Progress 05/01/23 to 04/30/24
Outputs
Target Audience:During this period, the target audiences included scientific communities such as American Society of Agricultural and Biological Engineers, and journals including Agriculture, Fuel, and Resources, Conservation, and Recycling. This project helps reduce food waste and greenhouse gas emissions at Champaign District Unit 4 public schools within disadvantaged communities. In the broader community, local grocery stores and food processing companies also benefit from reduced waste and landfill disposal costs. Changes/Problems:During the most recent pilot HTL run, the reactor experienced plugging that caused end-of-run. It was determined that the plug was likely caused by charring due to low flow rate at the entrance of the reactor zone. To combat this, future conversions will be operated with higher feedstock flows. What opportunities for training and professional development has the project provided?This year, we have 10 graduate students and 1 postdoc. Professional development opportunities have included workshop attendance and conference presentations. How have the results been disseminated to communities of interest?In the past year, we have published 2 papers related to waste valorization, with 2 more submitted and under review. 2 poster presentations and 1 oral presentation on related work was made at Rutgers University and University of Illinois-Champaign. 5 abstracts were accepted to present work at the ASABE Annual Conference. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period, bio-based fuel additives will be hydrotreated to remove unwanted heteroatoms (nitrogen, oxygen, sulfur) from the biocrude oil prior to blending with conventional diesel. Different types of heterogeneous molybdenum-based catalysts will be screened, along with hydrotreating parameters. Distillation parameters will also be tested to maximize the recovery and quality of biobinder obtained from the HTL biocrude oil. The pilot-scale HTL reactor will also continue to be run, at higher feedstock flows to both increase production rate and reduce reactor plugging. The aged binder will be rejuvenated and advanced binder characterization will be carried out. After receiving more biobinder volume, mixture scale testing will be conducted and the low-temperature characterization of biobinder will be completed. The mixtures will also be tested at a field site to assess the environmental impact of biobinder versus conventional binder on water runoff and air quality. The FMS will be integrated into the test cell and then utilized to test the bio-based fuel additives. Components will also be connected to power for pump and valve switching. Additionally, the fuel engine test cell will be calibrated to optimize the engine with bio-based fuel additives. Experiments on electrochemical oxidation of PHW with salt addition, increased temperature, and stirring will be carried out to slow nitrate loss, increase nutrient accumulation, and elucidate reaction mechanisms. Data analysis will be completed to determine the efficacy of changes in concentration and addition of electrolytes for nutrient recovery. Manuscripts on electrolysis of PHW food waste with different conductive materials and energy inputs for nutrient recovery will be submitted for publication. Experiments on the PHW concentration for microgreen crop growth and its data analysis on biomass production and nutrient profile will be completed. The nutrient profile will be completed, materials and design for a new hydroponics lab, and the experimental design of impacts of treated PHW on hydroponic lettuce production will be outlined. The hydrothermal system configuration will be continuously updated based on findings from the experimental team to reflect the actual pilot system. For YR2, we will continue to update our TEA analysis with new information from the experimental team and explore different deployment scenarios to improve the cost competitiveness of the system at smaller scales, and we will implement uncertainty and sensitivity analyses to identify key parameters for future improvement. The ML model will be incorporated into the TEA module.
Impacts
What was accomplished under these goals?
