Abstract

A partial removal of emerging organic micropollutants (EOMs) in conventional wastewater treatment plants (WWTPs) results in their continuous release to the aquatic terrestrial systems. Subsequently, EOMs such as pharmaceutical compounds, their respective metabolites as well as hormones and herbicides need a complementary treatment, e.g. sorption. However, sorptive material supposes to follow sustainable development principles as much as possible. Thus, utilizing low-cost alternative precursors for the production of sorptive material was considered in this study. Wasted activated sludge (WAS) and wood waste were used as viable primary materials for this purpose. The main objective of the present work was to remove of EOMs from a WWTP’s effluent by an effective alternative carbon adsorbent derived from the blends of sludge and woodchips. The study consisted of three stages. In the first stage, the presence of thirty multi-class EOMs was investigated in a WWTP effluent and its vicinity in Saint Lawrence River (SLR). Subsequently, the most popular EOMs were classified, then, target compounds were selected to be exposed to adsorption process. In the second stage, an effective method to produce pore enriched activated carbon from single-step activation of sludge with the additive of wood residues was developed. The produced new adsorbent increased the surface area from 1320 m2/g to 1565 m2/g after combining sludge precursor with hardwood chips. Also, the strength of the surface acidity and yield of products were mounted after wood addition. In stage 3, the sorption of an anti-depressant, venlafaxine (VEN), from aqueous solution onto the new adsorbent derived from the mixture of sludge and hardwood residues (SS:HW) was compared with a commercial granular activated carbon (CGAC). Maximum sorption capacity of the SS:HW was measured 131.57 mg/g from Langmuir isotherm while this value was 25.57 mg/g for CGAC. Then SS:HW adsorption efficiency was successfully validated on real WWTP effluent; while CGAC failed to remove a mixture of EOMs from the real matrix. The results revealed the new micro-mesoporous sludge-based (SS:HW) adsorbent could serve as an efficient tool for polishing WWTP effluent and protecting the quality of surface water resources.