The objective of this study was to determine the effect of advanced oxidation process with the use of Fenton’s reaction on the effectiveness of anaerobic treatment of wastewaters originating from the wood industry that were characterized by a high concentration of formaldehyde. Experiments were established to analyze changes in COD content and in the concentration of formaldehyde in treated wastewaters, additional analyses were carried out to assay quantitative and qualitative changes in the biogas produced. The first stage of the experiment involved analyses of the effectiveness of the tested wastewaters treatment only in the process of methane fermentation. At the second stage of the experiment, the biological process was preceded by chemical pre-treatment of wastewaters with Fenton’s reagent. The conducted study proved that the investigated variants of chemical pre-treatment of wastewaters had a significant effect on increasing the total biogas production. In contrast, no significant effect of the applied technology was demonstrated on changes in the concentration of the analyzed contaminants in the treated wastewaters.
The effects of Mg and Ca on sulfide modification of sulphur steel were studied to elucidate the difference between micromagnesium treatment and micro-calcium treatment for the inclusion of sulphur steel. The results show that the inclusions in the steel appeared with an oxide core of Al2O3 and MnS wrapped. After the addition of Mg, the core was changed to spinel, and the MnS coating was changed to Mn-Mg-S. After Ca was added, the core was changed to Ca-Al-O, and the MnS coating was changed to Mn-Ca-S. The Mg content was higher than Ca content in the sulfides of the steel. Therefore, Mg was more effective than Ca in terms of sulfide modification with the same content of Mg and Ca in steel, but the yielding rate of Mg was lower than that of Ca. The Mg content in the oxide core was higher than Mg of the coating of the inclusions in the steel treated with Mg or Mg-Ca. In contrast, the Ca content in the oxide core was lower than Ca of the coating of the inclusions in the steel treated with Ca or Mg-Ca. MnS formed and precipitated during the melt solidification process. The complex sulfide (Mg-Mn-S) was precipitated around MgO·Al2O3 in the Mg treated steel during the cooling process. CaS inclusion was precipitated on the CaO·Al2O3 inclusions in the liquid Ca-treated steel. Thus, CaS was formed first, whereas MnS was formed during the cooling process, followed by the formation of complex sulfide (CaS+MnS), which finally precipitated around CaO·Al2O3 in the Ca-treated steel.
The work presents the results of the experimental research concerning the impact of a heat treatment (toughening) of aluminum bronze CuAl10Fe4Ni4 on its mechanical properties. The conditions of the experiments and selected results are described. A detailed description of the effects of individual heat treatment conditions namely low and high temperature aging is also presented in the work.
Chalcedonite is a diatomaceous sedimentary rock, which, on account of a very small occurrence area, is included into a group of unique rocks. It occurs at Dęborzynka, Gapinin, Lubocz and Teofilów deposits, located on the Rawska Plateau in the region of Tomaszów Mazowiecki and Nowe Miasto. The deposit in Teofilów is the only documented one and it is now being exploited. The surface of this deposit is 577 437 m2 and its geological resources were determined to be 21.587 - 106 kg (21 587.0 thousand tones). The main component of this rock is chalcedon (69.0-96.6 vol.%), however quartz, opal, iron hydroxides, pyrite, manganese compounds and clay minerals occur in small quantities. The active surface of chalcedonite is relatively small and it was determined as 3-6 m2/g. Chalcedonite had a mesoporous structure of a significantly high pore homogeneity, and the total volume of these pores was 0.03-0.04 cm3/g. On account of its small spatial distribution chalcedonite is a unique rock, which has multi-resource properties. It is useful for manufacturing perlite-like material, crystobalite, wollastonite and mullite. It was also found to be a valuable raw material for the production of pastes, scouring powders, grinder tools and also as good filler for the production of : paints, varnishes, enamel ware, lute and putty materials. Because of its mesoporous structure and due to extended outer surface of the grains, chalcedonite is utilized in water treatment technology, mostly as an effective filtration material. A high usefulness of chalcedonite bed for manganese and iron removal from water shows mostly the presence of a low height of iron removal zone in the filter, and it is also manifested by a relatively short time of introduction into effective manganese(II) removal, as well as by good hydraulic properties of the material, which enable to achieve high mass capacities of the filter and to reach long filtration cycles. Chalcedonit is a very good carrier of manganese oxides and its surface modification of leads to the creation of chemically active bed, which enables removal of manganese(II) from water with high efficiency and without the introduction process. Chalcedonite bed effective removes of ammonia nitrogen from the water in the process of nitrification and waste water treatment. Chalcedonite can be also taken into account as a sorbent for the removal of oil spills.
