Identification of the Most Sustainable Alternative System for

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

Objectives 1. Application of ‘EIOLCA’. 2. Indicator Analysis – Environmental Indicator. – Natural Resource Consumption Indicator. – Economic Indicator. 3. Sustainability Index and Performance. 4. Possibility of obtaining LEED Credits.

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 - $4277. 00 for 1048 ccf (783, 904 gallons). • Materials required, quantities, and costs requires for LCA are obtained from online web search and open literature.

Data Collection Room No Type of Utility No. of facilities in the room Company / Manufacturer Flow rate 1262 Faucets Urinals Toilets 3 2 3 Crane Plumbing Zurn NA 3. 0 g/f 1. 6 g/f 1260 Faucets Toilets 2 3 Crane Plumbing Zurn NA 1. 6 g/f 2014 Faucets Urinals Toilets 3 2 3 Kohler Sloan NA 1. 6 g/f 2013 Faucets Toilets 3 5 Kohler Sloan NA 1. 6 g/f 2053 Faucets Urinals Toilets 3 2 3 Kohler Sloan NA 1. 6 g/f 2056 Faucets Toilets 3 5 Kohler Sloan NA 1. 6 g/f 1012 Faucets Urinals Toilets 3 2 3 Kohler Sloan NA 1. 6 g/f 1013 Faucets Toilets 3 5 Kohler Sloan NA 1. 6 g/f 1055 Faucets Urinals Toilets 3 2 3 Kohler Sloan NA 1. 6 g/f 1056 Faucets Toilets 3 5 Kohler Sloan NA 1. 6 g/f 0520 A Faucets Urinals Toilets 3 2 3 Kohler Sloan NA 1. 6 g/f 0600 Faucets Toilets 3 5 Kohler Sloan NA 1. 6 g/f

Current Water Usage in Restrooms • Assumptions Ø No. of people = 2370 Ø Usage of restroom = 1. 5 times/day. Ø 75% Male and 25% Female • 30% of total water consumption is used by toilets.

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

Components and Cost Estimates for Rainwater Harvesting Estimate Quantity Holding Tanks 2 Unit ea $ $113, 783. 00 Total $227, 566. 00 Pipe from downspouts to holding tank 300 lf $14. 50 $4, 350. 00 Pump-2 hp, 100 gpm Self Cleaning Tank inlet Filter 1 ea $965. 00 2 ea $750. 00 $1, 500. 00 Floating tank filter 6000 Gallon Header tank 2 ea $220. 00 $440. 00 1 ea $4, 611. 17 50 lf $11. 50 $575. 00 700 lf $32. 50 $22, 750. 00 $262, 757. 17 2" pipe from holding tank to header tank 4" pipe back to toilets piping Activity Labor Charges Cost $80 Power Consumption by Pumps $42. 34 Spare parts and Repairs Total O&M Charges $800 $922. 34

Greywater Recycling • Components : 1. Greywater Source 2. Collection through plumbing 3. Treatment System 4. Storage 5. Greywater Reuse

Greywater Loading Rates • Hydraulic Loading Rates Ø 0. 25 -1 gal/sq. ft /day – Fine media Ø 3 -10 gal/sq. ft/day – Recirculation • Organic Loading Rates Ø 0. 00025 lbs BOD 5/ft 2/day to 0. 0012 lbs BOD 5/ft 2/day - Fine media

Components and Cost Estimates for Greywater Recycling Components Cost 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 Labor Charges Power Consumption by Living Machines Power Consumption by pump to lift water to storage tank Spare parts and Repairs Cost $1, 040 $205 $4038. 94 $5, 222. 98 Total O&M Charges $10, 506. 92

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

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

Water Consumption and Effluent Quantity

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

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

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.

Environmental Indicator Conventional Air Pollutants Water Consumption Cost/year $ SO 2 mt CO mt Nox mt VOC mt LEAD mt PM 10 Mt Pre - Design RW & GW $15, 480 0. 020 0. 034 0. 016 0. 059 0 0. 002 Post - Design $4, 348 0. 006 0. 009 0. 005 0. 017 0 0 Composting $4, 608 0. 006 0. 010 0. 005 0. 018 0 0 Green House Gases Water Consumption Cost GWP CO 2 CH 4 N 20 CFC $ MTCO 2 E MTCO 2 E Pre - Design RW & GW $15, 480 121 10. 9 72. 2 37. 8 0. 106 Post - Design $4, 348 34 3. 07 20. 3 10. 6 0. 030 Composting $4, 608 36 3. 25 21. 5 11. 3 0. 032

Natural Resource Consumption Indicator • Overall % Water Consumption Reduction Ø Rainwater Harvesting: 21. 77% Ø Greywater Recycling: 45. 92% Ø Composting Toilets: 21. 72%

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

Payback Period Ø Rainwater Harvesting: 23. 42 yrs Ø Greywater Recycling: 40. 18 yrs Ø Composting Toilets: 9. 5 yrs

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

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 1 3 2. Quantity of water saved per day 2 3 1 3. Environmental Pollution 2 1 3 Maximum Achievable Score 9 9 9 2+2+2 = 6 1+3+1 = 5 3+1+3 = 7 66. 67% 55. 55% 77. 78% 12 15 21 Sustainable Score Achieved Sustainability Index Performance

Applicable LEED Credits ü 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.

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

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

Questions?