Fate of micropollutants in chemically enhanced primary treatment using recovered coagulants
Citation
Chakraborty, T., Balusani, D., Sabourin, L., Renaud, J., Sumarah, M., Nakhla, G., Ray, M.B. (2020). Fate of micropollutants in chemically enhanced primary treatment using recovered coagulants. Journal of Environmental Management, [online] 269 http://dx.doi.org/10.1016/j.jenvman.2020.110815
Plain language summary
Micropollutants in wastewater are a concern for regulators and the public. These compounds end up in the environment and ultimately in irrigation water for agriculture. In this study we examined the fate of 18 select compounds during treatment. A number of the compounds were removed completely or their presence was reduced indicating the value of treating wastewater prior to release to the environment.
Abstract
In this study, the fate of several micropollutants (MPs) in wastewater due to coagulation using both fresh and recovered aluminum and iron coagulants was determined. 18 MPs from different groups such as antibiotics, food additives, and surfactants were selected and spiked into the primary influent collected from a local wastewater plant. The distribution of MPs in the recovered coagulant and treated effluent after coagulation was determined for both fresh and recycled coagulants. The distribution of MPs in wastewater and the removal during coagulation were compound specific; MPs with log Kow < 2.5 were predominantly present in the effluent after coagulation, while MPs with log Kow > 2.5 were sorbed on the coagulated sludge. The distribution ratio (Kd) of all the MPs (diclofenac, clarithromycin, etc.) with log Kow > 2.5 was determined along with their extent of accumulation in sludge due to the recycling of coagulants. Compounds such as sulfamethoxazole, erythromycin and sulfathiazole, showed low removal during coagulation. The tetracycline group of compounds showed possible chelation with iron and aluminum. Only <10% of the initially spiked MPs with log Kow > 2.5 was being recycled with the recovered coagulant, thus alleviating the concern of accumulation of the MPs during recycle of the coagulants.