Model based process optimization of enhanced wastewater treatment plants

Avrupa Birliği’ne uyum sürecinde ele alınan atık sorunu kapsamında, alıcı ortamlara yapılacak deşarjlarda konvansiyonal parametrelerin yanısıra azot ve fosfor (besi maddesi) parametrelerinin de belli standart değerlerin altına indirilmesi gerekli hale gelmiştir. Bu nedenle, “Kentsel Atıksu Arıtımı Yönetmeliği, 2006” ile uyum sürecinde olan ülkemizde azot ve fosfor standartları mevzuatımıza dâhil edilmiştir. “Kentsel Atıksu Arıtımı Yönetmeliği, 2006” kapsamında mevcut tesislerin besi maddesi giderimine yönelik olarak geliştirilmesi, yeni kurulacak tesislerin ise besi maddesi giderecek şekilde en uygun arıtma teknolojisi kavramı çerçevesinde boyutlandırılması gereklidir. Besi maddesi giderimine yönelik en uygun arıtma teknolojisi biyolojik prosesler, bunlar arasında en ekonomik çözüm ise aktif çamur sistemleri olarak tanımlanmaktadır. Bu çalışma aktif çamur tesislerinin, Avrupa Birliği normlarında performansını sağlayabilecek optimum tasarım ve işletme süreçlerinin değerlendirilmesini amaçlamaktadır. Bu kapsamda, bir örnek olarak ele alınan İstanbul Su ve Kanalizasyon İdaresi (İSKİ) Paşaköy İleri Biyolojik Atıksu Arıtma Tesisi’nde mevcut durumda atıksu karakterizasyonu ve sistem performansı deneysel olarak belirlenmiş, elde edilen bilgiler kullanılarak sürekli kullanıma uygun olacak model-bazlı tasarım ile işletme simülasyon programları hazırlanmış ve işletme optimizasyonu çerçevesinde çıkış besi maddesi konsantrasyonlarının düşürülmesi amacıyla işletme senaryoları oluşturularak önerilerde bulunulmuştur. Yürütülen senaryo analizleri ile, havalandırma tanklarındaki çözünmüş oksijen seviyelerinin uygun ayarlanması, tesisin geri devir denitrifikasyonu prensibi yerine A2O veya UCT tipi sistem şeklinde işletilmesi ile sistem veriminin arttırılabileceği ve dolayısıyla çıkış besi maddesi konsantrasyonlarının azaltılabileceği belirlenmiştir. Anahtar Kelimeler: İleri biyolojik atıksu arıtma tesisi, atıksu karakterizasyonu, model-bazlı tasarım, işletme optimizasyonu.The Urban Wastewater Treatment Directive published in the Official Gazette No. 26047 of 08.01.2006 was adapted from the “The Council Directive (91/271/EEC)” concerning urban waste-water treatment was accepted in European Union Countries, which imposes enforcements about the collection and treatment of wastewater. This directive requires that also nitrogen and phosphorus (nutrients) to be removed together with the conventional parameters. In this context, it is very important to follow and apply the technological advances while the harmonization of legislations in Turkey with European Union Standards. Mathematical models are frequently used for the design and optimum operation of wastewater treatment systems. In order to use the activated sludge models for the process design and control, it is crucial to understand the behavior of complex biological reactions under steady and dynamic conditions. The initial step for the use of models should be, a model calibration according to the data obtained from the treatment plant and an analysis of the behavior of the treatment plant under dynamic influent and environmental conditions (Vanrolleghem