scholarly journals Submerged microfiltration membrane and activated carbon processes for recalcitrant compounds removal in Oil refinery effluent as electrodialysis pre-treatment

Author(s):  
Carolinne Ragazzi Piombini ◽  
Larissa Loureiro Salgueiro Silva ◽  
Fabiana Valéria da Fonseca ◽  
Juacyara Carbonelli Campos

Abstract The combination of suspended activated carbon (AC) and submerged microfiltration (SMF) processes was applied to polish a biotreated effluent generated in a refinery industry. Preliminary results indicated that Norit 1240 W AC was more suitable than Carbomafra AC brand for Total Organic Carbon (TOC) removal due to the highest Freundlich adsorption constant value (1.97 ± 0.42 and 0.96 ± 0.23 (mg/g)(L/mg)1/n, respectively), thus the first one was used in the combined system. Among all particle sizes of AC tested (0.041–1.01 mm), AC/SMF system was better performed, according to permeation flux, when applying granular AC instead of the powder one. On the other hand, the best response regarding TOC removal and Absorbance at 254 nm (ABS254 nm) reduction were observed when applying powder AC (89 and 97%, respectively). Statistical analysis with Two-sample T-test (p-value <0.05) endorsed the need of both air purge (20 L/h) and backwash strategies (8 min of permeation and 10 seconds of backwash) to diminish fouling occurrence in the SMF system. Finally, it was found that 2 g/L of Norit 1240 W PAC (0.041 mm particle size) condition fitted the effluent to further EDR process (3.4 mg/L TOC) with consistent normalized permeate flux after 5 h of permeation (0.76 ± 0.1 J/J0).

2001 ◽  
Vol 43 (11) ◽  
pp. 67-74 ◽  
Author(s):  
G. T. Seo ◽  
S. Ohgaki

Biological powdered activated carbon (BPAC) was incorporated with a microfiltration (MF, 0.2 μm pore size) system to remove the refractory organic matter contained in secondary sewage effluent. A synthetic secondary sewage effluent was used as influent in this study, containing both non-biodegradable organic substances (such as humic acid, lignin sulfonate, tannic acid and arabic gum powder) and biodegradable ones. These refractory organic materials were possibly degraded in contact with microorganisms for 20-27 days. Although humic acid and arabic gum were weakly adsorbed on the activated carbon, they could be effectively removed in the BPAC reactor. The TOC removal at a powdered activated carbon (PAC) concentration of 20 g/L was higher than at 0.5-2 g PAC/L (83% and 66-68%, respectively). The higher removal efficiency was due to the increased rejection at the membrane module in which most of the PAC was accumulated. More than 90% of non-biodegradable compounds removal (detected as E280 , UV absorption at 280 nm) occurred in the BPAC reactor. The biological growth parameter b/Y, used in system design, was estimated to be 0.017 d-1. Relatively high permeate flux of 1.88 m/d could be obtained even at higher PAC concentration of 20 g/L.


Membranes ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 84 ◽  
Author(s):  
Sarah Elhady ◽  
Mohamed Bassyouni ◽  
Ramadan A. Mansour ◽  
Medhat H. Elzahar ◽  
Shereen Abdel-Hamid ◽  
...  

In this study, polyamide (PA) thin film composite (TFC) reverse osmosis (RO) membrane filtration was used in edible oil wastewater emulsion treatment. The PA-TFC membrane was characterized using mechanical, thermal, chemical, and physical tests. Surface morphology and cross-sections of TFCs were characterized using SEM. The effects of edible oil concentrations, average droplets size, and contact angle on separation efficiency and flux were studied in detail. Purification performance was enhanced using activated carbon as a pre-treatment unit. The performance of the RO unit was assessed by chemical oxygen demand (COD) removal and permeate flux. Oil concentration in wastewater varied between 3000 mg/L and 6000 mg/L. Oily wastewater showed a higher contact angle (62.9°) than de-ionized water (33°). Experimental results showed that the presence of activated carbon increases the permeation COD removal from 94% to 99%. The RO membrane filtration coupled with an activated carbon unit of oily wastewater is a convenient hybrid technique for removal of high-concentration edible oil wastewater emulsion up to 99%. Using activated carbon as an adsorption pre-treatment unit improved the permeate flux from 34 L/m2hr to 75 L/m2hr.


