The Potential Use of Reverse Osmosis Concentrate as Water Source for Irrigation
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Date
2020
Journal Title
Journal ISSN
Volume Title
Publisher
Uva Wellassa University of Sri Lanka
Abstract
Reverse Osmosis (RO) membrane technology is one of the promising techniques used to
provide safe drinking water to the community, particularly chronic kidney disease of
unknown etiology (CKDu) affected areas in the dry zone of Sri Lanka. The rejected water
from the RO plant is known as the RO concentrate, which is generally released to the
environment without any beneficial use. The main objective of this study was to identify
the potential use of RO concentrate as irrigation source water. Therefore, water samples
were collected from different capacities of RO plants varying from household to
commercial, and the selected area was the North Central province and North Western
province, the total number of RO plants were fifty. The essential irrigation water quality
parameters for agriculture were tested to determine the characteristics of RO concentrate.
pH, electrical conductivity, total dissolved solids, alkalinity, carbonate, bicarbonate,
nitrate, and phosphate were measured. Furthermore, the concentration variation maps
were plotted (using ArcGIS 10.5) to identify the spatial variation of RO concentrate.
Finally, the findings were compared with existing irrigation water quality standards
provided by the United States Food and Agriculture Organization (FAO), and Agriculture
Department of Sri Lanka. As the obtained results average values of, pH was 7.25,
electrical conductivity was 1.48 dS m-1
, total dissolved solid was 725.4 mg L-1
, alkalinity
was 104.66 mg L-1
as CaCO3, bicarbonate was 1.05 meq L-1
, nitrate was 1.78 mg L-1
,
phosphate was 0.96 mg L-1
and carbonate was not identified. According to the results, this
study revealed that RO concentrate water quality complies with the requirement of both
water quality standards for agriculture, and there is a potential of using the RO
concentrate as a water source for irrigation.
Keywords: Reverse osmosis, RO concentrate, Irrigation, Agricultural water
Description
Keywords
Environmental Science, Water Management System, Irrigation, Health Science, Eco-Environmental Sciences