Biochar-modified constructed wetlands using Eclipta alba as a plant for sustainable rural wastewater treatment

• Published in: Environmental science and pollution research international 2024-03, Vol.31 (11), p.17299-17310
• Main Authors: Panghal, Vishal, Singh, Asha, Arora, Dinesh, Kumar, Sunil
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Artificial wetlands; Atmospheric Protection/Air Quality Control/Air Pollution; Biochemical oxygen demand; Carbon footprint; Charcoal; Chemical oxygen demand; Developing countries; Domestic wastewater; Earth and Environmental Science; Eclipta alba; Ecotoxicology; Efficiency; Environment; Environmental Chemistry; Environmental Health; Hydraulic retention time; LDCs; Nitrates; Phosphates; Pollutant removal; Pollutants; Pyrolysis; Research Article; Retention time; Substrates; Sulfates; Variance analysis; Waste Water Technology; Wastewater treatment; Water Management; Water Pollution Control; Water treatment; Wetlands
• ISSN: 1614-7499; 0944-1344; 1614-7499
• DOI: 10.1007/s11356-024-32144-0

Constructed wetlands (CWs) provide a low-cost, effective solution for domestic wastewater treatment in developing nations compared to costly traditional wastewater systems. Biochar which is an organic material created by pyrolysis offers straightforward, affordable methods for treating wastewater and lowering carbon footprint by acting as a substrate in CWs. Batch mode biochar-amended subsurface flow (SSF) CWs planted with Eclipta alba (L) with a hydraulic retention time (HRT) of 3 days were used for the treatment of rural domestic wastewater in the present investigation. Two control CWs, without plants (C1) and with plants (C2), and five different amendments of biochar 5% (B5), 10% (B10), 15% (B15), 20% (B20) and 25% (B25) in ratio with soil were set up to check the treatment efficiency of CWs. Removal efficiency (RE%) of the CWs for parameters namely chemical oxygen demand (COD), biochemical oxygen demand (BOD), phosphate (PO 4 2− ), sulphate (SO 4 2− ), nitrate (NO 3 − ) and total Kjeldhal nitrogen (TKN) was determined using standard methods. Removal efficiency of 93%, 91%, 74% and 77% was observed for BOD, COD, nitrate and sulphate, respectively, in the B25 amendment at HRT 72 h. The highest removal of TKN (67%) was also observed in the B25 amendment at HRT of 72 h. No stable trend for the removal of phosphates was found during the study, and maximum removal was observed at HRT 48 h; afterward, phosphate was slightly inclined with the increasing HRT. The findings of one-way ANOVA using Tukey’s test show significant variations ( p