• Journal of Korean Society of Water and Wastewater
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• v.21 no.3
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• pp.295-303
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• 2007

Nitrogen compounds in municipal wastewater can be divided into biodegradable and nonbiodegradable fractions with biodegradability. Biodegradable nitrogen compounds can be removed through biological nitrification and denitrification processes, and nonbiodegradable nitrogen compounds affect the effluent quality of biological nutrient removal processes. The amount of nitrifiable nitrogen compounds, which are the sum of ammonia and biodegradable organic nitrogen, has been estimated by respirometry. Respirometry shows good estimation of the concentration of nitrifiable nitrogen when a synthetic sample of ammonium chloride is dosed. The estimated concentration of nitrifiable nitrogen compounds in municipal wastewater is close to ammonia concentration in municipal wastewater, but it is lower than that for the synthetic sample. If nitrogen assimilated into cell synthesis of nitrifiers and heterotrophs is considered, the total amounts of nitrifiable nitrogen compounds, which are nitrified and assimilated, could be more accurately estimated. The concentration of nitrifiable nitrogen compounds, which are biodegradable, is about 31 mg N/l, and this is 119% of ammonia and 94% of total nitrogen. Ammonia, nitrate, biodegradable organic nitrogen, and nonbiodegradable nitrogen are about 79%, 1%, 15%, and 5% of the total nitrogen in municipal wastewater, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.2
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• pp.169-176
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• 1985

Six analytial methods for determing the available nitrogen in soils were tested to predict the optimum fertilizer rate for the flue-cured tobacco and to test the fertility level of soils for tobacco. All methods, nitrifiable $NO_3-N$ value for 2 and 4 weeks incubation, UV absorption value at 260nm and N-value in acid digestion of 0.01 M-$NaHCO_3$ extracts, N-value extracted in boiling with $CaCl_2$ solution, and autoclave-extractable $NH_4-N$ value in 0.01 M-$CaCl_2$, were closely correlated with total nitrogen uptake as well as yield. Therefore available nitrogen indices determined from above 6 analysis method could be used for the predicting of tobacco yield without fertilizer, criteria for fertility class, and recommendable range of optimum fertilization.