Poster presented at USU SBI Conference 2016 and ABO Conference 2017, along with the student design competition at IBE Conference 2017.

1. Bioenergy from Petroleum Wastewater Management
Background
Conclusions
Anaerobic Digestion
1. Figure 1: ABG project diagram by AlgEN and KOTO
2. Figure 2: Facer, George. Edexcel Chemistry Student Guide 2. Place of Publication Not Identified:
Philip Allan Updates, 2015. Print.
Support for this project was provided by Utah Science Technology and Research (USTAR) and the
Synthetic Biomanufacturing Institute (SBI).
Autotrophic Algae Culture
Heterotrophic Algae Culture
alan.hodges@usu.edu ron.sims@usu.edu
Wastewater derived from petroleum refining is an abundant source of
wastewater accounting for 33.6 million barrels per day globally. Currently
few wastewater treatment strategies exist to produce value-added
products from petroleum refining wastewater.
Anaerobic digestion was evaluated using biogas generation in bio--
-methane potential (BMP) assays.
Anaerobic digestion of the wastewater demonstrated successful reduction
of organic chemicals in the wastewater as measured by the chemical
oxygen demand (COD) assay reduction and as measured by biogas
production.
Anaerobic digestion was demonstrated to reduce the wastewater strength
(COD) by an average of 89 mg/L and produced 727 mL of methane (CH4)
per liter of wastewater (Table 1).
Alan Hodges, Jordan Wanlass, Zak Fica, Jessica VanDarlin, AJ Walters,
Ronald Sims
Department of Biological Engineering, Utah State University
These results demonstrated the successful treatment of the petroleum
refining wastewater, and also the utilization of the wastewater to produce
bioenergy through the cultivation of microalgae on the wastewater as a
culture medium for growth.
Petroleum refining wastewater therefore can be utilized as a resource
for bioenergy production under appropriate management conditions that
facilitate the cultivation of mixed culture microalgae in biofilm bioreactors
that have been pioneered at Utah State University.
In this study, petroleum refining
wastewater was obtained from
Utah industries. Three value
product--producing treatment
strategies were tested: (1)
phototrophic and naturally
occurring mixed culture
microalgal biofilm cultivation,
(2) anaerobic digestion for
bioenergy production, and (3)
heterotrophic cyanobacterial
(blue-- green algae)
biodegradation of organic
chemicals in the wastewater.
Algal biofilm cultivation and the biomass produced from heterotrophic
treatment have been shown to produce value-added products including
biofuels, agricultural feed, and other high value bioproducts. Anaerobic
digestion has been shown to produce methane rich biogas for energy,
heat, and power production. Ideally, these technologies can be used
synergistically as seen in Figure 2,3.
Figure 1. Typical oil refinery.
Sample Set
Initial
COD
Final COD
% COD
Reduction
Biomethane
Produced (mL)
g CH4 / g
COD
Algae-Amended
Wastewater
193.20 128.00 32.98 218.11 0.34
Wastewater 141.00 51.67 63.36 0.03 0.00
Figure 2. Algae-Based Energy Bioproduction.
0
20
40
60
80
100
120
140
160
0 2 4 6 8 10 12 14 16 18 20 22
mg/LCOD
Week
Aerobic Autoclaved Aerobic Cyano +
Aerobic Cyano - Anaerobic Autoclaved
Anaerobic Cyano + Anaerobic Cyano -
Figure 7. Petroleum wastewater heterotrophic
bioremediation.
Figure 4. Nitrogen uptake by RABR systems.
Figure 5. Phosphorus uptake by RABR systems.
Figure 6. TSS uptake by RABR systems.
Table 1. Gas production during Biomethane potential testing.
Figure 8. COD remediation through anaerobic digestion.
Autotrophic algae culture proved incapable of reducing organic
pollutants in the wastewater. Developing a heterotrophic algae culture
was then examined to reduce such constituents.
The aerobic autoclaved sample and all anaerobic samples showed
no significant change over time. Aerobic treatment successfully
decreased COD concentration from 160 to 60 mg/mL. No significant
improvement was found by adding LLC2 to the sample (Figure 7).
Autotrophic RABR based
algae culture proved very
successful in the removal of
nitrogen, phosphorus and
total suspended solids (TSS)
(Figures 4-6, respectively).
In order to evaluate the treatment ability and bioproduct production of a
microalgae culture in petroleum refining wastewater, aerobic Rotating Algal
Biofilm Reactor (RABR)
cultures were utilized. Each
reactor was monitored for
changes in nutrients, including
nitrogen and phosphorus, and
for changes in organic
chemical concentrations.
Biomass growth was
measured through harvesting
the biofilm and was produced
at a rate of
3.2 g ash free dry weight
(AFDW) per square meter of
surface area per day.
References/Acknowledgements
Results of BMP
assays highlight the
potential for
anaerobic digestion
to be used to both
reduce COD and
produce the
valuable byproduct
of methane gas
(Figure 8, Table 1).
Objectives
Develop a novel treatment strategy that for petroleum wastewater that
aids Utah Industry.
1. Reduce nutrient concentration in effluent wastewater
2. Reduce suspended solids concentration in effluent wastewater
3. Reduce organic chemical concentration in effluent wastewater
4. Produce value-added products to help offset costs