When the Well’s Dry, We Know the Worth of Water
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This page is based on an article published in AIC News: Nunberg, Sarah. (2011) "When the Well’s Dry, We Know the Worth of Water." AICNews 36(2): 12-13.
"When the Well’s Dry, We Know the Worth of Water" (Benjamin Franklin)
Water is one of our planet’s most precious resources. It is also the most useful, powerful and non-toxic solvent a conservator can employ. The AIC Committee on Sustainable Conservation Practice encourages responsible use of this limited asset.
Paper, textile, and archaeological conservators often engage in treatments that require large amounts of water. Understanding the environmental repercussions in producing/using/recycling large amounts of bottled or purified water is helpful as we set our goals to reduce energy use and minimize the waste we produce. Whenever possible, we encourage using tap water before purified water and only purchasing bottled water as a last resort.
The charts (link below) list various types of water and address:
- Water discarded during purification (ratio of feed water to purified product)
- Energy to run purification equipment
- Energy to make purification equipment and bottles
- Raw materials to make purification equipment and bottles
- Disposal of spent filters, equipment, and empty storage containers
We hope these charts help conservators to evaluate water purification methods and to begin using purified water only as necessary.
| Water Type | Production | Use | Disposal | Recycling |
|---|---|---|---|---|
| Bottled | Bottle production requires massive amounts of petroleum and water. Filled bottles are shipped internationally. | No energy required during use | 90% of used bottles end up in landfills. | 10% of bottles used are recycled. 90% of bottles used end up in landfills. |
| Activated Carbon Filtered | Carbon pellets and blocks are made from mined coal. The carbon membranes are housed in plastic filter containers made from petroleum based products. | No energy required during use. | Carbon filters impregnated with filtered impurities require proper disposal. Most plastic housing for carbon filters is not recyclable and increases landfill. | Brita recycles their cartridges, although the recycling plant is in Germany. |
| Distilled | Housing for mechanics. Requires activated car bon filter pretreatment. | High energy use to run distillation units, which are not energy efficient. | Disposal of distillation units after replacement. Disposal of carbon filters and other membranes from pretreatment. | No |
| Deionized | Housing for mechanics. Requires activated carbon filter pretreatment. | The resin bed is regenerated with concentrated acid to strip away accumulated ions. | Acid must be properly disposed as hazardous waste. Disposal of deionizing units after replacement. Disposal of carbon filters and other membranes from pretreatment. | No |
| Electrodeionized | Housing for mechanics. Requires activated carbon filter pretreatment. | High energy required to run units. Units must be cleaned twice a year. | Disposal of electro-deionizing units after replacement. Disposal of carbon filters and other members from pretreatment. | No |
| Reverse Osmosis (RO) | Housing for mechanics including electrodeionizing units/pretreatment. Requires carbon filtration and electrodeionization for pretreament. | Runs on high water pressure, so it does not require energy to run. Damaged membranes are hard to detect. | Disposal of carbon filters and membranes containing hazardous waste. | |
| High Efficiency Reverse Osmosis | Housing for mechanics including electrodeionizing units/pretreatment. Requires carbon filtration and RO for pretreatment. | Treats aggressive feedwater that RO cannot filter. High levels of acid are required to dissolve silica. | Disposal of the unit after use. Disposal of carbon filters and membranes containing hazardous waste. | |
| Ultraviolet Oxidation | Requires variety of pretreatment to remove impurities besides bacteria. UV light production requires mercury and petroleum based products. | UV-C light requires high energy to run. | Landfill waste created by production of the UV light and its disposal. Mercury is a hazardous waste and must be properly handled. | No |
| Water Type | Source | Combined methods Required | Purification Phase | Storage System | Target Impurities Removed | pH | Use | % Water Recovered | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Untreated | Brackish Water | Activated Carbon | Steam Condensate | Ion Exchange | Membrane | Chemically Pretreated to Adjust pH | Electrically Charged Cell | Single Stage System | Pretreatment | Ultra Pure | Containers | On Demand | Chlorine | Lead | Calcium | Ionized Salts | Heavy Metals | Bacteria | VOCs | Particles | Solids/ Organics | Desalination | Potable | Industry | Conservation | ||||
| Tap | Y | Y | 6-10 | Y | Y | ||||||||||||||||||||||||
| Boiled | X | X | X | X | A+ | X | X | X | 6-10 | Y | N/A | ||||||||||||||||||
| Bottled | Y | Y | 3.23-9.73 | Y | Y | N/A | |||||||||||||||||||||||
| Activated Carbon | Y | T | Y | Y | Y | X | X | A+ | B | A-B | A-B | B | Y | 99% | |||||||||||||||
| Distilled | Y | P | T | Y | Y | B | A+ | A | A+ | A | A | X | A | A | Y | Y | 5% | ||||||||||||
| Deionized | Y | P | T | T | T | Y | Y | Y | X | A | A | A+ | A | X | X | X | X | 5.5-9 | Y | Y | |||||||||
| Electro-deionized | Y | P | T | T | T | Y | Y | A+ | A+ | A+ | 7-9 | Y | Y | Y | 95% | ||||||||||||||
| Reverse Osmosis | Y | Y | P | T | T | Y | Y | Y | Y | Y | A+ | A+ | A+ | A+ | A+ | A+ | 6-8 | Y | Y | Y | Y | 45%-70% | |||||||
| High Efficiency Reverse Osmosis | Y | Y | P | T | T | Y | Y | A+ | A+ | A+ | A+ | 10.5 or higher | Y | Y | 95% | ||||||||||||||
| Ultra-violet Oxidation | Y | Y | P | Y | Y | X | X | X | X | X | A+ | X | X | X | Y | Y | N/A | ||||||||||||
A+ = 100% removal
A = 96-99% removal P = optional pretreatment step
B = partial removal
X = cannot remove
Y = yes
P = optional pretreatment step
T = integral part of treatment
Charts from: Nunberg, Sarah, "When the Well’s Dry, We Know the Worth of Water." AICNews. AICNews March 2011 vol. 36 no. 2: 12-13.
List of Water Treatments
Water Charts
Environmental Impact from Water Purification, Use and Disposal:
File:Environmental issues and water pur.xls
Overview of Water Treatment Methods:
File:Water chart 8-1.xls
