Surface Water Quality Assessment of Panchagnaga River and Development of DO-BOD Relationship Using Empirical Approach

Surface water samples were collected from selected locations along river Panchaganga, from Kolhapur to Narsobawadi during April 2019. Physicochemical parameters were determined in the laboratory and chemical mass balance approach was adopted to estimate the individual ionic loads in the river water. Streeter-Phelps equation was applied to derive a relationship between DO and BOD5. Model parameters such as De-oxygenation Rate (Kd) and Re-aeration Rates (Kr ) were optimized using different empirical methods. The result of chemical mass balance showed an increase in the loading of various ions from upstream to downstream which could be attributed to agricultural and industrial wastes that enter the main stream. De-oxygenation rate and re-aeration constants were calculated using various empirical methods. DO sag curve was developed using Streeter Phelp’s model and compared with the observed parameters which showed a significant correlation. DO-BOD concentration observed along the course of the river indicated that the self-purification capacity of the river is high due to which the river regains the lost DO level at a distance less than 50 meters.

Study on Sludge and Dissolved Oxygen Distribution in a Full-Scale A2/O Oxidation Ditch

The distribution of velocity, sludge, and dissolved oxygen in a full-scale anaerobic-anoxic-oxic (A2/O) oxidation ditch was numerically simulated under three rotation speed scenarios. The viscosity and settling rate of activated sludge were defined through a user-defined function (UDF), and the sludge phase was calculated using the mixture multiphase flow model. Dissolved oxygen (DO) was set as a user-defined source (UDS) and its generation and consumption rates were defined with UDFs. The relationship between velocity and sludge concentration was found to be contradictory, with dead zones leading to large sludge concentrations at the bottom of the oxidation ditch (OD), but not at the middle-curved wall of the anoxic pool. The flow rate of the reflux slot and aerator oxygenation rate were checked and correlated with DO concentrations in the anaerobic pool. The majority of the large sludge concentrations were concentrated in the biological selection pool and these remained constant with bed height. With reduced propeller and agitator rotation speed, the sludge concentrations reduced in the biological selection pool, but increased in the anaerobic and anoxic pools.

CENTRAL ACTIVITY ANALGETIC NEFOPAM AS A COMPONENT OF ANALGOSEDATION IN OPHTHALMOSURGERY

Prospective research was made to evaluate the efficiency of nefopam in anasthesiology manual- analgosedation with preserved consciousness- during anticataractal and antiglaucoma operations. The research involved 2 groups of patients: with nefopam analgesia and tramadol analgesia. Data of research includes evaluation of the dynamics of hemodynamic information and oxygenation, rate of intraoperation critical incidents (oculocardiac syndrome, other arrhythmias, hypertension and hypotension). By verbal pain assessment scale we have compared the level of intraoperation analgesia. We get the following results: combination of nefopam and droperidol provides analgosedation which is more hemodynamic stable and has significantly lower intraoperation critical incidents then analgosedation of tramadol. Nefopam has undesirable side effects like temperate increase in heart rate and pain during injection along the vein in combination with ketorolac. Sufficient dose for analgesia at old-aged patients in ophthalmosurgical practice is 10 mg of nefopam.

Quick Cultivation of Micro-Aerobic Granular Sludge for Simultaneous Nitrogen Removal

In order to accelerate the cultivation of micro-aerobic granular sludge for domestic sewage treatment, an expanded granular sludge bed (EGSB) reactor seeded with excess sludge was employed. It was found that micro-aerobic granules can form and grew compact within one month, and remained stable during the later operation, the mature cultivation had average particle size of 0.81mm, and 64% of the granules had settling velocity above 35m•h-1. Moreover, excellent COD and nitrogen removal were obtained. For hydraulic retention time (HRT) of 5h, as the recirculation ratio and oxygenation rate were set at 6.5 and 0.25g•L-1d-1respectively, COD removal ranged in 80%-91%, leaving effluent COD below 50mg•L-1. The removal efficiency of ammonium and total nitrogen (TN) were 72%-89% and 76%-87%, respectively with effluent concentration down to 3-12mg•L-1and 5-14mg•L-1. Results showed that the efficiency of simultaneous nitrogen removal was much influenced by effluent recirculation and oxygenation rate in micro-aerobic EGSB reactor.

Escherichia coli Resistance to Chlorine and Glutathione Synthesis in Response to Oxygenation and Starvation

ABSTRACT Reduced glutathione (GSH) levels and resistance to chlorine were measured for two isogenic Escherichia coli strains stressed by oxygenation and/or starvation. The E. coli mutant deficient in GSH was not more sensitive to the oxidant than its parent strain when the bacteria were cultured with a low oxygenation rate. Starvation or oxygenation increased the resistance of the parent strain to chlorine, while the resistance of the deficient strain remained unchanged.

Influence of ageing on the catalytic activity of ferric sludge for oxidation of fe(II)

The catalytic effect of freshly formed or added ferric iron on the Fe(II) oxidation has been demonstrated by previous studies. High Fe(III) concentrations significantly accelerate the oxygenation rate. High Fe(III) concentrations can be maintained only by sludge recycle which eventually leads to sludge ages as high as 10 days. Therefore, the aim of this study was to determine whether ageing of ferric hydroxide sludge affects its catalytic effect on the oxidation of ferrous iron by aeration. In order to reach this aim four different groups of experiments were carried out using ferric hydroxide sludge aged for a period of 0 to 10 days. Initial Fe(III) concentrations were varied within the range of 50 mg/l to 200 mg/l. It has been demonstrated that the catalytic effect of ferric hydroxide sludge on the oxidation of ferrous iron by aeration increases with increasing sludge age contrary to what is commonly expected. It has been concluded that, catalytic oxidation rate constant kcat obtained from the batch systems can safely be used in design of continuous flow iron oxidation reactors with sludge recycle.

Grain growth and the microstructural effects on the properties of YBa2Cu3O7−y superconductor

The microstructural development and grain growth of YBa2Cu3O7−y ceramics at 925, 950, and 975 °C were studied. Densification occurred quite rapidly at temperatures below 925 °C. The grain growth of YBa2Cu3O7−y followed a D5 − D50 = Kt relation when sintered at 925 and 950 °C. At 975 °C, the kinetics changed to cubic (D3) behavior, which can be attributed to the formation of a liquid phase at grain boundaries. A trend of decreasing Jc with increasing sintering temperature was observed. Other properties including Tc and the width of the transition were virtually unaffected by the change in microstructure. Without prolonged annealing, a relatively homogeneous oxygen stoichiometry of 6.8 was obtained for fairly dense samples (>93% of theoretical). These results suggest that the oxygenation rate of YBa2Cu3O7−y was quite rapid between the tetragonal phase and the orthorhombic composition of YBa2Cu3O6.8.