Combined effects of Ni(II) and Cr(VI) on activated sludge

The combined effects of Ni(II) and Cr(VI) on activated sludge kinetics were studied in this paper. The metals were added to a synthetic medium with a chemical oxygen demand (GOD) of 1300 mgl(-1) to give various combinations of Ni(II) and Cr(VI). Activated sludge performance, in terms of COD removal, was not adversely affected in an acclimatized culture by the metal combinations, compared with the single metals. The combination effects of Ni!II) and Cr(VI)on biokinetic constants, i.e. the maximum specific growth rate, mu(m), was found to be stimulatory in general. The same effect was observed on the half-saturation substrate concentration, K-s. Effects were therefore classified as synergistic with respect to these constants.


Combined effects of Cu2+ and Zn2+ on activated sludge process
Beyenal, NY; Ozbelge, TA; Özbelge, Hilmi Önder (1997-04-01)
The aim of this study is to investigate the combined effects of Cu2+ and Zn2+ in a synthetic wastewater (WW) on activated sludge process (ASP) over a wide range of mean cell residence times. Experiments were performed in two phases: (i) experiments without heavy metals (HMs), (ii) experiments with HMs using acclimated microorganisms (MOs). In the first phase, biokinetic constants of the synthetic WW inoculated with seed MOs were determined and a linear relationship between substrate removal efficiency and m...
Dynamic and steady-state analysis of oxidative dehydrogenation of ethane
Karamullaoğlu, Gülsün; Doğu, Timur; Department of Chemical Engineering (2005)
In this research, oxidative dehydrogenation of ethane to ethylene was studied over Cr-O and Cr-V-O mixed oxide catalysts through steady-state and dynamic experiments. The catalysts were prepared by the complexation method. By XRD, presence of Cr2O3 phase in Cr-O; and the small Cr2O3 and V2O4 phases of Cr-V-O were revealed. In H2-TPR, both catalysts showed reduction behaviour. From XPS the likely presence of Cr+6 on fresh Cr-O was found. On Cr-V-O, the possible reduction of V+5 and Cr+6 forms of the fresh sa...
The effects of alkali promoters on the dynamics of hydrogen chemisorption and syngas reaction kinetics on Ru/SiO2 surfaces
Üner, Deniz; Pruski, M; King, TS (1997-01-01)
The dynamics of chemisorbed hydrogen on unpromoted and promoted Ru/SiO2 catalysts was studied by means of single pulse and selective excitation H-1 NMR spectroscopy. Dynamic NMR studies indicated a reduced mobility of hydrogen in the presence of alkali promoters (Na and K) at high loadings (65 atomic %). On unpromoted Ru/SiO2 catalysts, the line due to hydrogen-on-metal was homogeneously broadened at pressures above 0.5 Torr H-2. Similar behavior was observed on promoted Ru/SiO2 catalyst with 66 atomic % K....
Catalytic reaction of propylene to propylene oxide on various catalysts
Kalyoncu, Şule; Önal, Işık; Şeker, Erol; Department of Chemical Engineering (2012)
Throughout this thesis work, various catalysts were investigated with combinational approach to develop highly active and selective novel catalysts for direct epoxidation of propylene to PO using molecular oxygen. The promoted and un-promoted silver (Ag), copper (Cu), ruthenium (Ru), manganese (Mn) mono and multimetallic catalytic systems over different silica supports were prepared via sol-gel method and incipient wetness method. In addition to support effect, the effects of different promoters on the cata...
Effect of EDTA on activated sludge properties
Sanin, Faika Dilek (2001-02-01)
Bacterial extracellular polymers have been found to be important in bioflocculation of activated sludge. In this study ethylene diamine tetra acetic acid (EDTA) method of extracting bacterial extracellular polymers is examined. Following extractions, it is observed that EDTA extracted significant amounts of biopolymers. However, the chemical treatment causes serious changes in sludge properties. Sludge particle size is reduced from 21 mum to 14.6 mum, filtration properties of sludge deteriorates, indicated ...
Citation Formats
F. B. Dilek and Ü. Yetiş, “Combined effects of Ni(II) and Cr(VI) on activated sludge,” Water Research, pp. 303–312, 1998, Accessed: 00, 2020. [Online]. Available: