Since wastewater has been treated by sewage treatment plants, people have wondered if it can be used to irrigate crops. Many have argued that wastewater, also known as recycled water, or non-potable water, should not be used for crops since it does not meet the standards required for drinking water. However, farmers, water purveyors, and water districts have recently been pushing to use recycled water to irrigate crops.
The main argument against this issue is that mentioned before—that it doesn’t meet drinking water standards. Critics claim that the water can contain harmful bacteria or other contaminants such as metals that are unhealthy for human consumption. However, this water is considered to be safe enough to swim in.
Environmentalists argue that the water is safe enough to be used for irrigation. If the water is not used by irrigation, it must be released into natural ecosystems such as lakes or streams. The surge of water often changes the temperature or chemical composition of the water, making it inhospitable for native species. For example, water that is either too warm or too cold will change the temperature of surrounding water enough that spawning salmon will not be able to breed.
To read more about the subject, visit: http://hanfordsentinel.com/articles/2010/01/19/news/doc4b54a8855769b557891315.txt
Extractive aquaculture, or bioextraction as it is sometimes called, is an up-and-coming technique used to purify water and remove contaminants. This technique uses organisms that are innately good at removing the nutrients, such as algae, and even shellfish. For example, algae takes in nutrients to grow and reproduce. One of the most common and plentiful nutrients in wastewater is…well…human excrement. Excrement has high concentrations of nitrogen and phosphorous—just what the algae needs. Other organisms, like shellfish require other nutrients to grow. For example, shellfish often need calcium and other materials to grow shells and exoskeletons, so these organisms are better at filtering these “pollutants” out of the water.
One of the most important lessons we can learn from nature is that one man’s garbage is another man’s treasure. That being said, we simply need to find organisms that thrive on our “pollutants” and use them to do it for us. Instead of spending millions of dollars on costly chemical means, treatment plants could potentially create man-made ecosystems to filter pollutants out of water. By creating something similar to a natural ecosystem, various species would thrive on different nutrients or pollutants, and each specializes in a different type. What could be better than getting an organism to do our work for us…for free?
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Donnie Maxwell, farm manager of a strawberry farm in Plant City, Florida discusses how the design of their fields helps to save water. Constructed by using various heavy machinery and precise equipment, the strawberry fields are designed to be 48 inches apart on center, with a very slight slope. The fields slope from north to south, and then the water runs through a drainage ditch into a pond where is it re-circulated into the irrigation. This innovative design was developed in part by the Berry Fresh Farms, and the South Florida Water management District to implement cutting-edge technology and conserve water.
This technology is relatively simple—very similar to how the Egyptian Pyramids were built perfectly level. The only difference is that lasers from the 21st century were used to add a slight tilt to the crops. As a result, the excess water is directed carefully downhill into drainage ditches which then deliver the water to a storage pond where it can be re-circulated. As a result of this design, the Farm has been able to recycle about 60% of its water.
This type of recycling is called Tailwater Recovery, where the water is recovered and recycled on the “tail” of post-use end. There, it is captured and re-circulated back through the irrigation system where it can be put to benefit by the strawberry plants, instead of being channeled into a river and wasted.
For more information on this project, visit: http://www.abcactionnews.com/dpp/news/region_east_hillsborough/plant_city/some-strawberry-farmers-are-recycling-irrigation-water
Often the most wasteful areas of water use is that of landscaping. Irrigating landscape often uses immense amounts of water because many decorative plants have high water demands. Also, poor landscape design can lead to wasted water by causing excess runoff and even small-scale flooding in areas.
Landscape irrigation often requires immense amounts of water because of the non-native choices that many homeowners make when designing their landscape. In California, for example, many gardeners select ornamental plants for the colorful flowers that last only a few weeks at a time. In order to significantly reduce the amount of water used to irrigate your garden, you should consider planting native species in your garden. Many of these plants have beautiful flowers and attract native wildlife such as birds and various mammal species.
Another significant cause of wastewater in landscape is poor landscape design. Extensive areas of non-permeable hardscape cause small-scale flooding because the water often has nowhere to drain. In my own yard, for example, there is a section of cement approximately 10’ wide by 25’ long that was used as a patio by the previous owner, which now fills with water every time it rains. One of the easiest solutions to this problem is replacing non-permeable hardscape with a permeable version. You can buy cement pavers at local hardware stores, and these allow the water to pass between each piece, helping drain water and replenish underground storage basins. When water is unable to enter the ground, it is most often channeled into sewage systems where it must be treated and re-released into the environment.
For more information, visit http://www.waterwise-consulting.com