Activated sludge nitrification

Aerobic digested sludge 0.02-0.4 0.11 1 Activated sludge + nitrification/ denitrification Australia [9]... 

An activated sludge nitrification-denitrification sequence includes an anoxia tank, possibly with an added organic substrate input and an extended aeration tank with an added neutralizing agent. On start-up, acclimatization may require many weeks depending on the quality of secondary settling, which accordingly requires particular care. 

FIGURE 19.7 Schematic representation of a nitrification-denitrification activated sludge plant. 

Eiroa, M., Kennes, C., and Veiga, M.C., Simultaneous nitrification and formaldehyde biodegradation in an activated sludge unit, Biores. Technol., 96, 1914-1918, 2005. 

The activated sludge process for meat processing wastewater treatment was reported by Annachhatre and Bhamidimarri.37 When a model reactor was operated at an HRT of 5-15 h, a COD removal of more than 85% was achieved. The COD loading for the above performance was 3.2kg COD/(m3d). An SRT of 13 d resulted in almost complete nitrification. El-Gohary et al.30 reported that the activated sludge process reduced the BOD and COD of a potato-chips factory wastewater by 86% and 84%, respectively. The organic loading rate and HRT were reported as 8.9 kg BOD/ (m3d) and 6h, respectively. 

Secondary 250-40 Percolation/activated sludge filters, biolog. oxidation, nitrification Flotation, coagulation by additives Alteration (e.g. PO 43, F , heavy metals), filtration... 

Donahue, R.T. Single stage nitrification activated sludge pilot plant study on a bulk pharmaceutical manufacturing wastewater. Proceeding of the 38th Industrial Waste Conference, Purdue University, West Lafayette, IN, 1984 173-180. 

Tomlinson T.G., A.G. Boon, and C.N.A. Trotman (1966). Inhibition of nitrification in activated sludge processes of sewage disposal. J. Appl. Bacteriol. 29 266-291. 

F. Braam, A. Klapwijk, Effects of copper on nitrification in activated sludge, Water Res. 15 (1981) 1093-1098. 

Activated sludge systems (ASS) vary considerably depending on cell residence time. The oxygen demand can range from 1.0 to 2.0 kg of oxygen per kg of BOD5 removed. If nitrification occurs, however, additional oxygen should be provided at the rate of 4.6 kg 02 per kg of ammonia removed. When... 

For activated sludge plants that produce only partial nitrification, it is a common complaint of operators that a residual chlorine cannot be obtained at the effluent. The reason for this is the reaction of nitrites with the chlorine disinfectant producing nitrates as shown in Reaction (17.30). 

ISO 9509 (1996). Water quality - Method for assessing the inhibition of nitrification of activated sludge micro-organisms by chemicals and wastewaters... 

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