Water Supply (Apr 2022)
River water treatment by continuous electrocoagulation: insights into removal of acetaminophen, and natural organic matter
Abstract
River water was treated by continuous electrocoagulation (EC) for acetaminophen (AP), natural organic matter (NOM measured as UV254), and removal of elements. HRT at 40 min with 0.5 mg/L AP exhibited the best removal efficiency for NOM (55.9%) and AP (53.4%) removal. Except for aluminium, other elements in river water were removed completely. The EC sludge (floating and settled) XRD spectrum showed peaks from AP were reduced, and the few peaks left were from aluminium hydroxide formed by EC. Several bonds in functional groups of AP and NOM were significantly deformed. FESEM images revealed that the sludge was highly porous material as needed for adsorption. EDAX showed that floating sludge had slightly higher carbon compared with settled sludge whereas nitrogen was higher in settled sludge. Other element concentrations in both sludges were similar, proving that water treatment was due to electro-floatation, adsorption, and sweep flocs. Single-factor ANOVA showed significant variance at HRT for NOM (F4.066 = 92.67, p = <0.05) and AP (F4.066 = 20.59, p = <0.05) removal. Variance was significant between treatments at different drug concentrations for NOM (F3.478 = 88.53, p = <0.05) and AP (F3.478 = 529.85, p = <0.05) removal. NOM removal correlated well with AP removal during continuous electrocoagulation. HIGHLIGHTS Continuous electrocoagulation with Al electrodes was effective for removal of acetaminophen and NOM from river water.; Continuous mode operation was influenced by HRT and acetaminophen at 2 mg/L.; Analysis of floating and settled sludge revealed that EC treatment was due to combination of electrofloatation, adsorption, and sweep flocs.; NOM can be used as a robust parameter to monitor removal of organic micropollutants;
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