Ammonia total oxygen demand

When nitrification occurs 4.57 gram oxygen are used per gram of ammonia nitrogen oxidised. Thus the total oxygen demand is then the sum of the autotrophic and heterotrophic respiration rates. 

The oxygen demand by the nitrifying bacteria is therefore a measure of the ammonia concentration in the sample. For this rapid determination method a detection limit for ammonium in the ppb-range was observed. Because this biosensor reacts also to nitrite and urea, but shows only little reaction to other C-compounds (see Table 7), it is further suitable for the summary quantitation of nitrifiable N-compounds, the so-called N-BOD [85,861. This parameter can be useful for the control of aerobic wastewater treatment processes, due to the fact that the oxygen demand for nitrifiable N-compounds can make up to 20-40% of the total oxygen demand. 

AAN-anode surface (cm ), Vact active volume, i.e., electrolytic cell volume (L), VxoT-total volume (L), d-inter-electrode distance (mm), J-current density (A m ), Q-specific electrical charge (Ah L ), q-volumetric recirculation flow rate (L h ), R-removal (%), CE current efficiency (%), FAC free available chlorine, COD chemical oxygen demand, TAA total ammonia nitrogen, DOC dissolved organic carbon, f/F-ultraviolet absorbance, SUVA254 specific UV absorbance at 254 nm, THMs trihalomethanes, HAAs haloacetic acids... 

While all analysts have the ability to learn and certify in all of the methods, generally, the analysts specialize in one or more of the following areas 1) analysis of nitrates and nitrites (7) 2) trace metal analysis by ICP-MS (8) 3) anions analysis by Ion chromatography (P) 3) Total Suspended Solids (TSS) 10) and Total Dissolved Solids (TDS) (ii) 4) Biological Oxygen Demand (BOD) 12) and, 5) determination of mineral cations by flame atomic absorption) 12). Other tests such as potentiometric measurement of fluoride 14) and ammonia 15), alkalinity 16) and cyanide 17) are non-systematically assigned to analysts. 

There are many examples of the detrimental effects of decaying organic material in cooling systems, for instance, seaweed, barnacles, mussels, and shellfish accumulated in heat-exchanger systems. For unpolluted seawater, it normally suffices to measure the salinity or chlorinity, the pH, and perhaps the oxygen content. However, in the case of polluted seawater, it is often necessary to obtain additional data. These can include the concentrations of heavy metal ions, sulfide, and ammonia as well as the chemical oxygen demand (COD) and total organic carbon (TOC) values. 

The reforming exchanger concept totally eliminates the furnace and uses a hot secondary reformer outlet as its heat source. Surplus air over the stoichiometric demand or oxygen-enriched air in the secondary reformer is required to balance the heat demand for the primary reforming reaction. Chiyoda proposed this concept in 1984 [26,271 however, ICI was the first one. to comr mercialize a reformer exchanger called the Gas Heat Reformer (GHR) as part of their Leading Concept Ammonia (LCA) process. The GHR is discussed further under the LCA process section. 

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