VARIATION OF SOME WATER QUALITY PARAMETERS OF HUWAIZA MARSH IN SOUTHERN IRAQ

Huwaiza marsh is considered the largest marsh in the southern part of Iraq. It is located between 31° and 31.75° latitude and extends over the Iraqi-Iranian border; but the largest part lies in Iraq. It is located to the east of Tigris River in Messan and Basra governorates. In this research, the variation of some water quality parameters at different locations of Huwaiza marsh were studied to find out its efficacy in the treatment of the contamination coming from the wastewater outfall of Kahlaa brokendown sewage treatment plant which lies on the Kahlaa River. This rive is the main feeder of Huwaiza marsh. Ten water quality sampling locations were chosen in this marsh. The water samples were taken during 2009 for three months; January, April and August representing winter, spring and  summer respectively. The results of water quality analyses showed that Kahlaa untreated sewage had a negative impact on the water quality of Huwazia marsh; especially in its upstream region. Analyses of water samples taken from the middle and downstream end of the marsh showed that the marsh water is safe for fishing and swimming in these regions

Multicomponent Biosorption of Heavy Metals Using Fluidized Bed of Algal Biomass

This paper aims to study the biosorption for removal of lead, cadmium, copper and arsenic ions using algae as a biosorbent. A series of experiments were carried out to obtain the breakthrough data in a fluidized bed reactor. The minimum fluidization velocities of beds were found to be 2.27 and 3.64 mm/s for mish sizes of 0.4-0.6 and 0.6-1 mm diameters, respectively. An ideal plug flow model has been adopted to characterize the fluidized bed reactor. This model has been solved numerically using MATLAB version 6.5. The results showed a well fitting with the experimental data. Different operating conditions were varied: static bed height, superficial velocity and particle diameter. The breakthrough curves were plotted for each metal. Pb2+ showed the largest breakthrough time compared with others, while Cd2+ had the lowest valu

The Saudi Critical Care Society practice guidelines on the management of COVID-19 in the ICU: Therapy section

BACKGROUND: The rapid increase in coronavirus disease 2019 (COVID-19) cases during the subsequent waves in Saudi Arabia and other countries prompted the Saudi Critical Care Society (SCCS) to put together a panel of experts to issue evidence-based recommendations for the management of COVID-19 in the intensive care unit (ICU). METHODS: The SCCS COVID-19 panel included 51 experts with expertise in critical care, respirology, infectious disease, epidemiology, emergency medicine, clinical pharmacy, nursing, respiratory therapy, methodology, and health policy. All members completed an electronic conflict of interest disclosure form. The panel addressed 9 questions that are related to the therapy of COVID-19 in the ICU. We identified relevant systematic reviews and clinical trials, then used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach as well as the evidence-to-decision framework (EtD) to assess the quality of evidence and generate recommendations. RESULTS: The SCCS COVID-19 panel issued 12 recommendations on pharmacotherapeutic interventions (immunomodulators, antiviral agents, and anticoagulants) for severe and critical COVID-19, of which 3 were strong recommendations and 9 were weak recommendations. CONCLUSION: The SCCS COVID-19 panel used the GRADE approach to formulate recommendations on therapy for COVID-19 in the ICU. The EtD framework allows adaptation of these recommendations in different contexts. The SCCS guideline committee will update recommendations as new evidence becomes available

Optimum efficiency of treatment plants discharging wastewater into river, case study: Tigris river within the Baghdad city in Iraq

The present study aims to manage and determine the most economical efficiency of five wastewater treatment plants discharging wastewater into the Tigris River in Iraq. The management system was based on ensuring the five-day biological oxygen demand concentration in the river is <30 mg/L according to the Iraqi standards. In many cases, the determined optimized efficiencies were found to be lower than the present working efficiencies. Although this was good for the environment, it was not cost-effective. This study revealed that the variation of river flow rates was not an important factor that effects on the results obtained. It was found that the variation of organic decomposition value in the river and the minimum efficiency limit of the first upstream plant greatly affected the operating efficiency of the downstream plants. Furthermore, no constant rank was recorded for the effects of the natural decomposition on the operating efficiency of each plant. Three points were highlighted from this study: • The optimization methods were used to determine the most economical efficiency of multi wastewater treatment plants. • The effects of the BOD decomposition value, the river flow, and the minimum efficiency limit were also investigated. • This study presents the linear modeling method in detail and has a scientific impact for similar studies

