Person: SEMERCİ, NESLİHAN
Loading...
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
SEMERCİ
First Name
NESLİHAN
Name
13 results
Search Results
Now showing 1 - 10 of 13
Publication Metadata only Quantitative analysis of candidatus accumilibacter phosphatis on lab scale denitrifying phosphorus removal sequencing batch reactors(2012-08-19) KOCAMEMİ, BİLGE; SEMERCİ, NESLİHAN; Esen E., DİTYAPAK D., KURT H., Kumru M., KOCAMEMİ B., SEMERCİ N., AKARSUBAŞI A. T.Publication Metadata only Evaluation of oxic and anoxic phosphate removal in a post-denitrification system(CURRENT BIOLOGY LTD, 2011) KOCAMEMİ, BİLGE; Semerci, Neslihan; Bakici, Nevin; Kocamemi, Bilge AlpaslanPublication Metadata only Combined and individual applications of ozonation and microwave treatment for waste activated sludge solubilization and nutrient release(ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2019) SEMERCİ, NESLİHAN; Cosgun, Sevil; Semerci, NeslihanThis study focused on the separate and combined applications of ozonation and microwave treatment to enhance the phosphorus and ammonia release from waste activated sludge. Twenty-six batch experiments were run with or without acidic (pH 2) and alkaline (pH 10) pretreatments and different ozone dosages. Also, microwave post treatments were applied to enhance phosphorus release efficiency. Results showed that ozonation is an effective technology for solubilization and release without any pre or post-treatment, reactive phosphorus content increased from 1.9 to 3.6 mg PO4-P/g MLSSin (89.5% increase) with 19.4% COD release. Alkaline pretreatment enhanced sludge solubilization and phosphorus release at most (23.9% COD release and 152.6% PO4-P increase); however, decreases in ammonia, calcium and magnesium concentrations pointed out a loss of a part of released phosphorus, due to struvite or apatite precipitation. Acidic pretreatment reduced the sludge solubilization during ozonation (10% COD release) but prevented the uncontrolled precipitation and enhanced the phosphorus release (115.8% PO4-P increase). For microwave treatment, acid pretreated sludge showed higher release than alkaline pretreated or neutral sludge. Among different process combinations, acid pretreatment/ozonation/microwave experiments have shown the highest sludge solubilization and nutrient release (48% COD release and 579% PO4-P increase); however, the difference between acid pretreatment/microwave and acid pretreatment/ozonation/microwave was not significant in terms of phosphorus release (479% PO4-P increase, p = 0.082). Thus, pH 2/microwave may be a cost-effective and feasible alternative for nutrient recovery from waste sludge. For struvite precipitation, pH 8.5 were determined as optimum level. Also using fine struvite particles as seed increased struvite precipitation efficiency.Publication Metadata only Inhibition of respiration and distribution of Cd, Pb, Hg, Ag and Cr species in a nitrifying sludge(ELSEVIER, 2010) SEMERCİ, NESLİHAN; Cecen, Ferhan; Semerci, Neslihan; Geyik, Ayse GuelThe study investigated the inhibitory effects of the heavy metals Cd, Pb, Hg, Ag and Cr (as Cr3+ and Cr6+) on a nitrifying sludge. The aim was to assess the IC50 concentrations leading to 50% inhibition. The method is based on respiration of nitrifying sludge in the presence of these metals. Both O-2 consumption and CO2 production were taken into account. The order of the inhibitory effect was Ag > Hg > Cd > Cr3+ = Cr6+. Metal speciation was calculated in terms of free metal, inorganic metal complexes and bound metal. Pb largely precipitated and 50% inhibition was never reached. Ag was always in the form of the free ion or labile complexes. Hg had apparently a lower toxicity than Ag, since most of it was initially highly complexed with ammonia. Cd was present in the form of free ion and complexes which caused inhibition although a large part of them were precipitated. The inhibitory effects of trivalent chromium (Cr3+) and hexavalent chromium (Cr6+) were similar. The latter was present in the form of the anion CrO42- and was not taken up by biomass. The study highlighted that IC50 values alone do not have an