Evaluation of the demographic characteristics and general health status of earthquake survivors affected by the 2023 Kahramanmaras earthquake; a section from Gaziantep Nurdagi district.

BACKGROUND: An earthquake with a magnitude of 7.7 occurred in Pazarcik District of Turkey at 04.17 on February 6, 2023 and another earthquake of 7.6 occurred at 13.24 on the same day. This is the second largest earthquake to have occurred in Turkey. The aim of this study is to investigate the earthquake-related level of knowledge, attitudes and behaviours, general health and psychological status of survivors who were affected by the 2023 Kahramanmaras Earthquake and who were living in Nurdagi District of Gaziantep after the earthquake. METHODS: Data of 2317 individuals older than 18 years of age who were living in earthquake neighbourhoods, tents and containers in Nurdagi District of Gaziantep were examined. Variables were evaluated to find out the demographic characteristics and general health status of earthquake victims. General Health Questionnaire (GHQ-12) was used to find out psychological states of earthquake victims. RESULTS: The rate of injuries was 14.2% and leg and foot injuries were the most common with 44.2%. The relationship between injury status; and age, marital status, and being trapped under debris was revealed (p < 0.05). Mean GHQ-12 score of the survivors was 3.81 ± 2.81 and 51.9% experienced psychological distress. In the evaluation with logistic regression, it was found that female gender, being injured in the earthquake, loss of first degree and second degree relatives (with a higher rate in loss of first degree relative), having a severely damaged -to be demolished house and having a completely destroyed house were correlated with higher level of psychological distress (p < 0.05). CONCLUSION: General characteristics, injury prevalence and affecting factors of earthquake survivors were evaluated in the present study. Psychological distress was found in victims. For this reason, providing protective and assistive services to fight the destructive effects of earthquake is vital. Accordingly, increasing the awareness of people residing in earthquake zones regarding earthquakes is exceptionally important.

The Lifesaving Impact of Transcatheter Interventions in the Early Post-Fontan Palliation Period.

Despite advancements in postoperative outcomes after Fontan surgery, there remains a risk of suboptimal outcomes and significant morbidity in the early postoperative period. Anatomical obstructions in the Fontan pathway can lead to prolonged pleural effusion or ascites, cyanosis, and low cardiac output syndrome (LCOS). Transcatheter interventions offer an alternative to early re-surgery for treating these complications. Over a 13-year period, early catheter angiography, performed within 30 days post-index procedure, was administered to 41 patients, identifying anatomical issues that necessitated re-intervention in 39 cases. This led to transcatheter interventions in 37 (10.4%) of the 344 Fontan surgery patients. The median age was 4.8 years (IQR: 4-9.4), and the median weight was 16.5 kg (IQR: 15-25.2), with females comprising 51.4% (19/37) of this group. The primary indications for the procedures were persistent pleural effusion or ascites in 27 patients (66%), LCOS in 8 patients (20%), and cyanosis in 6 patients (14%). Among the 37 undergoing transcatheter intervention, 30 were treated solely with this method and discharged, three died in ICU follow-up, and four required early re-surgery. No procedural mortality was observed. Our findings demonstrate that transcatheter interventions, including stent implantation, balloon angioplasty, and fenestration dilation, are safe and effective in the early post-Fontan period. Therefore, they should be considered an integral part of the management strategy for this patient group.

Utility of Balloon Occlusion Testing in Determining Fontan Suitability Among Patients with Elevated Pulmonary Artery Pressure and Additional Antegrade Pulmonary Blood Flow.

