Recipient Organization
VIRGINIA POLYTECHNIC INSTITUTE
(N/A)
BLACKSBURG,VA 24061
Performing Department
(N/A)
Non Technical Summary
An opportunity exists to expand the recirculating aquaculture system (RAS) industry in the U.S. to increase the domestic production of seafood, but it is important to further discover and implement innovative engineering technologies to ease the pathway to success by lowering operational costs and reducing impacts on the environment. The proposed novel technology, partial-nitrification/denitrification and anammox (PANDA), is a short-cut in the nitrogen cycle that is enabled by leveraging anaerobic oxidation. The benefits of implementing PANDA in RAS (RAS-PANDA) will be realized by reducing environmental impacts (decreasing water demand, effluent loading rates of pollutants, oxygen demand, greenhouse gas emissions) and decreasing operational costs. The proposed work herein is designed to improve our knowledge and understanding of how a novel engineering technology (PANDA) can be used to improve an animal system (RAS production of fish) using sensing/automation. Three aims will be conducted herein including Aim 1 the team will determine and assess the benefits of implementing PANDA in RAS by simultaneously evaluating traditional RAS (nitrification only) versus RAS-D (nitrification and denitrification) versus RAS-PANDA, Aim 2 the team will conduct technical and economic analyses (TEAs) to project the technologies to commercial applications and to understand how system type and feed loading rates impact operational costs, and Aim 3 the team will conduct life cycle assessments (LCAs) to characterize how the different systems and fish feed loading rates impact the environment and society. Implementing PANDA in RAS will provide a boost for the aquaculture industry and will increase our domestic production of safe, traceable, and high-quality seafood.
Animal Health Component
80%
Research Effort Categories
Basic
15%
Applied
80%
Developmental
5%
Goals / Objectives
The primary goal of this project is to assess the feasibility and optimize the implementation of a novel technology (PANDA) to be used in recirculating aquaculture systems (RAS) to reduce the industries impacts on the environment while reducing operational costs.There are three primary integrated aims that will be implemented to achieve our goal. Aim 1, to determine and assess the benefits of implementing the PANDA process in RAS. Aim 2, to determine the economic sustainability of RAS using PANDA technologies using Technoeconomic Assessments (TEA).Aim 3, to determine environmental sustainability using life-cycle assessment (LCA) to characterize the various systems implemented in RAS.?
Project Methods
We propose to use an integrated aim approach to relate impacts of the three different systems (RAS [nitrification only], RAS-D [nitrification and denitrification], and RAS-PANDA) on numerous variables that characterize fish production and health, microbial communities, environmental impacts, and operational costs. Below, we describe the experimental design and methods to support Aims 1, 2, and 3, followed by any additional general methods that apply to more than one aim. In summary, we will run all three systems in parallel for each of the four separate trials while rigorously controlling and monitoring water quality. The data generated during these trials will be used to adjust the model for the commercial system and to estimate the inputs needed for operational cost estimation (TEA) and LCA quantification of environmental impacts.Aim 1: To determine and assess the benefits of implementing the PANDA process in RAS. To determine and assess the benefits of implementing the PANDA process in RAS Four fish production trials will be conducted in parallel to evaluate RAS, RAS-D, and RAS-PANDA. Trial #1 (fish low density), Trial #2 (medium-low density), Trial #3 (medium-high density), and Trial #4 (high density).Experimental Recirculating Aquaculture SystemsThree indoor freshwater RAS systems will be operated in parallel for each of the four 5-to-6-month trials: System A (control, traditional process, RAS) will be equipped with four fish tanks, bubble bead filter for mechanical filtration, fluidized-bed reactor for complete nitrification, heat exchanger, and distributed diffuse aeration. Water renewal will be used to control nitrate levels.System B (denitrification process, RAS-D) will be equipped with four fish tanks, bubble bead filter for mechanical filtration, fluidized-bed reactor for complete nitrification, heat exchanger, and distributed diffuse aeration. Water will be diverted on a regular schedule every couple of days (or so) to a sequencing batch reactor for denitrification and treated water will be returned to the RAS. Denitrification will be used to control nitrate levels. System C (RAS-PANDA) will be equipped with four fish tanks (with nitrification) and with the added RAS-PANDA process. PANDA will be used to control nitrate levels. Overall, sodium bicarbonate will be supplemented to systems to maintain sufficient alkalinity levels for efficient nitrification. Water quality and temperature will be targeted to be optimal for tilapia at 30°C to minimize stress and maximize production potential. Water quality in each RAS will be rigorously monitored during the fish