BRCA 1/BRCA 2 Pathogenic/Likely Pathogenic Variant Patients with Breast, Ovarian, and Other Cancers

The demographic and clinical characteristics of patients who have BRCA 1/BRCA 2 pathogenic/likely pathogenic variants may differ from their relatives who had BRCA-related cancer. In this study, we aimed to demonstrate the clinical and demographic findings of patients who had BRCA-related cancer and to assess the differences comparing their relatives who had BRCA-related cancer with breast, genital tract, prostate, and pancreas cancers as well. The results of sequencing analysis of 200 cancer patients (190 women, 10 men) who have been directed to genetic counseling with an indication of BRCA1/BRCA2 testing from different regions across 9 medical oncology centers were retrospectively analyzed. A total of 200 consecutive cancer patients who harbored the BRCA1/BRCA2 pathogenic/likely pathogenic variant (130 (65%) patients harbored BRCA 1 pathogenic/likely pathogenic variant, and 70 harbored BRCA 2 pathogenic/likely pathogenic variant) were included. Of these, 64.0% had breast cancer (43.8% of them had the triple-negative disease, and about 2.3% had only the HER-2 mutant), 31.5% had genital cancers (92.1% of them had ovarian cancer, 3.2% had endometrium, and 1.6% had peritoneum cancer as the primary site and mostly serous adenocarcinoma was the most common histopathology and 14.3% of the patients had endometrioid adenocarcinoma), 3.5% had prostate (median time from metastasis to castration-resistant status was 28 months) and 1.0% had pancreas cancer. Newly diagnosed cancer (breast and ovary) patients who had BRCA 1/BRCA 2 pathogenic/ likely pathogenic variant were younger than their previous cancer diagnosed (breast, ovary, and pancreas) parents who harbored BRCA pathogenic/likely pathogenic variant. We suggest that the genetic screening of BRCA 1/ BRCA 2 pathogenic/likely pathogenic variant is needed as a routine screening for those with a personal or family history of breast, ovarian, tubal, or peritoneal cancer. In addition, once BRCA 1 or BRCA 2 germline pathogenic variant has been identified in a family, testing of at-risk next-generation relatives earlier can identify those family members who also have the familial pathogenic variant, and thus need increased surveillance.

Concordance between quantitative and semi-quantitative analysis of Tc-99m-pyrophosphate scintigraphy for the diagnosis of transthyretin cardiac amyloidosis in patients with HFpEF

Background

Transthyretin (TTR) cardiac amyloidosis (CA) is an underdiagnosed cause of heart failure with preserved ejection fraction (HFpEF). Cardiac scintigraphy with 99mTechnetium-pyrophosphate (99mTc-PYP) is referred as a simple, non-invasive and reliable method in the diagnosis of TTR-CA. American Society of Nuclear Cardiology Practice Points recommends two interpretative approaches: the quantitative heart-to-contralateral lung ratio (H/CL) at 1 hour or the semi-quantitative visual assessment at 3 hours after radiotracer injection.

Purpose

In this study, we evaluated the concordance between semi-quantitative and quantitative approaches in the diagnosis of TTR CA in patients with HFpEF.

Methods

This single-center, prospective study included 78 patients who had a diagnosis of HFpEF according to 2016 ESC HF guidelines. 99mTc-PYP cardiac scintigraphy was performed in 43 patients who have ≥2 red flags for TTR-CA including left ventricular hypertrophy (LVH) (wall thickness ≥12 mm), biventricular hypertrophy, sparkling pattern, reduction in longitudinal strain with apical sparing, thickening of the interatrial septum (>6mm), low-voltage, pseudo infarct pattern or atrioventricular block on ECG. In the absence of monoclonal protein in the serum and urine, Grade 2 to 3 myocardial uptake in semi-quantitative analysis at 3 hours or a H/CL ratio of ≥1.5 in quantitative analysis at 1 hour post injection of 99mTc-PYP is considered positive for TTR-CA. Grade 2–3 uptake with a H/CL ratio ≥1.5 or Grade 0–1 uptake with a H/CL ratio <1.5 were considered as concordant results. Grade 2–3 uptake with a H/CL ratio <1.5 or Grade 0–1 uptake with a H/CL ratio ≥1.5 were considered as discordant results.

