Evaluation of bipolar electrocoagulation applied to biofiltration for phosphorus removal

Abstract

To reduce the residual organic matter and phosphorus contained in secondary effluent, a biofiltration system combined with electrocoagulation using bipolar iron electrodes was evaluated as a supplementary treatment to existing small-community sewage treatment. Based on the results of batch tests, bipolar electrocoagulation (BEC) was found to be more effective on phosphorus removal than monopolar electrocoagulation (MEC) but energy consumption was less in monopolar electrocoagulation. Optimum conditions of BEC to treat the secondary effluent were current density 15 A/m2, electrode spacing 1 cm and pH < 8. The removals of COD(Cr) and phosphorus by biofiltration system without BEC were 69.1% and 9.6%, respectively. However, biofiltration system combined with BEC showed 76.6-83.7% and 70.7-93.0% removal for COD(Cr) and phosphorus respectively. Extraordinary increase in phosphorus could be achieved by introducing electrocoagulation to biofiltration, and BEC/biofiltration system was evaluated to be applicable to existing small-community sewage treatment plants as a supplementary process.

Improvement of Arsenic Electro-Removal from Underground Water by Lowering the Interference of other Ions

“…Only the highest current density of 45 A m −2 was selected to exemplify the EC process for GW because the treatment time was relatively large (>15 min) when lower current densities were applied. These used current density values are consistent with those reported in the literature for this process (Kumar et al 2004;Yu et al 2005;Yilmaz et al 2005).…”

An empirical model for treatment of arsenic contaminated underground water by electrocoagulation process employing a bipolar cell configuration with continuous flow

“…In On the other hand, the selected current density values are consistent with those reported in the literature for this process (Yu et al 2005).…”

“…Some researches have developed the electrocoagulation with batch reactors and large interelectrode space greater than 0.5 cm (Yu et al 2005;Gomes et al 2007). In most of the reported works, the EC process has been applied for treatment of wastewater and model water (Chen et al 2000;Cheremisinoff 2001;Chen 2004).…”

Treatment of rinse water from zinc phosphate coating by batch and continuous electrocoagulation processes

“…Removal mechanism of phosphate with iron electrode is complicated with respect to solution pH, iron concentration and presence of ferrous and ferric iron, respectively. In the case of ferric iron, at the Fe 3+ /PO 4 : 1/1 on the molar basis FePO 4 and at higher molar ratio Fe 2.5 PO 4 (OH) 4.5 is precipitated [40]. In the case of ferrous iron Fe 3 (PO 4 ) 2 ·8H 2 O is precipitated.…”