Enhancement of the mariculture wastewater treatment based on the bacterial-microalgal consortium

Though bacterial-microalgal consortium (BM) system showed significant advantages for the mariculture wastewater treatment, how the high saline to the degradation of nitrogen, phosphorus and organic component shift need to be further investigated. In this study, three systems including the microalgae system (MA), activated sludge system (AS) and BM were parallel operated. The mariculture wastewater treatment performance and the shifts of soluble microbial products (SMPs) components were compared among the above systems. The result showed that the highest removals of NH4+-N (92.78%), PO43−-P (79.47%) and total organic carbon (TOC) (81.67%) were obtained in the BM system. This result demonstrated that the confederate effect between bacteria and microalgae showed satisfying mariculture wastewater treatment performance compared to the individual MA or AS system. In terms of the SMP production, the high salinity resulted in much SMP accumulation (178.89 mg/L of protein and 71.35 chancinmg/L of carbohydrate) in the MA system. Fortunately, the high salinity inhibition effect was dramatic reduction with less SMP accumulation in the BM system. The EEM result showed amounts of macromolecular organics of protein (aromatic-like substances and tryptophan-like substances) were the main components in the MA system, which were much higher than that in the AS and BM system. This indicated the macromolecular protein-like matters could not be removed absolutely based the individual MA system. Comparatively, the composition of SMP was shifted by the bacterial-microalgal consortium with less humic-like matters and tryptophan-like matters production in the BM system. The less SMP release had advantage to the stable operation of the bacterial-microalgal consortium. Hence, the bacterial-microalgal consortium contributed to a much stable micro-ecological environment formation for enhancing the high salinity mariculture wastewater treatment performanc