Results

Mean age of study population was 68.26±9.97 years. 17 (39.5%) of 43 patients who underwent 99mTc-PYP cardiac scintigraphy showed a Grade 2 or 3 cardiac uptake and in these patients with Grade 2–3 uptake, 11 patients (65%) had a H/CL ratio ≥1.5 (concordant results) and 6 patients (35%) had a H/CL ratio <1.5 (discordant results). 26 (60.5%) of 43 patients showed Grade 0–1 cardiac uptake. All patients (100%) with Grade 0–1 uptake had a H/CL ratio <1.5 and therefore, showed concordant results. Overall, 37 (86%) patients had concordant and 6 (14%) patients had discordant results (Table 1).

Conclusion

The results of this study showed that although there was a high agreement between semi-quantitative and quantitative analysis of 99mTc-PYP cardiac scintigraphy, 14% of patients have discordant results and need further workup to confirm TTR-CA in patients with HFpEF.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Pfizer independent grant.

The impact of hydroxychloroquine and azithromycin on the corrected qt interval in patients with the novel coronavirus disease 2019

Funding Acknowledgements

Type of funding sources: None.

Background

Although long-term use of HCQ and AZT has been reported to cause QT prolongation and malign arrhythmia, there is not enough data about the effect of short-term use on arrhythmia. Purpose: The aim of this study was to assess the effect of HCQ alone and HCQ + AZT on corrected QT (QTc).Methods: A baseline ECG and on-treatment ECGs were retrospectively collected in COVID-19 patients who received HCQ and/or AZT. Also peak QTc intervals of monotherapy and combination therapy was compared. Results: Of the 155 patients included, 102 (65.8%) were using HCQ, 53 (34.2%) were using HCQ + AZT combination. The use of both HCQ alone and HCQ + AZT combined therapy significantly prolonged the QTc and the QTc interval was significantly longer in patients received combination therapy. QTc prolongation caused early termination in both groups, 5 (4.9%) patients in the monotherapy group and in 6 (11.3%) patients in the combined therapy group.Conclusion: Patients who received HCQ for COVID-19 were at high risk of QTc prolongation, and concurrent treatment with AZT was associated with greater changes in QTc.

Potantial clinical application of potassium binders in patients with chronic heart failure in real life clinical practice: results from TREAT HF study

Purpose

Hyperkalemia is increasingly prevalent and life-threatening condition in heart failure (HF). In clinical practice, hyperkalemia is also an important barrier to optimal application of RAASi. New potassium binders, sodium zirconium cyclosilicate and patiromer, were developed for the treatment of hyperkalemia. TREAT HF data were analyzed for the evaluation of potential clinical application of potassium binders in real life clinical care in HF patients.

Methods

TREAT HF is a network which undertakes multicenter, national, observational studies designed to evaluate HF patients' clinical characteristics and current treatment modalities. 1028 patients with the diagnosis of chronic HF, median age 64 years and median LVEF 30% who had potassium and GFR data were included in this analysis. In this patient population, 847 patients (82.6%) were receiving beta blockers, 739 (71.9%) were receiving ACE inhibitors or ARBs and 518 (50.4%) were receiving MRA. Patients with hyperkalemia (serum potassium ≥5.1 mEq/L) were considered candidate for potassium binders based on the criteria of HARMONIZE study. According to eGFR (mL/min) level, renal dysfunction was subclassified as: stage-1 (eGFR ≥90) (n=211), stage-2 (eGFR 60-<90) (n=398), stage-3 (eGFR 30-<60) (n=306) and stage 4–5 (eGFR <30) (n=113).

Results

In study population, median potassium level was 4.5 mEq/L, median creatinin level was 1.1 mg/dL and median eGFR was 65.5 mL/min. Overall, 82.9% of patients had normal serum potassium levels (≥3.5–5 mEq/l) and 14.3% of patients (n=147) were found to have hyperkalemia (≥5.1 mEq/L) and, hypokalemia was found in 2.8% of patients (n=30). Hyperkalemia was present in 10.9% (n=23) of patients with stage-1, 12.6% (n=50) of patients with stage-2, 17.0% (n=52) of patients with stage-3 and 19.5% (n=22) of patients with stage 4–5 renal dysfunction. In patients with eGFR <60 ml/min (n=419), hyperkalemia was much more prevalent than those with eGFR ≥60 ml/min (n=609) (17.6% and 11.9% respectively, p=0.011). In patients with stage 4–5 renal dysfunction who were receiving ACEI/ARB or combination of ACEI/ARB and MRA (RAASi), more patients had hyperkalemia than those not receiving RAASi therapy (23.4%, 20.0% and 12.5%, respectively).

