The role of MBR technology for the improvement of environmental footprint of wastewater treatment

This paper aims to demonstrate the relevance of membrane bioreactor (MBR) technology for the reduction of the environmental footprint of wastewater treatment in terms of removal of microbial and organic trace pollutants with increased reliability of operation. The application of a holistic approach using failure mode analysis, life cycle analysis (LCA), water quality fingerprints and environmental impacts underlines the lower environmental footprint of MBRs compared with conventional activated sludge. Several elements of this empirical approach can be included to upgrade the existing LCA tools in order to include the reduction of eco-toxicity, better human health protection and water reuse.     

The Multiverse of Plant Small RNAs: How Can We Explore It?

Plant small RNAs (sRNAs) are a heterogeneous group of noncoding RNAs with a length of 20–24 nucleotides that are widely studied due to their importance as major regulators in various biological processes. sRNAs are divided into two main classes—microRNAs (miRNAs) and small interfering RNAs (siRNAs)—which differ in their biogenesis and functional pathways. Their identification and enrichment with new structural variants would not be possible without the use of various high-throughput sequencing (NGS) techniques, allowing for the detection of the total population of sRNAs in plants. Classifying sRNAs and predicting their functional role based on such high-performance datasets is a nontrivial bioinformatics task, as plants can generate millions of sRNAs from a variety of biosynthetic pathways. Over the years, many computing tools have been developed to meet this challenge. Here, we review more than 35 tools developed specifically for plant sRNAs over the past few years and explore some of their basic algorithms for performing tasks related to predicting, identifying, categorizing, and quantifying individual sRNAs in plant samples, as well as visualizing the results of these analyzes. We believe that this review will be practical for biologists who want to analyze their plant sRNA datasets but are overwhelmed by the number of tools available, thus answering the basic question of how to choose the right one for a particular study.     

Differential Scanning Calorimetric Study of the Effect of Cholesterol on the Thermotropic Phase Behavior of the Phospholipid 1-Stearoyl-2-Oleoyl-sn-Glycero-3-Phosphocholine

Using the differential scanning calorimetric (DSC) technique, the thermal properties of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC) phospholipid and its mixture with cholesterol (Chol), in the range between 10 and 50 mol.%, were investigated. A considerable modification of the structural conformation and the biophysical properties of the bilayer of the phospholipid system after the Chol incorporation were detected. Concentrations below 30 mol.%, and especially in the range 10–20 mol.%, were found to be optimal in the effective miscibility of SOPC and Chol components. The effective miscibility completeness, mainly in the gel and liquid crystal phases, was indicated. It was discovered that Chol mixed with SOPC slightly shifts its gel (L _β) to liquid crystal (L _α) phase transition temperature, decreases cooperativity, expressed by the van't Hoff enthalpy, and markedly and progressively reduces the transition enthalpy to almost zero at 50 mol.%. By deep incubation of the cholesteric phospholipid mixture, it was revealed that the endothermic peak associated with laminar crystal to gel phase transition does not exist in conventional pure SOPC bilayer systems.     

Mechano mathematical models for mechatronic systems for vibration jaw crushing processes

The aim of this paper is creation, investigation of mono frequency and poly frequency plane and spatial vibrations of two mass vibration systems with a suitable adjustment of the mechanical system. The physical object is a vibrating jaw crusher. The mechanical and mathematical modeling is created on the basis of a two mass dynamic model with six degrees of freedom in plane case—three for each mass and 12 degrees of freedom in spatial model—six for each mass. The influence of the elastic linkages between the two masses and also the energy mutual linkages between the coordinates of the two bodies are investigated.

Natural frequencies and amplitudes of movement are obtained by means of computer experiment in plane and spatial aspect. The obtained results can be used for optimization of the constructive parameters of the vibrating jaw crusher and also for improving harmful resonance effects     

Microstructure and mechanical properties of P265GH cast steel after modification with TiCN particles

Particles of TiCN and TiC were produced by means of self-spreading high temperature synthesis and after covering with metal protector were studied in order to be applied for modification of molten steel. After microstructure characterization the TiCN nano- and micron-sized particles were selected for modification of castings of P265GH steel and the microstructure and mechanical properties of the modified steel were studied and compared with those of the steel without modification. The data from microstructure-properties analysis of the modified steel showed that the steel treated with nano- and micro-sized particles has significantly refined microstructure, increased strength and hardness and improved elongation in comparison with the non-modified castings.     

