Ion Exchange for Nutrient Recovery Coupled with Biosolids-Derived Biochar Pretreatment to Remove Micropollutants

Yiran Tong, Lee Kimbell, Anna Avila, Patrick J. McNamara, Brooke K. Mayer

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Wastewater, especially anaerobic treatment effluent, contains high ammonia nitrogen (NH4-N) and inorganic orthophosphate (PO4-P), which necessitate additional treatment to meet stringent discharge regulations. Ion exchange regeneration is a process that can be adopted for not only removing but also recovering nutrients. However, recovering nutrients by ion exchange from nutrient-rich effluents that also contain micropollutants (which typically pass through anaerobic treatment as well) may result in subsequent problems, since micropollutants could end up in ion exchange effluent, regenerant, or recovered fertilizer products. Micropollutant removal by a nonselective adsorbent, such as biosolids-derived biochar, before nutrient recovery processes would mitigate potential risks. The objective of this research was to evaluate the capability of biosolids-derived biochar as a pretreatment step for separating micropollutants from nutrient-rich water before ion exchange for nutrient recovery. In the presence of ammonium and phosphate, both pristine and regenerated biosolids-derived biochar could effectively adsorb triclosan (TCS) and estradiol (E2), and to a lesser extent, sulfamethoxazole (SMX) in batch sorption experiments. On the other hand, nutrient ions were not effectively adsorbed by biosolids-derived biochar. A continuous flow-through system consisting of columns in series filled with biochar, LayneRT, and then clinoptilolite was operated to test selective removal of micropollutants and nutrients in a flow-through system. The biochar column achieved more than 80% removal of influent TCS and E2, thereby reducing the chances of micropollutants being adsorbed by ion exchangers. Sulfamethoxazole removal through the biochar column was only 50%, indicating that biosolids-derived biochar would have to be optimized in the future for hydrophilic micropollutant removal. Influent nutrients were not effectively removed by the biochar column, but were captured in their respective selective ion exchanger columns. This research revealed that biosolids-derived biochar could be employed before ion exchange resins for removal of micropollutants from nutrient-rich water.

Original languageEnglish (US)
Pages (from-to)1340-1348
Number of pages9
JournalEnvironmental Engineering Science
Volume35
Issue number12
DOIs
StatePublished - Dec 2018

Bibliographical note

Funding Information:
This research was funded by a grant from the Lafferty Family Foundation. The authors acknowledge the use of the LC-MS from Marquette University, funded by the GHR foundation.

Publisher Copyright:
Copyright © 2018, Mary Ann Liebert, Inc., publishers.

Keywords

  • adsorption
  • ammonium
  • phosphate
  • pyrolysis
  • wastewater treatment

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