SUPPORT MATERIAL ALTERNATIVES FOR BIOLOGICAL FILTER REACTORS (BFRs)

Biyolojik Filtre Reaktörler (BFR) klasik filtre sistemlerinin modifiye edilerek atıksu arıtımı amacıyla kullanıldığı yeni teknolojilerdir. Günümüzde farklı isimler altında geliştirilen biyolojik filtreleri birbirinden ayıran özelliklerin başında filtrelerde kullanılan dolgu malzemeleri gelmektedir. Sunulan makalede “pellet†olarak isimlendirilen, su yumuşatma sistemlerinden atık olarak çıkan bir malzemenin BFR'de dolgu malzemesi olarak kullanılabilirliği incelenmiştir. Bu kapsamda, Türk Standartları Enstitüsü'nün (TSE) ilgili şartnamelerinde açıklanan analiz yöntemleri kullanılarak malzemenin tane boyutu dağılımı, özgül ağırlık, birim hacim ağırlık, porozite, özgül yüzey alanı gibi fiziksel özellikleri belirlenmiştir. Laboratuvarda kurulu bir filtre kolonundan yararlanılarak malzemenin akışkanlaşma özellikleri (minimum akışkanlaşma hızı) araştırılmıştır. Ayrıca, yukarı akışlı akışkan yatak olarak işletilen bir reaktöre “pellet†doldurularak malzemenin atıksu arıtımı amacıyla kullanılabilirliği incelenmiş; organik madde giderimi esas alınarak arıtma verimi değerlendirilmiştir. Biological Filter Reactors (BFRs) are modified conventional filter systems which were used for wastewater treatment in recent years. One of the most substantial differences among the BFRs, which are currently developed with various trade names, is the nature of support material. In this study, a new support material called as “pellet†which is the waste material of water softening process was investigated as filter media in the BFRs. The major physical characteristics of pellet such as particle size distribution, specific weight, porosity, specific surface area were determined by using standard test methods set by Turkish Institute of Standards (TSE). Fluidisation characteristics such as minimum fluidisation velocity of pellets were also studied in a deep bed filter column. In addition pellet material was used in an up-flow fluidised bed filter reactor and the performance of the reactor in terms of COD removal was evaluated

Stratigraphy of Cretaceous to Lower Pliocene sediments in the northern part of Cyprus based on comparative 87Sr/86Sr isotopic, nannofossil and planktonic foraminiferal dating

New age data from Sr isotope analysis and both planktonic foraminifera and nannofossils are presented and discussed here for the Upper Eocene–Upper Miocene sedimentary rocks of the Değirmenlik (Kythrea) Group. New dating is also given of some Cretaceous and Pliocene sediments. In a revised stratigraphy the Değirmenlik (Kythrea) Group is divided into ten formations. Different Upper Miocene formations are developed to the north and south of a regionally important, E–W-trending syn-sedimentary fault. The samples were dated wherever possible by three independent methods, namely utilizing Sr isotopes, calcareous nannofossils and planktonic foraminifera. Some of the Sr isotopic dates are incompatible with the nannofossil and/or the planktonic foraminiferal dates. This is mainly due to reworking within gravity-deposited or current-affected sediments. When combined, the reliable age data allow an overall biostratigraphy and chronology to be erected. Several of the boundaries of previously defined formations are revised. Sr data that are incompatible with well-constrained biostratigraphical ages are commonly of Early Miocene age. This is attributed to a regional uplift event located to the east of Cyprus, specifically the collision of the Anatolian (Eurasian) and Arabian (African) plates during Early Miocene time. This study, therefore, demonstrates that analytically sound Sr isotopic ages can yield geologically misleading ages, particularly where extensive sediment reworking has occurred. Convincing ages are obtained when isotopic dating is combined with as many forms of biostratigraphical dating as possible, and this may also reveal previously unsuspected geological events (e.g. tectonic uplift or current activity)

