Identification of the Most Sustainable Alternative Identification of the Most Sustainable Alternative

System for NE Toilets at UT: A comparative Study System for NE Toilets at UT: A comparative Study

of Implementation of Rainwater Harvesting, of Implementation of Rainwater Harvesting,

Greywater Recycling, and Composting Toilets Greywater Recycling, and Composting Toilets

Professor: Dr. Apul

Presenters: Akhil Kadiyala, Zheng Xue, Andrew E. Wright

Professor: Dr. Apul

Presenters: Akhil Kadiyala, Zheng Xue, Andrew E. Wright

CIVE 6900 Sustainability Science and Engineering

Fall 2008

CIVE 6900 Sustainability Science and Engineering

Fall 2008

ObjectivesObjectives

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.

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 CollectionData 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.

• 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 CollectionData CollectionRoom No Type of Utility No. of facilities in

the roomCompany /

ManufacturerFlow rate

1262 Faucets 3 Crane Plumbing NAUrinals 2 Zurn 3.0 g/fToilets 3 Zurn 1.6 g/f

1260 Faucets 2 Crane Plumbing NAToilets 3 Zurn 1.6 g/f

2014 Faucets 3 Kohler NAUrinals 2 Sloan 1.6 g/fToilets 3 Sloan 1.6 g/f

2013 Faucets 3 Kohler NAToilets 5 Sloan 1.6 g/f

2053 Faucets 3 Kohler NAUrinals 2 Sloan 1.6 g/fToilets 3 Sloan 1.6 g/f

2056 Faucets 3 Kohler NAToilets 5 Sloan 1.6 g/f

1012 Faucets 3 Kohler NAUrinals 2 Sloan 1.6 g/fToilets 3 Sloan 1.6 g/f

1013 Faucets 3 Kohler NAToilets 5 Sloan 1.6 g/f

1055 Faucets 3 Kohler NAUrinals 2 Sloan 1.6 g/fToilets 3 Sloan 1.6 g/f

1056 Faucets 3 Kohler NAToilets 5 Sloan 1.6 g/f

0520A Faucets 3 Kohler NAUrinals 2 Sloan 1.6 g/fToilets 3 Sloan 1.6 g/f

0600 Faucets 3 Kohler NAToilets 5 Sloan 1.6 g/f

Current Water Usage in Current Water Usage in RestroomsRestrooms

• 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.

• 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.

Rainwater HarvestingRainwater 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.

• 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.

Components and Cost Components and Cost Estimates for Rainwater Estimates for Rainwater

HarvestingHarvesting

Activity Cost

Labor Charges $80

Power Consumption by Pumps $42.34

Spare parts and Repairs $800

Total O&M Charges $922.34

Rainwater Harvesting Estimate

  Quantity Unit $ TotalHolding 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 ea $965.00 $965.00Self Cleaning Tank inlet Filter 2 ea $750.00 $1,500.00

Floating tank filter 2 ea $220.00 $440.006000 Gallon Header tank 1 ea $4,611.17 $4,611.17

2" pipe from holding tank to header tank 50 lf $11.50 $575.00

4" pipe back to toilets piping 700 lf $32.50 $22,750.00        $262,757.17

Greywater RecyclingGreywater Recycling• Components :

1. Greywater Source

2. Collection through plumbing

3. Treatment System

4. Storage

5. Greywater Reuse

• Components :

1. Greywater Source

2. Collection through plumbing

3. Treatment System

4. Storage

5. Greywater Reuse

Greywater Loading RatesGreywater Loading Rates

• Hydraulic Loading Rates

0.25-1 gal/sq .ft /day – Fine media

3-10 gal/sq .ft/day – Recirculation

• Organic Loading Rates

0.00025lbs BOD5/ft2/day to 0.0012 lbs BOD5/ft2/day - Fine media

• Hydraulic Loading Rates

0.25-1 gal/sq .ft /day – Fine media

3-10 gal/sq .ft/day – Recirculation

• Organic Loading Rates

0.00025lbs BOD5/ft2/day to 0.0012 lbs BOD5/ft2/day - Fine media

Components and Cost Estimates for Components and Cost Estimates for Greywater RecyclingGreywater 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 Cost

Labor Charges $1,040

Power Consumption by Living Machines $205

Power Consumption by pump to lift water to storage tank $4038.94

Spare parts and Repairs $5,222.98

Total O&M Charges $10,506.92

Composting ToiletsComposting Toilets

• Waterless or consume a minimum amount of flushing water.

• Human waste is converted into an organic compost and usable soil.

• Waterless or consume a minimum amount of flushing water.

• Human waste is converted into an organic compost and usable soil.

Composting Toilet Composting Toilet Replacements and EstimatesReplacements and Estimates

• Total Cost of Construction = $105,180

• Total Cost for O&M = $5268

• Total Cost of Construction = $105,180

• Total Cost for O&M = $5268

Room Type of toiletNumber of

toilets

Number of composting

tank(s)

1262Foam

flushing3 1

1260Foam

flushing3 1

1014 Waterless 55

2013Foam

flushing5

1015 Waterless 33

2014Foam

flushing3

1057 Waterless 33

2053Foam

flushing3

1058 Waterless 55

2056Foam

flushing5

Water Consumption and Effluent Water Consumption and Effluent QuantityQuantity

Life Cycle System BoundaryLife Cycle System Boundary

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

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

LCA ResultsLCA ResultsGreenhouse gases 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 CycleEnergy for “Construction” and “O&M” Stages of a Life Cycle

Environmental IndicatorEnvironmental 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.

• 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 IndicatorEnvironmental IndicatorConventional Air Pollutants

  Water Consumption Cost/year SO2 CO Nox VOC LEAD PM 10

  $ mt mt mt mt mt 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 CO2 CH4 N20 CFC

  $ MTCO2EMTCO

2EMTCO

2EMTCO

2EMTCO

2E

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 Natural Resource Consumption IndicatorIndicator

• Overall % Water Consumption Reduction

Rainwater Harvesting: 21.77%

Greywater Recycling: 45.92%

Composting Toilets: 21.72%

• Overall % Water Consumption Reduction

Rainwater Harvesting: 21.77%

Greywater Recycling: 45.92%

Composting Toilets: 21.72%

Economic IndicatorEconomic Indicator

Economical Choice Comparison based on Cost of Construction and O&MEconomical Choice Comparison based on Cost of Construction and O&M

Economical Choice Comparison based on Cost/gal of water saved/dayEconomical Choice Comparison based on Cost/gal of water saved/day

Payback PeriodPayback Period

Rainwater Harvesting: 23.42 yrs

Greywater Recycling: 40.18 yrs

Composting Toilets: 9.5 yrs

Rainwater Harvesting: 23.42 yrs

Greywater Recycling: 40.18 yrs

Composting Toilets: 9.5 yrs

Sustainability Index and Sustainability Index and Performance PercentagePerformance Percentage

Performance = Maximum Score of indicator × ∑Sustainable Score. Performance = Maximum Score of indicator × ∑Sustainable Score.

Points AllottedPoints Allotted

S.No Points of ComparisonRainwater 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

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

Applicable LEED CreditsApplicable 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.

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.

ConclusionsConclusions

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.

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.

Limitations and Scope for Future Limitations and Scope for Future WorkWork

• Limitations:

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.

• Limitations:

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.

Questions?Questions?