Vol.:(0123456789) International Journal of Environmental Science and Technology (2025) 22:273–288 https://doi.org/10.1007/s13762-024-05647-z ORIGINAL PAPER Impact of a mixture of metal ions on the eﬃciency of packed bed anaerobic reactor treating wastewater S. I. Abou‑Elela 1 · M. M. El‑Sorogy 2 · M. E. Fawzy 1 Received: 24 October 2022 / Revised: 7 March 2024 / Accepted: 10 April 2024 / Published online: 3 May 2024 © The Author(s) under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University 2024 Abstract Heavy metal bioremediation from wastewater has gained great attention due to their high toxicity and non-biodegradable nature. They should be treated before discharge to water bodies. Assessment and evaluation of the impact of diﬀerent concen- trations of a mixture of heavy metal ions, namely Zn 2+ , Pb 2+ , Cu 2+ and Cr 6+ on the eﬃciency of a pilot plant hybrid up-ﬂow anaerobic sludge blanket packed with novel packing media treating real municipal wastewater was investigated. The packing media is a novel non-woven polyester fabric (NWPF) that entraps heavy metal ions, subsequently reducing their toxicity on anaerobic sludge that aﬀects the performance of UASB. It promotes faster biomass propagation and organic matter removal due to their unique characteristics and morphology. The size of the reactor was 1.81 m 3 and was continually fed with diﬀerent heavy metal ions at a ﬂow of 5.76 m 3 /day. Incremental increase of the concentrations of metal ions from 1200 to 13,300 mg/ m 3 was carried out at diﬀerent experimental runs. Results indicated that the use of NWPF enhanced the removal eﬃciency of the mixture of metal ions compared with the conventional UASB. The removal rates of chemical and biological oxygen demands were 67.65 and 77.35% at a total metal concentration of 1200 mg/m 3 . Further increases in the total concentrations of metal ions to 11-fold decreased the organic removal by 15.43% for COD and 10.58% for BOD. In conclusion, the use of NWPF as a packing material proved to be a promising media for mitigating the eﬀect of heavy metals on UASB performance. Keywords Biological treatment · Biosorption · Domestic wastewater · Heavy metals · Linear regression model · Packing media Introduction Numerous human activities and rapid industrial development result in the release of organic and inorganic substances into the environment. Accumulation of toxic metals represent a potential hazard to receiving bodies, due to their non-bio- degradability (Ahmed et al. 2022). Additionally, they may enter into a water supply through the inﬁltration of speciﬁc consumer wastes or even acid rain, which dissolves soil and releases into rivers, ground water, streams, and lakes. Heavy metals are a signiﬁcant issue if they are discharged directly into groundwater or wastewater streams without treatment. Therefore, they should be eliminated prior to ﬁnal discharge (Abou-Elela et al. 2021). Some metals such as Pb and Cr are priority hazardous metals (Hargreaves et al. 2018). They are mainly discharged during industrial manufacturing pro- cesses and urban activities. The run-oﬀ of heavy metals in municipal wastewater could also be due to the corrosion of roofs, pipes, washing of asphalt, tires, and brake linings (Ida and Eva 2021). State-of-the-art reported that biological technologies such as trickling ﬁlters, sequencing batch reac- tors, membrane bioreactors, activated sludge process and anaerobic fermentation can be applied for remediation of metals from wastewater. Among the most aﬀordable, eco- friendly, and appropriate economic technologies is anaerobic digestion. It is currently applied globally for decentralized wastewater management due to its small space requirements, Editorial responsibility: Hari Pant. * M. E. Fawzy mariamemadeldin@hotmail.com S. I. Abou-Elela Sohairela@gmail.com M. M. El-Sorogy chem_maher05@yahoo.com 1 Water Pollution Research Department, National Research Centre, P. Box 12622, Dokki, Giza, Egypt 2 Holding Company for Water and Wastewater, Giza 12577, Egypt