2.5. Statistical analysis
The anaerobic ponds process performance data were
presented in terms of arithmetic averages of nine values
±standard deviation. The SMA tests were carried
out with two replicates. Common linear regression curve
was fitted to the data obtained from the two replicates
test and a relation between volumes of methane production
with respect to time was established. The SMA
was calculated based on the slope of methane volume
versus time curve and mass of sludge taken for the SMA
test. Likewise a linear relation was established between
the cumulative cyanide degradation with respect to time.
Data from settling experiments was used to establish a
non-linear relationship between the half-removal time
and influent total suspended solid concentrations. All statistical analyses (arithmetic average, standard deviation,
linear and non-linear regression and correlation
coefficient) were performed using Microsoft Excel 2000.