Treatability of U.S. Environmental Protection Agency Contaminant Candidate List Viruses: Removal of Coxsackievirus and Echovirus using Enhanced Coagulation

Enhanced coagulation was evaluated for removal efficacy of coxsackievirus and echovirus (Contaminant Candidate List [CCL] enteroviruses), poliovirus, four potential surrogate bacteriophages, and dissolved organic carbon (DOC). Viruses and DOC were effectively removed using enhanced coagulation, with removals generally improving as dose increased and pH decreased. Optimal enhanced coagulation conditions of 40 mg/L FeCl3 and pH between 5 and 6.5 resulted in a maximum removal of 3.0 logs of coxsackievirus B6, 1.75 logs of echovirus 12, 2.5 logs of poliovirus 1, 1.8 logs of fr, 1.3 logs of phi-X174, 0.36 logs of MS2, 0.29 logs of PRD1, and 41% DOC. Bacteriophages fr and phi-X174 appear to be the most representative surrogates for the physical removal of coxsackievirus, while MS2 and PRD1 are more conservative. For echovirus, MS2 and PRD1 appear to be the most appropriate surrogates. The relative removal profiles of the enteroviruses (greatest removal of coxsackievirus followed by poliovirus and then echovirus) suggest that studies of the physical removal of poliovirus may be extended to the CCL enteroviruses. These results contribute to evaluations of the CCL and regulatory status of coxsackievirus and echovirus and aid in building a database of the treatment efficiencies of enteroviruses and their surrogates

Evaluation of the Relationship between Bulk Organic Precursors and Disinfection Byproduct Formation for Advanced Oxidation Processes

Advanced oxidation processes (AOPs) are gaining traction as they offer mineralization potential rather than transferring contaminants between media. However, AOPs operated with limited energy and/or chemical inputs can exacerbate disinfection byproduct (DBP) formation, even as precursors such as dissolved organic carbon, UV254, and specific UV absorbance (SUVA) decrease. This study examined the relationship between DBP precursors and formation using TiO2 photocatalysis experiments, external AOP and non-AOP data, and predictive DBP models. The top-performing indicator, SUVA, generally correlated positively with trihalomethanes and haloacetic acids, but limited-energy photocatalysis yielded contrasting negative correlations. The accuracy of predicted DBP values from models based on bulk parameters was generally poor, regardless of use and extent of AOP treatment and type of source water. Though performance improved for scenarios bounded by conditions used in model development, only 0.5% of the model/dataset pairings satisfied all measured parameter boundary conditions, thereby introducing skepticism toward model usefulness. Study findings suggest that caution should be employed when using bulk indicators and/or models as a metric for AOP mitigation of DBP formation potential, particularly for limited-energy/chemical inputs

Efficacy of Removal of CCL Viruses under Enhanced Coagulation Conditions

The focus of coagulation as a water treatment process is shifting to accommodate recent regulatory additions that strive to balance the risks between microbial and chemical contamination of drinking water. In this work, enhanced coagulation using increased ferric chloride dose and/or pH adjustment was evaluated for removal efficacy of viruses on the United States Environmental Protection Agency (USEPA) Contaminant Candidate List (CCL), their surrogates, and dissolved organic carbon (DOC). Jar tests demonstrated that optimal DOC removal was achieved using 40 mg/L FeCl3 at a pH between 5 and 6. Under these conditions, bench-scale testing resulted in a maximum removal of 2.58 log units of adenovirus type 4, 2.50 log units of feline calicivirus, 2.32 log units of MS2, 1.75 log units of PRD1, 1.52 log units of phi-X174, 2.49 log units of fr, and 56% of DOC. The trend in virus removals (MS2 and fr \u3e PRD1 and phi-X174) was consistent between bench- and pilot-scale testing; however, pilot-plant removals exceeded bench-scale removals. Feline calicivirus was more efficiently removed than the bacteriophages, thereby suggesting potential for the bacteriophages as suitable surrogates, with MS2 and fr being more representative and PRD1 and phi-X174 (which were removed to a lesser extent) more conservative. The bacteriophages do not appear to be appropriate surrogates for adenovirus

Physicochemical Characterization of Safranal-β-Cyclodextrin Inclusion Complexes Prepared By Supercritical Carbon Dioxide and Conventional Methods.