The experimental pharmacologist Prof. Stanisław Jerzy Czuczwar, Vice President of the Polish Academy of Sciences, tells us about how he got into medical research, about the search for new epilepsy treatments, and how pharmaceuticals are in a way akin to cell phone towers.
22 representative antibiotics, including 8 quinolones (QNs), 9 sulfonamides (SAs), and 5 macrolides (MCs) were selected to investigate their occurrence and removal efficiencies in a Wastewater Treatment Plant (WWTP) and their distribution in the receiving water of the Chaobai River in Beijing, China. Water quality monitoring was performed in an integrated way at different selected points in the WWTP to explore the potential mechanism of antibiotics removal during wastewater treatment. Water quality of the Chaobai River was also analyzed to examine environmental distribution in a river ecosystem. The results showed that within all the 22 compounds examined, 10 antibiotics were quantified in wastewater influent, 10 in effluent, and 7 in river. Sulfadiazine (SDZ, 396 ng/L) and Sulfamethazine (SMZ, 382 ng/L) were the dominating antibiotics in the influent. Both the conventional treatment and advanced Biological Aerated Filter (BAF) system was important for the removal of antibiotics from the wastewater. And the concentrations of selected antibiotics were ranged from 0-41.8 ng/L in the effluent-receiving river. Despite the fact that the concentrations were reduced more than 50% compared to effluent concentrations, WWTP discharge was still regarded as a dominant point-source input of antibiotics into the Chaobai River.
In this work microbiological air pollution at several commune sewage treatment plants (capacity up to 15,000 PE) was investigated. The bioreactors in all plants had a covered construction. The air samples were taken indoors as well as outdoors (both on the windward and leeward side) during different seasons. The samples were collected using the collision method. The presence of indicator organisms in the samples was determined according to the Polish Standards. Identification of individual indicators was performed on solid selective-differentiating substrates. To verify the presence of bacteria from Salmonella, Shigella, coliforms and enterococci species, the colonies observed on the MacConkey substrate were then sifted onto SS and Endo substrates. At all facilities (with one exception) the average CFU for the total number of bacteria and fungi did not exceed 1000/m3, which is the limit set by the Polish Standards for a pollution-free atmospheric air. Bacteria and fungi concentrations, observed at windward and leeward sides of all plants, were relatively low (<100 CFU/m3 and <1000 CFU/m3, respectively) and comparable. A sewage collection point had only a slight impact on the bioaerosol emission. The concentration of microorganisms in the immediate vicinity of covered reactors (aeration chambers) was rather low and remained below the limits sets by the Polish Standards at three facilities. The CFU of individual indicators, measured in rooms accessible for the personnel, was comparable to the CFU in technological rooms. However some indicators, e.g. a number of Actinomycetes, were significantly higher and reached >100 CFU/m3, which means significant air pollution. Similarly, the CFU of hemolytic bacteria had nonzero values. The only place where higher concentrations of bioaerosol were found was the centrifuge room, where digested sludge was dewatered. The number of fungi stayed below the limits there, but the amount of heterotrophic and hemolytic bacteria exceeded the limits and reached the values of ~10000 CFU/m3 and 800 CFU/m3, respectively; it means that the personnel working in this area is exposed to microbiological agents.