et al., 2003). After the calibration of the prepared model according to the operational conditions of the treatment plant, the model can be used for the optimization of the plant, meeting the effluent quality standards, minimizing operational costs and for developing appropriate process control strategies. On the other hand the effect of changes in the process conditions on the model stability should be taken into consideration (Insel et al., 2007). The aim of this study was to evaluate the optimum design and operational criteria of advanced biological wastewater treatment plants by applying international monitoring and evaluation mechanisms that will increase the performance to norms required in the European Union. Accordingly, İSKİ Paşaköy Advanced Biological Wastewater Treatment Plant (ABWWTP) was chosen as a model plant and in the first stage on influent wastewater characterization, chemical oxygen demand (COD) fractionation and performance of the activated sludge system were experimentally determined. In the second stage, using the dimensions of the İSKİ Paşaköy ABWWTP units and the experimentally determined operational parameters, model calibration studies were conducted. On this context, theoretical parameters of model-based design and operational simulation programs applied for the plant were evaluated. In the last stage of the study, for operational optimization, according to the results obtained from the experimental and simulation studies conducted at İSKİ Paşaköy ABWWTP, operational scenarios were developed and suggestions were made. In the scenario analysis reduction of effluent phosphorus and total nitrogen concentration was aimed and the effect of (i) the aeration system control, (ii) recycle denitrification (iii) influent VFA concentration was analyzed and the effect of (iv) different system configurations was evaluated. The results of statistical data analysis of wastewater characterization studies conducted at İSKİ Paşaköy Advanced Biological Wastewater Treatment Plant aiming nitrogen and phosphorus removal revealed that due to low influent Chemical Oxygen Demand (COD), Total Kjeldahl Nitrogen (TKN), Total Phosphorus (TP) and Volatile Fatty Acids (VFA) concentrations, high efficiencies of biological phosphorus removal was not achievable. According to the scenario analysis performed for the treatment plant it has been concluded that it is possible to increase the removal efficiency of the system and achieve lower effluent total nitrogen and phosphorus concentrations by setting the dissolved oxygen levels to appropriate levels and operating the systems as an A2O or a UCT type system instead of a recycle denitrification system. It has been concluded that if the scenario analyses were applied it is not possible to meet the European Union Effluent Quality Standard of 1.0 mg/l for the phosphorus parameter. Experimental and model based studies have to be conducted for the installation of a fermentation process together with different system configurations that are required to meet the effluent quality standard by biological treatment. Keywords: Paşaköy wastewater treatment plant, wastewater characterization, model based optimization, process control

