SEMI-BATCH OPERATED CONSTRUCTED WETLANDS PLANTED WITH PHRAGMITES AUSTRALIS FOR TREATMENT OF DYEING WASTEWATER

The objective of present study is to evaluate the using of constructed wetland under semi-batch operation for the treatment of azo dye Acid Orange 7 (AO7) containing wastewater. The emergent plant selected in our study was Phragmites australis. Toxic signs were observed at the Phragmites australis after the addition of AO7 into the wetland reactors but it can adapt to the wastewater as shown in the increase of stem as the operation continue. Our result shows that the artificial aeration and the presence of Phragmites australis had a significant impact on the removal of organic matters, AO7, aromatic amines and NH4-N. The COD removal efficiency in the aerated and non-aerated wetland reactors was 95 and 62%, respectively. The NH4-N removal efficiency in the aerated wetland reactor (86%) was significantly higher than the non-aerated wetland reactor (14 %). All wetland reactors show high removal efficiency of AO7 (> 94%) but only the aerated wetland reactor perform better in the removal of aromatic amines

Biodegradation of redox dye Methylene Blue by up-flow anaerobic sludge blanket reactor

Abstract The objective of this study is to evaluate the decolorization of Methylene Blue (MB) by an up-flow anaerobic sludge blanket (UASB) reactor. The UASB reactor was operated under batch condition with total treatment volume of 3 l and operation time of 24 h per batch. It was found that the color of MB disappeared within a few minutes after entering into the UASB reactor due to reduction by anaerobic biomass. However, the reduced MB was re-oxidized again by air after discharged from the reactor and thus caused low color removal efficiency. The presence of suitable amount of organic content (sucrose and peptone) as an electron donor played an important factor for color removal. It was observed that more than 90% of color removal efficiency was achieved in the UASB reactor with 0.627 mmol l −1 of MB concentration and the presence of low amount of organic content (< 0.45 g COD/(l d)). Biological dye reduction kinetics depends on the concentration of dye and reducing equivalents. The kinetic behavior of MB biodegradation by microbes was also investigated to determine the model involved in the process

Enhanced photodegradation of phenol by ZnO nanoparticles synthesized through sol-gel method

Zinc oxide (ZnO) utilization in advanced oxidation process (AOP) via solar-photocatalytic process was a promising method for alternative treating wastewater containing phenol. The ZnO photocatalyst semiconductor was synthesized by sol-gel method. The morphology of the ZnO nanostructures was observed by using scanning electron microscope (SEM) and the crystallite phase of the ZnO was confirmed by x-ray diffraction (XRD). The objective of this study was to synthesis ZnO nanoparticles through a sol-gel method for application as a photocatalyst in the photodegradation of phenol under solar light irradiation. The photodegradation rate of phenol increased with the increasing of ZnO loading from 0.2 until 1.0 g. Only 2 h were required for synthesized ZnO to fully degrade the phenol. The synthesized ZnO are capable to totally degrade high initial concentration up until 45 mg L-1 within 6 h of reaction time. The photodegradation of phenol by ZnO are most favoured under the acidic condition (pH3) where the 100% removal achieved after 2 h of reaction. The mineralization of phenol was monitored through chemical oxygen demand (COD) reduction and 92.6% or removal was achieved. This study distinctly utilized natural sunlight as the sole sources of irradiation which safe, inexpensive; to initiate the photocatalyst for degradation of phenol

Decolorization and mineralization of batik wastewater through solar photocatalytic process

In this study, the photocatalytic degradation of batik wastewater in the presence of zinc oxide (ZnO) as photocatalyst was investigated. The effect of various operating parameters, such as pH of batik wastewater, catalyst dosage and aeration on the photocatalytic degradation process, was examined. The mineralization of batik wastewater was also evaluated through chemical oxygen demand analysis. The decolorization of batik wastewater was enhanced at acidic conditions (pH3) which was 88.2% after 10 h irradiated under solar light, meanwhile its mineralization was 286 mg/L after 12 h irradiation time. The data obtained for photocatalytic degradation of batik wastewater was well fitted with the Langmuir-Hinshelwood kinetic model. It can be concluded that batik wastewater could be decolorized and mineralized under solar light irradiation with presence of ZnO

Decolourization of an azo dye in aqueous solution by ozonation in a semi-batch bubble column reactor

ABSTRACT: The oxidative degradation of the azo dye Reactive Red 120 by ozonation was investigated. The decolourization was carried out by bubbling ozone at the bottom of a bubble column reactor containing the dye solution. The colour, chemical oxygen demand, and total organic carbon removal were evaluated, and the contaminants were characterized based on the changes in UV-Vis and FT-IR spectra. It was observed that changes of UV-Vis spectra represent the disappearance of both azo and aromatic groups, which causes the colour removal. FT-IR analysis indicated that ozonation shifts the functional groups in the azo dye which results in decolourization, a decrease in aromaticity, and an increase in acidity. The results indicate that the chromophore is destroyed and partially mineralized to small fragments during ozonation. The alkaline pH was favourable to decomposition by ozonation, initiated by the formation of the hydroxyl radicals. The oxidation followed first-order kinetics and the completed decolourization confirmed the capability of ozonation to cleave the azo bond from the dye

