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This study focuses on the elimination of residual dyes from industrial wastewater using talc as an adsorbent. Talc is an easily available, ecological, and inexpensive adsorbent. The adsorption process was tested on two model dye samples (Ecozol Blue LR Liquid and Cartasol Yellow 3GF Direct Yellow 132), and two samples of real wastewater from the pulp and paper industry (PM and TP). Kinetic studies revealed that the adsorption of Ecozol Blue LR Liquid followed pseudo-second-order kinetics, while the other tested samples followed pseudo-first-order kinetics. Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherm models were also evaluated. The Langmuir isotherm model best fitted the experimental data for the adsorption of model dye solutions and wastewater sample TP onto talc. For wastewater sample PM, the Dubinin-Radushkevich isotherm model provided the best fit to the experimental data. The results of the adsorption isotherms indicated that the adsorption of all tested systems was favorable and primarily involved physical adsorption. The adsorption efficiency for the model solutions exceeded 90 %. For real wastewater samples, the monitored adsorption efficiency in the COD pollution indicator was less efficient, ranging from 43 to 51 %. The lower efficiency of COD may have resulted from the adsorption of residual dyes with lower specific COD values before the adsorption of other organics. [ABSTRACT FROM AUTHOR]

We describe the case of a term newborn who presented with congenital testicular torsion at 10 hours of age. During the evaluation of this problem, additional malformations were encountered. Diagnostic and therapeutic considerations are addressed. [ABSTRACT FROM AUTHOR]

The kinetic study of the ozonation of atrazine as a single contaminant characterized as COD was studied. A jet loop ejector reactor was used to improve the mixing and transfer of ozone in the reaction system. The results show a higher efficiency of atrazine degradation in alkaline pH during the first 45 minutes. At the same time, the dechlorination of atrazine is faster than in neutral pH. Respirometric measurements carried out with activated sludge were used to evaluate the effect of atrazine and the ozonation intermediates on microorganisms' oxygen uptake rate. The results showed that ozonation performed at an alkaline pH resulted in the formation of substances that are more rapidly biodegradable compared to substances formed by ozonation at neutral pH, as well as compared to atrazine. [ABSTRACT FROM AUTHOR]

Arsenic contamination of water resources, which is characterized by strong carcinogenic and toxic impacts, is a global problem. Therefore, the present study is focused on the isotherm and kinetic studies of pentavalent arsenic As(V) adsorption with initial concentration of 1 000 µg L-1 from aqueous solutions onto granular ferric oxide (GFO). Adsorption experiments were carried out by batch method, and the equilibrium and kinetic data were evaluated by the Langmuir, Freundlich, Dubinin-Radushkevich, Redlich-Peterson and Sips isotherm model, and pseudo-first and pseudo-second order kinetic model. The results obtained from this study imply that the adsorption of As(V) onto GFO was favourable, physical and multilayer process. The Sips and Redlich-Peterson isotherm and the pseudo-first order kinetic model gave the best fit to experimental data according to the values of correlation coefficient. The maximum theoretical adsorption capacity from Langmuir isotherm model was determined to be 1 900 µg g-1. In addition, the impact of different operating conditions such as As(V) initial concentration, adsorbent dose, agitation speed, pH, temperature, and presence of phosphates and silica on adsorption capacity of GFO was also investigated. As(V) was efficiently recovered from GFO by 0.1 M NaOH desorbing solution during the three adsorption-desorption cycles. [ABSTRACT FROM AUTHOR]

The extension of biological processes from carbonaceous impurities removal to nitrogen and phosphorus removal had an impact on the biological system configuration. The system must be well designed, optimized, and operated at its optimum in order to meet the ever more stringent effluent standards. An intermittently aerated completely mixed lab-scale activated sludge bioreactor (IACMB) has been used for modelling biological processes of nutrients removal. Concerning the nitrogen removal, the operating cycles 15-30 (15 minutes of aeration, 30 minutes of only mixing without aeration) and 30-30 were tested. For the experiments with luxury uptake processes, the operating cycles 15-45, 15-90, 30-60 and 15-75 were used. The cycle 15-75 was the most satisfactory with convenient lengths of aerobic, anoxic, and anaerobic period, high efficiency of the nitrification and denitrification processes, and significant decrease in phosphorus concentration. The results have shown that the intermittently aerated bioreactors are suitable for nitrogen removal as well as luxury uptake of phosphorus. The main advantage is high flexibility in maintenance and control of biochemical environments in the bioreactor. [ABSTRACT FROM AUTHOR]

