Water conservation
Water conservation refers to reducing the usage of water and recycling of waste water for different purposes such as cleaning, manufacturing, and agricultural irrigation.
Introduction
Water conservation
Water conservation can be defined as:
- Any beneficial reduction in water loss, use or waste as well as the preservation of water quality.
- A reduction in water use accomplished by implementation of water conservation or water efficiency measures; or,
- Improved water management practices that reduce or enhance the beneficial use of water.[1][2] A water conservation measure is an action, behavioral change, device, technology, or improved design or process implemented to reduce water loss, waste, or use. Water efficiency is a tool of water conservation. That results in more efficient water use and thus reduces water demand. The value and cost-effectiveness of a water efficiency measure must be evaluated in relation to its effects on the use and cost of other natural resources (e.g. energy or chemicals).[1]
Goals
The goals of water conservation efforts include as follows:
- Sustainability. To ensure availability for future generations, the withdrawal of fresh water from an ecosystem should not exceed its natural replacement rate.
- Energy conservation. Water pumping, delivery, and wastewater treatment facilities consume a significant amount of energy. In some regions of the world over 15% of total electricity consumption is devoted to water management.
- Habitat conservation. Minimizing human water use helps to preserve fresh water habitats for local wildlife and migrating waterflow, as well as reducing the need to build new dams and other water diversion infrastructure.
Social solutions
Water conservation programs are typically initiated at the local level, by either municipal water utilities or regional governments. Common strategies include public outreach campaigns,[3] tiered water rates (charging progressively higher prices as water use increases), or restrictions on outdoor water use such as lawn watering and car washing.[4] Cities in dry climates often require or encourage the installation of xeriscaping or natural landscaping in new homes to reduce outdoor water usage.[5]
One fundamental conservation goal is universal metering. The prevalence of residential water metering varies significantly worldwide. Recent studies have estimated that water supplies are metered in less than 30% of UK households,[6] and about 61% of urban Canadian homes (as of 2001).[7] Although individual water meters have often been considered impractical in homes with private wells or in multifamily buildings, the U.S. Environmental Protection Agency estimates that metering alone can reduce consumption by 20 to 40 percent.[8] In addition to raising consumer awareness of their water use, metering is also an important way to identify and localize water leakage.
Some researchers have suggested that water conservation efforts should be primarily directed at farmers, in light of the fact that crop irrigation accounts for 70% of the world's fresh water use.[9] The agricultural sector of most countries is important both economically and politically, and water subsidies are common. Conservation advocates have urged removal of all subsidies to force farmers to grow more water-efficient crops and adopt less wasteful irrigation techniques.
Household applications
Water-saving technology for the home includes:
- Low-flow shower heads sometimes called energy-efficient shower heads as they also use less energy,
- Low-flush toilets and composting toilets. These have a dramatic impact in the developed world, as conventional Western toilets use large volumes of water.
- Dual flush toilets created by Caroma includes two buttons or handles to flush different levels of water. Dual flush toilets use up to 67% less water than conventional toilets.
- Saline water (sea water) or rain water can be used for flushing toilets.
- Faucet aerators, which break water flow into fine droplets to maintain "wetting effectiveness" while using less water. An additional benefit is that they reduce splashing while washing hands and dishes.
- Wastewater reuse or recycling systems, allowing:
- Rainwater harvesting
- High-efficiency clothes washers
- Weather-based irrigation controllers
- Garden hose nozzles that shut off water when it is not being used, instead of letting a hose run.
- using low flow taps in wash basins
- Automatic faucet is a water conservation faucet that eliminates water waste at the faucet. It automates the use of faucets without the use of hands.
- A valve which reduces water, gas, time, money and CO2 known as a Combisave
Water can also be conserved by landscaping with native plants and by changing behavior, such as shortening showers and not running the faucet while brushing teeth.