In individuals with a single ventricle undergoing evaluation before Fontan surgery, the presence of excessive pulmonary blood flow can contribute to increased pulmonary artery pressure, notably in those who had a Glenn procedure with antegrade pulmonary flow. 28 patients who had previously undergone Glenn anastomosis with antegrade pulmonary blood flow (APBF) and with elevated mean pulmonary artery (mPAP) pressure > 15 mmHg in diagnostic catheter angiography were included in the study. After addressing other anatomical factors that could affect pulmonary artery pressure, APBF was occluded with semi-compliant, Wedge or sizing balloons to measure pulmonary artery pressure accurately. 23 patients (82% of the cohort) advanced to Fontan completion. In this group, median mPAP dropped from 20.5 (IQR 19-22) mmHg to 13 (IQR 12-14) mmHg post-test (p < 0.001). Median PVR post-test was 1.8 (IQR 1.5-2.1) WU m2. SpO2 levels decreased from a median of 88% (IQR 86%-93%) pre-test to 80% (IQR 75%-84%) post-test (p < 0.001). In five patients, elevated mPAP post-test occlusion on diagnostic catheter angiography led to non-completion of Fontan circulation. In this group, median pre- and post-test mPAP were 23 mmHg (IQR 21.5-23.5) and 19 mmHg (IQR 18.5-20), respectively (p = 0.038). Median post-test PVR was 3.8 (IQR 3.6-4.5) WU m2. SpO2 levels decreased from a median of 79% (IQR 76%-81%) pre-test to 77% (IQR 73.5%-80%) post-test (p = 0.039). Our study presents a specialized approach for patients initially deemed unsuitable for Fontan due to elevated pulmonary artery pressures. We were able to successfully complete the Fontan procedure in the majority of these high-risk cases after temporary balloon occlusion test.

Enhancing hydrological modeling with transformers: a case study for 24-h streamflow prediction.

In this paper, we address the critical task of 24-h streamflow forecasting using advanced deep-learning models, with a primary focus on the transformer architecture which has seen limited application in this specific task. We compare the performance of five different models, including persistence, long short-term memory (LSTM), Seq2Seq, GRU, and transformer, across four distinct regions. The evaluation is based on three performance metrics: Nash-Sutcliffe Efficiency (NSE), Pearson's r, and normalized root mean square error (NRMSE). Additionally, we investigate the impact of two data extension methods: zero-padding and persistence, on the model's predictive capabilities. Our findings highlight the transformer's superiority in capturing complex temporal dependencies and patterns in the streamflow data, outperforming all other models in terms of both accuracy and reliability. Specifically, the transformer model demonstrated a substantial improvement in NSE scores by up to 20% compared to other models. The study's insights emphasize the significance of leveraging advanced deep learning techniques, such as the transformer, in hydrological modeling and streamflow forecasting for effective water resource management and flood prediction.

A Challenging Interventional Procedure: Transcatheter Closure of Tubular Patent Ductus Arteriosus in Patients with Pulmonary Hypertension.

Transcatheter closure of the tubular ducts remains the most challenging procedure, with higher complication rates than other types. This study evaluates the characteristics of transcatheter closure of tubular ducts with pulmonary hypertension. 73 patients with tubular ducts who underwent cardiac catheterization for transcatheter PDA closure were analyzed. The mean age and weight were 1.93 ± 2.68 years and 8.83 ± 6.14 kg, respectively. Transcatheter closure was attempted in 72 patients. Four cases (5.5%) were referred to surgery, while the procedure was completed in the remaining (94.5%). Amplatzer duct occluder (ADO) I or Cardiofix duct occluder (CDO) was the most commonly used devices. However, the use of Amplatzer vascular plug (AVP) II raised in recent years. The most common concern was aortic protrusion/stenosis in ADO I/CDO devices, but most regressed during follow-up. Iatrogenic coarctation of the aorta was observed in two with ADO I/CDO. Embolization of the device to the pulmonary artery was observed in three with CDO, AVP II, and AVP I. Significant left pulmonary artery stenosis requiring stenting developed in one after closure with an MVSDO device. Tubular ducts are highly associated with pulmonary arterial hypertension, and transcatheter closure of them is still challenging despite the developing device armamentarium. Although ADO I or similar devices are widely used, off-label devices are usually needed at increasing rates. The AVP II device is unsuitable for short tubular ducts but seems the best option for long ones.

Non-structural flood mitigation optimization at community scale: Middle Cedar Case Study.

Flooding is the leading natural hazard in Iowa and has resulted in billions of dollars of damage to properties and critical infrastructure over the past couple of decades. Land alterations, urbanization, and changing precipitation regimes increase the magnitude and frequency of flood events. Considering the increasing risk, flood mitigation efforts are significant to reduce future losses. In this study, we present a comprehensive flood mitigation assessment for the cities of Cedar Falls, Cedar Rapids, and Waterloo in Iowa, utilizing various datasets such as property information, flood inundation maps, mitigation costs, and depth-damage functions. The research revealed that flooding has a minimal impact on Waterloo below the 200-year return period flood scenario, but Cedar Falls and Cedar Rapids are significantly vulnerable, requiring more mitigation investments and planning. The study conducted a benefit-cost analysis, indicating that dry floodproofing is the most feasible option to reduce flood impacts in all studied communities. Moreover, the research conducted a climate data-driven analysis, which found that elevating structures significantly increases the number of feasible mitigation options, regardless of various long-term climate projections. The study also analyzed predetermined mitigation budgets, revealing potential avoided losses and benefit-cost ratios for properties with the highest BCRs and prioritizing them to maximize the total benefit to the communities. The study findings offer crucial insights and recommendations to guide decision-makers in the community on prioritizing cost-effective flood mitigation strategies and minimizing flood impact in the studied regions.