The paper is focused on the possibility of using ozonation process combined with iron nanoparticles (nZVI - nano zero-valent iron) to remove selected specific synthetic substances, such as hexachlorobutadiene, pentachlorobenzene, hexachlorobenzene, lindane and heptachlor. Experimental measurements were performed in order to evaluate the effectiveness of the removal of substances and their removal rates. Removal of pesticides was also monitored through calculated DOC (dissolved organic carbon) as cumulative wastewater quality indicator. We investigated the effectiveness of 5 mL L-1 nZVI suspension (equal to 1 g Fe0) for the optimization of micropollutants removal from model water. Applications of 5 mL L-1 nZVI suspension and combined O3/nZVI processes have been shown as the most effective. Increasing concentrations of nZVI had almost no impact on the efficiency of the degradation process. Higher degradation efficiencies of γ-HCH were measured in O3/nZVI compared to the ozonation process. Degradation of pesticides HCLB, HCLBD and PCLB in all tested processes achieved efficiencies above 88 %. [ABSTRACT FROM AUTHOR]

The results of the study of removal of nonylphenol, octylphenol and their ethoxylates from real industrial and municipal wastewater are presented. Industrial wastewater was pre-treated by coagulation with FeCl3 and adsorption on zeolite, before discharging into municipal sewer system. Their removal efficiencies in primary sedimentation tank of municipal WWTP were very low. From the practical point of view, the highest and the most significant removal efficiencies within the whole WWTP were observed for nonylphenol and nonylphenol ethoxylates. Dominancy of abiotic mechanisms of alkylphenols removal follows from adsorption measurements. Activated sludge cultivated in lab-scale extended aeration tank accounted for relatively high adsorption affinity to these substances. Activated sludge sampled from municipal wastewater treatment plant (MWWTP) receiving industrial wastewater containing alkylphenols accounted for very low adsorption affinity to these pollutants. Significantly higher removal efficiency of octylphenol ethoxylates was observed with the O3/granular active carbon (GAC) process compared to the ozonation process alone. Lower toxicity impact of intermediates and products of ozonation treatment on Vibrio fischeri was measured in comparison to the O3/GAC process. Actually, the municipal WWTP effluent discharge concentration values complies with EQS values, including nonylphenols. [ABSTRACT FROM AUTHOR]

The paper deals with the study of the use of ozonation for removal of benzothiazole rom model wastewater in order to perform chemical transformation and facilitate consecutive biological mineralization of ozonation products. Adsorption of benzothiazole on active carbon and integrated ozonation of benzothiazole with the addition of active carbon, were also studied. Lab-scale ozonation experiments were performed using ozone prepared from pure oxygen. Concentration values of benzothiazole as well as COD and TOC were measured during experiments. The oxidation intermediates of the processes were also studied. The best efficiency of benzothiazole degradation and transformation was observed when the combined ozonation/activated carbon process was applied. Respirometric measurements were carried out in order to evaluate the impact of ozonation products on the activated sludge microorganisms activity. Enhancement of biodegradability by ozonation was indicated by the increase in oxygen uptake rate with an increase in dosed volume of ozonated sample into respirometric cell. [ABSTRACT FROM AUTHOR]

The paper presents the results of a study aimed at the use of simple mathematical models of a sewer network, wastewater treatment plant (WWTP) and receiving water to control the discharge of diluted wastewater from combined sewer overflow system in order to protect water resources. The greatest burden on the receiving water usually occurs at the time of combined sewer system overflow, when diluted municipal wastewater is also discharged into the receiving water. Literature usually presents impact assessment results of either wastewater treatment plants or sewer system on the receiving water. In our work, we assess the impact of the integrated municipal wastewater system on the receiving water. The models for the sewer system, wastewater treatment plant, and receiving water under consideration were developed. Mathematical modelling of the subsystems of urban wastewater system was carried out using simulator SIMBA 6. Simulations were performed using real experimental data. Information about the sewer system overflow during the year (total amount of overflow, pollutant load of COD during overflow) was obtained by using dynamic simulations. The simulation results aimed at the impact assessment of the sewer system overflow and WWTP on the receiving water quality showed that the values of the monitored parameters in the river could exceed several times the environmental quality standards for receiving water. [ABSTRACT FROM AUTHOR]

