Optimization of algae production on urine

Kanjana Tuantet; Hardy Temmink; Grietje Zeeman; René H. Wijffels; Cees J.N. Buisman; Marcel Janssen

doi:10.1016/j.algal.2019.101667

Optimization of algae production on urine

Kanjana Tuantet, Hardy Temmink, Grietje Zeeman, René H. Wijffels, Cees J.N. Buisman, Marcel Janssen^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › Academic › peer-review

1 Citation (Scopus)

Abstract

Urine is a potential source of nutrients to grow microalgal biomass to be re-used as fertilizer and soil conditioner. In this study the impact of photobioreactor dilution rate on microalgae productivity and photosynthetic efficiency was assessed and used to determine operating conditions to reach both full nitrogen removal from urine and high biomass productivity. In addition, the possibility to work under day/night cycling was tested. To this end, the microalga Chlorella sorokiniana was grown on artificial urine and real human urine in bench-scale panel photobioreactors with short optical paths. At a light intensity of 1530 μmol⋅ m⁻²⋅s^-1 photobioreactor productivity and photosynthetic efficiency was demonstrated to be maximal at reactor dilution rates between 0.10 and 0.15 h^-1. A biomass yield of 1 g dry matter per mol of PAR photons was achieved. Biomass concentration, and accordingly nutrient removal efficiency, decreased at increasing reactor dilution rate. The experimental results could be reproduced by model simulations. These simulations allowed to demonstrate that the system must be operated at a dilution rate of less than 0.01 h^-1 in order to reach complete nitrogen removal. In that scenario more than half of the potential biomass productivity is lost due to severe self-shading within the algal culture. Experiments with real human urine illustrated the problem of incomplete nitrogen removal and ammonium inhibition of growth at too high dilution rates. It is therefore suggested to apply an optimized pre-dilution of pure urine prior to treatment in a photobioreactor. Experiments under day-night cycles demonstrated that microalgal cultures quickly acclimate to such variable light conditions. Additional model simulations illustrated that a phototrophic system is most effective when diluted urine is fed to the photobioreactor during day time only. In that situation the lowest nitrogen concentration in the effluent can be reached at a maximal areal removal rate and photosynthetic efficiency.

Original language	English
Article number	101667
Journal	Algal Research
Volume	44
DOIs	https://doi.org/10.1016/j.algal.2019.101667
Publication status	Published - Dec 2019

Keywords

Microalgae production
Nutrient removal
Photobioreactor control
Urine treatment

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@article{5fc90f0af32043a5ac68d3d607abc904,

title = "Optimization of algae production on urine",

abstract = "Urine is a potential source of nutrients to grow microalgal biomass to be re-used as fertilizer and soil conditioner. In this study the impact of photobioreactor dilution rate on microalgae productivity and photosynthetic efficiency was assessed and used to determine operating conditions to reach both full nitrogen removal from urine and high biomass productivity. In addition, the possibility to work under day/night cycling was tested. To this end, the microalga Chlorella sorokiniana was grown on artificial urine and real human urine in bench-scale panel photobioreactors with short optical paths. At a light intensity of 1530 μmol⋅ m−2⋅s-1 photobioreactor productivity and photosynthetic efficiency was demonstrated to be maximal at reactor dilution rates between 0.10 and 0.15 h-1. A biomass yield of 1 g dry matter per mol of PAR photons was achieved. Biomass concentration, and accordingly nutrient removal efficiency, decreased at increasing reactor dilution rate. The experimental results could be reproduced by model simulations. These simulations allowed to demonstrate that the system must be operated at a dilution rate of less than 0.01 h-1 in order to reach complete nitrogen removal. In that scenario more than half of the potential biomass productivity is lost due to severe self-shading within the algal culture. Experiments with real human urine illustrated the problem of incomplete nitrogen removal and ammonium inhibition of growth at too high dilution rates. It is therefore suggested to apply an optimized pre-dilution of pure urine prior to treatment in a photobioreactor. Experiments under day-night cycles demonstrated that microalgal cultures quickly acclimate to such variable light conditions. Additional model simulations illustrated that a phototrophic system is most effective when diluted urine is fed to the photobioreactor during day time only. In that situation the lowest nitrogen concentration in the effluent can be reached at a maximal areal removal rate and photosynthetic efficiency.",

keywords = "Microalgae production, Nutrient removal, Photobioreactor control, Urine treatment",

author = "Kanjana Tuantet and Hardy Temmink and Grietje Zeeman and Wijffels, {Ren{\'e} H.} and Buisman, {Cees J.N.} and Marcel Janssen",

year = "2019",

month = dec,

doi = "10.1016/j.algal.2019.101667",

language = "English",

volume = "44",

journal = "Algal Research",

issn = "2211-9264",

publisher = "Elsevier",

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TY - JOUR

T1 - Optimization of algae production on urine

AU - Tuantet, Kanjana

AU - Temmink, Hardy

AU - Zeeman, Grietje

AU - Wijffels, René H.

