Page 49 - {PDF Title}

Bioremediation of river water using Moringa oleifera seed extract

react with different organic substances, converting them in a refrigerator, for use in water treatment. The required
into carcinogens, such as trihalomethane. Another amount of powder was dissolved in 100 mL distilled
5
chemical coagulant, aluminum sulfate (alum), is also water stirred for 1 h with a magnetic stirrer and filtered
used for water purification; however, residual alum is using Whatman 41 filter paper used as stock solution.
potentially hazardous to human health, and relatively Fresh solutions of MO and CAMO were prepared daily
high concentrations are linked to Alzheimer’s disease. to avoid aging effects. The calculated volume of stock
6
Hence, locally available natural coagulants, such as solution was added to the water sample to obtain 50,
Moringa oleifera (MO), offer a non-toxic alternative for 100, and 200 mg/L concentrations for the treatment.
treating turbid and polluted water. 7-9 The mixture was shaken at 200 rpm for 10 min to ensure
MO belongs to a cultivated species of the Moringaceae total dispersal of coagulant and at 30 rpm for 30 min to
family. It was introduced to Africa from India for use aid effective flocculation of colloidal particles, then left
10
as health supplements. It is a fast-growing, medium, or for 1 h for the flocs to settle. The supernatant (water)
11
small tree found in the tropical and subtropical regions was collected and analyzed for various parameters. 21-23
of northern India, as well as different parts of Asia, Sample water was collected from two different sites
Africa, and South America. 10,11 Different parts of MO of the Bagmati River; one was the Pashupati area (B-1)
are useful for bio-remediation and water purification. 12-15 before the confluence of its tributaries, and the other
MO seeds contain a protein suitable for binding to toxic was the Balkhu area (B-2) after the mixing of tributaries
materials. 16,17 The positively charged surface molecules to the mainstream Bagmati River in Kathmandu valley
attract negatively charged particles from water through (Figure 1). The samples were collected in sterilized
adsorption and form a larger molecule (floc), which biological oxygen demand (BOD) bottles (3), Q
is capable of removing heavy metals and dirt, as well transported to the laboratory using a cooler box and
as killing bacteria from contaminated waters. 18,19 stored in a refrigerator for subsequent physicochemical
Omodamiro et al. evaluated the activity of ethanolic analysis and treatment. For microbiological analysis,
20
extract MO seeds in water purification and revealed that the samples collected in the sterilized BOD bottles were
the seeds possess inhibitory potential against various kept in a zip-lock pouch and then transported into the
pathogens, improving the physicochemical properties laboratory using a cooler box for immediate analysis.
of the water sample. The present study explored the Water quality parameters were measured according
effect of different concentrations of MO seed extract to the standard procedure; pH was measured using a
for the treatment of heavily polluted river water and digital pH meter (CE, pH600AQ; Milwaukee, USA),
compared the results with that of citric acid-modified turbidity was measured using a digital nephelometer
MO seed extract (CAMO). (no. Digital Turbidity Meter 341; Electronics India,
India), and conductivity was measured using a
2. Materials and methods conductometer (CE, 1739; NSAW, India). Total
hardness was determined by complexometric titration,
Dried MO seeds were collected from a local market and the concentration of heavy metals (Cr and Fe)
in Kathmandu, Nepal. The seeds were shielded and was determined using a visible spectrophotometer
dried for 3 days at 30°C. The seeds were ground to a (ELICO, SL-177; Hyderabad, India). 22,23 Before the
fine powder and sieved using a 212 µm sieve aperture. determination of iron concentration, ferric ions were
The surface functional group content of the MO and reduced to ferrous ions by boiling with hydroxylamine
CCMO seed powder was determined using Fourier hydrochloride, while chromium was oxidized into
transform infrared spectroscopy (FTIR; Nicolet 4700; hexavalent chromium using potassium permanganate.
Thermo Eectron, USA). CAMO was prepared by The total iron was determined using phenanthroline,
stirring a mixture of MO seed powder and 0.1 M NaOH and chromium was determined using diphenylcarbzide
at 300 rpm for 1 h. The excess base was removed by methods. Bacteriological parameters were estimated
washing the mixture with double-distilled water and using the most probable number (MPN) method and the
then mixed with citric acid in a 1:7 mass by volume spread plate count (SPC) method. The MPN technique
(g/mL) ratio. The slurry was kept at 50°C overnight, was conducted in three steps: presumptive, confirmed,
subsequently washed with distilled water, and the and completed tests. In the presumptive test, known
excess citric acid removed. The treated seed powder amounts of samples were tested in 10 sterile Durham
was dried and sieved to retain fine powder. The citric tubes. The inoculated broths were then incubated at
acid-modified seed powder was stored in a plastic bottle 37°C for 24 h. The change in color and gas formation

Volume 22 Issue 1 (2025) 43 doi: 10.36922/ajwep.8434