The objective of this investigation was determination of feasibility of ozonation for treatment of leachates from municipal landfill. Efficiency of ozonation was determined for two leachates, different in age, composition and toxicity. We have studied the impact of ozonation time on removal of organics. The efficiency of treatment was monitored by COD, BOD5 and DOC analyses, removal of nitrogen compounds, as well as changes in toxicity. Therefore, acute toxicity tests with luminiscent bacteria Vibrio fischeri, Daphnia magna and nitrifying organisms of activated sludge (ammonium oxidation) were performed prior and after ozonation experiments. It has been confirmed that longer time of ozonation does not bring significantly better results regarding treatment of young leachate (36% in 20 minutes, 42% in 120 minutes). Two steps kinetics observed resulted in minor detoxification regarding luminiscent bacteria and no changes in effects to daphnids. More effective was ozonation of the stabilized leachate. Removal of COD reached 50% in 80 minutes and 65% in 120 minutes. Detoxification was also observed. Presented research confirmed, that ozonation itself was not effective treatment methods for investigated types of leachates for reduction of their hazardous impacts to meet regulatory effluent limits. [ABSTRACT FROM AUTHOR]

Due to its structure, hexamethylenetetramine (HMT) is a slowly biodegradable substance, hydrolysing in acid environment to ammonium and formaldehyde. Formaldehyde is toxic under normal conditions for biological treatment processes. Following an adaptation, a formaldehyde concentration of 1000 mg·1-1 may become biodegradable both in aerobic and anaerobic conditions. Acidic conditions for hydrolysis may be created chemically or by using natural biological treatment processes. The process of nitrification may be used in aerobic treatment, when H+ ions are created and pH drops below 5. For anaerobic treatment, the process of acidification may be used, when volatile fatty acids are formed and pH of the environment is decreasing. This work examines HMT degradation in an anaerobic baffled reactor (ABR). Spatial segregation of individual anaerobic degradation phases was used in the ABR, when hydrolysis and acidification in the first reactor compartments are accompanied by low pH values in these compartments. ABR performance was compared with UASB (upflow anaerobic sludge bed) reactor performance working under the same conditions. The removal efficiency of 95.8% HMT in ABR reactor and of 85.4% in UASB reactor, respectively, was measured at the organic loading 4 kg·m-3·d-1 and retention time 84 hours. 98% overall COD (chemical oxygen demand) removal was measured in ABR reactor and 95.6% in UASB reactor. The ABR proved to be the appropriate reactor for HMT removal. Better results of HMT removal in the ABR reactor in comparison with the UASB reactor were proved. [ABSTRACT FROM AUTHOR]

Presents a study which investigated the anaerobic treatment of sugar beet pulp for biogas production. Methodology; Results; Discussion.

The present study looks at the adsorption of polyethylene glycol onto activated carbon with the different molecular weight. The amount of PEG adsorbed on activated carbon depends on temperatures and pH. The adsorption capacities were determined through the adsorption isotherms. The results of the adsorption isotherm and kinetic studies show that the adsorption process can be well described with the Langmuir model. After linearization of the Arrhenius equation the activated energy had been estimated. [ABSTRACT FROM AUTHOR]

Seven small wastewater treatment plants were chosen for evaluation. These WWTPs work on the principle of anaerobic pre-treatment and aerobic post-treatment and were made with the cooperation of Slovak Technical University with ASIO-SK s.r.o. Bytca and ASIO s.r.o. Brno. Wastewater treatment plants are made for 5-600 PE. When operated at suitable conditions, the results match the directive water discharge from small wastewater treatment plants in the Slovak Republic. [ABSTRACT FROM AUTHOR]