Removal of Benzene and Toluene from Synthetic Wastewater by Adsorption onto Magnetic Zeolitic Imidazole Framework Nanocomposites

Considering the risk associated with exposure to benzene and toluene in water resources, researchers have been motivated to conduct studies to remove them from aqueous solutions. Thus, by performing the present study, the potential of Fe3O4/zeolite imidazolate framework nanoparticles (Fe3O4@ZIF-8) was evaluated for the adsorption of benzene and toluene. Accordingly, the solution pH, Fe3O4@ZIF-8 dosage, mixing time, concentration of benzene and toluene, and temperature, were the parameters considered for conducting the batch experiments, for which their effect on adsorption efficiency was evaluated. Our conducted experiments introduced the neutral pH as the best pH range to obtain the maximum removal. Fitting the adsorption data into the various models revealed the aptness of the Langmuir isotherm equation in describing experimental information and highest adsorption capacity; for benzene it was 129.4, 134.2, 137.3, and 148.2 mg g−1, but for toluene it was 118.4, 125.2, 129.6, and 133.1 mg g−1, for temperature 20, 30, 40, and 50 °C, respectively. Using obtained optimal conditions, the adsorption efficiencies of benzene and toluene were obtained to be 98.4% and 93.1%, respectively. Kinetic studies showed acceptable coefficients for PSO kinetics and confirmed its suitability. Also, the recyclability results showed that for six consecutive periods of the adsorption-desorption process, the percentage of removal decreased by only 6% for benzene and toluene. Moreover, calculating thermodynamic parameter changes for benzene and toluene removal confirmed the favorability and spontaneity of the studied process and its endothermic nature. Considering the above findings, Fe3O4@ZIF-8 was found to be an operative adsorbent for removing pollutants

Biosorption of metronidazole using Spirulina platensis microalgae: process modeling, kinetic, thermodynamic, and isotherm studies

Abstract Metronidazole is well-known antibiotic which, globally, ranks high in popular usage. Therefore, traces of residues of this antibiotic were identified in aquatic bodies. A photosynthetic cyanobacterium, of the microalgae category, S. platensis, has been found to be efficient in the removal of this antibiotic. This study was performed to evaluate the efficiency of S. platensis in the removal of metronidazole from aqueous environments. To set up the optimum conditions for facilitating metronidazole removal, BBD model was employed. The experiment included the following parameters: the initial metronidazole level (10–80 mg/L), pH (4–10), contact time (10–60 min), and biomass dose (0.1–0.5 g/L). From the findings it was evident that S. platensis was able to remove 88.15% of the metronidazole under the following conditions: contact time 38.05 min, metronidazole level 35 mg/L, pH 7.71 and a biomass dose 0.3 g/L. The quadratic model revealed that metronidazole concentration was the chief variable that influenced its removal rate. MNZ removal rate was observed to follow the pseudo-second-order model and the Freundlich model. From the thermodynamic data it appeared that the process of metronidazole biosorption was spontaneous, exothermic and physical. The results of this study revealed that S. platensis could be used as an inexpensive and efficient biosorbent to remove the metronidazole from aqueous solutions

Photocatalytic Degradation of Humic Acid Using Bentonite@Fe₃O₄@ZnO Magnetic Nanocomposite: An Investigation of the Characterization of the Photocatalyst, Degradation Pathway, and Modeling by Solver Plugin

Humic acid (HA), the most highly prevalent type of natural organic matter (NOM), plays an effective role in the generation of disinfectant byproducts such as trihalomethanes and haloacetic acid, which are well known to be definitive carcinogens. Therefore, the proactive elimination of HA from water and wastewater is a crucial means of preventing this pollutant from reacting with the chlorine incorporated during the disinfection process. This study investigated the UV light photocatalytic elimination of HA, employing a bentonite@Fe3O4@ZnO (BNTN@Fe3O4@ZnO) magnetic nanocomposite. The most significant variables pertinent to the photocatalytic degradation process examined in this work included the pH (3–11), nanocomposite dose (0.005–0.1 g/L), reaction time (5–180 min), and HA concentration (2–15 mg/L). The synthesized materials were characterized via field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), energy-dispersive X-ray spectroscopy (EDX), and vibrating-sample magnetometer (VSM) techniques, all of which revealed outstanding catalytic properties for the BNTN@Fe3O4@ZnO. The conditions under which greater efficiency was achieved included a pH of 3, a nanocomposite dose of 0.01 g/L, and an HA concentration of 10 mg/L. Under these conditions, in just 90 min of photocatalytic reaction, an HA degradation efficiency of 100% was achieved. From the modeling study of the kinetic data, the Langmuir–Hinshelwood model showed good compliance (R2 = 0.97) with the empirical data and predicted values. Thus, it can be concluded that the BNTN@Fe3O4@ZnO catalyst acts very efficiently in the HA removal process under a variety of treatment conditions