2005 ◽  
Vol 5 (5) ◽  
pp. 1-8 ◽  
Author(s):  
K.Y. Choi ◽  
B.A. Dempsey

The objective of the research was to evaluate in-line coagulation to improve performance during ultrafiltration (UF). In-line coagulation means use of coagulants without removal of coagulated solids prior to UF. Performance was evaluated by removal of contaminants (water quality) and by resistance to filtration and recovery of flux after hydraulic or chemical cleaning (water production). We hypothesized that coagulation conditions inappropriate for conventional treatment, in particular under-dosing conditions that produce particles that neither settle nor are removed in rapid sand filters, would be effective for in-line coagulation prior to UF. A variety of pre-treatment processes for UF have been investigated including coagulation, powdered activated carbon (PAC) or granular activated carbon (GAC), adsorption on iron oxides or other pre-formed settleable solid phases, or ozonation. Coagulation pre-treatment is often used for removal of fouling substances prior to NF or RO. It has been reported that effective conventional coagulation conditions produced larger particles and this reduced fouling during membrane filtration by reducing adsorption in membrane pores, increasing cake porosity, and increasing transport of foulants away from the membrane surface. However, aggregates produced under sweep floc conditions were more compressible than for charge neutralization conditions, resulting in compaction when the membrane filtration system was pressurized. It was known that the coagulated suspension under either charge-neutralization or sweep floc condition showed similar steady-state flux under the cross-flow microfiltration mode. Another report on the concept of critical floc size suggested that flocs need to reach a certain critical size before MF, otherwise membranes can be irreversibly clogged by the coagulant solids. The authors were motivated to study the effect of various coagulation conditions on the performance of a membrane filtration system.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Yeit Haan Teow ◽  
Meng Teck Chong ◽  
Kah Chun Ho ◽  
Abdul Wahab Mohammad

AbstractAiming to mitigate wastewater pollution arising from the palm oil industry, this university-industry research-and-development project focused on the integration of serial treatment processes, including the use of moving bed biofilm reactor (MBBR), pre-treatment with sand filters and activated carbon filters, and membrane technology for aerobically-digested palm oil mill effluent (POME) treatment. To assess the potential of this sustainable alternative practice in the industry, the developed technology was demonstrated in a pilot-scale facility: four combinations (Combinations I to IV) of unit operations were developed in an integrated membrane-filtration system. Combination I includes a MBBR, pre-treatment unit comprising sand filters and activated carbon filters, ultrafiltration (UF) membrane, and reverse osmosis (RO) membrane, while Combination II excludes MBBR, Combination III excludes UF membrane, and Combination IV excludes both MBBR and UF membrane. Life cycle assessment (LCA) was performed to evaluate potential environmental impacts arising from each combination while achieving the goal of obtaining recycled and reusable water from the aerobically-digested POME treatment. It is reported that electricity consumption is the predominant factor contributing to most of those categories (50–77%) as the emissions of carbon dioxide (CO2), sulfur dioxide (SO2), nitrogen oxides, and volatile mercury during the combustion of fossil fuels. Combination I in the integrated membrane-filtration system with all unit operations incurring high electricity consumption (52 MJ) contributed to the greatest environmental impact. Electricity consumption registers the highest impact towards all life cycle impact categories: 73% on climate change, 80% on terrestrial acidification, 51% on eutrophication, and 43% on human toxicity. Conversely, Combination IV is the most environmentally-friendly process, since it involves only two-unit operations – pre-treatment unit (comprising sand filters and activated carbon filters) and RO membrane unit – and thus incurs the least electricity consumption (41.6 MJ). The LCA offers insights into each combination of the operating process and facilitates both researchers and the industry towards sustainable production.


Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Adrienne N Dula ◽  
Ian M Alrahwan ◽  
Steven J Warach

Introduction: The overall goal of this study is to evaluate the relationship of pretreatment perfusion mismatch volumes to outcomes in patients receiving alteplase (ALT) to those receiving tenecteplase (TNK). Methods: This study included patients receiving treatment with ALT (0.9 mg/kg; max, 90 mg) or TNK (0.25 mg/kg; max, 25 mg) between 09/01/2017 - 06/30/2020 identified through our local stroke registry stroke registry. Of the 505 patients meeting these criteria, 280 have been screened, including patients receiving EVT (n=94) and a sampling of n=111 from the ALT group and 75 from the TNK group. Final eligibility will be patients with a pretreatment perfusion deficit, mismatch > 15 mL, and mismatch (MM) ratio ≥ 1.2. Volumes are based on RAPID software (iSchemiaView). Using univariate (chi-squared with continuity correction or Mann-Whitney U) and adjusted logistic models, the effect of lysis type and pre-treatment imaging were assessed on the primary outcome of discharge disposition. Results: A total of 93 patients were included in our analysis, 40 receiving ALT and 53 patients receiving TNK, demographics found in Table 1. Discharge to home occurred in 48.8% (20/40) of patients treated with ALT and 30.7% (16/53) treated with TNK, odds ratio (OR), 0.47; 95% CI [0.20, 1.09], (P-value for OR=0.0766). Upon adjustment for EVT, age, sex, NIHSS on admission, imaging modality, cohort imbalances (marked by *), and MM, the relation of lysis type to discharge to home gave an OR of 0.25; 95% CI [0.06, 0.90], P= 0.0383) with age (P<0.0001) and imaging modality (P=0.0020) significantly contributing to the model. Lysis type did not significantly influence discharge to hospice or death (OR, 0.62; 95% CI [0.05, 6.86], P=0.6945) upon adjustment for baseline factors. Conclusion: In this preliminary analysis, MM volumes did not contribute to the outcome of discharged to home. Analysis of the full cohort is ongoing and final analyses will relate lytic type to infarct volume growth and clinical outcomes.


2009 ◽  
Vol 59 (11) ◽  
pp. 2281-2286 ◽  
Author(s):  
Chung-Yi Chou ◽  
Chien-Pin Huang ◽  
Neng-Chou Shang ◽  
Yue-Hwa Yu

This study investigates the oxidation of local scrubber wastewater (LSW) from semiconductor manufacture by using ozonation, catalytic ozonation (ozone/Al2O3 and ozone/TiO2–Al2O3), and photo-catalytic ozonation (UV/TiO2–Al2O3, ozone/UV and ozone/UV/TiO2–Al2O3). The results show that catalyst Al2O3 and TiO2–Al2O3 promotes the TOC removal under the condition of neutral or alkaline buffer solution during catalytic ozonation of LSW. The Al2O3 induces highest promotion in TOC removal efficiency, which is higher than ozone alone by 26% TOC removal under alkaline buffer solution. However, TiO2–Al2O3 and Al2O3 cannot display the promotion in TOC removal under acidic condition. In addition, a pre-treatment of anion ion-exchange is employed and the result indicates that decreasing the anion ions concentration before AOPs can imply higher TOC removal during AOPs of LSW. In this study, ozone/UV under raw LSW acidic condition and ozone/Al2O3 under alkaline buffer solution present 95% and 88% TOC removal rate respectively and show the higher TOC removal efficiency than other AOPs. Therefore, these two kinds of AOP can serve as the very viable AOP methods in the LSW reclamation for semiconductor.


