Jingjing Wu1, Shane W. Rogers1, Rebekah Schaummann1, Nichole Price2
1 Department of Civil and Environmental Engineering, Clarkson University, 8 Clarkson Ave, Potsdam, NY 13699-5710
2 Bigelow Laboratories for Ocean Sciences, Boothbay Harbor, ME
Though advanced wastewater nutrient removal processes in coastal water resource recovery facilities (WRRFs) can reduce nutrient inputs and mitigate marine eutrophication, they significantly increase economic and environmental costs, especially in small facilities. This study investigated the potential of using bioextractive macroalgae aquaculture (Saccharina latissima and Gracilaria tikvahiae cultivation) from economic and environmental perspectives to trade nutrients discharged from WRRF as an alternative or supplement to advanced wastewater treatment processes towards achievement of three levels of nutrient effluent goals (level 1: 8.0 N-mg/L and 1.0-P-mg/L; level 2: 3.0 N-mg/L and 0.1-P-mg/L; level 3: 1.0 N-mg/L and 0.01-P-mg/L). WRRFs ranging in size from 379 to 18 927 m3/d (0.1 to 5.0 MGD) were investigated using several (scale-appropriate) physical, chemical, and biotechnology options for nutrient management. Seaweed cultivation systems investigated included single and dual layer longlines and cultivation strips. Dual layer strip platforms (DLS) could reduce aquaculture size requirements by 44% over single layer longline platforms (SLL) with economic and environmental advantages. Compared to WRRF only scenarios, mixed scenarios of WRRF and bioextractive aquaculture reduced the net cost of nutrient removal by $0.71 to $5.37 per m3 of wastewater treated. Mixed scenarios are also associated with overall reduced environmental impacts. Net environmental benefits were observed in marine and freshwater eutrophication and human noncarcinogenic toxicity.