Monitoring and assessment of a novel halophyte-based two-stage electroecological system for remediation of brackish sewage

This study examines the performance of an innovative electroecological system for treating brackish sewage in five cycles with different salinity concentrations. Two systems were designed: a control and electroecological system using a halophytic-constructed wetland (Juncus rigidus, retention time 96 h) and an electrolytic cell (graphite electrode, external electric potential of 12 V applied for 8 h). The system effectively removed pollutants such as salinity (48–61.94%), COD (83.56–87.76%), BOD₅ (94.90–96.55%), TSS (90–92%), PO₄³⁻-P (98.46–99.6%), NH₄⁺-N (99.65%), NO₃⁻-N (71.94–91.96%), and NO₂⁻-N (79.66–86.88%) were achieved along with heavy metals like Cr (99.9%), Mn (47–55.97%), Mo (60.14–99.9%), Cd (30.77–99.9%), Zn (11.21–18.78%), and Al (14.93–99.9%) from wastewater and followed first-order kinetics. The electroecological system’s effectiveness was validated using statistical techniques like PCA and the Mann–Whitney U test. Pathogens, including Vibrio, E. coli, Pseudomonas, fecal Coliform, and Aeromonas, were nearly 99.9% removed, along with 99% of organic compounds, including emerging pollutants. Ion chromatography and inductively coupled plasma were used to study the accumulation of ions (Cl⁻, SO₄²⁻, Na⁺, K⁺, Mg²⁺, and Ca²⁺) in Juncus and their removal in water (around 83.15% K⁺, 30.53% SO₄²⁻, 29.53% Cl⁻, 26.45% Mg²⁺, 13.58% Na⁺, and 9.50% Ca²⁺). Juncus was efficient in accumulating K⁺ (66.99%) and Mg²⁺ (42.32%) ions. The electroecological system’s physical and biochemical analysis shows no salinity stress, showing potential for treating brackish sewage. No research has been reported on treating brackish sewage using a Junucs-based CW-electrolytic cell in the literature. It is a novel approach for independent wastewater treatment in coastal, remote, and rural areas.