An integrated three-step process was proposed for the treatment of the anaerobically digested swine manure (ADSM). The flocculation and struvite precipitation were used as the pre-treatment to remove the particles and reduce phosphorus to balance the condition for the algae growth. In the biological step, the 40% group (2.5× dilution) represented the optimal cultivation condition for the A + B co-cultivation, with the highest biomass concentration of 2.325 ± 0.16 g/L and performed well with nutrients removal (COD: 9770 ± 184 mg/L; TN: 235 ± 5.4 mg/L; TP: 25.3 ± 0.8 mg/L). 94.8% of the biomass from the 40% group could naturally settle down in 30 min which is good for harvest. The activated carbon adsorption was applied as the advanced treatment to resolve the issues with the dark color and residual compounds. After these processes, the removal efficiencies of COD, TN, TP and NH4-N reached 97.2%, 94.0%, 99.7% and 99.9%, respectively.
Bibliographical noteFunding Information:
This manuscript was supported in part by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative Citizen Commission on Minnesota Resources (LCCMR) and University of Minnesota Center for Biorefining . We also would like to express our great appreciation to the China Scholarship Council (CSC). Dr. Seema Thakral is acknowledged for help with data acquisition and phase identification. Parts of this work were carried out in the Characterization Facility, University of Minnesota, a member of the NSF-funded Materials Research Facilities Network ( www.mrfn.org )
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- Activated carbon adsorption
- Algae and bacteria co-cultivation
- Digested swine manure
- Struvite precipitation