FIG. 7.
A. Relationship between theoretical and measured AOB fractions in full-scale activated sludge reactors in the United Kingdom and a bench-scale reactor. The regression line has a statistically significant (P = 0.003) slope of 1.28 (standard error of 0.20) and an intercept (−2.8) that is statistically distinguishable from 0 (P = 0.022). The regression line explained 89% of the variation between the two estimates. Xaob/Xv is the proportion of the total biomass measured as MLVSS that is contributed by the AOB. Hydburn was identified as an outlier by using Dixon's test (P < 0.0.05). B. Relationship between theoretical and measured AOB fractions in full-scale activated sludge reactors in the United Kingdom and a bench-scale reactor, but with Hydburn removed. The slope is 1.23 (standard error of 0.16), r2 rises to 94%, and the intercept (−2.47) is still significantly different from zero (although only marginally so) (P = 0.034). CI, confidence interval.