Seawater reverse osmosis membrane fouling causes in a full scale desalination plant; through the analysis of environmental issues: raw water quality

Background: Membrane clogging is one of the most important problem for desalination plant operators in Iran, therefore, this study was conducted to investigate the main causes of this problem using field analysis. Methods: In this study, six continuous membranes in a reverse osmosis (RO) pressure vessel under the 33-month service period (April 2017 to November 2019) were selected. The membranes were analyzed through visual evaluation of the outer and inner membrane surface, analyzing the damages and physical harms, oxidative stress tests, iron spot test, fouling chemical analysis using loss on ignition (LOI) tests, X-ray fluorescence (XRF), and Fourier-transform infrared (FTIR) spectroscopy. Results: Particle size distribution in raw seawater (EC = 55 000 μs/cm, turbidity = 11 NTU) was 66.4% smaller than 1 μ and 28.3% between 1 to 1.9 μm. Physical damages were not seen on the membranes but telescopic damages were observed which was due to membrane fouling. Removal efficiencies of turbidity and silt density index (SDI) were 84% and 18%, respectively. Membrane oxidation was also seen. Most of the sediments compositions on the membranes were SiO2, Al2O3, MgO, and Fe2O3. Biological fouling was detected on the membranes surface. Conclusion: Inaccurate use of chlorine neutralizer caused the residual chlorine to be present in the membrane entering water, which damaged the membrane. Accumulation of clogging agents on membrane surface showed malfunction of pretreatment function, therefore, revision of design and operation of units is necessary. Biological fouling is due to non-effective pre-chlorination of drinking water. Metallic compounds sedimentation on the membrane is due to improper use of anti-fouling chemicals. High SDI in the influent shows the need to change the cartridge filters. Keywords: Seawater, Drinking, Chlorides, Particle size, Chloride, Spectroscopy, Fourier transform infrared, Ira

The Effects of the Toxicity of (Fe (so4).7H2o) on the isolated Mitochondria from the brain of rat

Introduction: Iron, through the reaction of Fenton, generates free radicals such as active oxygen radicals and activates the oxidative stress pathway. The oxidative stress due to the increased iron level in the brain regions plays  an important role in creation of neurodegenerative diseases. Methods and Results:In this study, the mitochondria of the brain tissue of Wild Wistar Rat isolated from various centrifuge rounds and with the concentrations of Fe (so4).7H2o were incubated at 30 and 60 minutes. To determine IC50 Fe (so4).7H2o, the mitochondrial survival ratio was measured by MTT test. Mitochondrial suspension with the concentration of 0.5 mg protein/ml at various concentrations of Fe (so4).7H2o was placed in a shaker incubator at 37° C for 30 and 60 minutes. Then the activity of mitochondrial complex 2 and the formation ratio of reactive oxygen species was investigated. The results showed that IC50 ratio for Fe (so4).7H2o was 20 and 5 μg/ml at 30 and 60 minutes, respectively, and mitochondria incubation isolated from the brain tissue of the rat with Fe (so4).7H2o can disrupt be the electron transfer chain and significantly increases the formation of reactive oxygen species compared to the control group (P <0.001). Conclusions:The findings of this study indicate that Fe (so4).7H2o disrupts electron transfer chain in the mitochondria and causes increasing ROS production. This excessive increase of ROS can activate the oxidative stress pathway and ultimately activate the cell toxicity pathways