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Bioremediation of river water using Moringa oleifera seed extract

Table 1. The Bagmati River water quality (507 µS/cm). The higher conductivity downstream is
observed at Pashupati (B‑1) and Balkhu (B‑2) attributed to the confluence of tributaries, and domestic
sites in Kathmandu Valley effluent extensively increased the levels of conductive
Measured parameters Site WHO pollutants in the Bagmati River downstream. The
Pashupati Balkhu observed concentration of iron and chromium at both
(B‑1) (B‑2) observation sites was very high. The concentrations were
Color Brown Black Colorless more than 4 times higher than the WHO-recommended
values (Table 1). The common biological pollutants are
Turbidity (NTU) 35.4 26.4 5 – 10 microorganisms. The MPN (total coliforms), calculated
pH 7.1 6.9 6.5 – 8.5 quantitatively in the river water samples, was 1100
Total hardness (ppm) 62 104 500 (Table 1). The presence of coliform designates that the
Conductivity (µS/cm) 95.7 507 1500 river water was polluted by fecal pollutants; hence, it is
Iron, Fe (ppm) 1.31 1.53 0.3 not safe for any domestic and agricultural use. The SPC
Chromium, Cr (ppm) 0.27 0.39 0.05 indicates total bacterial counts, which were calculated
MPN/100 mL 1100 1100 Nil quantitatively. The SPC of ten-fold serially diluted
water samples was beyond the standard limit (i.e., it was
SPC/100 mL TMTC TMTC 18×10 6 too many to count [TMTC]). Both total coliforms and
Note: The World Health Organization values are based on the bacterial counts were extremely high in both observation
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standard recommended measurements . sites, and both values were extremely high compared
Abbreviations: NTU: Nephelometric turbidity units; MPN: Most
probable number; SPC: spread plate count; TMTC: Too many to to the WHO limit (Table 1). From the observed water
count. quality parameters, the river water was heavily polluted
and cannot be used as it is for any domestic, agricultural,
or industrial purposes. The heavily polluted Bagmati
River water was treated using MO and CAMO.

3.2. FTIR spectroscopic analysis of MO seed
extracts
The MO seed is a lignocellulosic material consisting
of cellulose, hemicellulose, and lignin; its adsorption is
mainly controlled by the surface functional groups of
adsorbents. The treatment of water by MO is based on
the adsorption of oppositely charged particles for charge
neutrality that stabilizes the particles and binds with each
other by a coagulation mechanism. Hence, the surface
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functional groups in the adsorbents are important for the
Figure 2. Water samples collected from the Pashupati adsorption. The surface functional groups present on
site (B‑1) and Balkhu site (B‑2) the surface of MO and CAMO were determined using
FTIR spectroscopy (Figure 3). The peaks between 1750
The pH observed was 7.1 at the B-1 site and 6.9 at the and 1630 cm represent C=O stretching. The carbonyl
-1
B-2 site. Both pH values were within the WHO limit group may be partly bonded with fatty acids of lipids
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(i.e., 6.5 – 8.5) for drinking water, though water from B-2 or amides of protein. The carbonyl peak of lipids was
was slightly acidic. The calcium and magnesium ions observed at 1750 cm . The peak at 1650 cm was due
-1
-1
as bicarbonates, sulfates, and chlorides in the water are to the stretching of CN and the deformation of N-H in
represented by hardness. The observed total hardness of proteins. The high protein content (i.e., amide bonds)
the B-1 and B-2 sites was 62 and 104 ppm, respectively. in the seeds contributes to N-H stretching. The peaks
Conductivity measures the conducting species from at 2850 and 2900 cm in the spectra of both MO and
-1
inorganic and organic substances in the water. Inorganic CAMO correspond to symmetric and asymmetric
ions have higher mobility than organic ions, leading to C-H bond stretching. The intense peaks indicated the
a greater influence on conductivity. The conductivity possible presence of predominating lipid components.
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of the river water was very low (95.7 µS/cm) at B-1 A comparison of FTIR spectra of MO and CAMO
sites; however, it was 5 times higher at the B-2 site powder revealed a stronger stretching vibration band

Volume 22 Issue 1 (2025) 45 doi: 10.36922/ajwep.8434