Conclusions

This study suggested that in real life clinical practice, 14.3% of HF patients have hyperkalemia and seem to be eligible for the treatment of potassium binders. The risk of hyperkalemia increases with advanced stages of renal dysfunction and the use of RAASi, showing an increased clinical need for potassium binders in HF patients with renal dysfunction and in those receiving RAASi.

Funding Acknowledgement

Type of funding source: None

Regenerating islet-derived 1α (REG-1α) protein increases tau phosphorylation in cell and animal models of tauopathies

REG-1α, a secreted protein containing a C-type lectin domain, is expressed in various organs and plays different roles in digestive system cells in physiological and pathological conditions. Like other members of the Reg family, REG-1α is expressed also in the brain where it has different functions. For instance, we previously reported that REG-1α regulates neurite outgrowth and is overexpressed during the very early stages of Alzheimer's disease (AD). However, REG-1α function in neural cells during neural degeneration remains unknown. First, REG-1α and phosphorylated tau expression were assessed in tissue sections from the hippocampus, representing neurofibrillary tangles (NFTs), from patients with AD, and from basal ganglia, representing subcortical NFTs, from patients with progressive supranuclear palsy (PSP). We found an association between REG-1α expression, tau hyperphosphorylation and NFTs in human brain samples from patients with these neurodegenerative diseases. Then, the effects of REG-1α overexpression on tau phosphorylation and axonal morphology were investigated i) in primary cultures of rat neurons that express human tau P301L and ii) in a transgenic zebrafish model of tauopathy that expresses human tau P301L. In the tau P301L cell model, REG-1α overexpression increased tau phosphorylation at the S202/T205 and S396 residues (early and late stages of abnormal phosphorylation, respectively) through the AKT/GSK3-β pathway. This effect was associated with axonal defects both in tau P301L-expressing rat neurons and zebrafish embryos. Our findings suggest a functional role for REG-1α during tauopathy development and progression and, specifically, its involvement in the modification of tau phosphorylation temporal sequence.

The effect of thrombolytic therapy on QT dispersion in acute myocardial infarction and its role in the prediction of reperfusion arrhythmias

PURPOSE

We aimed to determine the effect of intravenous thrombolytic therapy on QT dispersion (QTd) and its role in the prediction of reperfusion arrhythmias.

MATERIALS AND METHODS

Twenty patients with acute myocardial infarction (MI) were enrolled in the study. Measurements of QTd were carried out prior to thrombolytic therapy and before discharge. The patients were examined for ventricular arrhythmias with 24-h Holter electrocardiography monitoring after treatment and the relationship between ventricular arrhythmias and the QTd values in the early phase of MI was investigated.

RESULTS

The values of QTd were significantly higher during the early phase of MI (60 ± 5.32 ms) than those in the late phase (53.35 ± 4.07 ms) (P = 0.032). There was no correlation between isolated, bigeminal, trigeminal and total ventricular premature beats, accelerated idioventricular rhythm (AIVR) with QTd values. However, the patients with sustained ventricular tachycardia (VT), prolonged VT and sustained AIVR had higher corrected QTd (92 ms 1/2 , 97.8 ms 1/2 , 81.7 ms 1/2 , respectively) than the patients without these arrhythmias (74 ms 1/2 , 56.3 ms 1/2 , 58.28 ms 1/2 , respectively) (P = 0.022, 0.013, 0.018).

CONCLUSION

The values of QTd may be significantly reduced in the 1 st week of acute MI and measurement of QTd in the early phase of MI may have a correlation with the following reperfusion arrhythmias: Sustained VT, prolonged VT and AIVR.

Accuracy of CBCT images in the assessment of buccal marginal alveolar peri-implant defects: effect of field of view

OBJECTIVES

To investigate the reliability and accuracy of cone beam CT (CBCT) images obtained at different fields of view in detecting and quantifying simulated buccal marginal alveolar peri-implant defects.

