Following biological treatment, wastewater continues to have endotoxic active materials. However,\nbecause there is a trend of potable reuse and because endotoxic active materials potentially\nhave harmful effects on human health, their removal from water is crucial. Lipopolysaccharide\nendotoxin has hydrophobic groups, and their removal using a coagulation-flocculation alternative\nis believed to be efficient. Thus, their removal from reclaimed wastewater using the coagulationflocculation\nprocess was assessed. Secondary effluent samples from a wastewater treatment plant\nlocated in Sapporo, Japan, were investigated. It was found that this process gave satisfactory results\nin removing endotoxins, with an optimum removal rate of up to 40.5%. The endotoxin removal\nwas maximized by adjusting the pH at the low range 4 - 5.5, with an aluminum sulfate dose\nof 80 mg/L. Further increases of the coagulant dose did not improve the removal efficiency. DOC\nand turbidity removal were at their optimum at higher pH range 5.5 - 6.5. Thus coagulation and\nflocculation could be considered as the first barrier and should be followed by other treatments to\nsafely reuse reclaimed wastewater.
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