Treatment of anaerobically digested swine manure using Chlorella vulgaris and bacteria in scaled-up systems

In previous studies, an integrated process (flocculation, struvite precipitation, Chlorella vulgaris and bacteria co-treatment) was shown to be a potentially effective treatment for anaerobically digested swine manure (ADSM). To assess the feasibility of engineering application, the biological treatment (Chlorella vulgaris and bacteria) of this integrated process was scaled up and implemented in an open vertical runway treatment system in this study. With continuous analysis and improvement of natural conditions, equipment and environmental factors, the effect of biomass accumulation and pollutant removal were significantly improved in the second 100 L batch. After 7 days of treatment, the biomass accumulation reached 2.06 ± 0.11 g/L, and the removal rates of chemical oxygen demands (COD), NH₄⁺-N, TN and TP reached 75.7 %, 99.3 %, 79.7 % and 76.9 %, respectively, in the second 100 L batch. Results showed that the integrated treatment process could become a reliable way in treating ADSM by optimizing operation conditions in scale-up system.