Drinking Water Treatment in Submerged Hollow Fiber Microfiltration: Effect of Backwashing

Extended Abstract Water falling onto earth surface creates surface runoffs and while portion of precipitation seeps underground, water dissolves loads of substances from earth layers. Therefore chemistry of water constantly changes. Surface waters are very sensitive to contamination and cause of that water quality decreases over time. In recent years, need for clean water is increasing due to population growth and industrialization. Intensive industrialization and unplanned urbanization threaten water resources while conventional treatment systems are inadequate against increasing pollution Membrane process (MP), has many advantages like less area requirement, high efficiency, easy operation and can be combined with conventional treatment systems. Therefore water treatment with MP is becoming popular. MP removes pathogens, decreases necessity for disinfection Purpose of this study, is to determine determining the effect of backwashing in treatment of drinking water of a dam with coagulation supported submerged PVDF hollow fiber (HF) filtration. In this way filtration mode which provides lesser pollution on membranes could be compared with conventional water treatment plant. In this study, raw influent of drinking water plant in Erzurum was used. Experiments were carried out with lab-scale full automated submerged membrane filtration unit. COD and turbidity measurements were made for system effluent. Membrane ΔP increases were noted while system was used in flux controlled mode. PVDF HF Membranes, which has 600 cm 2 surface area and 0.4 µm pore size, were used in the system and they were aerated with 5 L/min air. First of all, optimum alum dosage was determined and same dosage was used in continuous system with backwashing or relaxation for all operation period. Membrane flux of J=20 L/m 2 .h was kept constant and two different membrane cleaning methods were used. These are filtration + relaxation and filtration + backwashing. While filtration periods were 4.5, 9 and 18 min, relaxation and backwashing periods were selected as 0.5, 1 and 2 mins respectively. Backwashing flows were selected same as filtration flux. 10, 20, 30, 40, 60, 80 and 100mg/L alum dosages were used. Even with the minimum dosage of 10 mg/L alum, Coagulation + HF submerged membrane system provides water suitable for Turkey drinking water standards. The same water quality is reached at 40 mg/L alum dosage by conventional treatment system, which shows the superiority of membrane treatment systems again. Effluent turbidity values were found as 0.02 NTU. COD removal efficiency was increased up to %90 with increasing alum dosage. Effluent turbidity, TOC, TN and UV254 removal ratios were calculated as %99.8, %37, %43 and %40 respectively when the minimum dosage of 10 mg/L alum was applied. In continuous experiments with 4.5 min filtration + 0.5 min relaxation, ΔP pressure increase in 48 h period was %26 while 4.5min filtration + 0.5min backwashing mode resulted %5 increase in ΔP. Under these conditions, effluent turbidity value increased from 0.02 NTU to only 0.06 NTU. In 9 + 1 mode with relaxation ΔP increase was %27 while same mode with backwashing decreased the ΔP to %14. In same manner, 18+2 mode with backwashing decreased ΔP from %29 to %22

Impact of Obesity on the Metabolic Control of Type 2 Diabetes: Results of the Turkish Nationwide Survey of Glycemic and Other Metabolic Parameters of Patients with Diabetes Mellitus (TEMD Obesity Study)

Background: Obesity is the main obstacle for metabolic control in patients with type 2 diabetes. Turkey has the highest prevalence of obesity and type 2 diabetes in Europe. The effect of obesity on the metabolic control, and the macro-and microvascular complications of patients are not apparent. Objectives: This nationwide survey aimed to investigate the prevalence of overweight and obesity among patients with type 2 diabetes and to search for the impact of obesity on the metabolic control of these patients. We also investigated the independent associates of obesity in patients with type 2 diabetes. Methods: We consecutively enrolled patients who were under follow-up for at least 1 year in 69 tertiary healthcare units in 37 cities. The demographic, anthropometric, and clinical data including medications were recorded. Patients were excluded if they were pregnant, younger than 18 years, had decompensated liver disease, psychiatric disorders interfering with cognition or compliance, had bariatric surgery, or were undergoing renal replacement therapy. Results: Only 10% of patients with type 2 diabetes (n = 4,648) had normal body mass indexes (BMI), while the others were affected by overweight (31%) or obesity (59%). Women had a significantly higher prevalence of obesity (53.4 vs. 40%) and severe obesity (16.6 vs. 3.3%). Significant associations were present between high BMI levels and lower education levels, intake of insulin, antihypertensives and statins, poor metabolic control, or the presence of microvascular complications. Age, gender, level of education, smoking, and physical inactivity were the independent associates of obesity in patients with type 2 diabetes. Conclusion: The TEMD Obesity Study shows that obesity is a major determinant of the poor metabolic control in patients with type 2 diabetes. These results underline the importance of prevention and management of obesity to improve health care in patients with type 2 diabetes. Also, the results point out the independent sociodemographic and clinical associates of obesity, which should be the prior targets to overcome, in the national fight with obesity. (c) 2019 The Author(s) Published by S. Karger AG, Base