Saffron (Crocus sativus. Linn) has attracted much attention over the last decade because it has a large number of potent and biologically active compounds such as crocin, crocetin, picrocrocin and safranal. Researchers have shown that safranal has high antioxidant and cytotoxicity activities against several types of tumour cells (e.g., hepatocellular carcinoma) both in-vitro and in-vivo. However, the low aqueous solubility of safranal prevents using it as a therapeutic or preventive agent. β-cyclodextrin (β-CD) inclusion complexes are being used in pharmaceutical applications to alter physicochemical properties (e.g., solubility, volatility, stability, chemical reactivity, and bio-availability) of poorly water soluble drugs. Thus the aim of this work is to investigate the potential of different methods for the preparation of safranal-β-CD inclusion complexes in order to enhance the poor solubility and dissolution rate of safranal in aqueous solutions. Inclusion complexes having a molar ratio of 1:2 (safranal-β-CD) were prepared using different methods such as kneading (KN), co-evaporation (COE), sealed-heating (SH), and supercritical CO2 (SC-CO2). Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and proton nuclear magnetic resonance spectroscopy (H-NMR) were used to identify the physicochemical properties of inclusion complexes. Phase solubility and dissolution measurements were also studied. Effects of temperature (35 and 55 °C) and pressure (100 and 300 bar) on the inclusion complexes prepared using the SC-CO2 method were also investigated. The results indicated that the formation of safranal-β-CD inclusion complexes was affected by the preparation method being used, and the SC-CO2 method proved to be more effective than conventional techniques. FT-IR and H-NMR results indicated the formation of inclusion between β-CD and safranal in the complex prepared by different methods. A “Bs” type solubility with an apparent solubility constant (Ks) of 51.48 M-1 for safranal was obtained from the initial slope of phase solubility diagram. The intrinsic solubility of safranal was increased from 3.852 mM to 5.217 mM in the presence of 10.00 mM of β-CD. Therefore, the initial phase solubility of safranal was enhanced by about 35% in water solution. Dissolution rate studies showed that inclusion complexes might dissolve faster than pure safranal or even physical mixture of safranal-β-CD. Hence, β-CD could be useful for solid safranal formulations. The solvent-free product prepared by SC-CO2 showed high aqueous solubility and may provide minimal side effects for human use

The Impact of Capsid Proteins on Virus Removal and Inactivation During Water Treatment Processes

This study examined the effect of the amino acid composition of protein capsids on virus inactivation using ultraviolet (UV) irradiation and titanium dioxide photocatalysis, and physical removal via enhanced coagulation using ferric chloride. Although genomic damage is likely more extensive than protein damage for viruses treated using UV, proteins are still substantially degraded. All amino acids demonstrated significant correlations with UV susceptibility. The hydroxyl radicals produced during photocatalysis are considered nonspecific, but they likely cause greater overall damage to virus capsid proteins relative to the genome. Oxidizing chemicals, including hydroxyl radicals, preferentially degrade amino acids over nucleotides, and the amino acid tyrosine appears to strongly influence virus inactivation. Capsid composition did not correlate strongly to virus removal during physicochemical treatment, nor did virus size. Isoelectric point may play a role in virus removal, but additional factors are likely to contribute

The Effects of Different Ionic Liquid Coatings and the Length of Alkyl Chain on Antimicrobial and Cytotoxic Properties of Silver Nanoparticles

