Abstract The salt concentration of seawater is a significantly sensitive factor in the seawater reverse osmosis desalination plant that applies different pressures in freshwater production, depending on the salinity of the seawater. For the efficient operation of the plant, it needs to be grounded on investigations and analyses of seawater salt concentration and water temperature distribution and change. The conventional research methods, however, have temporal and spatial limitations. This research uses the latest satellite data to analyze the flows and the seasonal temperature distributions of ocean currents that affect mostly the changes in the seawater salt concentration in the neighboring waters of the seawater desalination plant that is being built in Gijang-gun, Busan, South Korea. The results of this research showed that the ocean current in the neighboring waters of Gijang-gun, Busan had a relatively slow velocity (average: 0.05 m/s) but formed very comprehensive flow shapes as the warm and cold currents met and that the degree of the salinity change was significant because the temperatures of the sea surface differed considerably in summer unlike in the other seasons.
Optimization of the nitrification processes in biofilms is important for effective nitrogen removal because nitrification in an aerobic biofilm is considered to be a less than reliable process. Thus, one of the main factors to improve biological nitrogen removal processes is a better understanding of the microbiology and population dynamics of ammonia oxidizing bacteria (AOB) in wastewater treatment biofilms. Although the AOB in wastewater treatment have been qualitatively and quantitatively studied, information on their actual populations and activities is still limited. Therefore, the areal cell density of AOB in domestic wastewater biofilms on a partially submerged rotating biological contactor (RBC) was determined by fluorescent in situ hybridization (FISH) with a set of 16S rRNA-targeted oligonucleotide probes. The growth kinetics of the in situ AOB was also studied. Although low numbers of AOB were found at the deeper layers where oxygen was depleted, they were primarily detected in the upper and middle layers of the biofilm. The maximum specific growth rate (µ b,max ) and half saturation constant (K s ) of AOB in the biofilm were 0.32 d –1 and 1.7 mM/L of NH 4 + , respectively. Key words: ammonia oxidizing bacteria (AOB), fluorescent in situ hybridization (FISH), growth rate, rotating biological contactor (RBC).
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