1999 ◽  
Vol 34 (3) ◽  
pp. 505-518 ◽  
Author(s):  
T. Viraraghavan ◽  
K.R. Ramakrishna

Abstract Fly ash was investigated for its ability to adsorb dyes from aqueous solutions. Batch pH, kinetic and isotherm studies were performed on a laboratory scale with synthetic dye solutions made up of four different commercial grade dyes. Fly ash samples with differing compositions and particle sizes were employed to understand the effect of fly ash composition and particle size on their dye removal capacity. The first-order rate equation by Lagergren was tested on the kinetic data, and isotherm data was analyzed for possible agreement with the Langmuir and Freundlich adsorption isotherm equations. The removal capacity of fly ash for the different dyes was compared with that of granular activated carbon under identical conditions. Results showed that fly ash exhibited reasonably good dye removals for Basic Blue 9, Acid Blue 29 and Acid Red 91, while the removals by fly ash exceeded that of granular activated carbon for Disperse Red 1. Lime content in fly ash seemed to influence dye adsorption to a significant degree — better adsorption was observed at lower particle sizes because of the increased external surface area available for adsorption. Acid Blue 29 adsorption by fly ash provided the best fit for the Lagergren first-order plot. Because high pH and heavy metals (leached from fly ash) in the treated wastewater may exceed the limits set in municipal sewer-use bylaws, engineering and economic feasibility assessment should include these aspects when considering fly ash for colour removal.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1729-1729
Author(s):  
Anna Jonasova ◽  
Lubomir Minarik ◽  
Vojtech Kulvait ◽  
Michal Pesta ◽  
Adel Schaffartzikova ◽  
...  

Introduction: Myelodysplastic syndrome (MDS) is characterized by differentiation blockade, cytopenias with commontransfusion dependency and immune defects. Upon progression the myeloblasts accumulate and the patients become vulnerable to severe infection complications. Based on the Prague Charles University General Hospital registry (N=164, median age 73), the AZA therapy in higher-risk MDS patients results in median OS 13.8 Mo with ORR 48.5%. We also noted from our retrospective data that AZA-treated patients with higher G-CSF consumption had significantly reduced occurrence of Grade 4 neutropenias and longer OS (19 vs 16 Mo, p value 0.039). Rationale: To improve poor clinical outcomes we initiated a randomized open labeled academic trial that compares standard AZA therapy (A) with novel AZA-based therapy combination involving use of G-CSF added prior AZA (GA). Both AZA and also decitabine were preclinically shown to induce myeloid differentiation upon G-CSF preincubation. G-CSF binds its receptor in granulocytic precursors and neutrophils to stimulate their survival, proliferation, and differentiation via myeloid master regulator transcription factor and leukemia-suppressor PU.1. We also have previously shown that AZA increases PU.1. expression. Study design & Methods: GA/MDS-2013 (EudraCT No 2013-001639-38). Expected for enrollment are 134 patients, currently enrolled 53 patients (GA arm N=29, A arm N=24) with median age 74 years, M:F ratio 32:21 (GA 16:16, A 13:8),median IPSS-R 6, median follow up 11.2 Mo, median cycles of therapy 6. Diagnosis included:MDS (EB1, EB 2) with IPSS int-2/high (75%), MDS/AML<30% MB (22.5%), and CMML II (2.5%). Transplant candidates were excluded. Randomization is 2:1 for GA vs A arm. Primary endpoints: OS, PFS, time to AML transformation, ORR, infections & QoL. Secondary endpoints: biomarkers. Therapy schedule: 75mg/m2 of AZA 5-2-2, in GA: G-CSF s.c. injected 48 hrs before dose 1 and dose 6. G-CSF is measured in patient sera (prior therapy), myeloid surface markers are determined by flow cytometry (day -2, day 1, and day 9 of cycle 1). Genomic libraries from whole bone marrow are prepared by NEBNext Direct Kit involving 33 gene panel, sequencing runs are performed on Illumina platform. Statistics involved longitudinal multivariate data analysis including the joint models for the OS and response. Results: The presented data include 2.5 years since the beginning of the trial. Median survival for GA arm was 11 vs 6 Mo in the A arm. ORR (CR, CRm, PR, HI) was 56% in GA arm vs 33% in the A arm. Transformation to AML for both arms was comparable. The stratified longitudinal Cox proportional hazards model containing time-varying covariates together with the ordinal multilevel logistic mixed model were utilized. From this joint fitted model, a negative coefficient for the G-AZA treatment (significant p-value 0.0442) can be noticed in the case of the Cox Proportional Hazard part of the model. This means that G-AZA treatment improves patient survival. The estimated odds for the GA arm that responded to the therapy with remission rather than progression is 12.4x higher than for the A arm, controlling for the remaining patients' characteristics (p-value 0.0016).Both the GA and A arms are comparably tolerated. Data on serious infections and neutropenia gr4 were not yet available. The levels of G-CSF in sera prior the study in both arms (GA vs A) were comparable. Flow cytometry revealed G-CSF mediated upregulation of FCgRI (CD64) in the GA but not in the A arm. Multivariate analysis indicates the following: mutated genes: DNMT3A (p-value 0.0157), EZH2 (p-value 0.0091), TP53 (borderline p-value 0.0510), & CSF3R (p-value 0.0057) shorten the overall survival. The significant negative effects on response was noted for mutated EZH2 (p-value 0.0208) and CSF3R (p-value 0.0424) genes. Conclusions: The current results supported by different methods and statistics indicates a beneficial effect of G-CSF pre-treatment to standard AZA therapy in higher risk MDS patients. G-CSF pre-treatment to AZA increases OS and ORR. In addition, we identified biomarkers that are negatively associated with patient survival and response including EZH2, DNMT3A, TP53, & CSF3R. Grant Support: Ministry of Health, #16-27790A. Institutional resources: Progres Q49 & Q26, UNCE/MED/016, LQ1604, SVV 260374/2017, RVO-64165. Disclosures No relevant conflicts of interest to declare.