Arsenic removal from drinking water by chemical methods

Arsenik içeren su kaynakları dünyanın pek çok ülkesinde karşılaşılan bir sorundur. Dünya Sağlık Örgütü, 1993 yılında yapmış olduğu düzenlemeyle içme sularında izin verilen azami arsenik miktarını 50 µg/L’den 10 µg/L’e indirmiştir. Ülkemizde de, “İnsani Tüketim Amaçlı Sular Hakkında Yönetmelik” kapsamında içme ve kullanma sularında 50 μg/L olan arsenik limiti, 2005 yılı itibariyle 10 μg/L şeklinde değiştirilmiş ve 2008 yılından bu yana uygulamaya konmuştur. Arsenik standardının 10 μg/L olarak uygulanması, ülkemizdeki bazı su kaynaklarının kullanımını kısıtlamıştır. Özellikle batı bölgelerimizdeki birçok yerleşimde (Kütahya, Emet, Simav, Uşak, İzmir, Manisa, vb.) arsenik kirliliğinin kontrolüne yönelik önlemler alınması ihtiyacı ortaya çıkmıştır. Gerek literatürde, gerekse uygulamada (laboratuvar ve arazi ölçeğinde) arsenik ile ilgili çeşitli arıtma yöntemleri mevcuttur. Bu yöntemler i) arıtılacak suyun miktarına (debisine), ii) sudaki arsenik konsantrasyonuna ve formuna (As3+ ve/veya As5+), iii) su içinde bulunan diğer parametrelere (pH, sülfat, fosfat, organik madde, silikat, vb.) bağlı olarak farklılıklar gösterir. Sunulan makalede arsenik arıtımında kullanılan kimyasal destekli yöntemler incelenmiştir. Bu kapsamda kireç-soda yöntemi, konvansiyonel koagülasyon-filtrasyon, koagülasyon destekli mikrofiltrasyon ve oksidasyon-filtrasyon yöntemleri irdelenmiş; karar alma sürecinde yapılması gerekenler özetlenmiştir. Ülkemizdeki içme suyu arıtma tesislerinde genellikle kimyasal arıtma ve filtrasyon üniteleri kullanılmaktadır. Arsenik bakımından problemli yerlerde mevcut içme suyu arıtma tesislerinde modifikasyonlar yapılarak arsenik giderimi sağlanabilir. Bu kapsamda ön oksidasyon kademesinin eklenmesi, koagülan türü ve dozunun optimizasyonu, konvansiyonel filtrelerin modifikasyonu (adsorban özelliği olan malzemelerin kullanılması), tesis sonunda adsorpsiyon, iyon değişimi, membran filtrasyon gibi sistemlerin kullanılması önerilmektedir. Anahtar Kelimeler: Arsenik, filtrasyon, kimyasal arıtma, kireç soda ile yumuşatma, koagülasyon, oksidasyon.Arsenic in natural waters is a worldwide problem. Weathering of arsenic rich minerals and volcanic activities are natural sources releasing arsenic to the environment. Apart from the natural phenomena, anthropogenic (man-made) inputs are also responsible from the arsenic contamination. Effluents from metallurgical industry, glassware and ceramic industries, dye and pesticide manufacturing industries, petroleum refining, leather processing, and other organic and inorganic chemical industries are major anthropogenic sources of arsenic. Furthermore agricultural uses of pesticides, herbicides, insecticides, defoliants, and soil sterilants which include arsenic and arsenic compounds increase the arsenic content in water resources. Arsenic is a fairly common environmental contaminant. Both groundwater and surface water sources of drinking water can contain arsenic. The levels of arsenic are typically higher in groundwater sources. Arsenic levels in groundwater tend to vary geographically. The major routes are through inhalation, skin absorption .and ingestion. Ingestion is the predominant form of exposure among others. High doses of arsenic can cause acute toxic effects including gastrointestinal symptoms (poor appetite, vomiting, diarrhea, etc.), disturbance of cardiovascular and nervous systems functions (e.g. muscle cramps, heart complains) or death. Because of the proven and widespread negative health effects on humans, in 1993, the World Health Organization (WHO) lowered the health-based provisional guideline for arsenic concentration in drinking water from 50 to 10 µg/L. The United States Environmental Protection Agency (USEPA) subsequently revised the maximum contaminant level (MCL) as 10 µg/L in 2001. New standards have been adopted as a national standard by most countries, including Japan, Jordan, Laos, Mongolia, Namibia, Syria and the USA, and the European Union (EU). However, many countries have retained the earlier WHO guideline of 50 µg/L as their standard or as an interim target including Bangladesh, India, Bahrain, China, Egypt, Indonesia, Philippines, Saudi Arabia, Sri Lanka, Vietnam, etc.. Since implementation of the new guideline value of 10 µg/L requires certain investments, those countries need additional time and support to harmonize their national standards with new regulations. Turkey is a country facing and struggling with those emerging arsenic problems. Stringent standards of drinking water were promulgated by Ministry of Health (MoH) in 2005, and arsenic level was lowered from 50  g/L to 10  g/L. The new standard has been enforced since February 2008. After this limitation a number of wells which have been (planned being) used for potable water supply are considered as "arsenic-contaminated". Besides prolonged drought induced by climate change caused release of arsenic from aquifer sediments and this resulted in elevated concentrations in groundwater sources. This fact triggered problems stemming from arsenic in water in some areas. Particularly, western parts of central Anatolia (e.g. Kutahya, Emet, Simav, Usak) have high risk due to their geological formations and geothermal inputs which pose suitable conditions for arsenic contamination of water resources. Inventory study results carried out by General Directorate of Mineral Research and Exploration (MTA) showed elevated arsenic concentrations in the Kutahya-Emet-Hisarcik and Nevsehir Basins (20-200 µg/L). There are several treatment technologies that are available for arsenic removal from drinking water. The most commonly used technologies include oxidation, co-precipitation and adsorption onto coagulated flocs, lime treatment, adsorption onto sorptive media, ion exchange resin and membrane techniques. Selection of an appropriate method is a quite complex decision and affected from a number of factors (e.g. arsenic compound, raw water quality, target arsenic concentration, existing water treatment plant, land availability, operational and maintenance costs, etc.). In the presented paper, chemical treatment methods used in arsenic removal (i.e. chemical oxidation, conventional coagulation and filtration, coagulation assisted microfiltration, oxidation filtration and lime-soda method etc.) are evaluated considering treatment performance, costs, operational features. In Turkey, generally chemical processes and filtration have been used in many water treatment plants. Existing water treatment plants can be modified for arsenic removal. In this framework, involvement of pre-oxidation stage, optimization of the coagulant type and dose, modification of conventional filters (utilization of adsorbent based filter materials), utilization of adsorption, ion exchange, membrane filtration processes for post-treatment purpose are recommended. Keywords: Arsenic, filtration, chemical treatment, coagulation, lime - soda softening, oxidation