Management of Nonocclusive Mesenteric Ischemia in Patients with Cardiac Failure.

AIM: This study aimed to evaluate the surgical procedures, outcomes, and prognostic factors in patients with ischemic heart disease who were operated on due to nonocclusive mesenteric ischemia (NOMI). MATERIAL AND METHODS: This research contains all patients diagnosed with congestive heart failure and NOMI between January 2011 to January 2020. The patients who had angiography or CT that showed occlusion of more than 50% in any of the main branches of the mesenteric artery or patients who presented with symptoms in correlation with a total occlusion were excluded from the study. Patients who underwent coronary heart surgery but were not diagnosed with congestive heart failure and those with atrial fibrillation also were excluded from the study. Patients divided into two groups, according to a medical database. RESULTS: A significant difference was found between the surviving and non-survivor groups in minutes, in terms of median time to segmenter intestinal resection (P = 0.042). CONCLUSION: An early diagnosis and surgical segmental intestinal resection before peritonitis worsens can be the key to better prognosis for NOMI patients.

Removal of micropollutants from municipal wastewater by membrane bioreactors: Conventional membrane versus dynamic membrane.

In this study, fate of micropollutants was investigated in a membrane bioreactor (MBR) having dynamic membrane (DM) and ultrafiltration (UF) membrane for the treatment of raw municipal wastewater. Removal efficiencies of different micropollutants including sulfamethoxazole, ciprofloxacin, trimethoprim, caffeine and acetaminophen were assessed. A commercial hollow fiber UF membrane was used in parallel with a DM that was formed on a low-cost hollow fiber support material, made of polyester. MBR was operated at a flux of 10 L/m2·h. High total suspended solids (>99%) and chemical oxygen demand (>91%) removal efficiencies were achieved with each membrane. Besides, high removal efficiencies of micropollutants (>68.3->99.7%) were achieved. Morphological analyses were conducted for each membrane in order to get insight to the cake (dynamic) layer that was accumulated on the membrane. DM technology provides an effective alternative to the conventional membrane systems for micropollutant removal from municipal wastewater.

The effectiveness of combined surgery and chemotherapy in primary hydatid cyst of thigh muscles, a rare localization and its management.

Hydatid cyst is a common infestation caused by helminths in humans and usually involves the liver and lungs. Primarily, cases of hydatid cysts in the thigh muscles are extremely rare and are generally in the form of case reports. It is an important disease due to its insidious course, its confusion with other soft tissue pathologies, delay in diagnosis and painstaking surgery. In our study, the largest case series in the literature, the clinical stages of the diagnosis, treatment and follow-up of 9 hydatid cysts that develop primarily in the thigh muscles were evaluated. The risk of recurrence in primary hydatid cyst of the thigh can be reduced with rapid diagnosis, careful preoperative planning, complete surgical resection by avoiding cyst rupture and concomitant anthelmintic chemotherapy.

Comparison of different pulmonary valve reconstruction techniques during transannular repair of tetralogy of fallot.

BACKGROUND: Transannular patch, which results in pulmonary insufficiency (PI), is usually required during repair of tetralogy of fallot (TOF). In this study, we compared three types of pulmonary valve reconstruction techniques during transannular repair of TOF. METHODS: Between February 2014 and January 2018, 50 patients with TOF underwent primary repair with transannular patch. These patients were divided into three groups. In Group 1, (n = 15), a single gluteraldehyde-treated autologous pericardial patch (standard method) was reconstructed as monocusp. In Group 2, (n = 16) Nunn's bileaflet pulmonary valve reconstruction technique was used with pericardial patch. In Group 3, (n = 19), Nunn's bileaflet technique was performed with expanded polytetrafluoroethylene membrane. The outcomes of the patients and early and midterm competency of the pulmonary valves were analyzed. RESULTS: These techniques were significantly effective in early postoperative period. Freedom from moderate to severe PI were 73.3%; 100% and 89.4%, respectively. Mortality, duration of intensive care unit and hospital stay were similar between the groups. The mean follow-up period was 17.5 ± 13.0 (3-57) months. Freedom from moderate to severe PI decreased to 40%; 81.2% and 73.7%, respectively at the end of the follow-up period. Presence of moderate to severe PI was significantly higher in Group 1 (p = .018 between Groups 1 and 2, p = .048 between Groups 1 and 3). CONCLUSION: All three pulmonary valve reconstruction techniques provided competent pulmonary valves. Nunn's bileaflet technique had better outcome at midterm. It has a potential to delay right ventricular dysfunction at long-term.

Early and midterm results of ductal stent implantation in neonates with ductal-dependent pulmonary circulation: a single-centre experience.

OBJECTIVE: We aimed to determine the early and midterm outcomes of ductal stenting in neonates with ductal-dependent pulmonary blood flow. METHODS: Between January, 2014 and July, 2018, 102 patients who underwent 115 cardiac catheterisation procedures for ductal stent implantation in our department were retrospectively reviewed. The age of the neonates ranged from 3 to 30 days (median: 11 days) and their weights ranged from 1.8 to 5.8 kg (mean, 2.8 ± 0.53 kg). Fifty-two patients had functional single ventricle and 50 had biventricular physiology. Thirty-one patients' weights were <2,500 g (30.3%). The patent ductus arteriosus was vertical in 60 patients (58.8%). The mean ductal length was 12.4 ± 4.1 mm (range, 7.8-23 mm), and the mean narrowest ductal diameter was 2.1 ± 0.7 mm (range, 1.2-3.4 mm). RESULTS: The technical success rate was 85.2%. Procedure-related mortality occurred in three patients (2.9%). After the procedure, the aortic oxygen saturation increased from a mean of 73.1 ± 6.2% to a mean of 90.4 ± 4.3% (p < 0.001), and the ductus diameter increased from a mean of 2.1 ± 0.7 mm to a mean of 4.2 ± 0.9 mm (p < 0.001). Either transcatheter or surgical reinterventions were required in 35 patients (34.3%) during the follow-up period after a median of 101 days (2-356 days). Thirty-three patients (32.3%) were bridged to surgical repair after a median of 288 days (163-650 days). The median duration of palliation with ductal stents was 210 days (range, 2-525 days). CONCLUSION: Ductus arteriosus stenting may be a reasonable and effective alternative to surgery for the initial palliation procedure in neonates with ductus-dependent pulmonary flow.

A web-based decision support system for collaborative mitigation of multiple water-related hazards using serious gaming.

The paper presents a web-based application developed as a medium for executing a serious game to enhance multi-jurisdictional collaborative planning and decision making for mitigation of multiple hazards related to water (i.e., floods, soil erosions, water quality). The gaming application is integrated into the Iowa Watershed Decision Support System (IoWaDSS) designed to serve as a comprehensive multi-sectoral data repository along with the simulation results of process modeling to educate and inform communities on the status of their watersheds during extreme conditions. The interactive serious gaming application was devised to encourage public engagement, facilitate communication and positive relationship between watershed communities, and make the decision process more attractive and transparent for the stakeholders. The web environment offers easily-accessible, user-friendly interfaces that match the skills and knowledge level of a non-technical user. Developed with adaptive design and flexible architecture, the gaming application is generalizable and extendable to support hazard mitigation in other watersheds.

A comprehensive review of deep learning applications in hydrology and water resources.

The global volume of digital data is expected to reach 175 zettabytes by 2025. The volume, variety and velocity of water-related data are increasing due to large-scale sensor networks and increased attention to topics such as disaster response, water resources management, and climate change. Combined with the growing availability of computational resources and popularity of deep learning, these data are transformed into actionable and practical knowledge, revolutionizing the water industry. In this article, a systematic review of literature is conducted to identify existing research that incorporates deep learning methods in the water sector, with regard to monitoring, management, governance and communication of water resources. The study provides a comprehensive review of state-of-the-art deep learning approaches used in the water industry for generation, prediction, enhancement, and classification tasks, and serves as a guide for how to utilize available deep learning methods for future water resources challenges. Key issues and challenges in the application of these techniques in the water domain are discussed, including the ethics of these technologies for decision-making in water resources management and governance. Finally, we provide recommendations and future directions for the application of deep learning models in hydrology and water resources.

