RESIDUAL METAL CONCENTRATIONS IN ENHANCED COAGULATION WITH FERRIC CHLORIDE AND ALUM FOR TOC REMOVAL

Chemical coagulation with metallic salts has traditionally been used in water treatment for turbidity removal. However, coagulation is also capable of some degree of natural organic matter (NOM) removal, with NOM functioning as a precursor to disinfection by-products (DBPs) formation. Enhanced coagulation is thus introduced to most water utilities treating surface water. Jar-test experiments were conducted to compare the effectiveness of alum and ferric chloride in removing DBPs precursors from eight synthetic water samples, each representing a different element of the USEPA’s 3×3 enhanced coagulation matrix, and the residual metal (aluminum/iron) concentration in the treated water was assessed. Coagulant type influenced the removal of total organic carbon (TOC) and which was enhanced with increasing coagulant dose. For all the treated samples coagulation with ferric chloride proved to be more effective than alum at similar doses and the mean values of treatment efficiencies were 51% and 32%, respectively. Ferric chloride was therefore considered the better chemical for enhancing the coagulation process. The results of residual metal concentration measurements in treated water showed that iron and aluminum concentrations had been increased as expected but the quality of water concerning the residual metal deteriorated much more in cases of under-dosing. Despite expecting high residual Al and Fe concentrations under enhanced coagulation, metal concentrations were frequently remained low and were not increased appreciably

RESIDUAL METAL CONCENTRATIONS IN ENHANCED COAGULATION WITH FERRIC CHLORIDE AND ALUM FOR TOC REMOVAL

Chemical coagulation with metallic salts has traditionally been used in water treatment for turbidity removal. However, coagulation is also capable of some degree of natural organic matter (NOM) removal, with NOM functioning as a precursor to disinfection by-products (DBPs) formation. Enhanced coagulation is thus introduced to most water utilities treating surface water. Jar-test experiments were conducted to compare the effectiveness of alum and ferric chloride in removing DBPs precursors from eight synthetic water samples, each representing a different element of the USEPA’s 3×3 enhanced coagulation matrix, and the residual metal (aluminum/iron) concentration in the treated water was assessed. Coagulant type influenced the removal of total organic carbon (TOC) and which was enhanced with increasing coagulant dose. For all the treated samples coagulation with ferric chloride proved to be more effective than alum at similar doses and the mean values of treatment efficiencies were 51% and 32%, respectively. Ferric chloride was therefore considered the better chemical for enhancing the coagulation process. The results of residual metal concentration measurements in treated water showed that iron and aluminum concentrations had been increased as expected but the quality of water concerning the residual metal deteriorated much more in cases of under-dosing. Despite expecting high residual Al and Fe concentrations under enhanced coagulation, metal concentrations were frequently remained low and were not increased appreciably

A framework for exploration and cleaning of environmental data : Tehran air quality data experience

Management and cleaning of large environmental monitored data sets is a specific challenge. In this article, the authors present a novel framework for exploring and cleaning large datasets. As a case study, we applied the method on air quality data of Tehran, Iran from 1996 to 2013. ; The framework consists of data acquisition [here, data of particulate matter with aerodynamic diameter ≤10 µm (PM10)], development of databases, initial descriptive analyses, removing inconsistent data with plausibility range, and detection of missing pattern. Additionally, we developed a novel tool entitled spatiotemporal screening tool (SST), which considers both spatial and temporal nature of data in process of outlier detection. We also evaluated the effect of dust storm in outlier detection phase.; The raw mean concentration of PM10 before implementation of algorithms was 88.96 µg/m3 for 1996-2013 in Tehran. After implementing the algorithms, in total, 5.7% of data points were recognized as unacceptable outliers, from which 69% data points were detected by SST and 1% data points were detected via dust storm algorithm. In addition, 29% of unacceptable outlier values were not in the PR.  The mean concentration of PM10 after implementation of algorithms was 88.41 µg/m3. However, the standard deviation was significantly decreased from 90.86 µg/m3 to 61.64 µg/m3 after implementation of the algorithms. There was no distinguishable significant pattern according to hour, day, month, and year in missing data.; We developed a novel framework for cleaning of large environmental monitored data, which can identify hidden patterns. We also presented a complete picture of PM10 from 1996 to 2013 in Tehran. Finally, we propose implementation of our framework on large spatiotemporal databases, especially in developing countries

National and sub-national environmental burden of disease in Iran from 1990 to 2013-study profile