Modelling the overdiagnosis of breast cancer due to mammography screening in women aged 40 to 49 in the United Kingdom

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, andreproduction in any medium, provided the original work is properly cited

One-year prevalence and the impact of migraine and tension-type headache in Turkey: a nationwide home-based study in adults

Several studies have shown that the prevalence of migraine and tension-type headache (TTH) varied between different geographical regions. Therefore, there is a need of a nationwide prevalence study for headache in our country, located between Asia and Europe. This nationwide study was designed to estimate the 1-year prevalence of migraine and TTH and analyse the clinical features, the impact as well as the demographic and socio-economic characteristics of the participant households in Turkey. We planned to investigate 6,000 representative households in 21 cities of Turkey; and a total of 5,323 households (response rate of 89%) aged between 18 and 65 years were examined for headache by 33 trained physicians at home on the basis of the diagnostic criteria of the second edition of the International Classification of Headache Disorders (ICHD-II). The electronically registered questionnaire was based on the headache features, the associated symptoms, demographic and socio-economic situation and history. Of 5,323 participants (48.8% women; mean age 35.9 ± 12 years) 44.6% reported recurrent headaches during the last 1 year and 871 were diagnosed with migraine at a prevalence rate of 16.4% (8.5% in men and 24.6% in women), whereas only 270 were diagnosed with TTH at a prevalence rate of 5.1% (5.7% in men and 4.5% in women). The 1-year prevalence of probable migraine was 12.4% and probable TTH was 9.5% additionally. The rate of migraine with aura among migraineurs was 21.5%. The prevalence of migraine was highest among 35–40-year-old women while there were no differences in age groups among men and in TTH overall. More than 2/3 of migraineurs had ever consulted a physician whereas only 1/3 of patients with TTH had ever consulted a physician. For women, the migraine prevalence was higher among the ones with a lower income, while among men, it did not show any change by income. Migraine prevalence was lower in those with a lower educational status compared to those with a high educational status. Chronic daily headache was present in 3.3% and the prevalence of medication overuse headache was 2.1% in our population. There was an important impact of migraine with a monthly frequency of 5.9 ± 6, and an attack duration of 35.1 ± 72 h, but only 4.9% were on prophylactic treatment. The one-year prevalence of migraine estimated as 16.4% was similar or even higher than world-wide reported migraine prevalence figures and identical to a previous nation-wide study conducted in 1998, whereas the TTH prevalence was much lower using the same methodology with the ICHD-II criteria

Predicting Academic Performance: A Systematic Literature Review

The ability to predict student performance in a course or program creates opportunities to improve educational outcomes. With effective performance prediction approaches, instructors can allocate resources and instruction more accurately. Research in this area seeks to identify features that can be used to make predictions, to identify algorithms that can improve predictions, and to quantify aspects of student performance. Moreover, research in predicting student performance seeks to determine interrelated features and to identify the underlying reasons why certain features work better than others. This working group report presents a systematic literature review of work in the area of predicting student performance. Our analysis shows a clearly increasing amount of research in this area, as well as an increasing variety of techniques used. At the same time, the review uncovered a number of issues with research quality that drives a need for the community to provide more detailed reporting of methods and results and to increase efforts to validate and replicate work.Peer reviewe

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries