Optimization of a continuous hybrid moving bed biofilm reactor and constructed wetland system for the treatment of paracetamol-spiked domestic wastewater

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2023-12, Vol.477, p.147139, Article 147139
• Main Authors: Kamilya, Tuhin, Majumder, Abhradeep, Saidulu, Duduku, Tripathy, Subhasish, Gupta, Ashok K.
• Format: Article
• Language: English
• Subjects: Artificial neural network; C/N ratio; Canna indica L; Nitrification; Plant uptake; Polyurethane foam carrier
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.147139

[Display omitted] •Recalcitrant fraction of the wastewater could be removed sustainably by PUMBBR-CW.•PUMBBR-CW could remove around 95% of paracetamol and COD from wastewater.•Paracetamol was uptaken and stored in the Canna indica L. plant leaves (216 µg/g)•Removal efficiency of NH4+ and paracetamol was relatively high at a low C/N ratio.•High COD concentration is favorable for paracetamol removal in anoxic conditions. A continuous system of moving bed biofilm reactor (MBBR) integrated with horizontal subsurface flow constructed wetland (HSSFCW) followed by a sedimentation tank (PUMBBR-CW) was used for the removal of chemical oxygen demand (COD), ammonia (NH4+), and paracetamol. The removal performance of the reactor was analyzed by varying the initial concentration of the pollutants, hydraulic retention time (HRT), and COD to NH4+ ratio (C/N ratio). Polyurethane foam (PUF) waste was used as the bio-carrier in the MBBR system. Microbial degradation, plant uptake, and substrate adsorption were the most dominant removal mechanisms in the PUMBBR-CW. Further insights into the degradation mechanisms were investigated by characterizing the substrate and bio-carrier and analyzing the degradation by-products. More than 95 % of COD removal was achieved with 30.6 h HRT and 550 mg/L initial concentration at a C/N ratio of 10. At 30.6 h HRT and a C/N ratio of 4, 87 % NH4+ and 94 % paracetamol removal were achieved. The low C/N ratio favors paracetamol removal, as the microorganism uses paracetamol as the sole carbon source under low C/N conditions. Moreover, it was found that paracetamol was uptake and stored in the Canna indica L. plant leaves (216 µg/g). An artificial neural network (ANN) was developed to find the optimum operating condition with maximum removal efficiency. The PUMBBR-CW system effectively overcame the drawbacks of conventional wastewater technologies, such as high footprint, variable pollutant loads, and high maintenance. Hence, it can be used as a highly efficient method of treating wastewater.