Introduction: The antibacterial efficacy and toxicity of silver nanoparticles (AgNPs) depends on their physicochemical properties including size, shape, surface charge and surface coatings. The Objectives of this study were: i) To synthesize and characterize positively charged AgNPs coated by different ionic-liquids with different alkyl chain lengths, ii) To evaluate the antimicrobial activity of these nanoparticles against Enterococcus faecalis compared to sodium hypochlorite (NaOCl) and chlorhexidine (CHX), iii) To compare the cytocompatibility of these solutions against L929 mouse fibroblasts. Methods and Materials: AgNPs with positive surface charges capped by two different ionic liquids [imidazolium (Im) and pyridinium (Py)] with two alkyl chain lengths (C12 and C18) were synthesized. Im and Py were also tested as control groups. The characterization revealed synthesis of spherical NPs in the size range of 6.7-18.5 nm with a surface charge ranging from +25 to +58 mV. To standardize the comparisons, the surface charge to radius ratio of each nanoparticle was calculated. The minimum inhibitory concentrations (MIC) of the AgNP solutions, NaOCl and CHX were determined against E. faecalis by a microdilution test. An MTT-based cytotoxicity assay evaluated the cytotoxicity of the solutions in different concentrations on L929 fibroblasts. One-way and two-way ANOVA were used for statistical analysis. Results: All tested AgNPs reached MIC90 in significantly lower concentrations compared to CHX and NaOCl. C12 Py-coated AgNPs had the lowest MIC90 value. CHX and NaOCl were more toxic on fibroblasts than all tested AgNPs. Im-coated AgNPs had better compatibility with fibroblasts than Py-coated particles; and C12 Im AgNPs had the best biocompatibility. Variations in alkyl chain length had no effects on the biocompatibility of AgNPs. Conclusion: Py improved the antibacterial efficacy of AgNPs compared to Im; however, it had a negative effect on cytocompatibility. Alkyl chain length had no effects on AgNPs’ bioactivity.Keywords: Antibacterial Agents; Chlorhexidine; Cytotoxicity; Metal Nanoparticles; Sodium Hypochlorit

Impact of Real-time Project Control on Capital Project Cost and Schedule Performance

This article assesses the combined influence of information integration and automated data analytics on project performance. To this end, retrospective data on 78 completed projects, with a total installed value of $8 billion, was collected. The level of internal and external information integration and automated analytics were used as surrogates of real-time project controls for statistical analyses purposes. Indeed, non-parametric statistical techniques were used to assess the impact of such technologies on cost and schedule performance. Overall, teams with a sophisticated degree of information integration and automated data analytics can control their projects with more reliable information and in a proactive manner so that informed decisions can be timely made on behalf of the project and the organization

Impact of Real-time Project Control on Capital Project Cost and Schedule Performance

This article assesses the combined influence of information integration and automated data analytics on project performance. To this end, retrospective data on 78 completed projects, with a total installed value of $8 billion, was collected. The level of internal and external information integration and automated analytics were used as surrogates of real-time project controls for statistical analyses purposes. Indeed, non-parametric statistical techniques were used to assess the impact of such technologies on cost and schedule performance. Overall, teams with a sophisticated degree of information integration and automated data analytics can control their projects with more reliable information and in a proactive manner so that informed decisions can be timely made on behalf of the project and the organization

Comparison of Antimicrobial Efficacy of IKI and NaOCl Irrigants in Infected Root Canals: An In Vivo Study

INTRODUCTION: Effective debridement of the root canal system with chemical irrigants prior to obturation is the key to long-term success of endodontic therapy. The purpose of this study is to compare the antibacterial activity of 2.5% sodium hypochlorite (NaOCl) and 2% iodine potassium iodide (IKI) solutions as intracanal disinfectant in infected root canals during one-visit endodontic treatment procedure. MATERIALS AND METHODS: Thirty single-rooted teeth with necrotic pulps in 27 patients were selected according to specific inclusion/exclusion criteria and divided into two random groups. In group I, canals were irrigated with 2.5% NaOCl during instrumentation and in group II canals were initially irrigated with sterile saline during biomechanical preparation and then exposed to a 5-minute final irrigation with 2% IKI. Bacterial samples were taken before treatment (S1), and at the end of treatment (S2). Mann-Whitney U test was used for analysis. RESULTS: Bacteria were present in all initial samples. NaOCl was able to significantly reduce the number of colony forming units (CFU) from S1 to S2 in approximately 90% of canals. Only 15% reductions in CFUs occurred after irrigation/instrumentation in group II; this degree of disinfection was not statistically significant. CONCLUSION: According to this study, although root canal irrigation with 2.5% NaOCl could not eradicate all bacteria within the canals; it was significantly superior in comparison with 2% IKI use