The aim of the work was to assess the efficiency of ozonation and ozonation in combination with H 2 O 2 in jet loop reactor to increase biotreatability of persistent veterinary antibiotic Tiamulin. The efficiency of oxidative processes was monitored by combined approach based on determination of efficiency of wastewater treatment and impact to waste sludge stabilization. Degradation of Tiamulin in model wastewater (100 mg L -1 ) during oxidation was followed by COD and DOC measurements while changes in biodegradability were determined by respirometric measurements. Biogas production potential was also determined to identify problems related to anaerobic digestion of waste sludge resulted in treatment of Tiamulin-contaminated wastewater. At ozone dose of 69 g ozone g COD -1 and 220 g ozone g DOC -1 removal for COD and DOC was 26% and 17%, respectively. Better biotreatability was confirmed by respirometric testing. H 2 O 2 addition did not improve removal efficiency (11-13%). The second stage of nitrification was suppressed by the addition of Tiamulin and ozonation again recovered N - NO 3 - formation. O 3 /H 2 O 2 treated sample reduced the nitrification, especially formation of N - NO 2 - in the first phase of the process. Simultaneously, quadratic model was developed to describe the relationship between oxygen uptake rate and changes in ammonium nitrogen concentration due to the oxidative treatment. The positive impact of ozone was also confirmed by ozonation of Tiamulin-contaminated (400 mg L -1 ) waste sludge where biogas production potential was increased for 6-times. Combination of approaches confirmed, that O 3 effectively increase the treatability of Tiamulin in wastewater and sludge while addition of the hydrogen peroxide generally did not improve the performance of the processes.

Polychlorinated biphenyls (PCBs) produced in Slovakia as a commercial mixture Delor 103 cause the main contamination of sediment, water and fish in the eastern part of Slovakia. Delor 103 is a mixture of 40% PCB congeners, nine of them: PCB 8 (2,4'-dichlorobiphenyl), PCB 28 (2,4,4'-trichlorobiphenyl), PCB 52 (2,2',5,5'-tetrachlorobiphenyl), PCB 101 (2,2',4,5,5'-pentachlorobiphenyl), PCB 118 (2,3',4,4',5-pentachlorobiphenyl), PCB 138 (2,2',3,4,4',5'-hexachlorobiphenyl), PCB 153 (2,2',4,4',5,5'-hexachlorobiphenyl), PCB 180 (2,2',3,4,4',5,5'-heptachlorobiphenyl), and PCB 203 (2,2',3,4,4',5,5',6-octachlorobiphenyl), were monitored for their removal by ozonation and biodegradation using Achromobacter xylosoxidans. Ozonation improved the removal of PCB 52, 118, 153, 138, 180, and 203 using biological method with A. xylosoxidans. Degradation of 55% of the total amount of nine selected PCB congeners was achieved by the biological method with A. xylosoxidans, while 86% of the total amount of the nine selected PCB congeners were removed by the ozonation method; using a combination of biological and chemical methods, ozonation and A. xylosoxidans, showed a 94% removal efficiency of the selected PCB congeners present in mixture Delor 103., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The reason of low mineral content in source water is its origin in poorly soluble mineral geological structures. There are many areas with very soft low-mineralised water around the world. All people involved in drinking water treatment as well as some public health experts and producers of chemicals used for water treatment may be interested in the study. Enrichment of drinking water by minerals including calcium and magnesium is very important particularly in regions where drinking water is prepared by desalination. The aim of this work was to study and intensify the recarbonization process. Half-calcined dolomite in combination with carbon dioxide constitutes the chemistry of the applied method. Advantages of using a fluidised bed reactor contributed also significantly to the process efficiency enhancement. Continuous input of carbon dioxide into the fluidised bed recarbonization reactor resulted in an increase in the recarbonization rate by about one order of magnitude compared with the process in without carbon dioxide addition. Very good fit of experimental data for hydrodynamic characteristics of fluidised bed was obtained using simple model based on the Richardson and Zaki expansion equation. The first order model describes kinetic data from the recarbonization process with a good accuracy. Higher recarbonization rates were observed with smaller particles of half-calcined dolomite.

