Journal of Applied and Natural Science 4(2):304-309(2012)
Efficiency of turbidity and BOD removal from secondarily treated sewage by electrochemical treatment
A. K. Chopra and Arun Kumar Sharma
Department of Zoology and Environmental Sciences Gurukula Kangri University, Haridwar-249404 (Uttarakhand), INDIA *Corresponding author. E-mail: email@example.com Received: September 12, 2012; Revised received: October 15, 2012; Accepted: November 20, 2012
Abstract : The present investigation observed the effect of operating time, current density, pH and supporting electrolyte on the removal efficiency of Turbidity (TD) and Biochemical oxygen demand (BOD) of secondarily treated sewage (STS) using electrochemical process. A glass chamber of 2 litre volume was used for the experiment with two electrode plates of aluminum, each having an area of 125 cm2 and 2 cm distance apart from each other. The treatment showed that the removal efficiency of TD and BOD increased to 87.41 and 81.38 % respectively with the increase of current density (1.82 -7.52 mA/cm2), time (5 - 40 mins.) and different pH (4-8) of the STS. The most effective removal efficiency was observed around the pH 7. Further, 0.5 g/l NaCl as a supporting electrolyte for electrochemical treatment of STS was found to be more efficient for an increase to 95.56 % and 86.99 % for the removal of TD and BOD at 7.52 mA/cm2 current density in 40 mins. respectively. The electrode and energy consumption was found to vary from 2.52 x10-2 to 10.51 x10-2 kg Al/m3 and 2.76 kwh/m3 to 45.12 kWh/m3 depending on the operating conditions. The kinetic study results revealed that reaction rate (k) increased from 0.0174 to 0.03 min-1 for TD and 0.0169 to 0.024 min-1 for BOD with increase in current density from 1.82 to 7.52 mA/cm2.
Keywords : Aluminium electrode, BOD, Current density, Electrochemical treatment, Supporting electrolyte