Evaluation of Vertical Subsurface Flow Constructed Wetland System For Polluted River Wastewater Treatment: A Case Study on Akaki River Source of Urban Agriculture in Addis Ababa
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Date
2019-05
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Urban Agriculture (UA) in Addis Ababa has a number of challenges and opportunities since
Urban farmers on the riverbank mainly dependent on irrigated water from Akaki River. A
number of studies have been conducted focused on characterization of Akaki River water
quality, challenges faced by farmers in UA , health risks associated with irrigated vegetables by
the river and economic losses resulted due to the river pollution. However a realistic solution to
the urgent situation of UA was not given yet. This study aims at performance evaluation of
Vertical subsurface flow constructed wetland (VSSFCW) as cheap and efficient onsite
wastewater treatment solution functioned by farmers. No odors or insects were detected during
the six month operation of VFCW, beside a beautiful landscape view. The efficiency of
VSSFCW was studied on pilot plant. An evaluation of the efficiency in the purification of the
main polluting agents were done. The average removal efficiencies of chemical oxygen demand
(COD), biological oxygen demand (BOD), total suspended solids (TSS), Turbidity, Facial
coliform(FC), Sulfide( ), Total ammonia( ), nitrate( ), Nitrite( ), total nitrogen(TN),
total
phosphorous(T-P),were
76
%,
87
%,
93
%,
100%,
94
%,
80
%,
16.7
%,
97.7
%,
43
%,
46
%
respectively.
The
physiochemical
characters
of
treated
wastewater
were
complying
with
the
WHO standard for wastewater reuse in Irrigation of crops likely to be eaten uncooked.
However biological parameters were slightly above the guidelines.
Description
Keywords
River Source, Polluted River, Urban Agriculture, Wastewater Treatment, Vertical Subsurface Flow, Wetland