خيارات البحث
النتائج 411 - 420 من 448
Distribution of components ass. Scirpo-Phragmitetum, Koch 1926, through the flow of the river Moravica [Serbia] and their indicative values
2007
Milenovic, V.,Osnovna skola Vuk Karadzic, Zitkovac (Serbia) | Randelovic, N.,Prirodno-matematicki fakultet, Nis (Serbia)
During the research of the flora of the river Moravica methodology of ass. Scirpo-Phragmitetum, Koch 1926, subass. typhetosum latifoliae, Pignotti 1953, with differential typa Typha latifolia with related marshy plants was applied. The community is developed as small units in the lower flow of the river Moravica (the part flowing through the town Aleksinac), where the anthropogenic influences are significant due to the empting of the sewage and industrial polluted waters of the town Aleksinac. Many diffuse forms of pollution are also present, particularly in the form of illegal dumps. Waste waters represent serious load on the recipient river and influence qualitative and quantitative content of the phytocenosis. Ecological index of the community shows change in water quality and presence of organic substances (above all nitrogen compounds) in the water and the riverbed ass. Scirpo-Phragmitetum, Koch 1926, subass. typhetosum latifoliae, Pignotti 1953, which indicates the riverbed loaded with organic substances (mezotrophic plants, N=3.50)
اظهر المزيد [+] اقل [-]Benthic community and phytoplankton in freshwater quality assessment of Jegricka protected area [Serbia]
2007
Miljanovic, B.,Prirodno-matematicki fakultet, Novi Sad (Serbia) | Jurca, T.,Prirodno-matematicki fakultet, Novi Sad (Serbia) | Mijic, I.,Prirodno-matematicki fakultet, Novi Sad (Serbia) | Pankov, N.,Prirodno-matematicki fakultet, Novi Sad (Serbia) | Sipos, S.,Prirodno-matematicki fakultet, Novi Sad (Serbia)
Composition of benthic macroinvertebrates and phytoplankton were examined during the period of July-November 2006, for purposes of freshwater quality assessment in protected area of Jegricka water body. Results of research show intensive sedimentation of organic matter in river bed, which is caused by eutrophication processes and small flow velocity in this canalized river of Vojvodina.
اظهر المزيد [+] اقل [-]Market aspects of waterworks - theory of natural monopoly
2007
Nestorovic, Z.,Hidroenergetski i plovidbeni sistem Djerdap 1, Kladovo (Serbia)
Scarce natural resources which are important for development of society or civilization itself are the issue of research for economists from the point of view of their efficient utilization. Theory of natural monopoly asserts that for society is better to treat scarce resources as monopoly than to put them on free market. The assertion is that it is better to invest in development of other markets than into free competition in sphere of some scarce resources. Main aim of this paper is to overview some elements of theory of natural monopoly.
اظهر المزيد [+] اقل [-]Color removal from raw water in drinking water treatment by coagulation with aluminium sulphate
2007
Ljubisavljevic, D.,Univerzitet u Beogradu, Beograd (Serbia). Gradjevinski fakultet
Removal of colour by coagulation in the drinking water treatment is described. Optimal results are obtained by pH correction. Buffer capacity of raw water is dominant on efficiency and rentability of the process.
اظهر المزيد [+] اقل [-]Enhanced coagulation and flocculation effects in drinking water treatment by flocculation sludge recirculation
2007
Agbaba, J.,Prirodno-matematicki fakultet, Novi Sad (Serbia) | Dalmacija, B.,Prirodno-matematicki fakultet, Novi Sad (Serbia) | Tubic, A.,Prirodno-matematicki fakultet, Novi Sad (Serbia) | Djurin, Z.,JKP Vodovod i kanalizacija, Zrenjanin (Serbia) | Pusic, I.,JKP Vodovod i kanalizacija, Zrenjanin (Serbia) | Ugarcina, S.,Prirodno-matematicki fakultet, Novi Sad (Serbia) | Roncevic, S.,Prirodno-matematicki fakultet, Novi Sad (Serbia)
This work considers the possibility of enhancing the iron (III) chloride coagulation process in natural organic matter removal by flocculation sludge recirculation. The results show that flocculation sludge has the potential to coagulate organic matter, and shows a dependence on the depth in the precipitator (0, 30 or 70 cm). Recirculation of flocculation sludge at a dose of 1.6 g/l (from a depth of 30 cm), results in a reduction of required coagulant by 25%.
