Optimization of the Sunset Yellow Dye removal by electrocoagulation using response surface method

In recent years, among the various treatment methods, the electrocoagulation process has been used for the treatment of effluents containing various dye pollutants. Sunset yellow (S.Y.) azo dye is one of the common food colors widely used in various food industries. This study investigated the removal of the dye S.Y. from aqueous media by the electrocoagulation method in an electrochemical reactor using concentric iron electrodes. The experiments were designed by the Response Surface Method (RSM) with the help of the Minitab software in such a way that the effect of various process-influencing parameters, such as current density, electrolysis time, electrolyte concentration, pH of the solution, and the effluent flow rate, on the desired pollutant removal efficiency was investigated. According to the results of the process optimization by RSM, the optimal conditions for the process were obtained as follows: pH of 10, current density of 2.65 mA/cm2, electrolysis time of 42.32 min, initial dye concentration of 20 mg/L, and effluent flow rate of 2.5 L/min. Under the above optimal conditions, the efficiency of dye removal was more than 99%.

Acclimatization studies for degradation of Acid Red 3BN dye and its treatment in moving bed biofilm reactor

In this study, acclimatization of microorganisms for the degradation of Acid Red 3BN dye bearing water (AR3BNDW) using activated sludge was performed in a cylindrical aerobic reactor. The initial value of chemical oxygen demand (COD), dye, and mixed liquor suspended solids (MLSS) of activated sludge were evaluated as 870.5, 80.6 and 1200 mg/L The experiments were performed at ambient temperature (25–35 °C) and the stabilization was achieved at 15 d. Maximum reduction of chemical oxygen demand (COD) and color were observed to be 94.2%, and 91% after 15 d of acclimatization. After completion of acclimatization process, degradation of dye was studied in moving bed biofilm reactor (MBBR). In the process, 38, 50, 68 and 76% color reduction were achieved with polymer carrier fill ratio (FR) of 40, 50, 60 and 70%, respectively in 24 h. For effluent flow rate of 180, 240, 300 and 360 mL/h, respectively, the dye reductions of 76, 60, 48 and 36% and COD reductions of 72, 58, 46 and 34% were achieved in 24 h

Regional Citrate Anticoagulation Protocol For Patients With Presumed Absent Citrate Metabolism

Background: Regional citrate anticoagulation (RCA) is not recommended in patients with shock or severe liver failure. We designed a protocol with personalized pre-calculated flow settings for patients with absent citrate metabolism that abrogates risk of citrate toxicity, maintains neutral CKRT circuit calcium mass balance and normal systemic ionized calcium levels. Methods: Single center prospective cohort study of patients in five Adult Intensive Care Units triaged to the CVVHDF-RCA "Shock" protocol. Results: Of 31 patients included in the study, 30 (97%) had acute kidney injury, 16 (52%) had acute liver failure, and 5 (16%) had cirrhosis at the start of CKRT. The median (interquartile range (IQR)) lactate was 5 (3.2 to 10.7), AST 822 (122 to 2950), ALT 352 (41 to 2238), total bilirubin 2.7 (1.0 to 5.1), INR 2 (1.5 to 2.6). The median first hemofilter life censored for causes other than clotting exceeded 70 hours. The cumulative incidence of hypernatremia (Na >148 mM), metabolic alkalosis (HCO3- >30 mM) and hypophosphatemia (P< 2 mg/dL) were 1/26 (4%), 0/30 (0%), 1/30 (3%) respectively and were not clinically significant. Mild hypocalcemia occurred in the first 4 hours in 2/31 patients and corrected by hour 6 with no additional Ca-supplementation beyond the per-protocol administered Ca-infusion. The maximum systemic total Ca (tCa; mM)/ionized Ca (iCa; mM) ratio never exceeded 2.5. Conclusions: The "Shock" protocol can be used without contra-indications and is effective in maintaining circuit patency with a high, fixed ACDA infusion rate to blood flow ratio. Keeping single-pass citrate extraction on the dialyzer >0.75 minimizes the risk of citrate toxicity even in patients with absent citrate metabolism. Pre-calculated, personalized dosing of the initial Ca-infusion rate from a table based on the patient's albumin level and the filter effluent flow rate maintains neutral CKRT circuit calcium mass balance and a normal systemic iCa level.

