La-based-adsorbents for efficient biological phosphorus treatment of wastewater: Synergistically strengthen of chemical and biological removal.

The present work demonstrated the invention of synergistically strengthen of chemical and biological removal of phosphorus (P) in biological wastewater treatment, which was achieved by exposure the bioreactors to different levels of La-based-adsorbents. We fabricated a high-performance LaOCO micro-adsorbent (H-LaOCO) and added it into sequencing batch reactors. When activated sludge was exposed to 40 mg/L H-LaOCO for 40 d, effluent total phosphorus (TP) concentration significantly decreased to approximately 0.18 mg/L, with the steady removal efficiency of 96.4%, which is superior to the biological phosphorus removal (BPR). The effect of H-LaOCO dosages on P removal in biological wastewater treatment was also detailedly investigated. The H-LaOCO adsorbent could not only capture P by chemical bonding itself, but also increased protein (PN) contents of extracellular polymeric substances (EPS) and changed the functional group of EPS to chemically adsorb P. Additionally, the results of 16s rDNA molecular analysis revealed that the species richness and microbial diversity varied with the different dosages of adsorbent. Sequence analyses showed that the appropriate concentration of H-LaOCO addition increased the contents of several polyphosphate accumulating organisms (PAOs) at genus level in sludge.