explanatory power of inhibition unless speciation is also considered. (C) 2010 Elsevier B.V. All rights reserved.Publication Metadata only Quantitative analysis of candidatus accumilibacter phosphatis on lab scale denitrifying phosphorus removal sequencing batch reactors(2012-08-19) SEMERCİ, NESLİHAN; KOCAMEMİ, BİLGE; Ergal İ., SEMERCİ N., KOCAMEMİ B., Kurt H., AKARSUBAŞI A. T.Publication Metadata 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. AlpaslanPublication Open Access Anammox start-up strategies: the use of local mixed activated sludge seed versus Anammox seed(IWA PUBLISHING, 2018-12-19) KOCAMEMİ, BİLGE; Kocamemi, Bilge Alpaslan; Dityapak, Duygu; Semerci, Neslihan; Keklik, Esra; Akarsubasi, Alper; Kumru, Mert; Kurt, HalilThe start-up period of Anammox systems is still a big challenge due to the unavailability of large volumes of slowly growing Anammox seed locally in most countries. This study aims to evaluate the effects of seeding strategy on the start-up and enrichment period of Anammox systems by monitoring both process performance and microbial population dynamics. Two different seeding strategies, the use of mixed activated sludge culture from a local STP and the use of enriched Anammox culture transported from abroad, were comparatively studied in SBR systems operated for 410 days. The enriched Anammox seed from abroad inhibited seriously during transportation. Anammox activity re-started after 195 days' recovery period. An active Anammox culture was successfully enriched within 95 days from a local activated sludge source without seeding any Anammox. The Anammox population reached levels of 10(11) copies/ng at the end of 410 days' enrichment period. Based on FISH, Ca. Brocadia anammoxidans and Ca. Scalindua species were dominant in the enriched culture. The maximum TNRR was observed as 430 mg N/day. DGGE analyses revealed a drastic change in the microbial community (56%) with Anammox enrichment. Phylogenetic analysis demonstrated a significant decrease in phylotype Proteobacteria and increase in phylotypes Planctomycetes, Chloroflexi and Acidobacteria with enrichment.Publication Metadata only Evaluation of pH, ORP and conductivity profiles in an Anammox reactor started-up using municipal activated sludge seed(CURRENT BIOLOGY LTD, 2011) KOCAMEMİ, BİLGE; Kocamemi, Bilge Alpaslan; Dityapak, Duygu; Semerci, NeslihanPublication Metadata only Phosphorus Recovery from Waste Activated Sludge: Microwave Treatment and Ozonation with Acid & Alkaline Pre-treatments(SPRINGER INTERNATIONAL PUBLISHING AG, 2017) SEMERCİ, NESLİHAN; Cosgun, S.; Semerci, N.; Mannina, GThis study investigated phosphorus recovery from activated sludge through ozonation and microwave treatment with acid and alkali pre-treatments. Three main groups (pH treatment & ozonation, pH treatment & microwave, pH treatment & ozonation & microwave) were studied for COD and P release. Results of batch experiments have shown that, optimum pH for sludge disintegration and phosphorus release is 10 according to center dot OH radical formation. Also studying at low pH levels gives an advantage due to effect of acidic condition on cell lysis. Besides, according to results of phosphorus fraction experiments in raw sludge, the other advantage of low pH levels is releasing of apatite (bound to calcium) phosphorus. Both ozonation and microwave treatments were effective for sludge disintegration, the highest COD release was observed after microwave treatment of ozonated samples. However, microwave was much more effective than ozonation on phosphorus, significant amount of phosphorus released into the bulk solution in both ozonation and microwave treatments. Despite of COD release, microwave and ozonation & microwave have similar efficiencies on phosphorus release, ozonation might be negligible before microwave due to high production cost. On the other hand, after analyses of struvite samples, pH = 8.5 and 2 days reaction time was determined as the optimum conditions for struvite purity.Publication Metadata 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 GuelBACKGROUND: 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