A new Adomian decomposition technique for a thermal analysis forced non-Newtonian magnetic Reiner-Rivlin viscoelastic fluid flow

This paper presents a new semi-analytical method, called the Adomian Decomposition Method (ADM), as well as Finite Element Methods, to study forced Reiner-Rivlin non-Newtonian Magnetohydrodynamic (MHD) fluid motion confined between two disks. The innovation presented in this paper is the utilization of both analytical and numerical methods, namely ADM and FEM, to solve coupled linear differential equations, which enables the calculation and examination of parameters such as heat transfer and fluid velocity between the two disks by simplifying these equations. This model incorporates the magnetic field, and the system of partial differential equations (PDEs) acts as the governing equation in this study, which are then transformed into a set of non-linear ordinary differential equations (ODEs) using von Karman analog variables. The Adomian decomposition method can be used to solve ODEs that are related to boundary conditions. The main findings of this article suggest that as the dimensionless force parameter increases, the displacement of the fluid velocity decreases, as the particles collide with each other, the temperature gradient around the disks decreases inversely. Moreover, when the stress tensor increases, the heat transfer rate reaches its maximum value, and the transverse velocity gradient between different disks decreases

Synthesis of a Doped α-Fe₂O₃/g-C₃N₄ Catalyst for High-Efficiency Degradation of Diazinon Contaminant from Liquid Wastes

In this work, a hematite/porous graphite carbon-nitride (α-Fe2O3/g-C3N4) catalyst was synthesized through the doping of hematite loaded onto porous graphite carbon-nitride using a heat treatment process. Then, the ability of catalyst was evaluated to degrade diazinon (DZN) for the first time, mainly via the sonophotocatalytic process. Among the samples, the greatest DZN degradation was observed in the sonophotocatalytic system, which separated 100% of DZN from the aqueous solution after 50 min, while the removal percentages for the sonocatalytic, photocatalytic, and adsorption systems were 72.9, 89.1, and 58.1%, respectively. The results of scavengers showed that both sulfate and hydroxyl radicals (•OH) participated in removing DZN, although positive holes and negative •OH played a major role. Moreover, the removal efficiencies of the target pollutant using the sonophotocatalytic process were higher than those using the photocatalytic, sonocatalytic, and adsorption processes. The reaction profile followed pseudo-first-order kinetics, and the reaction rate coefficient for the sonophotocatalytic system was 2.2 times higher than that of the photocatalytic system and 2.64 times higher than that of the sonocatalytic system. The energy consumption of the sonophotocatalytic system after 60 min was 11.6 kWh/m3, while it was 31.1 kWh/m3 for the photocatalytic system. A DZN removal percentage of 100% was obtained after 50 min under the following conditions: UV intensity of 36 watts, ultrasound frequency of 36 kHz, DZN concentration of 50 mg/L at pH 5, and α-Fe2O3/g-C3N4 dosage of 0.4 g/L. The catalyst reusability was examined with only a 9.9% reduction in efficiency after eight consecutive cycles. The chemical oxygen demand (COD) and total organic compound (TOC) removal percentages were 95.6% and 88.6%, respectively, and the five-day biochemical oxygen demand (BOD5)/COD ratio was 0.16 at the beginning of the degradation process and 0.69 at the end of the process. In addition, toxicological experiments showed that degradation of DZN by the sonophotocatalytic process exhibited low toxicity. All results confirmed that the sonophotocatalytic process using α-Fe2O3/g-C3N4 was a highly efficient process for DZN pollutant removal from liquid wastes