waste is converted into an organic compost and usable soil.

12. Composting Toilet Replacements and Estimates
Room
Type of toilet
Number of toilets
Number of composting tank(s)
1262
Foam flushing 3 1
1260
1014
Waterless 5
2013
1015
2014
1057
2053
1058
2056
Total Cost of Construction = $105,180
Total Cost for O&M = $5268

13. Water Consumption and Effluent Quantity

14. Life Cycle System Boundary
Functional Unit: savings per life cycle of each system ($/life cycle).

15. LCA Results Energy for “Construction” and “O&M” Stages of a Life Cycle
Greenhouse gases for “Construction” and “O&M” Stages of a Life Cycle
Energy for “Construction” and “O&M” Stages of a Life Cycle

16. Environmental Indicator
The need for potable water use for toilet flushing：
Cost for rainwater harvesting and grey water recycling with 811,950 gallons per year - $4,348.
For composting toilets, it would be 853,370 gallons with a cost of $4,608.

17. Environmental Indicator
Conventional Air Pollutants
Water Consumption Cost/year
SO2 CO
Nox
VOC
LEAD
PM 10 $ mt Mt
Pre - Design RW & GW
$15,480
0.020
0.034
0.016
0.059
0.002
Post - Design
$4,348
0.006
0.009
0.005
0.017
Composting
$4,608
0.010
0.018
Green House Gases
Water Consumption Cost
GWP
CO2
CH4
N20
CFC
MTCO2E
121
10.9
72.2
37.8
0.106 34
3.07
20.3
10.6
0.030 36
3.25
21.5
11.3
0.032

18. Natural Resource Consumption Indicator
Overall % Water Consumption Reduction
Rainwater Harvesting: 21.77%
Greywater Recycling: 45.92%
Composting Toilets: 21.72%

19. Economic Indicator
Economical Choice Comparison based on Cost of Construction and O&M
Economical Choice Comparison based on Cost/gal of water saved/day

20. Payback Period Rainwater Harvesting: 23.42 yrs
Greywater Recycling: yrs
Composting Toilets: 9.5 yrs

21. Sustainability Index and Performance Percentage
Performance = Maximum Score of indicator × ∑Sustainable Score.

22. Points Allotted S.No Points of Comparison Rainwater Harvesting
Greywater Recycling
Composting Toilets 1
Economical choice of cost of construction per gallon of water saved per day 2 3 2.
Quantity of water saved per day 3.
Environmental Pollution
Maximum Achievable Score 9
Sustainable Score Achieved
2+2+2 = 6
1+3+1 = 5
3+1+3 = 7
Sustainability Index
66.67%
55.55%
77.78%
Performance 12 15 21

23. Applicable LEED Credits
WE 3.1: Water Use Reduction 20%.
The intent is to maximize water efficiency within buildings to reduce the burden on municipal water supply and wastewater systems.

24. Conclusions Composting Toilets - Most Sustainable Alternative System.
Greywater Recycling is recommended for long term use – Ability to conserve large amounts of water, thereby reducing potable water demand.
Rain water harvesting can also be used similarly but the source of supply to this system is dependent on rainfall and seasons.

25. Limitations and Scope for Future Work
Difference in persons perspective.
Complete life cycle not taken into account.
Applicability to only toilet flushing is considered.
Scope for Future Work:
Study the combination of alternative systems studied individually in this study.

26. Questions?