Factors influencing arsenic and nitrate removal from drinking water in a continuous flow electrocoagulation (EC) process

J Hazard Mater. 2010 Jan 15;173(1-3):528-33. doi: 10.1016/j.jhazmat.2009.08.117. Epub 2009 Sep 2.

Abstract

An experimental study was conducted under continuous flow conditions to evaluate some of the factors influencing contaminant removal by electrocoagulation (EC). A bench-scale simulation of drinking water treatment was done by adding a filtration column after a rectangular EC reactor. Contaminant removal efficiency was determined for voltages ranging from 10 to 25 V and a comparative study was done with distilled water and tap water for two contaminants: nitrate and arsenic(V). Maximum removal efficiency was 84% for nitrate at 25 V and 75% for arsenic(V) at 20 V. No significant difference in contaminant removal was observed in tap water versus distilled water. Increase in initial As(V) concentration from 1 ppm to 2 ppm resulted in a 10% increase in removal efficiency. Turbidity in the EC reactor effluent was 52 NTU and had to be filtered to achieve acceptable levels of final turbidity (5 NTU) at steady-state. The flow regime in the continuous flow reactor was also evaluated in a tracer study to determine whether it is a plug flow reactor (PFR) or constantly stirred tank reactor (CSTR) and the results show that this reactor was close to an ideal CSTR, i.e., it was fairly well-mixed.

MeSH terms

  • Arsenic / isolation & purification*
  • Electric Conductivity
  • Electrochemistry
  • Electrodes
  • Hydrogen-Ion Concentration
  • Nephelometry and Turbidimetry
  • Nitrates / isolation & purification*
  • Sewage / analysis
  • Water Purification / methods*
  • Water Supply / analysis*

Substances

  • Nitrates
  • Sewage
  • Arsenic