production trials and for the different systems implemented. All water quality parameters will be analyzed using methods adapted from standard methods.System A Operations For system A (RAS, traditional configuration for fish farms) water will be discharged on a regular basis (e.g., every few days or so) to maintain a targeted steady-state concentration of Nitrate-N during each trial. The target concentration of nitrate-N will be the same concentration used in RAS-PANDA. Fish system water will be used to backwash the beadfilter that contains trapped solids (and organic carbon) and after the water and solids are sampled it will be sent down the drain.System B OperationsFor system B (RAS-D) water will be discharged on a regular basis (e.g., every few days or so) to maintain a targeted steady-state concentration of Nitrate-N during each trial. The target concentration of nitrate-N will be the same concentration used in RAS-PANDA. Fish system water will be used to backwash the beadfilter that contains trapped solids (and carbon), and this water will be collected in a sequencing batch reactor for denitrification. Water quality parameters will be rigorously monitored. System C OperationsIn this study, glycerol will be used as the carbon source because it is a relatively inexpensive and safe supplemental carbon source that has a high chemical oxygen demand (COD) density (1,000,000 mg/L) for low storage space needs and can be produced as a byproduct from the bioethanol production process (Sharp et al. 2020). Meanwhile, the biodegradable organic compounds in the fish tank also can be taken advantage as a free external carbon source for partial denitrification.A portion of the fish tank effluent will be pump to an aeration tank where a preset portion of the ammonia will be oxidized to NOx containing both nitrite and nitrate. This partial nitrification will be achieved through a smart feedback control loop by using an ammonia sensor in the tank, i.e., the aeration strength in terms of airflow rate will be reduced to the point where only a desired fraction of the influent ammonia is removed. The ammonia and NOx mixture will flow to the anoxic cell/tank where external carbon source will be dosed for achieving partial denitrification to provide nitrite for anammox. The carbon dose will be controlled by a smart feedforward control loop based on the influent concentrations of dissolved oxygen and nitrate as well as the effluent nitrate. The success of the project for denitrification will be greater than 85 to 90% nitrate removal at the end of each batch process. For PANDA success will be determined by the steady state external COD consumption for each unit of total inorganic nitrogen (TIN) removedFishAt the end of each of the four trials, fish fillets from each treatment group will undergo nutritional analysis. Fish health will be assessed using biometrics, blood biochemical panels, and histological examination of select organs. A randomly selected sample of fish will be collected at the beginning and end of each trial. One-way or two-way analysis of variance (ANOVA) will be used to determine the effects of experiment treatments on fish tissue biochemical analysis, fish survival and growth rate, food conversion ratios, health, etc.Microbiome The diversity within fish microbiome samples will be censured using high throughput 16S rRNA sequencing that targets the bacterial V4 region of the 16S gene. Analysis of the data will subsequently be performed using the QIIME2 package using the DADA2 program for identification of Amplicon Sequencing Variants (ASVs) to assess the taxonomic and phylogenetic composition of our samples. This approach leverages both widely used methods in bacterial microbiome studies together with cutting-edge bioinformatic developments that have been shown to improve the accuracy of the results, and overall, it will be highly effective at identifying spatiotemporal patterns of microbial diversity across the intestine samples analyzed. In addition, water column samples obtained via filtration of shared RAS water per system will also be processed to determine the environmental microbes present as well as sampling of biofilm and collected sludge communities associated with the biofilters. Aim 2: Perform TEA to understand how system type and feed loading rates impact operational costs. To perform the techno-economic analysis, the energy and cost saving for the partial treatment of RAS water using PANDA will be defined and compared to other options and to single-pass water use systems. Commercial scale will be defined as the average size of the five largest operating closed loop aquaculture systems. Typical RAS and RAS-D systems will be modeled to serve as baseline facilities for these analyses. The PANDA system being developed in this project will be scaled and adapted for commercial use and a modified model commercial scale RAS with PANDA developed.Aim 3: Conduct a LCA to characterize how the various system types implemented in RAS impact the environment and society. A life cycle assessment (LCA) for the RAS using PANDA technologies will be completed along with a water footprint and will be compared to RAS and RAS-D processes. System expansion and energy allocation methods will be used with adherence to ISO 14040 and ISO 14044 methodologies.