A self-design bioreactor system employing a fixed bed operation process with immobilized Bacillus subtilis AYC beads for NH4+-N removal from slightly polluted water was proposed. Polyvinyl alcohol and Na-alginate were used as a gel matrix to entrap Bacillus subtilis AYC to form the immobilized beads. The NH4+-N removal process was studied in a intermittent operation mode to examine the start-up...

sulfur utilizing autotrophic denitrification synthetic wastewater in up flow packed --bed reactor was evaluated under different concentrations of alkalinity and organic matter. the reactor was filled with granular elemental sulfur particles with diameters of 2.8-5.6 mm and porosity of 40%. the initial culture was prepared from sludge of shahrak ghods wastewater treatment plant. first, the stoic...

conclusions application of zinc oxide as the photocatalyst can be effective in the removal process. background one of the important achievements of the past decade was the rapid growth of industries and accordingly production of various chemical compounds. objectives this study presents a combined system of photocatalytic oxidation and absorption solution to remove nitrogen oxides from polluted...

This study deals with the influence of heterotrophic growth on autotrophic nitrogen removal from wastewater in a granular sludge reactor. A mathematical model was set-up including autotrophic and heterotrophic growth and decay in the granules from a partial nitritation-anammox process. A distinction between heterotrophic bacteria was made based on the electron acceptor (dissolved oxygen, nitrit...

background : the study examined the implementation of artificial neural network (ann) for the prediction of ammonia nitrogen removal from landfill leachate by ultrasonic process. methods : a three-layer backpropagation neural network was optimized to predict ammonia nitrogen removal from landfill leachate by ultrasonic process. considering the smallest mean square error (mse), the configuration...

Abstract Nitrogen-cycling microorganisms play key roles at the intersection of microbiology and wastewater engineering. In addition to well-studied ammonia oxidizing bacteria, nitrite heterotrophic denitrifiers, anammox there are some other N-cycling that less abundant but functionally important in nitrogen removal. These microbes include, not limited archaea (AOA), complete oxidation (comammox...

denitrification is a reduction of nitrate by heterotrophic and autotrophic bacteria that may ultimately produce molecular nitrogen (n2) through a series of intermediate nitrogen compounds.vermiculite is a hydrous phyllosilicate mineral (mg, fe+2,fe+3)3[(al,si)4o10](oh)2·4h2o with several layers for bacterial immobilization. the goal of this study was removal of nitrate from water with vermiculi...

Sludge retention time (SRT) is an important factor affecting not only the performance of the nutrient removal and sludge characteristics, but also the production of secondary pollutants such as nitrous oxide (N2O) in biological nutrient removal (BNR) processes. Four laboratory-scale sequencing batch reactors (SBRs), namely, SBR5, SBR10, SBR20 and SBR40 with the SRT of 5 d, 10 d, 20 d and 40 d, ...

Nitrogen is considered to be one of the most widespread pollutants leading to eutrophication of freshwater ecosystems, especially in drinking water reservoirs. In this study, an oligotrophic aerobic denitrifier was isolated from drinking water reservoir sediment. Nitrogen removal performance was explored. The strain was identified by 16S rRNA gene sequence analysis as Zoogloea sp. N299. This sp...