Integrating powdered activated carbon into wastewater tertiary filter for micro-pollutant removal

Abstract

Integrating powdered activated carbon (PAC) into wastewater tertiary treatment is a promising technology to reduce organic micro-pollutant (OMP) discharge into the receiving waters. To take advantage of the existing tertiary filter, PAC was pre-embedded inside the filter bed acting as a fixed-bed adsorber. The pre-embedding (i.e. immobilization) of PAC was realized by direct dosing a PAC solution on the filter top, which was then promoted to penetrate into the filter media by a down-flow of tap water. In order to examine the effectiveness of this PAC pre-embedded filter towards OMP removal, batch adsorption tests, representing PAC contact reactor (with the same PAC mass-to-treated water volume ratio as in the PAC pre-embedded filter) were performed as references. Moreover, as a conventional dosing option, PAC was dosed continuously with the filter influent (i.e. the wastewater secondary effluent with the investigated OMPs). Comparative results confirmed a higher OMP removal efficiency associated with the PAC pre-embedded filter, as compared to the batch system with a practical PAC residence time. Furthermore, over a filtration period of 10 h (approximating a realistic filtration cycle for tertiary filters), the continuous dosing approach resulted in less OMP removal. Therefore, it was concluded that the pre-embedding approach can be preferentially considered when integrating PAC into the wastewater tertiary treatment for OMP elimination.

Consolidated vs new advanced treatment methods for the removal of contaminants of emerging concern from urban wastewater

“…However, if the sewage sludge is used for agricultural purposes, direct dosing or recycling of PAC into the biological treatment is not practicable. Different dosing locations (Streicher et al, 2016) and dosing approaches -continuous (Altmann et al, 2015a;Hu et al, 2016) or singlepulse PAC dosing (Karelid et al, 2017;Mailler et al, 2015) -have been investigated. The continuous dosing resulted in decreasing CECs effluent concentrations with increasing reactor runtime due to adsorption onto accumulating PAC in the reactor bed (Altmann et al, 2015a).…”

Removal of micropollutants from municipal wastewater using different types of activated carbons

“…Furthermore, better performance of Norit is due to the smaller specific pore volume (cm 3 /g) on its surface than the other one (Rúa-Gómez et al, 2012) due to which small suspended micropollutants get entangled inside the pores on Norit surface and become unable to release. The laboratory experiments mostly performed with powdered activated carbon have provided a fundamental understanding of adsorption mechanisms also stated in previous studies (Hu et al, 2016;Kårelid et al, 2017b;Margot et al, 2013).…”

Fixed-bed performance of a waste-derived granular activated carbon for the removal of micropollutants from municipal wastewater

“…of pharmaceuticals onto AC using fixed-bed reactors were carried out under very distinct operational conditions, making extremely difficult to establish valid comparisons between them (Ahmed and Hameed, 2018;Ek et al, 2014;Hu et al, 2016;Sotelo et al, 2013;Sperlich et al, 2017;Torrellas et al, 2015;Yu et al, 2009;Zuo et al, 2016).…”

“…The amount of SMX adsorbed onto the studied PAC at saturation time was 846 mmol kg -1 , corresponding to 214.29 mg g -1 . The adsorption of SMX and CBZ onto a PAC in a fixed-bed system for application as wastewater tertiary treatment was also evaluated by Hu et al (2016).…”