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Bioremediation of river water using Moringa oleifera seed extract

A 4. Conclusion

The Bagmati River water is excessively polluted with
physicochemical and microbial pollutants, which were
more pronounced after the mixing of tributaries. The
color, turbidity, heavy metal concentration (chromium
and iron), MPN, and SPC exceeded the WHO limit. MO
(200 mg/L) reduced turbidity by up to 89.54% in B-2
water samples, transforming the black-colored water
B into clear and transparent. CAMO reduced turbidity
by 93.78% in B-1 water samples and by 92.80% in
B-2 water samples. The removal efficiency of heavy
metals by CAMO was 73.238% for Fe and 92.30% for
chromium. Similarly, there was a progressive decrease
in coliform counts, MPN, and SPC, with increasing
concentrations of MO. After treatment with CAMO,
the heavily polluted turbid river water became clean
and clear (i.e., within WHO standards). The results
collectively suggest that CAMO remediated the heavily
polluted river water more effectively than MO (i.e.,
without citric acid treatment) at 100 mg/L, although
both extracts are effective coagulants and bio-adsorbents
in water treatment. Despite the necessity for further
investigations regarding purification on a pilot scale,
Figure 6. Percentage removal/reduction of turbidity, the analytical results suggest that MO seed extracts are
heavy metals, and hardness using Moringa oleifera effective in treating the Bagmati River water on a small
(MO) and citric acid‑treated MO seed extracts in scale, providing clean and clear water. MO seed extracts
water samples from (A) Pashupati (B‑1) and (B) are useful as an eco-friendly, economical, non-toxic, and
Balkhu (B‑2) sites simple natural coagulant for the purification of highly
polluted and microbiologically contaminated water.
92.80%, respectively, when treated with CAMO. There
was a 57.2% and 55.5% reduction in iron concentration Acknowledgments
in B-1 and B-2 samples treated with MO; the reduction
was more than 70% in both water samples when Authors are thankful to the University Grants
treated with CAMO. Similarly, the removal efficiency Commission, Nepal for their support.
of chromium was up to 90% for CAMO treatment and
approximately 80% for MO treatment. The hardness Funding
reduction efficiency of CAMO was also higher than
that of MO for both the river water samples B-1 and This research was partially supported by the University
B-2. The MPN and SPC were reduced by more than Grants Commission, Nepal, through the Collaborative
2 times for CAMO treatment than that for MO in the Research Grants (CRG-79/80-S and T-01).
B-2 river water sample (Table 2). Taken together, the
results suggest that MO efficiently reduces turbidity, Conflict of interest
heavy metals (iron and chromium), and microorganisms
from polluted river water. The chemical treatment of The authors declare no competing interest.
MO enhances metal removal capacity and other bio-
remedial activity by developing efficient adsorption sites Author contributions
to increase coagulation activity. Therefore, chemical
modification increases the surface areas and adsorption Conceptualization: All authors
sites, thereby enhancing the coagulation ability of MO Investigation: Manisha Neupane
and the uptake of pollutants from water. 19 Methodology: Manisha Neupane

Volume 22 Issue 1 (2025) 49 doi: 10.36922/ajwep.8434