Location: Cool and Cold Water Aquaculture ResearchTitle: Modeling and mitigation of denitrification 'woodchip' bioreactor phosphorus releases during treatment of aquaculture wastewater Author
|Sharrer, Kata - Freshwater Institute|
|Christianson, Laura - Freshwater Institute|
|Lepine, Christine - Freshwater Institute|
|Summerfelt, Steven - Freshwater Institute|
Submitted to: Aquacultural Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/7/2016
Publication Date: 5/21/2016
Citation: Sharrer, K.L., Christianson, L.E., Lepine, C., Summerfelt, S.T. 2016. Modeling and mitigation of denitrification 'woodchip' bioreactor phosphorus releases during treatment of aquaculture wastewater. Aquacultural Engineering. 93:135-143. doi:10.1016/j.ecoleng.2016.05.019.
Interpretive Summary: Woodchip bioreactors are used to remove nitrate in row crop tile drainage and aquaculture effluent applications. Woodchip bioreactors that remove nitrate from water can export phosphorus. Batch tested woodchips leached approximately 20 -30 mg phosphorus per kg wood over 24 days. The most rapid phosphorus leaching occurred within the first 24 hours. Dissolved phosphorus loss transitioned to removal in slow flowrate bioreactors (by day 100). Pilot-scale bioreactors showed 15 -54% total phosphorus removal from aquaculture wastewater. Thus, woodchip bioreactors can effectively remove nitrate, phosphorus, and total suspended solids from aquaculture waste waters.
Technical Abstract: Denitrification 'woodchip' bioreactors designed to remove nitrate from agricultural waters may either be phosphorus sources or sinks. A 24 d batch test showed woodchip leaching is an important source of phosphorus during bioreactor start-up with a leaching potential of approximately 20 -30 mg P per kg wood. The most rapid phosphorus release occurred within the first 24 h regardless of deionized water or aquaculture wastewater matrices; the Elovitch equation generally best modeled this multi-phasic P leaching. Four pilot-scale bioreactors consistently removed total phosphorus from aquaculture wastewater (15 -54% removal efficiency). All bioreactors initially exported dissolved reactive phosphorus, although the lower flow rate treatments eventually resulted in dissolved reactive phosphorus removal. Filtered wastewater solids may have contributed more to longer-term P leaching than the woodchips.