Norm

NEN-EN-ISO 9509:2005 Ontw. en

Water - Methode voor de beoordeling van de remming van de nitrificatie van micro-organismen in actief slib door chemicaliën en afvalwater

  • Deze norm is ingetrokken sinds 12-09-2006

25,62

Over deze norm

Status Ingetrokken
Aantal pagina's 18
Commissie Anorganische parameters
Gepubliceerd op 01-06-2005
Taal Engels
This International Standard specifies a method for assessing the short-term inhibitory effect of waters, waste waters or test substances on nitrifying bacteria in activated sludge. The inhibitory effect is estimated over an exposure period of usually 4 h or up to 24 h with weakly nitrifying sludge. The method is applicable with nitrifying activated sludge derived from domestic and synthetic sewage and also to sludges from industrial and mixed domestic and industrial waste waters. The nitrifying activity of the sludge is verified by testing in the presence and absence of a specific inhibitor (e.g. N-allylthiourea; see Annex A). If the nitrification rate is within a suitable range for the test, i.e. 2 milligrams of nitrogen per gram of suspended solid and hour (mg of N per (g·h) to 6,5 milligrams of nitrogen per gram of suspended solids and hour (mg of N per (g·h) , the sludge may be used directly; if adjustments are not necessary (see Clause 9). The method is applicable to water-soluble, non-volatile chemicals, and also to waste waters Sludges from different sources respond differently to a given concentration of an inhibitor mainly due to a reaction between the inhibitor and components of the sludge. This results in a partial neutralisation of the toxic effect. Also, since the test lasts only hours, any inhibitory effects may diminish or increase over a longer period, e.g. in the continuous activated sludge system (see ISO 5667-16 ).

Details

ICS-code 13.060.70
Nederlandse titel Water - Methode voor de beoordeling van de remming van de nitrificatie van micro-organismen in actief slib door chemicaliën en afvalwater
Engelse titel Water quality - Method for assessing the inhibition of nitrification of activated-sludge micro-organisms by chemicals and waste waters
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