اظهر المزيد [+] اقل [-]Industrial waste water refinement by precipitation treatment using dithiocarbamate: Changing process duration and pH effect on refinement efficiency
2007
Milenkov, Lj.,JKP Vodovod, Bor (Serbia) | Gardic, V.,Institut za bakar, Bor (Serbia) | Stankovic, S.,Institut za bakar, Bor (Serbia)
Stable complexes formation caused by usage of complexing agents as additive in plating solutions, made waste water treatment aggravated and expensive. The investigation results of samples that contain some cations expected in waste waters from this type of facilities, are presented in this paper. The precipitation of disolved heavy metals by neutralization, in the presence of strong chelators, do not give requested results. The dithiocarbamates are effective in complexing heavy metal ions forming insoluble compounds, with solubility far below that of the corresponding hydroxides. Inductively Coupled Plasma Optical Emission Spectroscopy is used for wastewater samples analysis. After the reduction of Cr6+ into Cr3+ ions and homogenization, dithiocarbamate is added. Modified neutralization process with unchanged retention time and pH 9.0 +/- 0.2 results the Law permitted wastewater quality.
اظهر المزيد [+] اقل [-]The utilization of the waste sludge produced during the process of waste water purification in Kolubara - Prerada as mineral-organic fertilizer in the process of biological reclamation of deposol in RB Kolubara DOO, Lazarevac [Serbia]
2007
Djikic, G.,Kolubara-Usluge doo, Lazarevac (Serbia) | Mandic, S.,Kolubara-Usluge doo, Lazarevac (Serbia) | Todorovic, N.,RB Kolubara doo, Lazarevac (Serbia) | Radisic, Z.,RB Kolubara doo, Lazarevac (Serbia)
During technological process of coal treatment and coal improvement in RB Kolubara waste water is produced in the waste water cleansing installation and waste mud is separated. The examination have been executed concerning agrochemical and mechanical properties of this material as well as the presence of heavy metals and phenol. Based on the results which appeard during examination, this materail can be included in the biological reclamation process as bonifactor and deposol fertilizer. Inserting such organic materials, the requared organogenic features are increased and the physical and mechanical characteristics of deposol substrate are improved. The economical effects are important for RB Kolubara as well as for Kolubara-Prerada. The most important contribution is to environmental protection and fulfilling the legal regulations for bringing back of degraded soil to the primary purpose.
اظهر المزيد [+] اقل [-]Environmental assessment within Boka Kotorska bay according to presence of sea urchin Paracentrotus lividus (Lamarck, 1816)
2007
Kascelan, S.,Institut za biologiju mora, Kotor (Montenegro)
Sea urchin, Paracentrotus lividus belongs to Echinoderms and has wide distribution as well in Meditarranean Sea as in the Adriatic Sea. It is very appreciated as object for testing negative impact of pollution, so can be used as bio indicator of sea water and sediments quality. Identification of the presence of this animal is done at 11 locations inside the Bay of Boka Kotorska (Montenegro), during 2005/2006. Obtained results show that the sea-urchin inhabit only outer part of Boka Kotorska Bay, where is open sea impact very strong, while inner part of the Bay is characterized by absence of Paracentrotus lividus, what can be caused by potential low quality of the sea water in the Bay.
اظهر المزيد [+] اقل [-]Monitoring of demersal resources in the Montenegrin coast and influence [of] hydrographic parameters on their distribution
2007
Joksimovic, A.,Institut za biologiju mora, Kotor (Montenegro) | Kasalica, O.,Institut za biologiju mora, Kotor (Montenegro) | Mandic, S.,Institut za biologiju mora, Kotor (Montenegro)
Monitoring of demersal resources in the Montenegrin coast start at 1997. We used commercial trawl vessels by monthly dynamic trawling. Processed total catch, estimated percentage part in total catch and CPUE (Catch per Unit Effort). We used standard fishery biology methods, estimation of population dynamic parameters, economical important fish, Red Pandora, Pagellus erythrinus, Red Mullet, Mullus barbatus, and crustaceans species, Pink shrimp, Parapenaeus longirostris. Also, we estimated relative and absolute biomass and MSY (Maximum Sustainable Yield) of this important demersal resources. This data give support to Ministry of Agriculture, Forestry and Water Management (of the Republic of Montenegro) to organize responsible exploitation of this resources. We finded center of higher biomass and relation to hydrographic factors, influence of income freshwater in the sea and increase of trophic level in this areas.
اظهر المزيد [+] اقل [-]Saprobiological characteristics of Skadar lake and Bojana river [Montenegro]
2007
Radonjic, D.,Institut za javno zdravlje, Podgorica (Montenegro) | Ceprnic, D.,Vodovod i kanalizacija, Herceg Novi (Montenegro)
Research of phytoplankton is conducted in different seasons during 2004 and 2005. River Bojana and Ada Bojana are analyzed on several locations. The objective of research is based on algae as reliable indicator of water quality and ecological condition of water. We would like to show the need for protection of these water ecosystems from permanent contamination, basically sewage waste. Saprobiotic index is determined by Gulyas Pal method. Pantle Buck method is used to calculate saprobiotic level. Chlorophyll A is analyzed by spectrophotometer. Presence of Cyanophytae was established.
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