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Hybrid coagulation/ozonation treatment of pharmaceutical wastewater using ferric chloride, polyaluminum chloride and ozone
Shirafkan, A.; Nowee, S. M.; Ramezanian, N. & Etemadi, M. M.
Abstract
In recent years, concerns about the occurrence
and fate of active pharmaceutical ingredients, solvents,
intermediates and raw materials that could be present in
pharmaceutical industry effluents have gained increasing
attention. Conventional treatment methods, such as activated
sludge, are not sufficient enough to remove active
pharmaceutical ingredients completely. As a result, complementary
treatment methods like coagulation and flocculation
are often used and play a critical role in industrial
and municipal wastewater treatment. The primary goal of
these methods is to destabilize and remove colloidal particles
along with other organic/inorganic contaminants.
Recently empirical works have considered ozone as the
most promising oxidant for the removal of micro-pollutants.
The current study examined the effectiveness of
coagulation/flocculation process using ferric chloride,
polyaluminum chloride, and aluminum sulfate as a reasonable
approach to tackle the issue of treating pharmaceutical
wastewater. In addition, the results were compared
with the process using only ferric chloride that was the
coagulant of an actual treatment plant. Then, improvement
of the process performance was investigated using ozone as
an oxidant. In conclusion, it was found out that polyaluminum
chloride presented better performance among two
other coagulants and also adding 200 mg/L of polyaluminum
chloride can lead to 97–98 % turbidity removal
efficiency. Moreover, polyaluminum chloride was capable
of reducing most of the environmental parameters such as
chemical oxygen demand and total dissolved solid with the
removal efficiency of 70 and 68 %, respectively. Additionally,
ozonation improved the coagulation process,
especially iron ion removal, and dramatically decreased the
concentration from 5.68 to 0.19 mg/L.
Keywords
Coagulation; Environmental chemistry; Pharmaceuticals; Ozonation; Wastewater
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