Quantitative Evaluation of an Integrated System for Valorization of Wastewater Algae as Bio-Oil, Fuel Gas, and Fertilizer Products

Timothy Strathmann, Yalin Li, William Tarpeh, Kara Nelson

Research output: Contribution to journalArticlepeer-review

37 Scopus Citations

Abstract

Algal systems have emerged as a promising strategy for simultaneous treatment and valorization of wastewater. However, further advancement and real-world implementation are hindered by the limited knowledge on the full energetic and nutrient product potentials of such systems and the corresponding value of these products. In this work, an aqueous-based system for the conversion of wastewater-derived algae and upgrading of crude products was designed and demonstrated. Bio-oil, fuel gas, and fertilizer products were generated from algal biomass harvested from a municipal wastewater treatment facility. Experiments showed that 68% of chemical energy contained in the algal biomass could be recovered with 44% in upgraded bio-oil and 23% in fuel gas (calculated as higher heating values), and 44% and 91% of nitrogen and phosphorus element contents in the original feedstock could be recovered as fertilizer products (ammonium sulfate and struvite), respectively. For 1,000 kg of such dry algal biomass, these products had an estimated total value of $427 (in 2014 U.S. dollars). For the first time, experiment-based energy and nutrient recovery potentials of wastewater-derived algae were presented in an integrated manner. Findings also revealed critical research needs and suggested strategies to further improve resource recovery and waste valorization in these systems.
Original languageAmerican English
Pages (from-to)12717-12727
Number of pages11
JournalEnvironmental Science and Technology
Volume52
Issue number21
DOIs
StatePublished - 2018

NREL Publication Number

  • NREL/JA-5100-72823

Keywords

  • algae
  • biofuels
  • biomass
  • nitrogen compounds
  • nitrogen fertilizers
  • nutrients
  • recovery
  • sulfur compounds

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