Objective: This study was carried out to determine the prevalence of microdontia among patients undergoing orthodontic treatment. Materials and Methods: This was a cross-sectional study conducted at Sindh Institute of Oral Health Sciences, (JSMU) from January-2020 to May-2020. Pre-treatment casts were taken of 140 subjects. The mesiodistal dimension of each tooth was recorded through the vernier caliper. Frequency and percentage were calculated for the presence of microdontia. The test applied was Pearson’s Chi-square test to assess the relationship between microdontia and variables like age and gender. P-value <0.05 was taken as statistically significant. Data analysis was performed on SPSS version 22. Results: A total of 140 subjects were selected i.e. 105 (75%) females and 35 (25%) males aged range 13 -30 years with mean age 18.29 ± 3.88. Out of 42, single tooth microdontia was found in 3 (7.1%), more than one tooth microdontia, and generalized microdontia was present in 36 (85.7%) and 3 (7.1%) respectively. Microdontia was found to be more common in the maxilla (n=42, 100%) than the mandible (n=14, 33.3%). It was found more common in females (n=37, 35.2%) as compared to males (n=5, 14.3%). Statistically significant relationship was found among gender and prevalence of microdontia (p=0.019) with a statistically insignificant relationship between age and presence of microdontia (p=0.228). Conclusions: Microdontia was found to be a frequent dental anomaly, was more common in maxilla and females with a significant association with gender.


2018 ◽  
Vol 44 ◽  
pp. 00072
Author(s):  
Małgorzata Komorowska-Kaufman ◽  
Filip Ciesielczyk ◽  
Alina Pruss ◽  
Teofil Jesionowski

The paper presents the results of analyzes of the granulometric composition of suspended solids in backwash water from biological activated carbon (BAC) filters and its changes during sedimentation. Backwash water samples were taken during backwashing of two pilot filters after different filtration time. It was found that regardless of the concentration of suspended solids in the collected backwash water, particle sizes vs. their percentage volume contributions for all samples were similar. Particle sizes were in the range of 2–100 μm. However, the two-hour sedimentation for most of the samples proved to be effective (total suspended solids removal up to 93%), which is caused by self-coagulation of the sample.


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