In the past year, two types of food waste (industrial food processing waste, and grocery store food waste) was collected and homogenized for conversion. 40 gallons of each food waste was processed in a pilot-scale continuous HTL reactor to produce biocrude oil and PHW. The biocrude oil was pretreated to produce fuel precursors, while preliminary work on biobinder recovery was started. A distillation system for atmospheric and vacuum distillation of biocrude oil was installed and tested for bio-based fuel additive and biobinder recovery. The biocrude oil and subsequent product derivatives were characterized at each treatment step for its physical, chemical, and thermogravimetric properties. Two biocrude fractions were tested for potential use as biobinder and rejuvenator for recycled asphalt. 10% biobinder blends were assessed using conventional performance grading based on reduction of one PG (6 degrees C), which makes biobinder suitable for use with reclaimed asphalt pavement to increase asphalt recycling. Using the poker chip test it was found that ductility was reduced by addition of biobinder, which remains a challenge to overcome. We also began the process of lab-aging base binder for simulated rejuvenation using the medium biocrude fraction. A custom fuel measurement system (FMS) was designed and constructed to test both conventional diesel fuel and fuel with bio-based fuel additives. Specifically, the system was designed to meet the appropriate flow and pressure specifications of the engine. The materials procurement and plumbing build was completed. The electrical box was also mounted and room for the installation was prepared. Emissions exemption from the EPA was approved for the test engine. Water quality analysis was performed on PHW from food waste to obtain its nutrient profile and organic composition before and after treatment. Laboratory materials were acquired, and experiments were conducted for electrochemical oxidation of nitrogen cyclic conversion to nitrate. Evapotranspiration experiments were completed to determin the ideal irrigation rate for lab-scale microgreen crop growth. Preliminary data analysis was done for the environmental conditions and water use efficiency of two microgreen varieties for the optimization of methods. The experimental design was outlined for impacts of PHW on the production of lab-scale ornamental crops. Inputs from the experimental teams were used to design a preliminary hydrothermal system for the TEA and LCA models. Specifically, after gravity separation and skimming, the collected biocrude and char products are fractioned by distillation, with the light and medium fraction used as biofuel additives and the heavy fraction as biobinder. Aqueous products are treated by three potential approaches (sand filtration, electrochemical oxidation, or fungi treatment), after which the collected liquid can be used as liquid fertilizer to supplement crop nutrient (particularly N) requirements. A TEA module was established based on capital cost data of different scales. For smaller systems (dry biomass flowrate <1,000 kg/hr), we calculated the cost based on of the pilot reactor with (i) actual costs from the reactor (ii) vendor quotes from online sources, (iii) well-established heuristic cost models (for components with limited cost information). For larger systems, cost information from literature TEA models (PNNL report 23227 and 27186) were used. These cost bases were then scaled with appropriate exponential factors (depending on the type of the equipment) based on the flowrates of key streams (e.g., feedstock, biocrude) to reflect the capacity of the system. Experimental results from the pilot reactor (salad dressing waste) were used in the baseline analysis. Our current results (preliminary and subject to change with model updates) suggested that the small scale of the pilot reactor (dry biomass flowrate around 11.5 kg/hr) led to a very high minimum selling price (MSP) of the biobinder product, but the economic performance of the system can be substantially improved with the increase in capacity, leading to even negative MSP values. A machine learning model for the prediction of hydrothermal biocrude yield was also examined because of biocrude yield's significant driver of MSP.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2024
Citation:
Lopez K, Leme VFC, Warzecha M, Davidson PC. Wastewater Nutrient Recovery via Fungal and Nitrifying Bacteria Treatment. Agriculture. 2024; 14(4):580. https://doi.org/10.3390/agriculture14040580
- Type:
Journal Articles
Status:
Accepted
Year Published:
2024
Citation:
Reynolds LP, Leme VFC, Davidson PC. Investigating the Impacts of Wastewaters on Lettuce (Lactuca sativa) Seed Germination and Growth. Agriculture. 2024; 14(4):608. https://doi.org/10.3390/agriculture14040608
- Type:
Journal Articles
Status:
Under Review
Year Published:
2024
Citation:
Zhang, Y. et al. A Scalable Index for Quantifying Circularity of Bioeconomy Systems. Resources, Conversation, and Recycling. 2024. Under review.
- Type:
Journal Articles
Status:
Under Review
Year Published:
2024
Citation:
Summers, S., et al. Pretreatment of hydrothermal liquefaction biocrude oil for efficient hydroprocessing. Fuel Processing Technology. 2024. Under review.
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