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Title: Seasonal treatment and economic evaluation of an algal wastewater system for energy and nutrient recovery

Abstract

Algal systems have been proposed for treating wastewater while simultaneously recovering energy and nutrients. In this study, an integrated system with algal treatment of municipal wastewater followed by hydrothermal liquefaction (HTL) conversion and upgrading steps was evaluated. Pilot-scale treatment of primary clarified municipal wastewater effluent was evaluated in different seasons (cold, warm, and a transitional period in between) with different strains of algae selected for each season, and the warm season strain successfully met all local discharge regulations. The collected wastewater algae biomass was subjected to HTL at 300 and 350 °C and both energy and nutrient recoveries were much improved at the higher temperature. The transitional batch was found to have the highest biocrude oil yields, and its co-products had the highest nutrient (nitrogen and phosphorus) contents. Economic analysis of conversion processes informed by the observed HTL product yields was conducted. While this revealed that targeting biofuel products alone was not profitable, adding nutrient co-products (e.g., ammonium sulfate fertilizer), adjusting algae harvesting time, and incorporating component-specific conversion processes could substantially improve system economics. Overall, this study highlights connections between treatment and conversion processes, and demonstrates how these connections can be leveraged for more efficient resource recovery without compromising treatmentmore » operations.« less

Authors:
ORCiD logo [1];  [1];  [2];  [2]; ORCiD logo [3]
  1. Engineering Research Center for Re-inventing the Nation's Urban Water Infrastructure (ReNUWIt); Colorado School of Mines, Golden, CO (United States)
  2. Engineering Research Center for Re-inventing the Nation's Urban Water Infrastructure (ReNUWIt); New Mexico State Univ., Las Cruces, NM (United States)
  3. Engineering Research Center for Re-inventing the Nation's Urban Water Infrastructure (ReNUWIt); Colorado School of Mines, Golden, CO (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE); National Science Foundation (NSF)
OSTI Identifier:
1562865
Report Number(s):
NREL/JA-5100-74863
Journal ID: ISSN 2053-1400; ESWRAR
Grant/Contract Number:  
AC36-08GO28308
Resource Type:
Accepted Manuscript
Journal Name:
Environmental Science: Water Research & Technology
Additional Journal Information:
Journal Volume: 5; Journal Issue: 9; Journal ID: ISSN 2053-1400
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; 54 ENVIRONMENTAL SCIENCES; algal treatment; municipal wastewater; hydrothermal liquefaction

Citation Formats

Li, Yalin, Slouka, Sydney A., Henkanatte-Gedera, Shanka M., Nirmalakhandan, Nagamany, and Strathmann, Timothy J. Seasonal treatment and economic evaluation of an algal wastewater system for energy and nutrient recovery. United States: N. p., 2019. Web. doi:10.1039/C9EW00242A.
Li, Yalin, Slouka, Sydney A., Henkanatte-Gedera, Shanka M., Nirmalakhandan, Nagamany, & Strathmann, Timothy J. Seasonal treatment and economic evaluation of an algal wastewater system for energy and nutrient recovery. United States. doi:10.1039/C9EW00242A.
Li, Yalin, Slouka, Sydney A., Henkanatte-Gedera, Shanka M., Nirmalakhandan, Nagamany, and Strathmann, Timothy J. Tue . "Seasonal treatment and economic evaluation of an algal wastewater system for energy and nutrient recovery". United States. doi:10.1039/C9EW00242A.
@article{osti_1562865,
title = {Seasonal treatment and economic evaluation of an algal wastewater system for energy and nutrient recovery},
author = {Li, Yalin and Slouka, Sydney A. and Henkanatte-Gedera, Shanka M. and Nirmalakhandan, Nagamany and Strathmann, Timothy J.},
abstractNote = {Algal systems have been proposed for treating wastewater while simultaneously recovering energy and nutrients. In this study, an integrated system with algal treatment of municipal wastewater followed by hydrothermal liquefaction (HTL) conversion and upgrading steps was evaluated. Pilot-scale treatment of primary clarified municipal wastewater effluent was evaluated in different seasons (cold, warm, and a transitional period in between) with different strains of algae selected for each season, and the warm season strain successfully met all local discharge regulations. The collected wastewater algae biomass was subjected to HTL at 300 and 350 °C and both energy and nutrient recoveries were much improved at the higher temperature. The transitional batch was found to have the highest biocrude oil yields, and its co-products had the highest nutrient (nitrogen and phosphorus) contents. Economic analysis of conversion processes informed by the observed HTL product yields was conducted. While this revealed that targeting biofuel products alone was not profitable, adding nutrient co-products (e.g., ammonium sulfate fertilizer), adjusting algae harvesting time, and incorporating component-specific conversion processes could substantially improve system economics. Overall, this study highlights connections between treatment and conversion processes, and demonstrates how these connections can be leveraged for more efficient resource recovery without compromising treatment operations.},
doi = {10.1039/C9EW00242A},
journal = {Environmental Science: Water Research & Technology},
number = 9,
volume = 5,
place = {United States},
year = {2019},
month = {7}
}

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Works referenced in this record:

Process development for hydrothermal liquefaction of algae feedstocks in a continuous-flow reactor
journal, October 2013


Wastewater treatment high rate algal ponds for biofuel production
journal, January 2011