Preparation of polycaproamide yarns with reduced static

Conclusions Yarns with a high antistatic effect, which is stable to wet treatments, have been obtained by introducing product DETA80 into polycaproamide.DETA80 antistat causes changes in the supermolecular structure of yarns which lead to a reduction in strength and deformation properties of the yarns and to an increase in their ability to be dyed.The antistats do not exert an effect on the light-resistance of the yarns, nor on resistance of the color to set treatment.Translated from Khimicheskie Volokna, No. 5, pp. 54–55, September–October, 1984.     

On-site evaluation of the removal of 100 micro-pollutants through advanced wastewater treatment processes for reuse applications

The next challenge of wastewater treatment is to reliably remove micro-pollutants at the microgram per litre range in order to meet reuse applications and contribute to reach the good status of the water bodies. A hundred priority and relevant emerging substances were measured to evaluate at full-scale the removal efficiencies of seven advanced treatment lines (one membrane bioreactor process and six tertiary treatment lines) that were designed for reuse applications. To reliably compare the processes, specific procedures for micro-pollutants were applied for sampling, analysis and calculation of removal efficiencies. The membrane bioreactor process allowed to upgrade the removal efficiencies of about 20% of the substances measured, especially those that were partially degraded during conventional processes. Conventional tertiary processes like high rate clarification, sand filtration and polishing pond achieved significant removal for some micro-pollutants, especially for adsorbable substances. Advanced tertiary processes, like ozonation, activated carbon and reverse osmosis were all very efficient to complete the removal of polar pesticides and pharmaceuticals; metals and less polar substances were better retained by reverse osmosis.     

Electrochemical study of the adsorption and inhibiting properties of halogen derivatives of aniline on iron in sulfuric acid

The adsorption of halogen derivatives of aniline on an iron electrode in sulfuric acid medium has been studied in relation to their inhibiting properties using electrochemical a.c. impedance and d.c. polarization techniques, as well as quantum chemical calculations of chemical structure and distribution of electron charges in the organic molecules. It is established that the adsorption process is described by Frumkin's isotherm. The adsorption parameters characterizing the interaction forces between the molecules in the adsorbed layer, the free energy of adsorption, the maximum surface excess of adsorbed species, the area occupied by each molecule etc. have been calculated on the basis of this isotherm. It is shown that the inhibition efficiency, as well as the free energy of adsorption, increases in the sequence: aniline < p-Cl-aniline < p-Br-aniline < p-I-aniline. It was found that the adsorption behaviour of the substances studied is characterized by two adsorption states: vertical and planar orientation of the molecules. Combining data from electrochemical measurements with data from quantum chemical calculations the correlation between the chemical structure of the aniline derivatives and their adsorption capability and inhibition efficiency has been ascertained.     

Development of a hybrid ozonation biofilm-membrane filatration process for the production of drinking water.

Drinking water sources in Norway are characterized by high concentrations of natural organic matter (NOM), low alkalinity and low turbidity. The removal of NOM is therefore a general requirement in producing potable water. Drinking water treatment plants are commonly designed with coagulation direct filtration or NF spiral wound membrane processes. This study has investigated the feasibility and potential of a hybrid process combining ozonation and biofiltration with a rotating disk membrane for treating drinking water with high NOM concentrations. Ozonation will oxidize the NOM content removing colour and form biodegradable organic compounds, which can be removed in biological filters. A constructed water was used in this study which is representative of ozonated NOM-containing water. A rotating membrane disk bioreactor downstream the ozonation process was used to carry out both the biodegradation as well as biomass separation in the same reactor. Maintenance of biodegradation of the organic matter while controlling biofouling of the membrane and acceptable water production rates was the focus in the study. Three operating modes were investigated. Removal of the biodegradable organics was consistent throughout the study indicating that sufficient biomass was maintained in the reactor for all operating conditions tested. Biofouling control was not achieved through shear-induced cleaning by periodically rotating the membrane disks at high speed. By adding a small amount of sponges in the membrane chamber the biofouling could be controlled by mechanical cleaning of the membrane surface during disk rotation. The overall results indicate that the system can favorably be used in an ozonation/biofiltration process by carrying out both biodegradation as well as biomass separation in the same reactor.     

Change in properties of polycaproamide during a heat-treatment process

Conclusions -- The change in basic molecular and certain specific characteristics of PCA during the process of heat-treating it in the presence of air has been studied.-- It has been shown that the degree of thermo-oxidative degradation of PCA may be judged from the change in molecular weight characteristics in combination with the results of change in the Huggins constant, the relative chemical nonuniformity, the content of carbonyl compounds, and the integral UV-absorption.-- The inhibiting action of a Bulgarian copper thermostabilizer and of N-1 thermostabilizer on the thermo-oxidative degradation of PCA has been evaluated.Translated from Khimicheskie Volokna, No. 6, pp. 42–44, November–December, 1990.