Semi-Empirical Characterization of Ground Motions Including Source, Path and Nonlinear Site Effects

The objective of this thesis is to improve the physical understanding of earthquake ground motion characteristics related to source, path and nonlinear site effects and our ability to model those effects with engineering models. This was achieved through four research studies consisting of: (1) calibrating broadband simulation procedures to remove previously recognized sources of bias in distance attenuation and standard deviation; (2) enhancing a site database used for assigning site parameters to ground motion recordings, particularly with regard to the level of rigor and transparency with which the database is populated; (3) leveraging a state–of–the–art ground motion database and recent simulation–based studies to develop a nonlinear site amplification model suitable for use in ground motion predictions equations (GMPEs) and relatively simplified building code applications; and (4) developing GMPEs that provides mean and standard deviation of ground motion intensity measures in active crustal regions.The high–frequency component of the simulation procedure considered in this study combines deterministic Fourier amplitude spectra (dependent on source, path, and site models) with random phase. Significantly too–fast distance attenuation bias identified in prior work has been removed by increasing the quality factor (Q). We introduced random site–to–site variations to Fourier amplitudes using a log–normal standard deviation ranging from 0.45 for M < 7 to zero for (M8 to achieve dispersion terms that are more compatible with those from empirical models but remain lower at large distances (e.g., > 100 km).Site database work was performed within the context of the NGA–West 2 project. Starting with the site database from original (2008) NGA project (last edited in 2006), we provided site classifications for 2538 new sites and re–classifications of previous sites. The principal site parameter is the time–averaged shear wave velocity in the upper 30 m (Vs30), which is characterized using measurements where available, and proxy–based relationships otherwise. We improved the documentation and consistency of site descriptors used as proxies for the estimation of Vs30, developed evidence–based protocols for Vs30 estimation from available proxies, and augmented estimates of various basin depth parameters.Site factors typically have a small–strain site amplification that captures impedance and resonance effects coupled with nonlinear components. Site factors in current NEHRP Provisions are empirically–derived at relatively small ground motion levels and feature simulation–based nonlinearity. We show that current NEHRP site factors have discrepancies with respect to the site terms in the original NGA GMPEs both in the linear site amplification (especially for Classes B, C, D, and E) and the degree of nonlinearity (Classes C and D). We analyzed the NGA–West 2 dataset and simulation–based models for site amplification to develop a new model. The model has linear and nonlinear additive components. The linear component is fully empirical, being derived from worldwide ground motion data (regional effects were examined but found to not be sufficiently important to be included in the model). The model features linear Vs30–scaling in a log–log sense below a corner velocity (Vc), and no Vs30–scaling for velocities faster than Vc. The nonlinear component is developed from consideration of empirical data analysis and simulation results within a consistent context. The resulting nonlinearity operates principally at short periods and soft soils. This model is suitable for use as a site term in GMPEs and was applied to develop a proposal for updating the NEHRP site factors. The recommended factors remove a discrepancy between the reference condition used in the site factors and the national seismic hazard maps published by USGS. We have developed empirical equations for predicting the average horizontal component of earthquake ground motions from active crustal region earthquakes worldwide. The equations build upon a previous ground-motion model by Boore and Atkinson in 2008. Significant new features of the proposed GMPEs include: modified site terms; a modified magnitude scaling function that produces a higher degree of saturation at large magnitude for high–frequency ground motions; region–specific apparent anelastic attenuation term; basin depth correction factors that are centered on the average level of basin amplification conditional on Vs30; standard deviation terms that depend on M for between–event standard deviations and M–, Rjb– and Vs30–dependent within–event standard deviations. The resulting equations are applicable for events over a magnitude range of 3 to 8.5 for strike–slip or reverse–slip events (M3 to 8 for normal–slip events), distance range up to 400 km, and site conditions ranging from Vs30 = 150 to 1500 m/s. The equations are useful for prediction of the ground motion intensity measures (IMs) PGA, PGV, and PSA at periods T = 0 to 10 sec

Common Mistakes Made in Clinical Research Ethics Committee Applications: Experience of a Training and Research Hospital

Introduction: It is the responsibility of the ethical committees to ensure that the studies carried out on volunteers are carried out in accordance with ethical rules. In this study, it is aimed to analyze the deficiencies in the 2018-2021 application forms of the Istanbul Haydarpaşa Numune Training and Research Hospital Clinical Research Ethics Committee. Methods: The number of applications and revisions, the quality and type of research, area of application and acceptance rate were analyzed retrospectively in the archives of the ethics committee, in 598 files that were finalized between January 2018 and December 2020. Results: In the examined period, the total number of applications has doubled as of the end of 2020 compared to January 2018 (131, 194 and 273 for the years 2018, 2019 and 2020, respectively), and almost all of the applications are non-pharmacologic clinical trials. Among these studies, the highest number of applications are individual research projects, and more than half of them are prospective (63.06%, 66.46% and 58.30%, respectively). The number of applications for which corrections were requested is 77 (58.77%), 107 (55.15%) and 107 (39.19%) according to years. Most of the corrections requested are method related. The highest increase in the number of revisions was in the misidentification of the research type (0.78%, 6.02% and 6.94% for 2018-2020, respectively). Discussion and Conclusion: It was determined that the researchers had difficulties in the study methodology, informed consent and preparation of the scientific basis. Planning periodical Good Clinical Practices (GCP) trainings on an institutional basis under the leadership of ethics committees and that the specialty students have completed their current GCP training before starting their specialty thesis studies will ensure that the research projects to be carried out will be of higher quality in terms of ethics and scienc

Variant nonketotic hyperglycinemia caused by a novel pathogenic mutation in the glrx5 gene

