Abstract
Coagulation–flocculation has been proven as one of the effective processes in treating palm oil mill effluent (POME), which is a highly polluted wastewater generated from palm oil milling process. Two pairs of natural coagulant–flocculant were studied and evaluated: peanut–okra and wheat germ–okra. This research aims to optimize the operating parameters of the coagulation flocculation process in removing turbidity, total suspended solid and chemical oxygen demand (COD) from POME by using a central composite design in the Design Expert® software. Important parameters such as operating pH, coagulant and flocculant dosages were empirically determined using jar test experiment and optimized using response surface methodology module. Significant quadratic polynomial models were obtained via regression analyses (R2) for peanut–okra (0.9355, 0.9534 and 0.8586 for turbidity, total suspended solids and COD removal, respectively) and wheat germ–okra (0.9638, 0.9578 and 0.7691 for turbidity, total suspended solids and COD removal, respectively). The highest observed removal efficiencies of turbidity, total suspended solids and COD (92.5, 86.6 and 34.8%, respectively, for peanut–okra; 86.6, 87.5 and 43.6%, respectively, for wheat germ–okra) were obtained at optimum pH, coagulant and flocculant dosages (pH 11.6, 1000.1 mg/L and 135.5 mg/L, respectively, for peanut–okra; pH 12, 1170.5 mg/L and 100 mg/L, respectively, for wheat germ–okra). The coagulation flocculation performance of peanut–okra and wheat germ–okra were comparable to each other. Characterizations of the natural coagulant–flocculant, as well as the sludge produced, were performed using Fourier transform infrared, energy-dispersive X-ray spectroscopy and field emission scanning electron microscope. More than 98% of water was removed from POME sludge by using centrifuge and drying methods, indicating that a significant reduction in sludge volume was achieved.
Original language | English |
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Pages (from-to) | 1951-1970 |
Number of pages | 20 |
Journal | Clean Technologies and Environmental Policy |
Volume | 20 |
Issue number | 9 |
Early online date | 13 Oct 2018 |
DOIs | |
Publication status | Published - Nov 2018 |
Bibliographical note
Publisher Copyright:© 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
Acknowledgements
We want to express our gratitude to Seri Ulu Langat Palm Oil Mill Sdn Bhd for providing the POME samples throughout the research studies.
Keywords
- Coagulation–flocculation
- Okra
- Peanut
- POME
- Water treatment
- Wheat germ
ASJC Scopus subject areas
- Environmental Engineering
- Environmental Chemistry
- Management, Monitoring, Policy and Law