LIVING BIOMASS SUPPORTED ON A NATURAL-FIBER BIOFILTER FOR LEAD REMOVAL

Living biomass biofilters constitute an excellent alternative for heavy metal bioremediation. In situ biomass and exopolysaccharides production involve a crucial advantage over other bioremediation alternatives such as lignocellulosic biomass-based materials. In this study, a biofilm-forming bacterium was isolated from an ambient exposed to heavy metals. Bacterial biomass was inoculated on a biofilter packed with Furcraea andina fibers. The goal was to develop a continuous low-cost biofilter to remove low-to-moderate concentrations of Pb2+. Adsorption equilibrium and kinetics were determined for the fibers and the biofilm developed on the fibers. Biofilm presence had positive effects on the maximum adsorption capacity and the process kinetics. Biofilters packed with 20 g of F. andina fibers, with and without living biomass biofilm, were evaluated under continuous inflow of Pb2+ (325mg/day) at a concentration of 50 mg/L. The best results were obtained with the biofilm- fiber biofilter where total adsorption on Pb2+ were observed for 72 h. Maximum absorption capacity was 48.75 mg/g at pH=7

The Prediction of Partial-Nitrification-Anammox Performance in Real Industrial Wastewater based on Granular Size

To date, the partial nitrification-Anammox (PN-A) granular sludge size has been exclusively analyzed in synthetic substrates. In this work, different ranges of granular size of PN-A sludge were studied at low oxygen concentration using real industrial wastewater as, well as a synthetic substrate. The granular sludge was characterized by the specific nitrification activity (SNA), specific anammox activity (SAA), and granule sedimentation rate. The relative abundance of the bacterial consortium was assessed for each range of diameters through the fluorescence in situ hybridization (FISH) technique. SNA exhibits a direct association with the specific surface of granules, which proves the importance of the outer layer in the nitrification process. Even more critical, the flocculent sludge allowed the stability of the nitrifying activity. The SAA showed different performances faced the real industrial and synthetic substrates. With the synthetic substrate, the SAA decreased at higher diameter ranges, whereas with the industrial substrate, the SAA increased at higher diameter ranges. This situation is explained by the oxygen protection in the sludge maintained with industrial wastewater. The relative abundance of heterotrophic bacteria increased from 9.6 to 22%, due to the presence of organic matter in the industrial substrate. The granular sedimentation rate increased with the diameter of the granules with a linear correlation (R2>0.98). Thus, granular sizes can be selected through sedimentation rate control. A linear correlation between SAA and granular sludge diameter ranges was observed. With this correlation, an error of less than 11% in the prediction of SAA was achieved. The use of diameter measurement and granular sedimentation rate as routine techniques could contribute to the control and start-up of PN-A reactors. In the same sense, organic matter present in defined concentrations, can be beneficial for the granular sludge stability, and thus, for nitrogen removal