METHODS

Simulated buccal defects were prepared in 69 implants inserted into cadaver mandibles. CBCT images at three different fields of view were acquired: 40 × 40, 60 × 60 and 100 × 100 mm. The presence or absence of defects was assessed on three sets of images using a five-point scale by three observers. Observers also measured the depth, width and volume of defects on CBCT images, which were compared with physical measurements. The kappa value was calculated to assess intra- and interobserver agreement. Six-way repeated analysis of variance was used to evaluate treatment effects on the diagnosis. Pairwise comparisons of median true-positive and true-negative rates were calculated by the χ² test. Pearson's correlation coefficient was used to determine the relationship between measurements. Significance level was set as p < 0.05.

RESULTS

All observers had excellent intra-observer agreement. Defect status (p < 0.001) and defect size (p < 0.001) factors were statistically significant. Pairwise interactions were found between defect status and defect size (p = 0.001). No differences between median true-positive or true-negative values were found between CBCT field of views (p > 0.05). Significant correlations were found between physical and CBCT measurements (p < 0.001).

CONCLUSIONS

All CBCT images performed similarly for the detection of simulated buccal marginal alveolar peri-implant defects. Depth, width and volume measurements of the defects from various CBCT images correlated highly with physical measurements.

Quantitative phosphoproteomics unravels biased phosphorylation of serotonin 2A receptor at Ser280 by hallucinogenic versus nonhallucinogenic agonists

The serotonin 5-HT_2A receptor is a primary target of psychedelic hallucinogens such as lysergic acid diethylamine, mescaline, and psilocybin, which reproduce some of the core symptoms of schizophrenia. An incompletely resolved paradox is that only some 5-HT_2A receptor agonists exhibit hallucinogenic activity, whereas structurally related agonists with comparable affinity and activity lack such a psychoactive activity. Using a strategy combining stable isotope labeling by amino acids in cell culture with enrichment in phosphorylated peptides by means of hydrophilic interaction liquid chromatography followed by immobilized metal affinity chromatography, we compared the phosphoproteome in HEK-293 cells transiently expressing the 5-HT_2A receptor and exposed to either vehicle or the synthetic hallucinogen 1-[2,5-dimethoxy-4-iodophenyl]-2-aminopropane (DOI) or the nonhallucinogenic 5-HT_2A agonist lisuride. Among the 5995 identified phosphorylated peptides, 16 sites were differentially phosphorylated upon exposure of cells to DOI versus lisuride. These include a serine (Ser²⁸⁰) located in the third intracellular loop of the 5-HT_2A receptor, a region important for its desensitization. The specific phosphorylation of Ser²⁸⁰ by hallucinogens was further validated by quantitative mass spectrometry analysis of immunopurified receptor digests and by Western blotting using a phosphosite specific antibody. The administration of DOI, but not of lisuride, to mice, enhanced the phosphorylation of 5-HT_2A receptors at Ser²⁸⁰ in the prefrontal cortex. Moreover, hallucinogens induced a less pronounced desensitization of receptor-operated signaling in HEK-293 cells and neurons than did nonhallucinogenic agonists. The mutation of Ser²⁸⁰ to aspartic acid (to mimic phosphorylation) reduced receptor desensitization by nonhallucinogenic agonists, whereas its mutation to alanine increased the ability of hallucinogens to desensitize the receptor. This study reveals a biased phosphorylation of the 5-HT_2A receptor in response to hallucinogenic versus nonhallucinogenic agonists, which underlies their distinct capacity to desensitize the receptor.

Assessment of buccal marginal alveolar peri-implant and periodontal defects using a cone beam CT system with and without the application of metal artefact reduction mode

OBJECTIVES

To investigate the accuracy of cone beam CT (CBCT) images obtained with and without artefact reduction (AR) in detecting simulated buccal peri-implant and buccal periodontal defects.

METHODS

42 implants inserted into edentulous mandibles, and 38 teeth present in dry mandibles were used. Simulated buccal peri-implant defects (n = 22) and buccal periodontal defects (n = 22) were prepared. 20 implants and 18 teeth without simulated defects were the control group. Images of the mandibles were obtained using a Planmeca ProMax(®) 3D Max CBCT unit (Planmeca Oy, Helsinki, Finland). Image reconstructions were prepared without and with low, medium and high AR modes. Images were viewed randomly by six observers twice for the presence of defects. Kappa coefficient was calculated. F2_LD_F1 design for non-parametric analysis of longitudinal data was used. Area under curves (AUCs) were calculated for each observer. Significance level was taken as α = 0.05.