The feasibility of ozonation process for 2-mercaptobenzothiazole (2-MBT) removal follows from results of ozonation of the model wastewater. Total removal of 2-MBT was observed after 20 minutes of ozonation. Very good reproducibility of repeated ozonation trials including sampling and analysis was observed. However, the majority of dissolved organic carbon (DOC) and chemical oxygen demand (COD) remained in the reaction mixture. Benzothiazole (BT) and 2-hydroxybenzothiazole (OBT) intermediates were identified during degradation of 2-MBT with ozone. In addition to the above benzothiazole derivatives, the creation of some other organic compounds follows from results of mass balance. The best fits of experimental data were obtained using the first kinetic model for 2-MBT and zero-order kinetic model for COD and DOC. The reaction time of 60 minutes can be considered as effective with regard to controlled oxidation in order to increase a portion of partially oxidized substances. Higher biodegradability and lower toxicity of ozonation products on respiration activity of activated sludge microorganisms was observed at higher ozonation time.

Asbestos cement materials, mainly the eternit roof ceiling, being widely applied in the past, represent a serious environmental load. The solar radiation, rain and frost cause the deliberation of cement from the eternit roofing and consequently the wind contaminates the surrounding area by the asbestos (chrysotile) fibers. In combination with other carcinogens (e.g. smoking), or at reduced immunity of a man, they may cause serious respiratory diseases and lung cancer. The article presents the procedure and experimental results of artificial carbonatization, applied in the asbestos cement (eternit). The wet crushed and pulverized asbestos cement was thermally modified at 650°C and then the chrysotile fibers easily and completely reacted with the mixture of CO2 and water, producing new Mg-rich carbonates - hydromagnesite and magnesite: [Formula: see text] Applying this methodology, the asbestos-bearing waste can be stabilized and environmentally friendly permanently deposited. Finding a way of neutralizing of extreme pH values (around 12) at large eternit dumps represents also an asset of presented research. Simultaneously, the artificial carbonatization of chrysotile asbestos, applying CO2, offers an alternative way for permanent liquidation of a part of industrial CO2 emissions, contributing to multiple benefit of this methodology., (Copyright © 2013 Elsevier B.V. All rights reserved.)

This study compares efficiency of Fenton's oxidation and ozonation of 17beta-estradiol (E2) and 17alpha-ethinylestradiol (EE2) as two possible processes for removal of estrogens from aqueous solutions. The effectiveness of Fenton's oxidative removal was studied at different ratios of reagents Fe2+:H2O2 (1:0.5; 1:10; 1:20; 1:33), where with some molar ratios up to 100% removal of E2 and EE2 was achieved in the first few minutes of reaction. The best molar ratio for E2 (17beta-estradiol) removal was 1:33, while in the case of EE2 the most efficient one was 1:20 ratio. Ozonation was much faster, because complete removal of estrogens was achieved in 30 seconds (pH approximately eaqual 6), but the time of ozonation was extended up to 60 minutes trying to decompose formed by-products, expressing estrogenic activity, detected by YES (Yeast Estrogen Screening) assay. The obtained results showed that the removal efficiency of estrogens from waters should be assessed by a combination of chemical analyses and bioassay.

The objective of this investigation was determination of feasibility of ozonation for treatment of leachates from municipal landfill. Efficiency of ozonation was determined for two leachates, different in age, composition and toxicity. We have studied the impact of ozonation time on removal of organics. The efficiency of treatment was monitored by COD, BOD(5) and DOC analyses, removal of nitrogen compounds, as well as changes in toxicity. Therefore, acute toxicity tests with luminiscent bacteria Vibrio fischeri, Daphnia magna and nitrifying organisms of activated sludge (ammonium oxidation) were performed prior and after ozonation experiments. It has been confirmed that longer time of ozonation does not bring significantly better results regarding treatment of young leachate (36% in 20 minutes, 42% in 120 minutes). Two steps kinetics observed resulted in minor detoxification regarding luminiscent bacteria and no changes in effects to daphnids. More effective was ozonation of the stabilized leachate. Removal of COD reached 50% in 80 minutes and 65% in 120 minutes. Detoxification was also observed. Presented research confirmed, that ozonation itself was not effective treatment methods for investigated types of leachates for reduction of their hazardous impacts to meet regulatory effluent limits.