An attached microalgae platform for recycling phosphorus through biologically mediated fertilizer formation and biomass cultivation

Journal Article · Thu Nov 30 00:00:00 EST 2023 · Cleaner Engineering and Technology

DOI:https://doi.org/10.1016/j.clet.2023.100701· OSTI ID:2222978

Goldsberry, Parker ^[1]; Jeppesen, Peter ^[1]; McLean, Joan ^[1]; Sims, Ron ^[1]

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1. Utah State University, Logan, UT (United States)

Nutrient management is a global challenge for protecting water bodies from eutrophication and for retaining and sustainably recycling phosphorus within the biosphere. This challenge is especially important for water resource recovery facilities (WRRFs) in jurisdictions that limit nutrient loads in plant effluent. A microalgae-based biofilm platform has been designed, constructed, and tested to remove phosphorus and nitrogen from anaerobic digester (AD) effluent filtrate through cultivating biomass and inducing the precipitation of a mineral called struvite (NH₄MgPO₄ · 6H₂O) using a rotating algae biofilm reactor (RABR). RABRs function by rotating a growth substratum through nutrient rich water and then into the atmosphere, immersing microalgae in both sunlight and water. Photosynthesis is utilized in RABR operation to enhance struvite formation by increasing the pH value within the biofilm through the uptake of carbon dioxide from solution. Measurements of pH trended higher with depth through the biofilm when exposed to light confirming the function of photosynthesis in increasing pH and, as a consequence, struvite formation. In addition, reducing RPM allows more time for water to evaporate through exposure of the biofilm to the atmosphere and provides a management option to exceed struvite solubility product. Struvite precipitation was predicted based on chemical analysis and MINTEQ modeling of ADE, was confirmed using Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy, and quantified by determining ash content. Increase in pH within the biofilm was confirmed as photosynthetic photon flux density increased. While struvite precipitation and removal from wastewater is conventionally accomplished through physicochemical methods, this research is the first report of struvite enhanced formation through algae biofilm-based photosynthesis processes.

• Research Organization: Utah State University, Logan, UT (United States)
• Sponsoring Organization: USDOE; USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Sustainable Transportation. Bioenergy Technologies Office (BETO)
• Grant/Contract Number: EE0009271
• OSTI ID: 2222978
• Alternate ID(s): OSTI ID: 3007845
• Journal Information: Cleaner Engineering and Technology, Journal Name: Cleaner Engineering and Technology Vol. 17; ISSN 2666-7908
• Publisher: Elsevier BV
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
RABR
algae
biofertilizer
biofilm
phosphorus
struvite