RESULTS

Intraobserver kappa ranged from 0.140 to 0.792 for peri-implant and from 0.189 to 1.0 for periodontal defects. All factors were statistically significant (p < 0.001), except for image mode and implant brand. Pairwise interactions were found between periodontal defects and peri-implant defects (p < 0.001), observers (p < 0.001), observer and image mode (p < 0.001), defect model and observer (p < 0.001) and defect model, image mode and observer (p = 0.04). AUC values ranged from 0.39 to 0.52 for peri-implant and from 0.45 to 0.71 for periodontal defects. Higher AUC values were found for periodontal defects than for peri-implant defects.

CONCLUSIONS

Buccal peri-implant defects were more difficult to detect than buccal periodontal defects. No difference was found among CBCT images obtained with and without AR modes.

Evaluation of erectile dysfunction in permanent pacemaker implanted patients with cardiac rhythm disorder prediagnosis

Background and aims

To evaluate the anxiety, depression and related psychogenic erectile dysfunction that might be developed before and after pacemaker implantation in patients with cardiac arrhythmias.

Material and methods

Thirty permanent pacemaker implanted male patients, were enrolled to study between September 2006 and September 2008. Erectile function domain questions of International Index of Erectile Function (IIEF‐6) and Hospital Anxiety and Depression Scale (HAD) questionnaires were applied to patients, 6 months before pacemaker implantation (BP6) and on month 1 (AP1) and 6 after application (AP6). Patients were included in a multidisciplinary cardiac rehabilitation-adaptation program with a duration of 1–2 months. Patients were evaluated in subgroups.

Results

Mean age was 51.5 ± 10.3. Most frequent diagnosis was observed as AV block in etiology. The mean IIEF values were changed 22.8→20.2→24.6 in BP6, AP1 and AP6 time frames consecutively. However, the mean HAD-Anxiety scores were evaluated as 8.1→17.0→7.3 and the mean HAD-Depression as 3.9→7.9→8.9 consecutively in the same time frames.

Conclusion

Cardiac arrhythmia plus permanent pacemaker implantation, increased anxiety and depression of patients and decreased erectile function at AP1; however, the improvement in cardiac symptoms at AP6 with the possible positive effects of rehabilitation program, helps to reduce anxiety and increased IIEF scores, although there was still a slight increase in depression levels.

Visibility of Artificial Buccal Recurrent Caries Under Restorations Using Different Radiographic Techniques

The aim of the present study was to assess intraoral images and two cone beam computed tomography (CBCT) systems for detection of artificial buccal recurrent caries under restorations. Class V cavities were made for composite (30 teeth) and amalgam (30 teeth). Full restorations with thermoplastic polymer (30 teeth) and nickel-chromium metal crown (30 teeth) were constructed. In 60 teeth, artificial buccal recurrent caries were simulated; 60 other teeth served as controls. Intraoral film, intraoral digital, Veraviewepocs 3D, and Kodak 9000 images were scored twice. κ Coefficients were calculated and Az values were compared using Z-tests, with a significance level of α=0.05. Higher interobserver agreement was obtained from the CBCT images compared with the intraoral images. The Az values of both readings of all three observers were highest for the Veraviewepocs 3D followed by Kodak 9000 except for the second reading of the third observer. CBCT outperformed intraoral radiography in detection of artificial buccal recurrent caries under restorations.

Radiographic detection of artificially created horizontal root fracture using different cone beam CT units with small fields of view

OBJECTIVES

To compare limited cone beam computerized tomography (CBCT) units with different field of views (FOVs) and voxel sizes in detecting artificially created horizontal root fracture (HRF) in extracted human teeth.

METHODS

Artificial HRF was created in the horizontal plane in 40 teeth. Another 40 intact teeth served as a control group. 80 teeth were placed in the respective maxillary anterior sockets of a human dry skull in groups. Six image sets were obtained: (1) Accuitomo 170, 40 × 40 mm FOV (0.080 mm(3)); (2) Accuitomo 170, 60 × 60 mm FOV (0.125 mm(3)); (3) Kodak 9000, 50 × 37 mm FOV (0.076 mm(3)); (4) Kodak 9000, 50 × 37 mm FOV (0.100 mm(3)); (5) Vatech Pax-Duo3D 50 × 50 mm FOV (0.080 mm(3)) and (6) Vatech Pax-Duo3D 85 × 85 mm FOV (0.120 mm(3)). Images were evaluated twice by five observers. Kappa values were calculated for observer agreement. Areas under the receiver operating characteristic (ROC) curves (Az values) were calculated, and the Az values for each image type were compared using t-tests (α = 0.05).

