Engineered biomaterials for reducing phosphorus and nitrogen levels from downstream water of aquaculture facilities

Authors: BARE, WILLIAM - University Of Idaho; STRUHS, ETHAN - University Of Idaho; MIRKOUEI, AMIN - University Of Idaho; Overturf, Kenneth - Ken; SMALL, BRIAN - University Of Idaho

Submitted to: Processes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/2023
Publication Date: 3/29/2023
Citation: Bare, W., Struhs, E., Mirkouei, A., Overturf, K.E., Small, B. 2023. Engineered biomaterials for reducing phosphorus and nitrogen levels from downstream water of aquaculture facilities. Nature Sustainability. 11(4). Article 1029. https://doi.org/10.3390/pr11041029.
DOI: https://doi.org/10.3390/pr11041029

Interpretive Summary: The aquaculture industry faces strict regulation on the level of phosphorus, ammonia, and nitrogen which can be released from production facilities into receiving waters. The continual reduction of allowed levels for the above listed contaminants will curtail fish production if current management and rearing practices are not changed. The US has an annual seafood trade deficit of nearly $17 billion. This study explores the sustainability benefits of producing biomaterials, such as locally processed pinewood, and utilizing this material to capture harmful micronutrient effluent. Pinewood biochar was tested and demonstrated its ability to absorb phosphorus from water. After economic evaluation of local biochar production it was concluded that this could be a promising solution to address micronutrient removal from aquaculture water, thereby allowing producers to continue or increase production and still meet regulations.

Technical Abstract: Aquaculture industry faces strict phosphorus, ammonia, and nitrogen level mandates in the United States (US) that may have negative economic impacts on fish producers. The US has an annual seafood trade deficit of nearly $17 billion. This study explores the sustainability benefits of producing biomaterials near collection sites via portable biorefinery units and transporting biomaterials to fish farms for capturing harmful micronutrients. Environmental and techno-economic impact assessments are performed on a case study in southern Idaho, the US largest commercial producer of rainbow trout. Total pinewood-based biomaterial production cost ranges from $213-$242/metric ton. Total greenhouse gas emission is 47-54kg CO2eq./ton of biomaterial, while eutrophication potential is reduced by -5 to -17kg PO4eq./ton. This study concluded that engineered, porous-structured biomaterials from pinewood could be a promising solution to address challenges the aquaculture industry faces, such as removing overabundant micronutrients from eutrophic water and reusing it as nutrient-rich soil conditioners or fertilizers.