Commercial applications
Many water-saving devices (such as low-flush toilets) that are useful in homes can also be useful for business water saving. Other water-saving technology for businesses includes:
- Waterless urinals
- Waterless car washes
- Infrared or foot-operated taps, which can save water by using short bursts of water for rinsing in a kitchen or bathroom
- Pressurized waterbrooms, which can be used instead of a hose to clean sidewalks
- X-ray film processor re-circulation systems
- Cooling tower conductivity controllers
- Water-saving steam sterilizers, for use in hospitals and health care facilities.
- Rain water harvesting.
Agricultural applications
For crop irrigation, optimal water efficiency means minimizing losses due to evaporation, runoff or subsurface drainage while maximizing production. An evaporation pan in combination with specific crop correction factors can be used to determine how much water is needed to satisfy plant requirements. Flood irrigation, the oldest and most common type, is often very uneven in distribution, as parts of a field may receive excess water in order to deliver sufficient quantities to other parts. Overhead irrigation, using center-pivot or lateral-moving sprinklers, has the potential for a much more equal and controlled distribution pattern. Drip irrigation is the most expensive and least-used type, but offers the ability to deliver water to plant roots with minimal losses. However, drip irrigation is increasingly affordable, especially for the home gardener and in light of rising water rates. There are also cheap effective methods similar to drip irrigation such as the use of soaking hoses that can even be submerged in the growing medium to eliminate evaporation.
As changing irrigation systems can be a costly undertaking, conservation efforts often concentrate on maximizing the efficiency of the existing system. This may include chiseling compacted soils, creating furrow dikes to prevent runoff, and using soil moisture and rainfall sensors to optimize irrigation schedules.[8] Usually large gains in efficiency are possible through measurement and more effective management of the existing irrigation system.
Minimum water network target and design
The cost effective minimum water network is a holistic framework/guide for water conservation that helps in determining the minimum amount of freshwater and wastewater target for an industrial or urban system based on the water management hierarchy i.e. it considers all conceivable methods to save water. The technique ensure that the designer desired payback period is satisfied using Systematic Hierarchical Approach for Resilient Process Screening (SHARPS) technique.
See also
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References
- ^ a b Vickers, Amy (2002). Water Use and Conservation. Amherst, MA: water plow Press. p. 434. ISBN 1-931579-07-5.
- ^ Geerts, S.; Raes, D. (2009). "Deficit irrigation as an on-farm strategy to maximize crop water productivity in dry areas". Agric. Water Manage 96 (9): 1275–1284. doi:10.1016/j.agwat.2009.04.009.
- ^ "Water - Use It Wisely." U.S. multi-city public outreach program. Park & Co., Phoenix, AZ. Accessed 2010-02-02.
- ^ U.S. Environmental Protection Agency (EPA) (2002). Cases in Water Conservation (Report). http://www.epa.gov/watersense/docs/utilityconservation_508.pdf. Retrieved 2010-02-02. Document No. EPA-832-B-02-003.
- ^ Albuquerque Bernalillo County Water Utility Authority (2009-02-06). "Xeriscape Rebates". Albuquerque, NM. http://www.abcwua.org/content/view/132/222/. Retrieved 2010-02-02.
- ^ "Time for universal water metering?" Innovations Report. May 2006.
- ^ Environment Canada (2005). Municipal Water Use, 2001 Statistics (Report). http://www.ec.gc.ca/water-apps/en/info/pubs/sss/e_mun2001.pdf. Retrieved 2010-02-02. Cat. No. En11-2/2001E-PDF. ISBN 0-662-39504-2. p. 3.
- ^ a b EPA (2010-01-13). "How to Conserve Water and Use It Effectively". Washington, DC. http://www.epa.gov/owow/nps/nps-conserve.html. Retrieved 2010-02-03.
- ^ Pimentel, Berger, et al. (October 2004). "Water resources: agricultural and environmental issues". BioScience 54 (10): 909. doi:10.1641/0006-3568(2004)054[0909:WRAAEI]2.0.CO;2.
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