pollution sources into the water, the necessity of qualitative studies of water resources is one of the most important new challenges for mankind in almost every parts of the world. dissolved oxygen (do) and biochemical oxygen demand (bod) are among parameters of water quality indexes which are considered as water pollution indexes. in the present research, do and bod of dez river basin water (...

many constants and coefficient effect on the modeling results. in many cases, it is possible these constants and coefficients differ from their real values in the environment, but the modeling results adapted with real boundary conditions due to other factors adjustment during modeling. uncertainty analysis is a tool for assessing the effect of uncertainty of various factors on the modeling res...

polarographic method is considered as an alternative laboratory technique for analytical method in determination of dissolved oxygen and n-n03. analytical method is a time consuming technique and is subject to several interferences due to some of constituents in sewage. in this laboratory research, the polar graphic technique with, mercury drop electrodes and titrometric method were applied in ...

large amounts of degradable wastes including sewage water and agricultural waste or nutrients that stimulate growth of organic matter are discharged into the caspian sea. as a result, average dissolved oxygen concentration in deeper layers is decreasing. this paper presents distribution and seasonal variations of the concentration of dissolved oxygen over the southern shelf of the caspian sea a...

one of the most paramount processes that play a considerable role in reducing the concentration of heavy metals during estuarine mixing is flocculation. not only does such a process cause a huge percentage of metals to come into the particulate phase, but also it provides ample nutrients for the aquatic life. in the present study, impact of such factors as salinity, ph and do on flocculation of...

Rivers can absorb certain amounts of contamination relying on different factors such as: river discharge, the primary conditions of the river, the river depth, discharge and the river viscosity of the offloaded wastes in the river. From parameters of water quality point of view, it is recom-mended to determine some parts of the river which are lower than the standard level in order to find out ...

water quality aspect with regard to dissolved oxygen was studied for a 24 kilometer stretch of malaprabha river in karnataka state, india. main objective of the research was to simulate the predicted dissolved oxygen depletion due to the waste load allocation in the river with the ambient observed values of dissolved oxygen, and to ascertain the application of mathematical modeling for predicti...

We assessed the physico-chemical status of twelve surface water samples from the Birjand flood plain (east of Iran) during fall 2010. The sampling points were selected on the basis of their importance. The physico-chemical parameters such as pH, temperature (T), electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), calcium (Ca2+), magnesium (Mg2+ ), sodium (Na+), pota...

Cell growth and retamycin production in Streptomyces olindensis So20 were studied at different dissolved oxygen levels during fermentation. The profiles for cell growth and retamycin production in an experiment with dissolved oxygen control at 5% air saturation during production were similar to those in an experiment without dissolved oxygen control. However, despite slower cell growth, a twofo...