Nitrogen removal and microbial diversity of activated sludge entrapped in modified poly(vinyl alcohol)–sodium alginate gel

• Published in: International biodeterioration & biodegradation 2017-11, Vol.125, p.243-250
• Main Authors: Xu, Xiaoyi, Lv, Chenpei, You, Xiaolu, Wang, Bin, Ji, Fangying, Hu, Bibo
• Format: Article
• Language: English
• Subjects: Acclimation; Acclimatization; Activated sludge; Alcohols; Alginic acid; Alumina nanoparticles; Aluminum oxide; Ammonia; Beads; Biological denitrification; Chemical reactions; Community structure; Denitrification; Embedding; Embedding beads; Entrapment; Fourier transforms; Functional groups; Infrared spectroscopy; Mechanical properties; Microbial community diversity; Microorganisms; Nanoparticles; Next-generation sequencing; Nitrification; Nitrifying performance; Nitrogen; Nitrogen removal; Raman spectroscopy; Scanning electron microscopy; Sodium; Sodium alginate; Spectroscopy; Studies; Wastewater; Wastewater treatment
• ISSN: 0964-8305; 1879-0208
• DOI: 10.1016/j.ibiod.2017.07.014

We investigated nitrogen removal from secondary effluent via microbial entrapment with poly (vinyl alcohol)–sodium alginate gel modified with alumina nanoparticles. Fourier transform infrared spectroscopy (FT–IR) and Raman spectroscopy revealed changes in functional groups on the embedding beads with the modification and the Brunauer–Emmett–Teller (BET) demonstrated that the mechanical strength of beads improved. Batch experiments were conducted to investigate nitrogen removal in synthetic wastewater with initial total nitrogen concentrations of 10–45 mg L−1. The maximum ammonia removal loads ranged from 9.63 to 59.58 mg L−1 h−1. Scanning electron microscope (SEM) observations showed that the beads were highly porous and conducive for microorganism adhesion. Microbial diversity analysis (High throughput sequencing) demonstrated that the microbial community structure inside the beads changed significantly after acclimation to the reactor environment and the reaction process. Alcaligenaceae_uncultured and Comamonadaceae_unclassified, which can conduct both heterotrophic nitrification and aerobic denitrification, were identified. They may facilitate pathways for non-traditional biological denitrification inside embedding beads. [Display omitted] •Alumina nanoparticles were added to PVA-SA gel using ultra-sonication.•Mechanical strength of modified beads improved.•Ammonium removal rate of modified beads was in the range of 89%–100% for low strength ammonium wastewater.•Pore structure of modified beads was conducive to microorganism adhesion.