Phosphorus biorecovery from wastewater contaminated with multiple nitrogen species by a bacterial consortium

Growth, nutrient removal, and lipid productivity promotion of Chlorella sorokiniana by phosphate solubilizing bacteria Bacillus megatherium in swine wastewater: Performances and mechanisms

Effects of a phosphorus-solubilizing bacteria (PSB) Bacillus megatherium on growth and lipid production of Chlorella sorokiniana were investigated in synthesized swine wastewater with dissolved inorganic phosphorus (DIP), insoluble inorganic phosphorus (IIP), and organic phosphorus (OP). The results showed that the PSB significantly promoted the algal growth in OP and IIP, by 1.10 and 1.78-fold, respectively. The algal lipid accumulation was also greatly triggered, respectively by 4.39, 1.68, and 1.38-fold in DIP, IIP, and OP. Moreover, compared with DIP, OP improved the oxidation stability of algal lipid by increasing the proportion of saturated fatty acids (43.8 % vs 27.9 %), while the PSB tended to adjust it to moderate ranges (30.2-41.6 %). Further, the transcriptome analysis verified the OP and/or PSB-induced up-regulated genes involving photosynthesis, lipid metabolism, signal transduction, etc. This study provided novel insights to enhance microalgae-based nutrient removal combined with biofuel production in practical wastewater, especially with complex forms of phosphorus.

Microbial community analysis of membrane bioreactor incorporated with biofilm carriers and activated carbon for nitrification of urine

The integration of powdered activated carbon and biofilm carriers in a membrane bioreactor (MBR) presents a promising approach to address the challenge of long hydraulic retention time (HRT) for nitrification of hydrolysed urine. This study investigated the effect of the incorporation in the MBR on microbial dynamics, focusing on dominant nitrifying bacteria. The results showed that significant shifts in microbial compositions were observed with the feed transition to full-strength urine and across different sludge growth forms. Remarkably, the nitrite-oxidizing bacteria Nitrospira were highly enriched in the suspended sludge. Simultaneously, ammonia-oxidizing bacteria, Nitrosococcaceae thrived in the attached biomass, showing a significant seven-fold increase in relative abundance compared to its suspended counterpart. Consequently, the incorporated MBR displayed 36% higher nitrification rate and 40% HRT reduction compared to the conventional MBR. This study provides valuable insights on the potential development of household or building scale on-site nutrient recovery from urine to fertiliser.