The Combination of Anaerobic Digestion and Electro-Oxidation for Efficient COD Removal in Beverage Wastewater: Investigation of Electrolytic Cells

Abstract

The world’s ever-growing population is driving an increased demand for clean water, which makes treating and reusing wastewater an essential practice. In recent years, biological and physicochemical methods have been preferred for wastewater treatment, with combined systems proving particularly effective. In this study, the combination of anaerobic digestion (AD) and electro-oxidation (EO) was investigated as a process for removing chemical oxygen demand (COD) from actual beverage wastewater. The effect of hydraulic retention time (HRT) on AD, electrolysis time, sodium chloride (NaCl) dosage, initial pH, and electro-properties on EO was investigated. At optimum conditions, namely an HRT of 2 days for AD, NaCl concentration of 3 g L−1, 80 min of EO time, natural pH (7.45), and applied voltage of 20 V for EO, the removal efficiency for COD was an impressive 96.47%, with energy consumption and specific energy consumption calculating 177.33 kWh m−3 and 33.79 kWh kgCOD−1, respectively. The amount of by-product gases (CH4 and H2) were also meagerly determined in this study. The results confirm that combining the AD and EO methods is an effective COD removal solution that can benefit the industry, while also offering a sustainable solution to combat water scarcity and meet the growing demand for clean water.

Integrated Electrochemical Oxidation and Biodegradation for Remediation of a Neonicotinoid Insecticide Pollutant

“…Among all NEOs, AC was efficiently degraded by P. oleovorans due to its mineralization activity. 50 This study confirms the effective degradation of NEOs by the potential isolate Pseudomonas sp. Previous studies have demonstrated that Pseudomonas stutzeri OX1 undergoes similar hydroxylation for the degradation of nicotinoid (IM) through the secretion of enzymes.…”

“…The newly shifted peaks at aromatic stretching 1609.33 cm –1 shifted to 1638.12 cm –1 and CH aliphatic group 1372.58 cm –1 shifted to 1379.61 cm –1 , and the C–N stretching peaks at 1107.04 cm –1 shifted to 1121.43 cm –1 and 999.86 cm –1 shifted to 1007.06 cm –1 . Peaks of aromatic and aliphatic compounds (peaks) 2921.83, 2850.65, 1609.33, 1372.58, and 619.95 cm –1 were highly reduced due to the EO compared to those of the untreated NEOs. ,, The IR spectrum of the CL system showed that the peaks at 2929.36, 2857.34, 1315.62, 1221.78, and 1120.96 cm –1 were highly reduced, which was due to the degradation of the molecules. − …”

“…process effectively reduces the concentration of nicotinoids, particularly at the initial concentration. 50,51 Estimation of TOC and COD. The removal of TOC during EO, BD, and integrated EO and BD (BEO) is presented in Figure 4.…”

“…51 EO of NEOs. FTIR spectroscopy spectra of untreated and treated NEOs by EO are presented in Figure S4 and Tables 50,51,54 The IR spectrum of the CL system showed that the peaks at 2929.36, 2857.34, 1315.62, 1221.78, and 1120.96 cm −1 were highly reduced, which was due to the degradation of the molecules. 55−58 In EO-treated AC, the IR spectrum showed significantly reduced peaks at 3453.47 cm −1 (N−H stretch), 2929.36, 2864.54 cm −1 (C−H aliphatic stretch), 1630.67 cm −1 (C�C aromatic stretch), 1106.55 cm −1 (C−N stretch), and 805.69 cm −1 (aromatic nuclei peak).…”

“…The biodegradation efficiency of COD removal from IM was 69%, followed by CL (61%), AC (79%), and TH (57%), respectively. Among all NEOs, AC was efficiently degraded by P. oleovorans due to its mineralization activity …”