How do vertebroplasty and kyphoplasty affect the quality of life of patients with multiple myeloma spinal metastasis?

BACKGROUND: Metastatic spinal lesions are diseases that impair the quality of life and require early diagnosis and treatment. The count of spinal metastasis patients rises day by day. Increased life expectancy has increased the incidence of cancer, making metastases more observable. The aim of our study was to investigate how the quality of life is affected in the patient group with vertebral fracture due to spinal metastases of multiple myeloma and undergoing vertebroplasty and kyphoplasty. MATERIALS AND METHODS: Forty-two patients with fracture due to spinal metastasis and adequate follow-up between the years of 2011 and 2018 were included in the study. Patients were listed according to their primary malignancy and metastases. The effect of vertebroplasty and kyphoplasty was investigated by evaluating preoperative and postoperative VAS and Oswestry Disability Index scores. All patients' radiographic kyphosis angle, compression ratio and wedging index were calculated before operation and after operation. RESULTS: A total of 76 vertebrae were operated in 42 patients. Significant differences were found in the comparison of preoperative and postoperative quality of life according to VAS and Oswestry Disability Index scores in the patients undergoing vertebroplasty, kyphoplasty or both procedures after spinal metastases (VAS; p = 0.0001, ODI; p = 0.002/0.0001). There were statistically significant differences in preoperative local kyphosis angle, compression ratio and wedging index and post-op local kyphosis angle, compression ratio and wedging index (p = 0.001). CONCLUSION: Vertebroplasty and kyphoplasty, minimally invasive procedures performed after spinal metastases, improve the quality of life of the patients.

Cerebral Protection with a Temporary Ascending Aorta-External Carotid Artery Bypass during Common Carotid Artery Revascularization.

Atherosclerosis is a systemic disease, and multiarterial involvement is common. Involvement of all the supra-aortic arteries may occur in the same patient making cerebral revascularization challenging. In this report, we present complete supra-aortic revascularization, that is, revascularization of the bilateral common carotid and subclavian arteries in a 51-year-old male patient with occluded brachiocephalic trunk, left subclavian artery, and proximally stenotic left common carotid artery. A temporary ascending aorta to left external carotid artery bypass provided meticulous cerebral protection with pulsatile cerebral flow in the presence of a proximal arterial clamp; hence, a neurologically uneventful procedure during bilateral common carotid artery revascularization.

Greenhouse gas contribution of municipal solid waste collection: A case study in the city of Istanbul, Turkey.

This article estimates greenhouse gas emissions and global warming factors resulting from collection of municipal solid waste to the transfer stations or landfills in Istanbul for the year of 2015. The aim of this study is to quantify and compare diesel fuel consumption and estimate the greenhouse gas emissions and global warming factors associated with municipal solid waste collection of the 39 districts of Istanbul. Each district's greenhouse gas emissions resulting from the provision and combustion of diesel fuel was estimated by considering the number of collection trips and distances to municipal solid waste facilities. The estimated greenhouse gases and global warming factors for the districts varied from 61.2 to 2759.1 t CO2-eq and from 4.60 to 15.20 kg CO2-eq t-1, respectively. The total greenhouse gas emission was estimated as 46.4E3 t CO2-eq. Lastly, the collection data from the districts was used to parameterise a collection model that can be used to estimate fuel consumption associated with municipal solid waste collection. This mechanistic model can then be used to predict future fuel consumption and greenhouse gas emissions associated with municipal solid waste collection based on projected population, waste generation, and distance to transfer stations and landfills. The greenhouse gas emissions can be reduced by decreasing the trip numbers and trip distances, building more transfer stations around the city, and making sure that the collection trucks are full in each trip.

Closure of aortopulmonary window using Nit-Occlud® PDA-R device in a 3-month-old infant.

Aortopulmonary window (APW) is a rare abnormality in which a pulmonary defect exists between the ascending aorta and the main pulmonary artery. Given that it may result in cardiac failure and pulmonary vascular disease in the early period, treatment needs to be performed without delay. In addition to surgical treatment, transcatheter closure may also be performed for selected patients. This study describes the case of an infant diagnosed with APW and who underwent successful transcatheter closure using a Nit-Occlud® PDA-R device.

