ie/cases/water-diapers.html

Owens, J.W. 2001. Water resources in life-cycle impact assessment: Considerations in choosing category indicators.

Two areas essential for water sustainability are

water quanity

the sources are renewable

the volumes used are returned for further use

water quality

utility is not impaired for further use

The LCA presents technical challenges and tradeoffs

not all water quality standards can be applicable to all situations

want the resulting indicator to inform decisions

 

An appropriate set of indicators

distill the information

indicate movement (toward or away from a goal)

support good decisions

--> need a battery of indicators

 

Definitions of water resources

in-stream water use (such as a dam)

off-stream water use (pumping from an aquifer)

surface water

groundwater

water release or return (release after off-stream use)

water use (return of water that was used)

water consumption (loss of water from off-stream use, such as evaporation from irrigation)

water depletion (withdrawal from a source that is not replenished)

 

Indicators of water quality and degradation of that quality

eutrophication (addition of nutrients that support algal growth)

problematic because the nutrient status of the recieving water needs to be characterized

dissolved oxygen demand

biological

chemical

themal

pathogenic microorganisms

contaminated water kills millions of children per year

color and turbidity

suspended solids

toxicity

accute

chronic

interactions

Example of LCA on water resources focusing on diapers

studies had different boundaries and considered different functions

water use for 6 months of diapering

single-use	8,423 liters
cloth, washed by commercial laundry	21,884
cloth, washed at home	18,269

summary hid the complexity of the water resources and differences in use vs. depletion

Cloth diapers are cotton - a crop that requires high irrigation

cotton irrigation water use accounted for

10% of the home laundry budget

47% of the commercial laundry budget

water irrigation depends on the local

state	L of water per kg of cotton fiber	sources
California	7280	diversion in N.Calif. Colorado river
Arizona	7984	Colorado, Yuma several overdrawn aquifers
Texas	4595	Ogallaha, Trinity-Edwards aquifers
Mississippi	814	surface and ground water not overdrawn

Washing, rinsing and flushing

% of total use for each category

single use	3%
home laundry	90%
commercial laundry	49%

the impact depends on the source and fate of this water

New York gets its water from renewable resources

Memphis - from aquifers that are not overdrawn

Los Angeles - diversion and where ever

a liter is not a liter

 

Loss of water in the process

drying is the highest consumptive loss

spin dry gets 2kg water per diaper down to 1 kg water per diaper

this kg is lost in the drier

 

Single use diapers use water in the manufacturing phase

84% of water use in pulp and paper production

 

other differences

cotton in chemically intensive crop - leachate and runoff

municpal sewage is treated for BOD and toxicity

pulp mills are treated for their effluents