Oxidation of p-Cresol by ozonation

Oxidation of p-Cresol was investigated by using ozonation process. The aim of this research is to assess the effectiveness of ozonation on oxidation of micropollutant such as p-Cresol. Ozonation performance was evaluated based on p-Cresol concentration reduction and chemical oxidation demand (COD) reduction. It was found ozonation at pH11 achieved the highest p-Cresol degradation, with 95.8% of p-Cresol reduced and 96.0% of COD reduced, for an initial 50 mgL-1 of p-Cresol. The degradation of p-Cresol could be expressed by second-order of kinetic model. The second-order rate constant k increases as the initial pH increased, but decreases with the increasing of initial p-Cresol concentrations. Besides, the absorption spectra of p-Cresol over ozonation time were analyzed by spectrophotometry. The evolution of absorption spectra of p-Cresol degradation suggests that the oxidation of p-Cresol follows three stages mechanisms with cycloaddition as the first step to produce aromatic intermediates followed by ring-opening reactions, degradation of the intermediates, and subsequently achieved mineralization

Biochar : A review of its history, characteristics, factors that influence its yield, methods of production, application in wastewater treatment and recent development

Biochar can alleviate several issues, and it should also be inexpensive to produce. Most biochars have a high pore structure and diverse functional groups that assist in the adsorption process. Due to the attributed properties of biochar, several studies have demonstrated that biochar is getting more attention for its efficiency in facilitating wastewater treatment. However, to ensure the feasibility of biochar in wastewater treatment, the factors involved in the preparation of biochar that influences its characteristics and adsorption capacity must be understood. This study reviews the history, characteristics, factors that influence its yield, production methods, application, and recent development of biochar in wastewater treatment

Generative Embedding for Model-Based Classification of fMRI Data

Decoding models, such as those underlying multivariate classification algorithms, have been increasingly used to infer cognitive or clinical brain states from measures of brain activity obtained by functional magnetic resonance imaging (fMRI). The practicality of current classifiers, however, is restricted by two major challenges. First, due to the high data dimensionality and low sample size, algorithms struggle to separate informative from uninformative features, resulting in poor generalization performance. Second, popular discriminative methods such as support vector machines (SVMs) rarely afford mechanistic interpretability. In this paper, we address these issues by proposing a novel generative-embedding approach that incorporates neurobiologically interpretable generative models into discriminative classifiers. Our approach extends previous work on trial-by-trial classification for electrophysiological recordings to subject-by-subject classification for fMRI and offers two key advantages over conventional methods: it may provide more accurate predictions by exploiting discriminative information encoded in ‘hidden’ physiological quantities such as synaptic connection strengths; and it affords mechanistic interpretability of clinical classifications. Here, we introduce generative embedding for fMRI using a combination of dynamic causal models (DCMs) and SVMs. We propose a general procedure of DCM-based generative embedding for subject-wise classification, provide a concrete implementation, and suggest good-practice guidelines for unbiased application of generative embedding in the context of fMRI. We illustrate the utility of our approach by a clinical example in which we classify moderately aphasic patients and healthy controls using a DCM of thalamo-temporal regions during speech processing. Generative embedding achieves a near-perfect balanced classification accuracy of 98% and significantly outperforms conventional activation-based and correlation-based methods. This example demonstrates how disease states can be detected with very high accuracy and, at the same time, be interpreted mechanistically in terms of abnormalities in connectivity. We envisage that future applications of generative embedding may provide crucial advances in dissecting spectrum disorders into physiologically more well-defined subgroups

Contributions of mean and shape of blood pressure distribution to worldwide trends and variations in raised blood pressure: A pooled analysis of 1018 population-based measurement studies with 88.6 million participants

© The Author(s) 2018. Background: Change in the prevalence of raised blood pressure could be due to both shifts in the entire distribution of blood pressure (representing the combined effects of public health interventions and secular trends) and changes in its high-blood-pressure tail (representing successful clinical interventions to control blood pressure in the hypertensive population). Our aim was to quantify the contributions of these two phenomena to the worldwide trends in the prevalence of raised blood pressure. Methods: We pooled 1018 population-based studies with blood pressure measurements on 88.6 million participants from 1985 to 2016. We first calculated mean systolic blood pressure (SBP), mean diastolic blood pressure (DBP) and prevalence of raised blood pressure by sex and 10-year age group from 20-29 years to 70-79 years in each study, taking into account complex survey design and survey sample weights, where relevant. We used a linear mixed effect model to quantify the association between (probittransformed) prevalence of raised blood pressure and age-group- and sex-specific mean blood pressure. We calculated the contributions of change in mean SBP and DBP, and of change in the prevalence-mean association, to the change in prevalence of raised blood pressure. Results: In 2005-16, at the same level of population mean SBP and DBP, men and women in South Asia and in Central Asia, the Middle East and North Africa would have the highest prevalence of raised blood pressure, and men and women in the highincome Asia Pacific and high-income Western regions would have the lowest. In most region-sex-age groups where the prevalence of raised blood pressure declined, one half or more of the decline was due to the decline in mean blood pressure. Where prevalence of raised blood pressure has increased, the change was entirely driven by increasing mean blood pressure, offset partly by the change in the prevalence-mean association. Conclusions: Change in mean blood pressure is the main driver of the worldwide change in the prevalence of raised blood pressure, but change in the high-blood-pressure tail of the distribution has also contributed to the change in prevalence, especially in older age groups

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700