Predicting As removal during metal hydroxide precipitation

Journal Article · Wed Jan 01 04:00:00 EST 1997 · Journal of the American Water Works Association

OSTI ID:435408

McNeill, L S; Edwards, M ^[1]

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1. Univ. of Colorado, Boulder, CO (United States). Dept. of Civil Engineering

A simplified isotherm is described that can predict the extent of arsenate removal at drinking water utilities practicing coagulation or iron-manganese (Fe-Mn) removal. If all possible sources of particulate iron and aluminum hydroxide present in the system are accounted for, the model predicts arsenic (As) removal to within {+-}13 percent (90 percent confidence) for Fe coagulation at pH 6.5--8 and alum coagulation at pH < 7.6. Analysis of full-scale treatment data suggests that colloidal aluminum (Al) flocs with sorbed arsenate [As(V)] may pass through filters, thereby decreasing overall As removal efficiency. Thus, Al solubility and particle stability must be minimized to improve As removal. If stability and solubility of aluminum hydroxide flocs are not a problem, alum and Fe coagulants have nearly equal capacity for sorbing As(V). Survey results also demonstrate the importance of particulate As.

• OSTI ID: 435408
• Journal Information: Journal of the American Water Works Association, Journal Name: Journal of the American Water Works Association Journal Issue: 1 Vol. 89; ISSN 0003-150X; ISSN JAWWA5
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
ARSENIC
MATHEMATICAL MODELS
WATER POLLUTION ABATEMENT
WATER TREATMENT
WATER TREATMENT PLANTS