Study on turbulence characteristics and sensitivity of quadrant analysis to threshold level in Lake Taihu

Environmental Science and Pollution Research - The identification of coherent structures is very important in investigating the sediment transport mechanism and controlling the eutrophication in...     

Characterization of extracellular polymeric substance (EPS) fractions produced by Microcystis aeruginosa under the stress of linoleic acid sustained-release microspheres

Environmental Science and Pollution Research - This paper focuses on the characterization of extracellular polymeric substances (EPS), which are composed of soluble EPS (SL-EPS), loosely bound EPS...     

Treatment of high-strength pet food wastewater using two-stage membrane bioreactors.

A two-stage membrane bioreactor was used to treat dissolved-air-flotation pretreated, high-strength pet food wastewater characterized by oil and grease concentrations of 50 000 to 82 000 mg/L and total chemical oxygen demand (COD) and five-day biochemical oxygen demand (BOD5) concentrations of 100 000 and 80 000 mg/L, respectively, to meet stringent surface discharge criteria (i.e., BOD5, total suspended solids [TSS], and ammonium-nitrogen [NH4(+)-N] of < 10 mg/L at an overall hydraulic retention time of 6.3 days). Organic contaminants were removed primarily in the first stage, followed by almost complete removal of ammonia in the second stage. Despite a rise in poorly biodegradable COD in the second stage, overall removal of TSS, BOD5, COD, and ammonia was 100, 99.9, 95.2, and 99.7%, respectively, thus readily achieving the required criteria. Consistent nitrite accumulation over a period of more than 100 days, even at dissolved oxygen concentrations of more than 2.5 mg/L, was remarkable. A residual alkalinity requirement for nitrification was quantified. Membrane performance was extensively studied in this work.     

The fetal circulation

Accumulating data on the human fetal circulation shows the similarity to the experimental animal physiology, but with important differences. The human fetus seems to circulate less blood through the placenta, shunt less through the ductus venosus and foramen ovale, but direct more blood through the lungs than the fetal sheep. However, there are substantial individual variations and the pattern changes with gestational age. The normalised umbilical blood flow decreases with gestational age, and, at 28 to 32 weeks, a new level of development seems to be reached. At this stage, the shunting through the ductus venosus and the foramen ovale reaches a minimum, and the flow through the lungs a maximum. The ductus venosus and foramen ovale are functionally closely related and represent an important distributional unit for the venous return. The left portal branch represents a venous watershed, and, similarly, the isthmus aorta an arterial watershed. Thus, the fetal central circulation is a very flexible and adaptive circulatory system. The responses to increased afterload, hypoxaemia and acidaemia in the human fetus are equivalent to those found in animal studies: increased ductus venosus and foramen ovale shunting, increased impedance in the lungs, reduced impedance in the brain, increasingly reversed flow in the aortic isthmus and a more prominent coronary blood flow. Copyright © 2004 John Wiley & Sons, Ltd.     

Influence of Fiber Diameter on Pressure Drop and Filtration Efficiency of Glass Fiber Mats

Abstract

A method using direct flame ionization detector (FID) measurement was developed to study total volatile organic compound (VOC) emissions during thermal degradation of polymers. This method was used to estimate organic emissions from different polymers, such as low-density polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and commingled postconsumer streams, such as recycled carpet residue and auto shredder residue (ASR). The effects of process parameters, such as temperature, heating rate, and residence time, were also studied. Significant VOC emissions were observed at normal processing temperatures, particularly from recycled polymers. Each polymer showed a distinct evolution pattern during its thermal degradation. The kinetics of VOC emissions were also studied using a nonisothermal technique. The kinetic parameters were in agreement with data from the literature.     

Influence of sublethal ammonia toxicity on some physiological parameters of Labeo rohita (Hamilton-Buchanan) fingerlings

Fingerlings of Labeo rohita subjected to sublethal unionized ammonia (0.132mg/l) for 30 days exhibited significant changes. Increase in haemoglobin, haematocrit, plasma cortisol, plasma glucose, plasma cholesterol and plasma lactic acid levels whereas, decrease in plasma chloride, liver and muscle glycogen, hepatosomatic index and DNA/RNA ratio of muscles with stable plasma protein was observed. Metabolic recovery was not observed within 30 days of exposure.     

Use of fly ash for the removal of phenol and its analogues from contaminated water

This work attempts to elucidate the effects of different operational variables affecting the mechanistic function of fly ash for removal of some priority organic pollutants viz. phenol and its analogues. Thermodynamic parameters like free energy change, enthalpy and entropy of the process, as well as the sorption isotherms for phenols on fly ash, were measured and the most suitable isotherm was determined. Results of the study indicate that the extent of solute removal is determined by the initial solute concentration, molecular size and molecular arrangement of the solute. At the fixed set of experimental conditions, a model equation can be developed from which the percent removal corresponding to the load of the particular solute is determined. It is assumed that the mechanism of adsorption is governed by the surface characteristics of fly ash; pH has a vital role in influencing the solute removal as both the ionizing power (acidity, pKa) of the solutes and the zero point charge of fly ash (pH(ZPC)) depend on the solution pH. Isotherm pattern and the free energy change indicate that the process is favorable, as well as spontaneous. The information gathered from the study will serve as a predictive modeling procedure for the analysis and design of the removal of organic pollutants and decontamination of water. The leaching experiment indicates that the retained solutes do not release from fly ash. The retained solutes can be recovered and utilized as industrial raw material.     

Consultant Guide/1989

The European Economic Community (EEC) has proposed strict limits on emissions of dioxins and furans from hazardous waste incinerators. The proposed limit is 0.1 ng/Nm³, expressed as the 2,3,7,8 TCDD toxic equivalent of 17 specific dioxin and furan congeners. These limits will potentially redefine technology selection and design for combustion, energy recovery, and air pollution control. The EPA has a different approach for controlling emissions of products of incomplete combustion (PICs) and reformation products such as dioxins and furans. Rather than limiting these contaminants individually and quantitatively, EPA proposes controlling them by assuring good combustion as measured by stack emissions of carbon monoxide (CO) and total hydrocarbons (THC).

Dioxins and furans are combustion by-products and emission control relies mainly on control of the combustion process. These compounds can also be reformed from certain precursor compounds and elements in lower temperature regions of the system downstream of the combustion process. Air pollution control technologies have demonstrated the ability to remove dioxins and furans as contaminants on fine particulate.

This paper will discuss the two regulatory approaches, the mechanisms for the formation and reformation of dioxins and furans, and the technologies available to control emissions.     

Second International Conference on “Recent Trends in Environment and Sustainable Development” (RTESD 2019)

Environmental Science and Pollution Research -