CONSTRUCTED WETLANDS – A full and sustainable solution for pollution and water shortage in arid zones
The Middle East is facing severe water problems:
In arid zones these issues are much more severe. Very often the source water is already saline, and keeping the water in reservoirs causes further salination. On the other hand, the need for water and green spaces is far greater.
CONSTRUCTED WETLANDS are designed to give a renewed answer to these issues.
In order to keep our planet in a reasonable state we have to use what we produce. In the past farmers used human and animal waste for agricultural use, and no residue was left. In modern life we aspire to do the same, but it takes more effort.
Constructed Wetlands enhance natural processes, and combined with today’s know how in engineering, chemistry and biology, are a powerful system for wastewater treatment.
In the long run Constructed Wetlands are both the most cost effective and efficient system available to treat the global water crisis. Properly designed Constructed Wetlands get better with the years and will serve for much longer than any other system. A Constructed Wetland is a self-sustaining system that offers a solution with an added value to the environment. A system we can live with, and live by.
The people of Kibbutz Lotan considered these issues when they asked Ofra Aqua to design a Constructed Wetland system for the Kibbutz.
Lotan, located in Israel’s Southern Arava Desert, is an ecology conscious community with a focus on sustainable development. It is also home to a large and significant bird reservation. With an awareness of Lotan’s governing ethos, Ofra Aqua designed a self-sustaining system that can also provide environmentally friendly water for bird ponds and irrigation.
The choice of Constructed Wetlands for such an arid zone is not self-evident. Traditional CW using Phragmites Australis does not fit due to the high rate if evapotranspiration and consequent salinity. Constructing a CW system in the desert requires special characteristics. Ofra Aqua has led vast experimental efforts to identify plants, substrates and flow systems that will result in actual reduction of Chlorides and Boron levels in these harsh conditions. At the experimental site, a source of saline water was used (1,200 and 3,000 mg/l of Chlorides), and within 2 years the beds had achieved a significant reduction in salinity levels. (Graph) As expected, high salinity was measured in the control ponds.
The knowledge gained from our research was put to the test when in the design of the Neot Smadar water reservoir, situated in the Arava Desert. Special wetland beds were constructed to surround the shores of this 27,000sq.m pond. The water is pumped and distributed through these beds.
The reservoir is used for irrigation, and as a fish farm. Although the water source is slightly saline, even when combined with the addition organic load from the fish, the water at the outlet is better than in the inlet and fit irrigation use. The Neot Smadar pond now attracts many bird species not seen in the region for many years, and as a result has established itself as an important bird watching site.
Both The Lotan system and the Neot Smadar WWTP were designed using the following guidelines:
The Constructed Wetlands system is self-sustaining and requires little maintenance. While it does require observation and monitoring as well as some gardening for esthetic and tourism purposes, gardening is not required for the system to function. Its effectiveness and efficiency when coping with a diverse range of pollutants, together with its seamless integration into the environment, make Constructed Wetlands the solution for our times. The Ofra Aqua system has proved its effectiveness in arid Zones with their special requirements.