Bioaugmentation of the green alga to enhance biogas production in an anaerobic hollow-fiber membrane bioreactor.

Anaerobic membrane reactors (AnMBRs) offer an alternative wastewater treatment system, presenting both reclamation of value through biogas production, and efficient treatment of recalcitrant contaminants such as antibiotics from wastewater. The effects of bioaugmentation with the green alga Haematococcus pluvialis on anaerobic treatment of pharmaceutical wastewaters, alleviating membrane biofouling, biogas production and impact on the indigenous microbial communities were evaluated using AnMBRs. The outputs of the bioreactor experiments revealed that bioaugmentation strategies with the green alga increased removal of chemical oxygen demand by 12% and delayed membrane fouling by 25% and increased biogas production by 40%. Furthermore, bioaugmentation with the green alga led to a significant change in relative abundance of archaea and the main methanogenesis pathway shifted from Methanothermobacter to Methanosaeta, accompanied by their respective syntrophic bacteria.

Enhanced removal of antibiotics using Eichhornia crassipes root biomass in an aerobic hollow-fiber membrane bioreactor.

The impact of water hyacinth (Eichhornia crassipes) root biomass (WHRB) on pharmaceutical wastewater treatment with an aerobic hollow-fiber membrane bioreactor (HF-MBR) was investigated. The performance of the bioreactor was assessed in terms of COD (Chemical Oxygen Demand) and antibiotic removal and membrane biofouling rate. For deeper insight, microbial communities in sludge and biofilm layers were analyzed through Illumina sequencing. The addition of WHRB into the HF-MBR increased the COD (by 6%), as well as antibiotics and transformation products removal efficiency. Removal efficiencies of 97%, 98% and 84% were obtained for removal of erythromycin, sulfamethoxazole, and tetracycline. Furthermore, WHRB modified the biodegradation network, increased the relative abundances of Chloroflexi, Proteobacteria and Nitrospirae and decreased Firmicutes, compared with the control with antibiotics. The addition of WHRB also enriched Actinobacteria and Bacteroidetes while decreasing the phylla Chloroflexi and Saccharibacteria in the biofilm.

Eichhornia crassipes root biomass to reduce antibiotic resistance dissemination and enhance biogas production of anaerobic membrane bioreactor.

ABSTRACTTo address the inadequate removal of antibiotic resistance genes in wastewater treatment plants, this study investigated the impact of bioaugmentation with dried Eichhornia crassipes roots on removal of antibiotics sulfamethoxazole, tetracycline and erythromycin from pharmaceutical wastewater while optimizing potential for reclaiming value through biogas production, utilizing an anaerobic membrane bioreactor (AnMBR). Three sets of AnMBRs were set up for the experiment, C1 (inoculum), C2 (inoculum + antibiotics) and EC (inoculum + antibiotics + E. crassipes). The results showed that E. crassipes mitigated some of the toxic effects of antibiotics on the microbial community and prevented negative impact on the archaeal community, and significantly increased average biogas production (by 37% compared to control without antibiotics and 42% compared to control with antibiotics) as well as antibiotics removal. Furthermore, bioaugmented reactor showed significant reduction of erythromycin (97%) and tetracycline (83%) concentrations in effluent. Utilization of E. crassipes root offers a simple yet powerful tool for preventing the emergence of antimicrobial resistance and dissemination of such pollutants into the environment.

Addition of Trichocladium canadense to an anaerobic membrane bioreactor: evaluation of the microbial composition and reactor performance.

Membrane bioreactors are powerful systems for wastewater treatment and the removal of toxic compounds. However, membrane biofouling stands in the way of their widespread usage. In this study, the saprophytic fungus Trichocladium canadense was used as the bioaugmentor in an anaerobic membrane bioreactor (AnMBR) and its impact on membrane biofouling, biogas production, the microbial communities of the reactor and removal of the common antibiotics erythromycin (ERY), sulfamethoxazole (SMX) and tetracycline (TET) from synthetic wastewater was investigated. The results indicated that through bioaugmentation with 20% T. canadense, membrane biofouling was slowed by 25%, the chemical oxygen demand removal increased by 16% and a higher efficiency removal of ERY and SMX was achieved. The presence of T. canadense significantly increased the abundance and diversity of the biofilm archaeal community and the bacterial phylum Firmicutes, a known bio-foulant.

Bioaugmentation with immobilized endophytic Penicillium restrictum to improve quorum quenching activity for biofouling control in an aerobic hollow-fiber membrane bioreactor treating antibiotic-containing wastewater.

The effects of bioaugmentation with immobilized Penicillium restrictum on the removal efficiency of sulfamethoxazole (SMX), erythromycin (ERY) and tetracycline (TC) antibiotics as well as membrane biofouling was studied using hollow-fiber membrane bioreactor (HF-MBR). Bioaugmentation with P. restrictum led to a significant change in the antibiotic removal efficiency and relative abundance of aerobic microbial community, most probably as a result of its quorum quenching activity. Furthermore, in addition to its role in the increase of SMX and ERY removal efficiencies and the decrease of their sorption on solid phase, bioaugmentation significantly reduced the transmembrane pressure which in turn reduced membrane clogging. The most abundant phyla in sludge and biofilm samples in the presence of P. restrictum were observed to be Proteobacteria, Bacteroidetes and Firmicutes. Differences in bacterial compositions and their specificity in biodegradation of antibiotics in different reactors showed that bacteria were specifically selected under the pressure of antibiotics and growing fungus.