Pesticides are intensively used for the protection of field crops, orchards and vineyards, but they are also used in the removal of undesirable stands on non-agricultural land (railway embankments, playgrounds, handling areas, etc.), in water management (in coastal management, destruction of growths in irrigation canals), in forestry, etc. Regular application of pesticides increases their content in the aquatic environment and agricultural products. Their occurrence in water is relatively common and it follows that these substances are used in large quantities. Residues of these substances can persist in soils for 2 to 12 weeks. Due to their good solubility in water, they are easily transported from the soil to aquifers. Several methods can be used to remove pesticides from water, e.g., coagulation, filtration, precipitation, ozonation, adsorption, ion exchange, nanofiltration, reverse osmosis and advanced oxidation processes. Their effectiveness varies considerably and depends mainly on the chemical nature of the pesticide being removed. This article studies adsorption on two granular activated carbons Filtrasorb 400 and Norit 1240. Mixture of the pesticide standards (acetochlor, alachlor, dimethachlor, propachlor, metazachlor and metolachlor) was added to drinking water with concentration of approximately 1 µg/L. The experiments were performed in the glass bottles with the volume of 200 mL of water. The granular activated carbons (200 mg) were added to the bottles. Subsequently these bottles were regularly stirred, and the samples were taken out at times 0, 30, 60, 90, 120, 180, 240 and 360 minutes. Samples were taken by pipette into the 40 ml glass vials with added thiosulphate for preservation. Analyses of target pesticides were performed in laboratories of ALS Czech Republic in Prague. LC-MS using the internal standard method was used to determine chlorinated pesticides in water samples. The adsorption efficiency of pesticides removal and the adsorption capacity of granular activated carbon depends on the time of contact of water with the material. The results showed that the efficiency of selected pesticides removal and adsorption capacity for two granular activated carbons used varied. Filtrasorb F400 proved to be a better sorption material than Norit 1240. The efficiency of this material ranged from 18 to 60%, while the efficiency of Norit 1240 was significantly lower. Adsorption capacity of activated carbons for selected pesticides and reaction kinetics of 0th, 1st, 2nd and 3rd order was also studied.
This article focuses on the creation of the sixteen-channel DWDM (Dense Wavelength Division Multiplex) system according to the recommendation ITU-T G.694.1. Currently it is not possible to form a fully optical communication system without testing all non-linear effects possibly influencing its performance. The trend in high-speed transfer communication systems is using the multiplex, so we focused on the AWG (Arrayed Waveguide Grating) multiplexor/demultiplexor. For the purpose of this article we have created a DWDM system with the speed of 10Gbps where we compared two line codes, namely NRZ (Non Return Zero) and BRZ (Bipolar Return Zero) for the channel gaps of 12.5GHz and 100GHz. The individual codes were created in the "Matlab" programme and consequently implemented into the environment generated by "OptSim" by the RSoft company. The resulting signal was evaluated based on BER (Bit Error Rate) and the connected Q-factor for the channel No.3. The created system shows the influence of the system by the non-linear effect FWM (Four Wave Mixing) during the compression between the channels. Streszczenie. Niniejszy artykuł ma na celu utworzenie szesnastowego kanału DWDM (Dense Wavelength Division Multiplex) zgodnie z normą ITU-T G.694.1. Obecnie nie jest możliwe wdrożenie w pełni optycznego systemu komunikacyjnego bez testowania wszystkich zjawisk nieliniowych, które mogą działać w danym systemie w czasie rzeczywistym. Ponieważ w systemach transmisji danych o dużej szybkości wykorzystuje się multipleks, skupiliśmy się na multiplekserze i demultiplekserze AWG (Arrayed Waveguide Grating). W artykule zbadano system DWDM o szybkości 10Gbps, porównujący dwa kody linii NRZ (Non Return Zero) i BRZ (Bipolar Return Zero) dla kanałów 12.5 GHz i 100 GHz. Poszczególne kody zostały utworzone w programie Matlab, a następnie zostały wdrożone w środowisku OptSim przez firmę RSoft. Powstały system jest obliczany na podstawie szybkości błędu bitowego BER i związanego z tym współczynnika Q dla określonego kanału nr 3. Utworzony system pokazuje wpływ na system poprzez efekt nieliniowy FWM (Four Wave Mixing) podczas kompresji między kanałami. (Wpływ FWM z multiplekserem AWG w systemie DWDM).
