Electrocoagulation process for phosphate recovery of agricultural wastewater: effect of calcium adding, voltage, and time

• Published in: Environmental monitoring and assessment Vol. 196; no. 9; p. 842
• Main Authors: Oktiawan, Wiharyanto, Sarminingsih, Anik, Hadiwidodo, Mochtar, Purwono, Purwono
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-09-2024; Springer Nature B.V
• Subjects: Agricultural wastes; Agriculture - methods; Atmospheric Protection/Air Quality Control/Air Pollution; Calcium; Calcium - analysis; Calcium - chemistry; Calcium channels (voltage-gated); Calcium content; Calcium phosphates; Cathodes; Coagulation; Configurations; Earth and Environmental Science; Ecology; Ecotoxicology; Efficiency; Electric potential; Electrocoagulation; Electrocoagulation - methods; Electrodes; Electrolysis; Environment; Environmental Management; Flocculation; Flotation; Heavy metals; Hydroxides; Monitoring/Environmental Analysis; Nitrogen; Nutrient cycles; Phosphate; Phosphates; Phosphates - analysis; Phosphonates; Power supply; Precious metals; Reactors; Recovery; Response surface methodology; Stainless steel; Stainless steels; Statistical analysis; Statistical methods; Statistical models; Total organic carbon; Voltage; Waste Disposal, Fluid - methods; Waste recovery; Wastewater; Wastewater - chemistry; Wastewater treatment; Water Pollutants, Chemical - analysis; Water treatment; Calcium concentration; Helical electrodes; TOC; Phosphate recovery, Electrocoagulation; Wastewater treatment
• ISSN: 0167-6369; 1573-2959; 1573-2959
• DOI: 10.1007/s10661-024-13034-x

Recovery of valuable resources, such as phosphate recovery from wastewater, can help close the nutrient cycle and is interesting to investigate. This study aims to evaluate phosphate recovery and set aside TOC, OC, and IC in agricultural wastewater using electrocoagulation with a helix electrode configuration. This study employed the Response Surface Methodology (RSM) for statistical analysis and modeling, utilizing a central composite design (CCD). Variation of calcium concentration (2–7 mg/L), voltage (15–45 V), and electrocoagulation time (5–15 min) was applied in an electrocoagulation reactor with a helix-shaped stainless steel cathode and a solid cylindrical Mg anode. Based on RSM analysis, electrocoagulation with a helical electrode configuration significantly affects phosphate recovery and the removal of TOC, OC, and IC when treating agricultural wastewater. Under operating conditions of 15 V, 15 min time, and 2 mg/L calcium concentration, we achieved the lowest phosphate concentration of 0.003 mg/L (99.74% reduction). The highest TOC allowance is > 100% of the initial concentration, the TC allowance is 55.79%, and the IC allowance is 30.91%. The formation of metal hydroxides affects the efficiency of TOC removal in the electrocoagulation process, and higher electrolysis times lead to higher TOC removal efficiency. Higher voltages also improve the coagulation and flotation processes in the reactor. Calcium concentration plays a role in enhancing the flocculation process and binding phosphonates from wastewater.