Extracorporeal Ammonia Clearance for Hyperammonemia in Critically Ill Patients: A Scoping Review

<b><i>Introduction:</i></b> Hyperammonemia is a life-threatening condition. However, clearance of ammonia via extracorporeal treatment has not been systematically evaluated. <b><i>Methods:</i></b> We searched EMBASE and MEDLINE databases. We included all publications reporting ammonia clearance by extracorporeal treatment in adult and pediatric patients with clearance estimated by direct dialysate ammonia measurement or calculated by formula. Two reviewers screened and extracted data independently. <b><i>Results:</i></b> We found 1,770 articles with 312 appropriate for assessment and 28 studies meeting eligibility criteria. Most of the studies were case reports. Hyperammonemia was typically secondary to inborn errors of metabolisms in children and to liver failure in adult patients. Ammonia clearance was most commonly reported during continuous renal replacement therapy (CRRT) and appeared to vary markedly from &#x3c;5 mL/min/m² to &#x3e;250 mL/min/m². When measured during intermittent hemodialysis (IHD), clearance was highest and correlated with blood flow rate (<i>R</i>² = 0.853; <i>p</i> &#x3c; 0.001). When measured during CRRT, ammonia clearance could be substantial and correlated with effluent flow rate (EFR; <i>R</i>² = 0.584; <i>p</i> &#x3c; 0.001). Neither correlated with ammonia reduction. Peritoneal dialysis (PD) achieved minimal clearance, and other extracorporeal techniques were rarely studied. <b><i>Conclusions:</i></b> Extracorporeal ammonia clearance varies widely with sometimes implausible values. Treatment modality, blood flow, and EFR, however, appear to affect such clearance with IHD achieving the highest values, PD achieving minimal values, and CRRT achieving substantial values especially at high EFRs. The role of other techniques remains unclear. These findings can help inform practice and future studies.

Water reuse potential for irrigation in Brazilian hydrographic regions

The present paper carried out an evaluation of the reuse potential of the Wastewater Treatment Plants (WWTPs) effluents for irrigation in the 12 Brazilian Hydrographic Regions (BHRs). For this purpose, initially, the WWTPs were categorized and the effluent flow rate was estimated. Category 1 represents secondary effluent with an efficiency of organic matter removal greater than 80%; Category 2 represents effluent that underwent some disinfection step; and effluents that perform less than the other categories were called ‘Uncategorized’. After that, the irrigation water demands for each BHRs were compiled, and finally, the production of water for reutilization was compared with the demand for irrigation. Thus, it was observed that all the sewage flow rates generated in Brazil classified in Categories 1 and 2 represent 9% of the total irrigation water demand in the country (1,078.71 m3/s) and it stands out that only 7% of the flows treated in Brazil undergo a tertiary treatment step.

Ceftolozane/tazobactam exposure in critically ill patients undergoing continuous renal replacement therapy: a PK/PD approach to tailor dosing

Objectives To investigate the influence of continuous renal replacement therapy (CRRT) intensity on the clearance of ceftolozane/tazobactam in critical care patients, and to evaluate if the reported doses would achieve an optimal pharmacokinetic/pharmacodynamic (PK/PD) target against Pseudomonas aeruginosa exhibiting different MICs. Methods The MEDLINE–PubMed database was searched from inception to January 2020 to retrieve observational studies or case reports investigating the PK behaviour of ceftolozane/tazobactam during CRRT. Relevant CRRT settings and PK variables were extracted, and the influence of CRRT intensity on ceftolozane/tazobactam total clearance (CLtot) was determined by simple linear regression. The optimal PK/PD target for the reported doses was deemed to be achieved when ceftolozane trough concentrations (Cmin) were above the MIC (less intensive target) or four times the MIC (intensive target) for P. aeruginosa. Results Data from six studies including 11 patients (mean age 56.6 years) were analysed. Mean blood flow rate and effluent flow rate were 161.8 mL/min and 2383.4 mL/h, respectively. Ceftolozane Cmin ranged from 25.8 to 79.4 mg/L. A significant correlation was found for ceftolozane CLtot and effluent flow rate (P = 0.027). The intensive PK/PD target was achieved by 100% and 50% of the reported doses for MIC, respectively, up to 4 and 8 mg/L. Conclusions A significant correlation between effluent flow rate and ceftolozane clearance during CRRT could be identified. Higher dosing regimens coupled with continuous/extended infusion may be required in the case of higher CRRT intensity, deep-seated infections or poorly susceptible isolates. Larger studies assessing ceftolozane PK in different CRRT settings are warranted.