In this study, music teachers' exposure to sound was tested by measuring the A-weighted equivalent sound pressure level (SPL), the A-weighted maximum SPL and the C-weighted peak SPL. Measurements were taken prior to and after acoustic treatment in four rooms during classes of trumpet, saxophone, French horn, trombone and percussion instruments. Results showed that acoustic treatment affects the exposure of music teachers to sound. Daily noise exposure levels (LEX, 8 h) for all teachers exceeded a limit of 85 dB while teaching music lessons prior to room treatment. It was found that the LEX, 8 h values ranged from 85.8 to 91.6 dB. The highest A-weighted maximum SPL and C-weighted peak SPL that music teachers were exposed to were observed with percussion instruments (LAmax = 110.4 dB and LCpeak = 138.0 dB). After the treatments, daily noise exposure level decreased by an average of 5.8, 3.2, 3.0, 4.2 and 4.5 dB, respectively, for the classes of trumpet, saxophone, French horn, trombone and drums, and did not exceed 85 dB in any case.
System Dynamics is methodology for modeling and analyzing complex systems. Such systems can be characterized by interconnectedness and feedback. Applying risk assessment to the results of System Dynamics models is a challenge. Though in some cases the resulting time series data generated by a simulation may appear approximately random at a specific scale, there is often a high-degree of auto-correlation within the data series due to the deterministic nature of generation and feedback loops inherent in the system. This paper presents proposed Dynamic Risk Assessment Method (DRAM) that allows for the estimation of risk for system dynamics data series that appear to be approximately random. DRAM is based on standard risk assessment methods and is simple both to calculate and apply. In this article, the proposed method is applied to determine the risk connected with hypothetical costs of illness stemming from water supply system contamination with Cryptosporidium.
The dominance, diversity and activity density of rove beetles were studied in Central European apple and pear orchards. Altogether 6 877 individuals, belonging to 271 species and 11 subfamilies were collected. Thirteen species presented a relative abundance from 9 to 2% and amounted to almost 56% of all staphylinids recorded. In dominance order they were: Dinaraea angustula (Gyllenhal), Omalium caesum Gravenhorst, Drusilla canaliculata (F.), Sphenoma abdominale Mannerheim, Palporus nitidulus (F.), Xantholinus linearis (Olivier), Dexiogya corticina (Erichson), Coprochara bipustulata L., Mocyta orbata (Erichson), Oligota pumilio Kiessenwetter, Xanthlinus longiventris (Olivier), Tachyporus hypnorum (F.) and Pycnota vicina (Kraatz). The alpha diversity of staphylinids for different environmental conditions was relatively similar but the Shannon-Weiner Index (H`) was higher than of other similar studies. However, the activity density was higher in pear, in sand and in abandoned plantations; under different environmental conditions this could not be considered uniform in time. After the cumulative studies on the population dynamics, one can conclude that the highest number of species can be found in spring and in summer. Species D. canaliculata and P. nitidulus presented the similar seasonal dynamics in orchards located in different environmental areas, while O. caesum had the same activity density both in apple and pear orchards.
The study was aimed at evaluating microbial contamination on the premises of the sewage treatment plant by determining the concentrations of selected groups of airborne microorganisms. Another objective was to determine the antibiotic sensitivity patterns of isolated strains of staphylococci. The research was conducted in a seasonal cycle, by the impaction method using Merck MAS-100 air sampler. Samples were collected at six sites, each representing a different stage of sewage treatment. The susceptibility of isolated staphylococci was assessed with the disc-diffusion method, following the recommendations of the EUCAST. The results indicate that the microbial population in the air of the investigated area was dominated by mold fungi, whose highest average concentration was recorded at site IV located near the final clarifier (7672 CFU•m-3). Heterotrophic bacteria and mannitol-positive staphylococci were the most numerous at locations where sewage undergoes primary treatment. In each subseuqent stage the number of microorganisms emitted into the air from the sewage was lower. Antibiograms show that more than 50% of Staphylococcus spp. exhibited resistance to penicillin and 20% to rifampicin. In addition, 90% of the analyzed strains were sensitive to other antibiotics. The fungal community included the following genera: Cladosporium, Fusarium, Alternaria, Penicillium, Aspergillus, Aureobasidium, and Acremonium.The highest air contamination with all studied groups of microorganisms was recorded at the locations where mechanical sewage treatment was performed. During the subsequent stages lower numbers of heterotrophic bacteria were emitted into the air. The air in the investigated sewage treatment plant did not contain multidrug-resistant staphylococci.
