Original scientific paper

Application of electrocoagulation devices for reducing ammonium concentrations

Goran Lončar orcid.org/0000-0002-6466-3677 ; Faculty of Civil Engineering, University of Zagreb, Zagreb, Croatia
Ivan Halkijević orcid.org/0000-0003-0694-3993 ; Faculty of Civil Engineering, University of Zagreb, Zagreb, Croatia
Hana Posavčić orcid.org/0000-0001-6555-482X ; Faculty of Civil Engineering, University of Zagreb, Zagreb, Croatia
Ivica Ban orcid.org/0000-0002-2297-9008 ; Faculty of Civil Engineering, University of Zagreb, Zagreb, Croatia

Abstract

The efficiency of an electrocoagulation (EC) device in the treatment procedure of wastewater in treating wastewater loaded with increased ammonium concentrations was analysed. The EC treatment optimisation procedure was carried out using measurements on the pilot device and a 3D numerical model of flow and transport. During the analyses, the flow through the reactors with iron (Fe) and aluminium (Al) electrodes was varied, including initial NaCl concentrations. Aside from the ammonium concentration (measured via NH4-N), the changes in the concentrations of nitrates (NO3-N), dissolved oxygen (DO), aluminium (Al3+) and chlorides (Cl-) as well as the changes in water temperature and pH in the in the chamber of the EC device were also monitored. Additionally, flow velocities were measured in a suitable number of positions.
By using a 3D numerical model, the flow fields and concentrations of primary process variables (NH4-N and NO3-N) in the process of their transport were determined. The model parameterization relies on the measurement results.
The results of the conducted research showed that the treatment efficiency primarily depends on the initial NaCl concentration, followed by the flow through the reactors while the selection of the electrodes’ material (Fe or Al) plays a less significant role. At the flow through the reactor’s electrodes of 0.03 dm s-1, applied current density of 150 A m-2 and initial NaCl concentration of 2 g dm-3, a reduction of ammonium concentration NH4-N of 36 % (Al electrode) i.e. 17 % (Fe electrode) was achieved after 120 minutes of the electrode operation. The increase in the nitrate concentration (NO3-N) in the stated conditions equalled 81 % (Al electrode) i.e. 19 % (Fe electrode).

Keywords

electrocoagulation; pilot device; numerical model; ammonium

Hrčak ID:

223140

URI

https://hrcak.srce.hr/223140

Publication date:

28.6.2019.

Article data in other languages: croatian

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