Analytical Method Development and Stability Studies for Estimation of Oseltamivir In Bulk and Capsules Using RPHPLC

A simple and reproducible method of isocratic reverse phase liquid chromatography (RP-LC) was developed for the quantitative determination of oseltamivir phosphate in bulk drug and capsules, used to treat antiviral (influenza). The proposed RP-HPLC method uses X terra C18, 4.6 mm, 150 mm 4.6 mm i.d. column (at room temperature), using 0.1% octa-sulfonic acid: acetonitrile 30: 70 v / v, effluent flow rate (1.0 ml / min) and UV detection at 237 nm for oseltamivir analysis. The method was validated according to the ICH guidelines in terms of specificity, linearity, precision and accuracy. The retention time for oseltamivir was 2.31 min. The recovery determinations allowed the calculation of a confidence interval from 99.79 to 101.30% with a relative standard deviation value of 0.5%. LOD and LOQ were estimated at 2.98 and 9.98 µg/mL respectively. The validated method was successfully applied to the determination of oseltamivir in dosage form in capsules (Tamiflu 75 mg, Roche). Oseltamivir was exposed to conditions of acid, basic, oxidative and thermal stress and the stressed samples were analyzed with the proposed method. The chromatographic peak purity results indicated the absence of elution peaks with the main oseltamivir peak, which demonstrated the specificity of the test method for estimating oseltamivir in the presence of degradation products. This method has advantages that include a short execution time, a simple and rapid sample preparation which makes this method used for routine oseltamivir analysis in quality control laboratories.

A Methodology for the Estimation of Microplastic Concentration in Relation to the Meteorological Forcing and WWTPs Effluents in Urban Coastal Areas

The study of the urban coastline is of great significance for understanding the impacts of human activities on the marine environment. Only recently the emission of microplastics is starting to be considered as a threat to aquatic and terrestrial ecosystems and currently, little information on this topic is available. The present study focuses on the development of a methodology based on the implementation of the hydrodynamic circulation model ELCOM (Estuary and Lake Computer Model) for the estimation of microplastics distribution in Kavala Gulf coastline. The approach aims to include the effects of the high seasonal touristic activity and consequent large fluctuations in wastewater treatment plants (WWTPs) discharge rates. Parameters such as microplastic concentration, effluent flow rate and temperature, meteorological forcing and scalars at the boundaries were applied and the simulation was designed to cover the entire 2006 in order to include an approximation of the seasonal 3D dispersion patterns. The microplastic concentration was estimated based on the suspended particulate matter (SPM) concentration measurements applying the approach of [1]. The physical and chemical parameters of the particles were assumed to conform with the assumptions of [2]. The results showed a strong correlation between the microplastics dispersion patterns, the wind climate and the seasonal increase in population during the summer. Microplastic concentrations reached up to 0.185 μg/l in the WWTPs adjacent coastline in correspondence to the beaches with the highest touristic activity. The periodical formation of anticyclonic flows resulted in a net transport towards the center of the gulf and an increase in microplastic concentration in the bottom layer. On the other hand, the simulation showed that considerable quantities of microplastics tend to be transported outside the study area and far from the coastline in deeper waters.

Utilization of Hydroturbines in Wastewater Treatment Plants

Wastewater treatment plants (WWTPs) are a significant energy consumer, yet there are several opportunities for implementing on-site power generation systems. Within the treatment process, the high flow rate of effluent is produced and discharged to a nearby water body by gravity. Thus, hydroturbines can be utilized to generate power in such an application due to a difference in elevation and high flow rate. This paper presents a case study of introducing a hydroturbine in a WWTP in Wisconsin and evaluating the power output in addition to determining the energy savings. The WWTP considered in this study has an effluent flow rate of 190 MGD (million gallons per day) and elevation difference of 3 m (10 ft) between the final stage of treatment and the discharge point. Based on the parameters above; hubless rim-drive Kaplan type hydroturbine (RDT) is the optimal choice to be used in such an application. The RDT is designed and optimized by using in-house code. A computational fluid dynamics (CFD) software is applied to evaluate the performance of the proposed model, and the system is simulated through homer software to validate the results generated by the CFD. The expected savings is estimated to be 1564 MWh/yr.

Head Loss Reduction in Surcharged Four-Way Junction Manholes

Head loss in surcharged four-way junction manholes is a factor that increases damage due to urban inundation; thus, the flow characteristics of such manholes must be analyzed to reduce the head loss. In this study, a physical model was constructed; this model included a manhole and a connection pipe, fabricated on a 1/5 scale by applying sewer facility standards to perform a physical model investigation. Numerical simulations were performed using the Fluent model to derive efficient benching designs that can reduce head loss. Physical model investigations were performed by varying the ratio of the lateral influent flow rate to the effluent flow rate as well as by varying the effluent flow rate and benching designs. The result of physical model investigations showed that the installation of half rectangular benching reduced the head loss coefficients by 7% and 10% on average compared with square and circular manholes, respectively. The installation of full rectangular benching reduced the head loss coefficients by 28% and 17% on average compared with square and circular manholes, respectively. Thus, the benching proposed herein can be installed and used to improve the drainage capacity of urban stormwater conduit facilities.