FA discharged from the wastewater treatment plant were extracted from purifi ed effl uents for the quantitative
and qualitative analysis. The treated sewage from municipal treatment plants was acidifi ed to pH <2 and extracted
with ion exchange resins in a laboratory column. After desorption with NH4
OH, the fulvic acids were condensed
under vacuum and tested for mass performance, UV-VIS light spectra, IR absorption spectra, elementary composition
and other elements. Their structure was analysed and compared to FA present in surface waters and in sewage treated
in other sewage treatment plants based on the authors’ own research and the literature data. The concentration of
FA in the treated sewage was 5.2 mg/L. There is a high interdependence between the IR spectrum analysis in the
visible light and the elementary composition of FA extracted from different environments, confi rming the conclusions
pertaining to the structure and properties of the acids being tested. The longer sewage is subjected to a biological
treatment process, the greater the degree of aromatic condensation and humus maturity of the FA contained within it.
FA contained in the sewage treated in the three biological sewage treatment plants have the ratio A2
/A3
(the ratio of the
absorbance of light with the wavelength of 250 and 300 nm) equal to the value 1.7. There is a high interdependence
between the IR spectrum analysis in the visible light and the elementary composition of FA extracted from different
environments, confi rming the conclusions pertaining to the structure and properties of the acids being tested.
Secondary or multiple remelted alloys are common materials used in foundries. For secondary (recycled) Al-Si-Cu alloys, the major problem is the increased iron presence. Iron is the most common impurity and with presence of other elements in alloy creates the intermetallic compounds, which may negatively affect the structure. The paper deals with effect of multiple remelting on the microstructure of the AlS9iCu3 alloy with increased iron content to about 1.4 wt. %. The evaluation of the microstructure is focused on the morphology of iron-base intermetallic phases in caste state, after the heat treatment (T5) and after natural aging. The occurrence of the sludge phases was also observed. From the obtained results can be concluded that the multiple remelting leads to change of chemical composition, changes in the final microstructure and also increases sludge phases formation. The use of heat treatment T5 led to a positive change of microstructure, while the effect of natural aging is beneficial only to the 3rd remelting.
Improvement of Al-Si alloys properties in scope of classic method is connected with change of Si precipitations morphology through:
using modification of the alloy, maintaining suitable temperature of overheating and pouring process, as well as perfection of heat
treatment methods. Growing requirements of the market make it necessary to search after such procedures, which would quickly deliver
positive results with simultaneous consideration of economic aspects. Presented in the paper shortened heat treatment with soaking of the
alloy at temperature near temperature of solidus could be assumed as the method in the above mentioned understanding of the problem.
Such treatment consists in soaking of the alloy to temperature of solutioning, keeping in such temperature, and next, quick quenching in
water (20 0
C) followed by artificial ageing. Temperature ranges of solutioning and ageing treatments implemented in the adopted testing
plan were based on analysis of recorded curves from the ATD method. Obtained results relate to dependencies and spatial diagrams
describing effect of parameters of the solutioning and ageing treatments on HB hardness of the investigated alloy and change of its
microstructure. Performed shortened heat treatment results in precipitation hardening of the investigated 320.0 alloy, what according to
expectations produces increased hardness of the material.
Mechanical and technological properties of castings made from 3xx.x alloys depend mainly on properly performed process of melting and
casting, structure of a casting and mould, as well as possible heat treatment. Precipitation processes occurring during the heat treatment of
the silumins containing additives of Cu and/or Mg have effect on improvement of mechanical properties of the material, while choice of
parameters of solutioning and ageing treatments belongs to objectives of research work performed by a number of authors. Shortened heat
treatment, which is presented in the paper assures suitable mechanical properties (Rm), and simultaneously doesn’t cause any increase of
production costs of a given component due to long lasting operations of the solutioning and ageing. Results of the research concern effects
of the solutioning and ageing parameters on the Rm tensile strength presented in form of the second degree polynomial and illustrated in
spatial diagrams. Performed shortened heat treatment results in considerable increase of the Rm tensile strength of the 320.0 alloy as early
as after 1 hour of the solutioning and 2 hours of the ageing performed in suitable.
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