RESULTS

Intraobserver kappa coefficients ranged from 0.81 to 0.95 for the Accuitomo 170 images, from 0.80 to 0.92 for the Kodak 9000 images and from 0.76 to 0.95 for Vatech PanX-Duo3D. The Az values for different image types and observers ranged from 0.93 to 0.97 for Accuitomo 170 images, from 0.93 to 0.98 for Kodak 9000 images and from 0.93 to 0.97 for the Vatech PanX-Duo3D images. No statistically significant differences (p > 0.05) were found between the Az values.

CONCLUSIONS

Limited CBCT units performed similarly in detecting simulated HRF.

Proximal caries detection accuracy using intraoral bitewing radiography, extraoral bitewing radiography and panoramic radiography

OBJECTIVE

To compare proximal caries detection using intraoral bitewing, extraoral bitewing and panoramic radiography.

METHODS

80 extracted human premolar and molar teeth with and without proximal caries were used. Intraoral radiographs were taken with Kodak Insight film (Eastman Kodak Co., Rochester, NY) using the bitewing technique. Extraoral bitewing and panoramic images were obtained using a Planmeca Promax Digital Panoramic X-ray unit (Planmeca Inc., Helsinki, Finland). Images were evaluated by three observers twice. In total, 160 proximal surfaces were assessed. Intra- and interobserver kappa coefficients were calculated. Scores obtained from the three techniques were compared with the histological gold standard using receiver operating characteristic analysis. Az values for each image type, observer and reading were compared using z-tests, with a significance level of α = 0.05.

RESULTS

Kappa coefficients ranged from 0.883 to 0.963 for the intraoral bitewing, from 0.715 to 0.893 for the extraoral bitewing, and from 0.659 to 0.884 for the panoramic radiography. Interobserver agreements for the first and second readings for the intraoral bitewing images were between 0.717 and 0.780, the extraoral bitewing readings were between 0.569 and 0.707, and the panoramic images were between 0.477 and 0.740. The Az values for both readings of all three observers were highest for the intraoral bitewing. Az values for the extraoral bitewing images were higher than those of the panoramic images without statistical significance (p > 0.05).

CONCLUSION

Intraoral bitewing radiography was superior to extraoral bitewing and panoramic radiography in diagnosing proximal caries of premolar and molar teeth ex vivo. Similar intra- and interobserver coefficients were calculated for extraoral bitewing and panoramic radiography.

Performance evaluation of SBR treatment for nitrogen removal from tannery wastewater

Performance of SBR treatment for nitrogen removal from tannery is evaluated for a wide range of wastewater temperature between 7 and 30 degrees C. A pilot-scale SBR unit fed with plain-settled wastewater is operated on site for this purpose. Effective nitrogen removal is sustained by adjustment of the sludge age from 28 to 5 days. Concentration profiles of nitrogen compounds within a selected complete SBR cycle during the steady state operation at different wastewater temperatures and sludge ages are evaluated by model simulation. System performance is also interpreted in terms of modeling and stoichiometric calculation. Additional nitrate loss was observed during aerobic period when the aeration intensity was reduced by the factor of 50%.

Effect of temperature on the nitrogen removal performance of a sequencing batch reactor treating tannery wastewater

The effect of temperature on the nitrogen removal performance of the sequencing batch reactor technology is evaluated for tannery wastewater. The study involved the operation of a pilot-scale sequencing batch reactor installed on site to treat the plain-settled effluent. The nitrogen balance of the system is observed for a wide temperature range between 9 to 30 degrees C. The results are evaluated by means of model calibration of COD, nitrate and ammonia nitrogen concentration profiles during cyclic operation. The fates of the major nitrogen parameters are also interpreted on the basis of fundamental stoichiometry for nitrification and denitrification.

Sequencing batch reactor treatment of tannery wastewater for carbon and nitrogen removal

The paper evaluates the organic carbon and nitrogen removal performance of the sequencing batch reactor (SBR), technology for tannery wastewater. For this purpose, a pilot-scale SBR was installed on site to treat the plain-sealed tannery effluent. The study involved wastewater characterization, start-up and operation of the reactor for carbon and nitrogen removal and model evaluation of system performance. Its removal efficiency was compared with that of the existing continuous-flow activated sludge system providing full treatment to wastewater from the Istanbul Tannery Organized Industrial District.