Optimization of phosphorus recovery using electrochemical struvite precipitation and comparison with iron electrocoagulation system

Abstract

A batch monopolar reactor was developed for total phosphorus (TP) recovery using electrochemical struvite precipitation. This study involves the optimization of factors using response surface methodology to maximize the TP recovery. The optimal parameters for this study were found to be a pH of 8.40, a retention time of 35 min, a current density of 300 A/m2, and an interelectrode distance of 0.5 cm, resulting in 97.3% of TP recovery and energy consumption of 2.35 kWh/m3. A kinetic study for TP removal revealed that at optimum operating conditions, TP removal follows second‐order kinetics (removal rate constant(K) = 0.0117 mg/(m2·min)). The system performance was compared to the performance of an iron electrocoagulation system. The composition of the precipitate obtained during the optimal runs were analyzed using X‐ray diffraction and EDS analysis. X‐ray diffraction analysis of the magnesium precipitate revealed the presence of struvite as the only crystalline compound. Practitioner Points Electrochemical struvite precipitation has the potential to recover total phosphorus from anaerobic bioreactor effluent. Optimum conditions for phosphorus recovery was found at a pH of 8.4, retention time of 35 min, current density of 300 A/m2, and interelectrode distance of 0.5 cm. The quadratic model predicted complete (100 %) TP recovery under optimized conditions, whereas 97.3 % recovery was observed under experimental conditions. TP removal under optimum conditions followed second‐order rate equation (removal rate constant(K) = 0.0117 mg/(m2·min)). XRD analysis of the precipitate revealed struvite as the only crystalline compound.

Optimizated Operational Conditions for Removal of Discharged Toxic Silver Nanoparticles from Wastewater using Electrocoagulation

“…Color removal 100% at 80 min., COD concentration 147 ppm, at 13.56 kWh/L. For durable biochar cathode, 0.0058 kWh/m3 for 90% phosphate removal that was 65% less than that of using carbon cathode [51]. 4.75 KWh/kg were required for removal nitrogen [52].…”

“…Alexandria Journal of Science and Technology, 2023, 1(1),[44][45][46][47][48][49][50][51][52][53][54] Online ISSN: 2974-3273 Article…”

Phosphate Removal Efficiency and Life Cycle Assessment of Different Anode Materials in Electrocoagulation Treatment of Wastewater

“…Omwene et al used aluminum and ferrous metals as anodes in electrocoagulation tests and discovered that aluminum anodes required shorter energization times and achieved improved treatment efficiency [41]. Meanwhile, magnesium metal has drawn increasing attention as a potential anode because of the nonrenewable nature of phosphorus [42,43].…”