Integrated process for anaerobically digested swine manure treatment.

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.