Effect of chromium(VI) on the biomass yield of activated sludge

Yetiş, Ülkü
Gokcay, CF
Effect of 1-25 mg/l of influent Cr(VI) concentrations on true biomass yield (Y-t) and decay coefficient (k(d)) of activated sludge units was investigated in this study. To this purpose, completely mixed, once-through laboratory scale activated sludge units with acclimated cultures were operated. After obtaining dilute-out curves for each Cr(VI) concentration, the values of Y-t and k(d) were determined. The results revealed that presence of Cr(VI) caused stimulatory effects on biomass yield and maintenance up to the Cr(VI) concentration of 25 mg/l. Lower Cr(VI) concentrations exerted higher stimulation of the system. Extended oxidation due to the presence of Cr(VI) and/or increased synthesis of cellular material due to the stimulatory effects of Cr(VI) were thought to be the mechanisms of the observed stimulation. (C) 1999 Elsevier Science Inc. All rights reserved.


Effect of nickel(II) on the biomass yield of the activated sludge
Gokcay, CF; Yetiş, Ülkü (1996-01-01)
Biomass yield of microorganisms is important in applied microbiology since it is the ultimate factor determining the amount of product produced regardless of whether product is growth-linked or not. In the case of environmental microbiology the opposite is true and minimizing the biomass produced, or the sludge in the relevant jargon, often is the prime goal. In this paper, a unique means of manipulating the microbial biomass yield of a heterogeneous culture to fulfil either of the two goals is presented. 5...
Effect of carbon to nitrogen ratio on the composition of microbial extracellular polymers in activated sludge
Durmaz, B; Sanin, Faika Dilek (2001-01-01)
Effect of carbon to nitrogen ratio (C/N) on the sludge extracellular polymer composition is studied in synthetically fed semi-continuous reactors with 8 days of sludge age. Results show that C/N ratio influences the relative distribution of polymer carbohydrate and protein. At low C/N ratio of 5, polymer extracts have high protein and low carbohydrate content. As the C/N ratio is increased to 17.5 and then to 40, carbohydrate concentration increases sharply and protein concentration decreases.
Effect of sodium carbonate on carbothermic formation of hexagonal boron nitride
Akyıldız, Uğur; Sevinç, Naci; Department of Metallurgical and Materials Engineering (2010)
Effect of Na2CO3 on formation of hexagonal boron nitride (h-BN) by carbothermic method has been studied by subjecting B2O3-C and Na2CO3-added B2O3-C mixtures to N2 (g) atmosphere. Na2CO3 amount in the mixtures was changed in the range of 0-40 wt. %. Time and temperature were used as experimental variables. Reaction products were analyzed by XRD and scanning electron microscope. Na2CO3 was found to increase both the amount and the particle size of h-BN similar to CaCO3 [1]. Na2CO3 was found to be less effect...
Effect of calcium carbonate addition on carbothermic formation of hexagonal boron nitride
ÇAMURLU, HASAN ERDEM; SEVİNÇ, NACİ; Topkaya, Yavuz Ali (Elsevier BV, 2008-01-01)
Effect of CaCO3 on formation of hexagonal boron nitride (h-BN) was investigated by holding CaCO3 free and CaCO3 added activated carbon-boric oxide mixtures under nitrogen atmosphere at 1500 degrees C for 30-120 min. Amount of CaCO3 addition was varied in the range of 0-50 wt.% of the initial mixture. Products were characterized by powder X-ray diffractometry, FT-IR analysis, quantitative chemical analysis, scanning electron microscopy and BET specific surface area analysis. It was observed that calcium carb...
Effect of carbon to nitrogen ratio on the physical and chemical properties of activated sludge
Durmaz, B; Sanin, Faika Dilek (2003-11-01)
The effect of carbon to nitrogen ratio (C/N) of the feed on the physical and surface chemical properties of activated sludge is investigated. Semi-continuous reactors with 2 liters volume were operated at a mean cell residence time of 8 days. These mixed culture reactors were operated at 3 different carbon to nitrogen ratio. The operation of conventional activated sludge plants treating municipal wastewater is represented with reactors having a C/N ratio of 21 (in terms of the ratio of COD to TKN). Carbon a...
Citation Formats
Ü. Yetiş and C. Gokcay, “Effect of chromium(VI) on the biomass yield of activated sludge,” ENZYME AND MICROBIAL TECHNOLOGY, pp. 48–54, 1999, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/38126.