AU - Buisman, Cees J.N.

AU - Janssen, Marcel

PY - 2019/12

Y1 - 2019/12

N2 - Urine is a potential source of nutrients to grow microalgal biomass to be re-used as fertilizer and soil conditioner. In this study the impact of photobioreactor dilution rate on microalgae productivity and photosynthetic efficiency was assessed and used to determine operating conditions to reach both full nitrogen removal from urine and high biomass productivity. In addition, the possibility to work under day/night cycling was tested. To this end, the microalga Chlorella sorokiniana was grown on artificial urine and real human urine in bench-scale panel photobioreactors with short optical paths. At a light intensity of 1530 μmol⋅ m−2⋅s-1 photobioreactor productivity and photosynthetic efficiency was demonstrated to be maximal at reactor dilution rates between 0.10 and 0.15 h-1. A biomass yield of 1 g dry matter per mol of PAR photons was achieved. Biomass concentration, and accordingly nutrient removal efficiency, decreased at increasing reactor dilution rate. The experimental results could be reproduced by model simulations. These simulations allowed to demonstrate that the system must be operated at a dilution rate of less than 0.01 h-1 in order to reach complete nitrogen removal. In that scenario more than half of the potential biomass productivity is lost due to severe self-shading within the algal culture. Experiments with real human urine illustrated the problem of incomplete nitrogen removal and ammonium inhibition of growth at too high dilution rates. It is therefore suggested to apply an optimized pre-dilution of pure urine prior to treatment in a photobioreactor. Experiments under day-night cycles demonstrated that microalgal cultures quickly acclimate to such variable light conditions. Additional model simulations illustrated that a phototrophic system is most effective when diluted urine is fed to the photobioreactor during day time only. In that situation the lowest nitrogen concentration in the effluent can be reached at a maximal areal removal rate and photosynthetic efficiency.

AB - Urine is a potential source of nutrients to grow microalgal biomass to be re-used as fertilizer and soil conditioner. In this study the impact of photobioreactor dilution rate on microalgae productivity and photosynthetic efficiency was assessed and used to determine operating conditions to reach both full nitrogen removal from urine and high biomass productivity. In addition, the possibility to work under day/night cycling was tested. To this end, the microalga Chlorella sorokiniana was grown on artificial urine and real human urine in bench-scale panel photobioreactors with short optical paths. At a light intensity of 1530 μmol⋅ m−2⋅s-1 photobioreactor productivity and photosynthetic efficiency was demonstrated to be maximal at reactor dilution rates between 0.10 and 0.15 h-1. A biomass yield of 1 g dry matter per mol of PAR photons was achieved. Biomass concentration, and accordingly nutrient removal efficiency, decreased at increasing reactor dilution rate. The experimental results could be reproduced by model simulations. These simulations allowed to demonstrate that the system must be operated at a dilution rate of less than 0.01 h-1 in order to reach complete nitrogen removal. In that scenario more than half of the potential biomass productivity is lost due to severe self-shading within the algal culture. Experiments with real human urine illustrated the problem of incomplete nitrogen removal and ammonium inhibition of growth at too high dilution rates. It is therefore suggested to apply an optimized pre-dilution of pure urine prior to treatment in a photobioreactor. Experiments under day-night cycles demonstrated that microalgal cultures quickly acclimate to such variable light conditions. Additional model simulations illustrated that a phototrophic system is most effective when diluted urine is fed to the photobioreactor during day time only. In that situation the lowest nitrogen concentration in the effluent can be reached at a maximal areal removal rate and photosynthetic efficiency.

KW - Microalgae production

KW - Nutrient removal

KW - Photobioreactor control

KW - Urine treatment

U2 - 10.1016/j.algal.2019.101667

DO - 10.1016/j.algal.2019.101667

M3 - Article

AN - SCOPUS:85074146888

VL - 44

JO - Algal Research

JF - Algal Research

SN - 2211-9264

M1 - 101667

ER -