Serum NGAL, cystatin C and urinary NAG measurements for early diagnosis of contrast-induced nephropathy in children.

AIM: The study investigated a number of biomarkers for the early diagnosis of contrast-induced nephropathy (CIN), which is an important cause of acute kidney injury (AKI). MATERIAL AND METHODS: The study included 91 children scheduled for elective cardiac angiography and 50 healthy controls. Biomarkers including serum (s) and urinary (u) sodium, serum and u-creatinine, s-cystatin-C, serum neutrophil gelatinase-associated lipocalin (NGAL) and urinary N-acetyl beta glucosaminidase (u-NAG)/creatinine ratio were measured 4 times sequentially in the patients and once in the controls. RESULTS: The patient group comprised 40 males (44%) and 51 females (56%) while the control group comprised 16 males (32%) and 34 females (68%). Age, gender, s-creatinine, estimated-glomerular filtration rate (eGFR), s-cystatin-C and fractional-excretion of sodium did not differ significantly between the groups. Serum sodium and s-NGAL were found to be lower in the patients than those of in the controls, while their u-NAG/creatinine ratio was found to be higher. Sequential data analysis revealed that s-NGAL and u-NAG/creatinine ratio increased in the first 6 h after radiocontrast media (RCM) administration and decreased at 12 and 24 h. Serum BUN and s-cystatin-C levels also showed a significant difference during the 24-h follow-up. eGFR, s-sodium and s-creatinine levels did not change in the following period. Serum cystatin-C levels revealed a significant negative correlation with eGFR. Administered RCM doses showed a positive correlation only with u-NAG/creatinine ratios. CONCLUSION: In the first 24 h, s-cystatin-C, s-NGAL and especially u-NAG/creatinine ratio showed promise as biomarkers, but eGFR is not adequate for early diagnosis of CIN. Sequential measurement of biomarkers may contribute to more accurate diagnosis of AKI.

Efficacy of very low-dose prostaglandin E1 in duct-dependent congenital heart disease.

AIM: The present study aims to define the lowest effective prostaglandin E1 dose in patients with inadequacy of pulmonary blood flow and/or intracardiac blood mixing and those with inadequate systemic blood flow. METHODS: Patients with inadequacy of both pulmonary blood flow and/or blood mixing (Group 1) and those with inadequate systemic blood flow (Group 2) were retrospectively evaluated in two separate groups with regard to the prostaglandin E1 starting dose given in the referring facility, the lowest and the highest dose administered in our centre, treatment duration, adverse effects, and administered treatment. RESULTS: No difference between the groups could be detected with respect to sex or birth weight (p=0.95 and 0.42, respectively). Group 1 and Group 2 were statistically similar in aspect of prostaglandin treatment duration (9.73±0.81 days versus 11.6±1.05 days, p=0.064). When compared with Group 2, the initial, maintenance and lowest efficient doses of prostaglandin E1 treatment were significantly lower and the titrated dose of prostaglandin E1 was significantly higher in Group 1 (p=0.001 for each). CONCLUSION: Our findings indicate that the infusion of prostaglandin at a very low dose (0.003-0.005 mcg/kg/minute) is sufficient to maintain the patency of the ductus arteriosus. A higher dose of prostaglandin E1 may be necessary in patients with inadequate systemic blood flow.

An Autopsy of Nanofiltration Membrane Used for Landfill Leachate Treatment.

Komurcuoda leachate treatment plant, Istanbul, which consists of membrane bioreactor (MBR) and nanofiltration (NF) system, faced rapid flux decline in membranes after 3-year successful operation. To compensate rapid flux decline in membranes, the fouled membranes were renewed but replacement of the membranes did not solve the problem. To find the reasons and make a comprehensive analysis, membrane autopsy was performed. Visual and physical inspection of the modules and some instrumental analysis were conducted for membrane autopsy. Membranes were found severely fouled with organic and inorganic foulants. Main foulant was iron which was deposited on surface. The main reason was found to be the changing of aerator type of MBR. When surface aerators were exchanged with bottom diffusers which led to increasing of dissolved oxygen (DO) level of the basin, iron particles were oxidized and they converted into particulate insoluble form. It was thought that probably this insoluble form of the iron particles was the main cause of decreased membrane performance. After the diagnosis, a new pretreatment alternative including a new iron antiscalant was suggested and system performance has been recovered.