Nonketotic hyperglycinemia (NKH) is caused by defects in the glycine cleavage system. Hyperglycinemia without biallelic mutations in one of the 4 genes that encode the constituents of the glycine cleavage system is classified as ‘variant NKH’. The defects in these cases are in the iron-sulphur cluster biogenesis and lipoate synthesis pathways. The GLRX5 gene is one of the genes in these new pathways. We report here an 8.5-year-old male patient presented with spasticity, ataxia and optic atrophy. He lost his ability to walk after a febrile infection at the age of 1.5 year. The patient’s cognitive functions were preserved. His plasma glycine level and cerebrospinal fluid/plasma glycine ratio were high. A novel homozygous mutation p.Gly116Asp (c.347G>A) in the GLRX5 gene was identified by whole exome sequencing. In conclusion, in a child, who have neurological regression, spasticity, ataxia, and whom cognitive functions are partially preserved, if plasma glycine level is high, variant NKH should be considered in the differential diagnosis

Site response in NEHRP Provisions and NGA models

Site factors are used to modify ground motions from a reference rock site condition to reflect the influence of geologic conditions at the site of interest. Site factors typically have a small-strain (linear) site amplification that captures impedance and resonance effects coupled with nonlinear components. Site factors in current NEHRP Provisions are empirically-derived at relatively small ground motion levels and feature simulation-based nonlinearity. We show that NEHRP factors have discrepancies with respect to the site terms in the Next Generation Attenuation (NGA) ground motion prediction equations, both in the linear site amplification (especially for Classes B, C, D, and E) and the degree of nonlinearity (Classes C and D). The misfits are towards larger linear site factors and stronger nonlinearity in theNEHRP factors. The differences in linear site factors result largely from theirnormalization to a reference average shear wave velocity in the upper 30 m of about 1050 m/s, whereas the reference velocity for current application is 760 m/s. We show that the levels of nonlinearity in the NEHRP factors are generally stronger than recent simulation-based models as well as empirically-based models

A study exploring the autism awareness of students attending the department of pre-school teacher education of a public University in Istanbul, Turkey

Objectives: Early detection of autism might largely depend on pre-school teachers' awareness and their prompt referral of these children to health authorities for accurate diagnosis. The purpose of our study was to assess the awareness about childhood autism among students attending the Department of Pre-school Teacher Education of a public university. Materials and Methods: This descriptive study was carried out on 181 out of 218 students. Results: The best known characteristic of a child having autism was having a hard time in social relations (90.1%). The majority (85.6%) of the study group believed that autism was curable and thought that a child having autism could pursue a family life in the future with his/her spouse (51.3%). Around 60.7% of all participants were of the opinion that a child with autism cannot participate in conversations. Conclusion: The idea of a child with autism disturbing the teaching environment (50.8%) exists which might be a very important obstacle for his/her education; thus interfering with his/her treatment. Autism awareness of respondents could be considered to be relatively good among the senior students

Energy drink consumption among pre-clinical medical students attending a public medical school in Istanbul, Turkey

Objective: It has been reported that energy drink usage is increasing worldwide despite reports of severe adverse health effects. This study aimed to explore pre-clinical medical students' attitudes and perceptions in relation to energy drinks. Materials and Methods: This was a questionnaire-based descriptive study of pre-clinical medical students attending a public medical school in Istanbul, Turkey. Questions covered the students' sociodemographic characteristics, personal habits (e.g., smoking and alcohol consumption), energy drink perceptions and energy drink consumption, and their experience of side effects from energy drinks. Chi-square tests were used to compare the categorical data. Results: The mean age of the participants was 21.27 +/- 1.37 (range: 19-28) years, and 54.0% (n: 81) were females and 46.0% (n: 69) were males. Overall, 68.0% (n: 102) reported that they had consumed an energy drink at least once in their lives, with 29.4% of these reporting use in combination with alcohol, 22.6% reporting use before exams, 20.6% reporting use before a physical activity, 13.7% reporting use to relieve fatigue, and 48.0% reporting that they had only tried an energy drink out of curiosity. Conclusion: A large number of participants tried energy drinks out of curiosity, but energy drink consumption was quite common in combination with alcohol. Case studies are needed to provide detailed information on the actual adverse health effects of energy drinks, but in the meantime, energy drink consumption should not be encouraged. Health care providers should educate children and families for the adverse effects of energy drinks