Figure 28 The normalised variation of DO, pH and NH +4 plotted together to illustrate the correlation between the variables. A closer inspection shows that there is a time delay of a few hours between a change in DO level and a change in NH +4 . The pH also seemed to be delayed but by a shorter amount of time. It was obvious from Figure 28 that both pH and NH +4 were affected by the DO. However, the pH and NH +4 have opposing effects on the efficiency so the one affecting the efficiency the most would in effect be the controlled parameter. The NO -3-estimate was calculated from the pH-values and compared to the NH +4 values and the efficiency in Figure 29.
Published on Nov 9, 2011