Development of national evidence-based public health strategies requires a deep understanding of the role of major risk factors (RFs) and the burden of disease (BOD). In this article, we explain the framework for studying the national and sub-national Environmental Burden of Disease (EBD) in Iran as a part of the National and Sub-national Burden of Disease (NASBOD) study.; The distribution of exposures to environmental RFs and their attributable effect size over 1990-2013 will be estimated through comprehensive reviews of either published or unpublished sources. Statistical modeling will be used to impute missing data in the distribution of RFs exposures for each district-year. National and sub-national BOD attributable to these RFs will be estimated in the following metrics: Prevalence, death, years of life lost due to premature death (YLL), years of life lost due to disability (YLD), and disability-adjusted life years lost (DALYs). The BOD attributable to the current distribution of exposures will be compared with a counterfactual exposure distribution scenario-here, the theoretical-minimum-risk exposure distribution. Inequalities in the distribution of exposure to RFs will be analyzed and manifested nationwide using geographic information systems.; The EBD study aims to provide an official report to Iranian Ministry of Health and Medical Education, to publish a series of articles on the exposure trends of the selected environmental RFs, to estimate the BOD attributable to these RFs, and to assess inequalities and its determinants in the distribution of exposure to RFs. Iran's territory is large with diverse population, socioeconomic, and geographic areas. Results of this comparative risk assessment study may pave the way for health policy makers to plan more comprehensive and cost-effective evidence-based strategies

The Photocatalytic Removal of Ortho Chlorophenol from Aqueous Solution Using Modified Fly Ash - Titanium Dioxide

The photocatalytic process is a useful method for the effective removal of phenolic compounds. Conducted in the spring‒summer 2013 at the Engineering Research Center for Environmental Health, Kerman University of Medical Sciences, this experimental study used a modified fly ash‒TiO2 mixture to enhance the photocatalytic removal efficiency of ortho-chlorophenol. Fly ash obatined from the Thermal Power Plant in Zarand, Kerman, was initially washed with sulfuric acid before being oxidized with potassium permanganate. The mixture of modified fly ash and TiO2 was then used for the removal of ortho-chlorophenol in the presence of UV light and the factors involved in the removal process were optimized. It was found that the ortho-chlorophenol removal efficiency recorded by the mixture of modified fly ash and TiO2 was higher than that by each of the modified fly ash or TiO2/UV alone. It was, further, observed that removal efficiency with a modified fly ash to TiO2 ratio of 3:1 rose to 98.8% under optimum conditions (i.e., pH: 2; contact time: 2 h; room temperature (29±2˚C), and a catalyst dose of 0.6 g). The ortho-chlorophenol removal efficiency in real wastewater from the Coal Wash Plant in Zarand was recorded at 88.4%. Based on the results obtained from simultaneous use of modified fly ash and TiO2, the proposed method may be recommended for industrial applications

Evaluation of removal efficiency of 2-chlorophenol in aquatic environments by modified fly ash

Background: Chlorophenols are classified as priority toxic pollutants. These acidic organic compounds present a serious potential hazard for human health and aquatic life. Chlorophenols accumulate in water, soil and air due to high stability, and impart an unpleasant taste and odor to drinking water and can exert negative effects on different biological processes. Among the different methods of removal, adsorption process by low price adsorbents, such as fly ash (FA) is common. Therefore, in this study, the effects of oxidation of FA as modified adsorbent were investigated when the adsorption of 2-chlorophenol (2-CP) was increased. Methods: This experimental study was conducted from March to September of 2013. FA obtained from Zarand power plant (located in Kerman province) was oxidized with potassium permanganate. Effective factors on the oxidation of FA, such as temperature, oxidation time and concentrations of oxidizers were optimized. Raw sewage of Zarand coal washing plant was tested under optimal conditions. All tests were carried out according to the standard methods book for the examination of water and wastewater. Results: Optimal condition for the preparation of oxidized FA was obtained at 70°C, 1 hour, and 1 mM of potassium permanganate concentration. The absorber obtained was able to remove 96.22% of 2-CP under optimized conditions (pH=3, 2 hours, adsorbent dose 0.8 g and room temperature). The removal efficiency of the real wastewater under optimal conditions was 82.1%. Conclusion: Oxidized FA can be used for the removal of this pollutant from industry wastewater due to its high efficiency of removal in real wastewater, it is easy and inexpensive to prepare and could modify the sorbent

Spirituality and leader forgiveness: The role of spiritual self-regulation

In the context of monotheistic religions, it is argued that spirituality transforms the meaning of phenomena related to transgression and forgiveness, and thereby paves the way for a spiritual (as opposed to mundane) self-regulation which facilitates forgiveness by leaders. “Do not try to get even. Do not hold anything against any of your people. Instead, love your neighbor as you love yourself.” (Leviticus 19:18) “Love your enemies. Pray for those who hurt you.” (Matthew 5:44) “Adopt forgiveness (as your way of life)” (Quran 7:199) “[The Paradise is prepared for the God-wary]... those who restraint their anger, and those who forgive people. And God loves the benevolent.” (Quran 3:134

Enhancement of the Biodegradability of Methyl tert- Butyl Ether (MTBE) by Advanced Oxidation

The effectiveness of ozone treatment for improving the biodegradability of recalcitrant pollutants has been proved by investigating the ozonation reaction of Methyl tert-Butyl Ether (MTBE) as a bioresistant gasoline oxygenate. Laboratory scale experiments have been carried out at room temperature by bubbling for 120 minutes ozonated air (3.4 ppm/min) into 3 liter of an alkaline (pH=11.5) aqueous solution (100 mg/L) of MTBE. The experimental results indicated that during the ozonation, complete MTBE degradation occurs in 100 minutes and after this time, ozone consumption goes on very slowly. At the end of the ozonation, after 100 minutes, the initial value of COD (256 mg O2/L) is 98 and corresponds to a relative removal of about 62%. As for MTBE solution biodegradability expressed as (BOD5) / (COD) ratio, during the first 90 minutes, its value regularly increases from lowest 0.01 up to a maximum of 0.68 that corresponds to an ozone consumption of 1.25 mg per each mg of COD initially present in the solution. The research showed that partial degradation of MTBE in the advanced oxidation processes results an increase in its biological degradation. But more oxidation results lower  (BOD5) / (COD) ratio. Also the research showed that for idealization of the chemical oxidation conditions of MTBE, it needs to decrease COD to 46-68% before the biological degradation. The experimental results for determining the rate of MTBE removal due to stripping showed that about 14% of MTBE strips out after an hour of sparging with oxygen gas. The fraction of MTBE oxidized and/or striped increases to about 28% (in pH=7) and 70% (in pH=11.5) with ozonation over the same time period

Fenton Oxidation Efficiency in Removal of Detergents from Water

Advanced oxidation processes are associated with the production of very active hydroxyle radicals with a high potential for oxidation of organic compounds. One such process is Fenton process which reacts with ferrous ions in acidic media to produce a hydroxyle radical. It is an oxidation-reduction reaction in which the metallic ion accepts the transfer of one electron. A variety of factors such as pH, temperature, reaction time, and ferrous and H2O2 concentrations may affect the efficiency of the method. In this study, synthetic solutions of anionic LAS and ABS both having wide household and industrial applications were obtained and  used to evaluate the efficiency of Fenton process in the removal and treatability of different concentrations of ferrous and H2O2 for a variety of contact times. Experiments were performed with different concentrations of H2O2 and ferrous iron at a constant pH of 3 in a jar test apparatus  adjusted at 200 rpm and for different contact times (20, 40, 60, and 80 minutes). Results showed that increase in catalyst and oxidant concentrations increased removal efficiency. At a H2O2 concentration of 750 mg/l and a ferrous ion concentration of 130mg/l, 86% of LAS and ABS was removed in 80 minutes. Under these conditions, Fenton oxidation reduced the COD content of the ABS sample from 470 mg/L to 187 mg/L. The BOD5/COD ratio improved by 0.225 for a concentration of 600 mg/L of H2O2 and 130 mg/L of ferrous ion in 60 minuets. Measurements after the reaction revealed that pH reduced from 3 to 2.6 as a result of acidic intermediaries produced; this can be interesting for reaction control investigations

Using Coagulation Process in Optimizing Natural Organic Matter Removal from Low Turbidity Waters

Optimization of coagulation process  for efficient removal of Natural Organic Matters (NOM) has gained a lot of focus over the last years to meet the requirements of enhanced coagulation. NOM comprises both particulate and soluble components which the latter usually comprises the main portion. Removal of soluble NOM from low turbidity waters by coagulation is not a successful process unless enough attention is paid to stages of formation and development of both micro and macro-flocs. This study, which presents experimental results from pilot scale research studies aimed at optimizing coagulation process applied to synthetic raw waters supplemented by adding commercial humic acid with low turbidity levels, explains how pH and turbidity can be controlled to maximize soluble NOM removal. The removal of NOM at various coagulant doses and coagulation pHs has been assessed through raw and treated (coagulated-settled) water measurements of total organic carbon (TOC). For low turbidity waters, essential floc nucleation sites can be provided by creating synthetic turbidities, for example by adding clay. Adjusting the initial pH at 5.5 or adding clay before coagulant addition allows the formation of micro-flocs as well as formation of the insoluble flocs at low coagulant doses