Potential of biochar filters for onsite sewage treatment: Adsorption and biological degradation of pharmaceuticals in laboratory filters with active, inactive and no biofilm

Abstract

This study investigated the potential of biochar filters as a replacement or complement for sand filters for removal of pharmaceutically active compounds (PhACs) from wastewater in onsite sewage facilities (OSSF). Specifically, the study investigated the effects of biodegradation, adsorption and a combination of these processes on removal of four model PhACs from wastewater in biochar filters operated under hydraulic loading conditions mimicking those found in onsite infiltration beds. Concentrations and removal of the four PhACs (i.e. carbamazepine, metoprolol, ranitidine and caffeine) were investigated over 22 weeks in four treatments: biochar (BC) with active or inactive biofilm (BC-active-biofilm, BC-inactive-biofilm), biochar without biofilm (BC-no-biofilm) and sand with active biofilm (Sand-active-biofilm). The adsorption of carbamazepine was high in BC-no-biofilm (99% removal after 22 weeks), while biodegradation was very low in Sand-active-biofilm (7% removal after 22 weeks). Removal of carbamazepine in BC-active-biofilm was high and stable over the 22 weeks (>98%), showing a significant role of biofilm in filter biogeneration. However, carbamazepine removal declined over time in BC-inactive-biofilm, from 99% in week 13 to 73% in week 22. Metoprolol was poorly degraded in Sand-active-biofilm (37% after 22 weeks), while adsorption seemed to be the major pathway for removal of metoprolol in biochar. Ranitidine and caffeine were efficiently removed by either adsorption (97% and 9S%, respectively, after 22 weeks) or biodegradation (99% and >99%, respectively, after 22 weeks). In conclusion, biochar is a promising filter medium for OSSF, especially for persistent PhACs such as carbamazepine and metoprolol. (C) 2017 Elsevier B.V. All rights reserved.

Keywords

Active biofilm; Adsorption; Biochar; Biodegradation; Inactive biofilm; Pharmaceuticals; Onsite sewage facilities

Published in

Science of the Total Environment
2018, volume: 612, pages: 192-201

SLU Authors

• Dalahmeh, Sahar

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

• Ahrens, Lutz

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Gros Calvo, Meritxell

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    
  • Catalan Institute for Water Research (ICRA)

• Wiberg, Karin

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Pell, Mikael

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    

Global goals (SDG)

SDG3 Good health and well-being
SDG6 Clean water and sanitation

UKÄ Subject classification

Other Environmental Engineering
Environmental Management

Publication identifier

• DOI: https://doi.org/10.1016/j.scitotenv.2017.08.178

Permanent link to this page (URI)

https://res.slu.se/id/publ/87073