in pond A1 was tested by treating the 14 ‘percent remaining’ values shown in Fig.
1B as independent samples, resulting in a single significance value.
All ponds significantly reduced TSS concentration except for pond B2, where the
result was not significantly less than 100%. Both ponds B1 and C had similarly good
performance at removing TSS, with only about 40% of the intake TSS concentration
remaining in the discharge water (Fig. 3A). These ponds had residence times of 0.67
and 1.98 days. Even ponds B2 and A2, with residence times of only 0.15 and 0.25 day,
appeared to remove some of the TSS, with discharge concentrations 89% and 80% of
Fig. 1. (A) Intake and discharge of total nitrogen (TN) concentrations in sedimentation pond A1, measured on 14
occasions (meanFS.E. of three replicates). (B) Discharge concentration of TN expressed as a percentage of
intake concentration.
Fig. 2. (A) Intake and discharge of total suspended solids (TSS) concentrations in sedimentation pond C,
measured on 13 occasions (meanFS.E. of three replicates). (B) Discharge concentration of TSS expressed as a
percentage of intake concentration.
C.J. Jackson et al. / Aquaculture 226 (2003) 23–34 29