Person:
SEMERCİ, NESLİHAN

Profile Picture

Email Address

Birth Date

Research Projects

Organizational Units

OrgUnit Logo
Organizational Unit

Job Title

Last Name

SEMERCİ

First Name

NESLİHAN

Name

Filters

2007 - 20103
Reset filters

Settings

Subject: inhibition ×

Search Results

Now showing 1 - 3 of 3
  • No Thumbnail Available
    PublicationMetadata only
    Importance of cadmium speciation in nitrification inhibition
    (ELSEVIER, 2007) SEMERCİ, NESLİHAN; Semerci, Neslihan; Cecen, Ferhan
    In this study, the influence of Cd speciation on nitrification inhibition was investigated in batch suspended growth activated sludge systems which contain biomass enriched in terms of nitrifiers. For this purpose, parallel measurements of specific oxygen uptake rates (SOUR), ammonium utilization rates (q(NH4)-N) and Cd uptake were carried out. Cd speciation was adjusted with a strong complexing agent, ethylenediaminetetraacetic acid (EDTA). Free and biosorbed Cd concentrations were theoretically determined by using the MINEQL+ program and the Cd adsorption constant, whereas labile Cd was determined by voltammetric measurements. The presence of EDTA decreased nitrification inhibition by lowering the available Cd species and by preventing biosorption of Cd. Almost complete recovery from inhibition was attained by EDTA addition to nitrifying bacteria which were inhibited by Cd for a certain time. These results suggested that the sites sensitive to Cd were rather located on the surface of bacterial cell than inside. Nitrification inhibition depended on equilibrium concentrations of free (Cd2+), labile (Cd-volt) and biosorbed Cd (Cd-volt) and did not correlate with the total Cd. The measurement of labile metal by voltammetry in inhibition studies is a promising approach since it is easy to apply in practice. (C) 2007 Elsevier B.V. All rights reserved.
  • No Thumbnail Available
    PublicationMetadata only
    Effects of nitrite, oxygen and initial pH on biological phosphorus removal in a post-denitrification system
    (ELSEVIER SCIENCE BV, 2010) SEMERCİ, NESLİHAN; Semerci, Neslihan; Bakici, Nevin; Kocamemi, B. Alpaslan
  • No Thumbnail Available
    PublicationMetadata only
    Inhibitory effects of Cu, Zn, Ni and Co on nitrification and relevance of speciation
    (WILEY, 2010) SEMERCİ, NESLİHAN; Cecen, Ferhan; Semerci, Neslihan; Geyik, AySe Guel
    BACKGROUND: The speciation of metals is often overlooked in understanding their observed inhibitory effect in biological systems, in particular in nitrification systems. This study examines the effects of Cu, Zn, Ni and Co on a nitrifying sludge, where the aim is to relate inhibition to speciation. RESULTS: Nitrification inhibition was monitored by O-2 and CO2 measurements, an approach rarely followed to date. The IC50 value of each metal was expressed in terms of total, free and labile metal. Zn and Cu formed similar species, but had different free and labile fractions. Although free and labile fractions of Cu were much lower than the others, it was the most inhibitory metal. Ni and Co exhibited quite different inhibitory effects on nitrification despite the formation of similar metal species. Co was the least inhibitory metal and exhibited its effect very slowly. CONCLUSION: The study is among the few which examine inhibition and speciation of several metals in a comparative way. In the same nitrification medium each metal formed different species, which is a factor to be considered in interpretation of inhibition. The results may be projected to nitrifying systems to clarify the underlying factors in inhibition. (C) 2009 Society of Chemical Industry