Adsorption on a suitable adsorption material is the most frequently used methods in water treatment. In terms of plant operation, filtration (sorption) process represents a simple, effective and economical friendly method of heavy metals removal namely for the possibility of using a large scale of substances with a sorption ability - sorbents. Oxides, oxyhydroxides and hydroxide containing iron are among the most frequently used sorbents of the heavy metal removal. The quality of the treated water (pH, silica, phosphorus, fluorides, sulphates, total mineralization, iron and manganese, organic matter, etc.), redox conditions, the valency of metal and filtration conditions has the impacts on heavy metal removing efficiency. The objective of this work was to verify the sorption properties of granular iron-based sorption materials (CFH12, CFH18, Bayoxide E33, GEH) in removal of arsenic, antimony and nickel from drinking water. Under the given operational conditions (average concentration of arsenic in raw water 52,96 μg/L, average velocity 5.6 m/h, concentration As 10 μg/L at the outlet of media) adsorption capacity of filtration material CFH12 and Bayoxide E33 for arsenic was 1.203 mg/g and 1.463 mg/g, respectively. The limit of 10 μg/L of as was exceeded after 24048 BV and 28623 BV (Bed volume), respectively. According to the model tests (concentration of nickel in raw water of about 50 μg/L, filtration rate 5.8 m/h, concentration Ni 20 μg/L at the outlet of media, pH 7.0) the adsorption capacity of nickel for Bayoxide E33 was set to 198 μg/g, for CFH18 107.5 μg/g, GEH 97.5 μg/g and CFH12 38.1 μg/g. The limit of 20 μg/L of Ni was exceeded after 4808 BV for Bayoxide E33, 1409 BV for CFH12, 3007 BV for CFH18 and 3218 BV for GEH. For the average antimony concentration of 58.35 μg/L in raw water and filtration rate between 4.27-4.51 m/h, the limit concentration of 5 μg/l at the outlet of the sorption column was reached at the bed volume 3470 for GEH, 2225 for CFH 12 and 1274 for Bayoxide E33. The adsorption capacities were as follows: 167.8 μg/g for GEH, 105.7 μg/g for CFH12 and 90.9 μg/g for Bayoxide E33. The experiments proved that iron-based sorption materials GEH, CFH12, CFH18 and Bayoxide E33 can help reduce the concentration of heavy metals in water below the limit of the Slovak Republic Decree No. 247/2017 on Drinking Water.
Pesticides, as one of the main monitored micropollutants these days, are monitored and determined even in the drinking water, because of their toxic effect on the living organisms. Presence of these pesticides in the drinking water is undesirable and, therefore, they need to be removed. Chloroacetanilides belong to the group of herbicides, which are commonly used in agriculture. Their complex structure prevents common biological degradation, so more complex processes are needed. One of the most efficient process for their removal is adsorption on activated carbon. In this article adsorption of certain chloroacetanilides from water for two different types of granular activated carbon is presented. Matrix used for dilution of pesticides was drinking water and the efficiency of the removal of pesticides ranged from 5 to 60 % for the specific sorption materials and pesticides. This research has shown that adsorption material Filtrasorb 400 is far more efficient than Norit 1240.
Theory of constraints (TOC) is about thinking in logical, systematic, or structured processes similar to the PDCA learning loop. It is about analyzing cause and effect, verifying basic assumptions, exploring alternatives and process improvement. The goal of TOC is to maximize the efficiency of a process selectively at the most critical points and thereby maximize profitability, quality, or other corporate objectives. This paper include basic theoretical information about TOC and following application during process improvement. This paper was realised with VEGA support No. 1/0229/08 Perspectives of quality management development in coherence with requirements of Slovak republic market.
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