The study was
conducted in the city of Heraklion, Crete in Greece at the Technological
Educational Institute of Heraklion, a foremost agricultural university on the
island of Crete, an institute that specializes in giving Greek and
international students practical agricultural experience.
This study
examined the effectiveness of different concentrations of treated gray and
black water for five different species of spice plants with a total of 150
plants in six different growing conditions (control versus black versus gray
water, with each group divided into low and high water concentrations).
Various
measurements of these plants were taken such as height, length and width to create
a data growth index over a period of four months, along with chlorophyll
levels, blossom/flower counts, and water absorption speeds.
The study provides
evidence that plant growth was higher when irrigated with treated wastewater
compared to the freshwater irrigation control group, and the number of blossoms
of the plants were also higher. This effect should be studied in more detail in
further experimentation, but is likely due to the anaerobic bacteria used to
treat the plants.
Additionally, the
study also suggested that certain spices respond better to treated wastewater
than others, with Dictamnus and Origanum responding well and Salvia responding
poorly and showed high mortality.
These results have
potential to change the way water is irrigated around the world, especially in areas
vulnerable to drought such as California, but more plants and crops should be
studied for conclusive results.
