|Ultima descărcare din IBN:|
| SM ISO690:2012|
SANDU, Maria; TARITA, Anatol; MOSANU, Elena; LOZAN, Raisa; GOREACIOC, Tatiana; TURCAN, Sergiu. Index of ammonia ions nitrification in Bac river water. In: Achievements and perspectives of modern chemistry. 9-11 octombrie 2019, Chişinău. Chisinau, Republic of Moldova: Tipografia Academiei de Ştiinţe a Moldovei, 2019, p. 190. ISBN 978-9975-62-428-2.
|Achievements and perspectives of modern chemistry 2019|
Conferința "International Conference "Achievements and perspectives of modern chemistry"" |
Chişinău, Moldova, 9-11 octombrie 2019
Ammonia and nitrogen concentrations more than 1 mg/L in natural waters have been given as indicator of organic pollution, caused by livestock, intensive agriculture, industrial effluents and liberation of domestic sewage in courses of superficial waters, and can be toxic to aquatic species if they are higher than 2.5 mg/L . Unpolluted waters contain small amounts of ammonia and ammonia compounds, usually <0.1 mg/L nitrogen. Total ammonia concentration in surface water are typically less than 0.2 mg/L N but may reach 2-3 mg/L N . In the nitrogen cycle the oxidation of ammonia to nitrate by microorganisms is a key process, resulting in nitrogen loss from ecosystems, eutrophication of surface and ground waters. One Nitrification Index (NI) was proposed for chloraminated drinking water in distribution system . In order to evaluate the nitrification process in surface waters was developed a NI, which characterizes the intensity of ammonium nitrification under natural conditions (in the presence of biota and the existing pollution level) with the formula (in mg/L N): NI = (N-NO3 · 100) : (N-NO3- + N-NO2-+ N-NH4+). In this study was determinated the ammonia, nitrite and nitrate nitrogen content in river Bâc in comparison with Dniester river water for calculation of theNI. It has been found that the NI of Dniester river water has value of 94% (effective nitrification) with the exception of water downstream of the Bâc river, where NI is only of 13%. Nitrification is practically absent in Bâc river water until the Dniester spill (2.6%) (Table).Based on the NI values, obtained in the laboratory modelling, it is concluded that in the addition of ammonium ions, which can be discharged by the waste water, in just 30 days nitrification of the ammonium ions has passed both stages.Table. Dynamic of NI in the study of surface waters, based on the laboratory modelling results