Table S1: Quality limits for treated wastewater according to the Cyprus Law 106 (I)/2002

Table S2: ANOVA analysis for the Z-values of the log-transformed values for the inlet of the sewage treatment plants A and B (STP A and B-INsamples)

Table S3: ANOVA analysis for the Z-values for the secondary treated effluent of sewage treatment plants A and B (STP A and B-STEsamples)

Table S4: ANOVA analysis for the Z-values for the outlet of sewage treatment plants A and B (STP A and B-OUTsamples)

Table S1

Parameters / STP A, STP B / Frequency of sampling
Values / (year-1)
BOD5 (mg L-1) / 10 / 4
COD (mg L-1) / 70 / 4
SS (mgL-1) / 10 / 4
Conductivity (μS cm-1) / 2200[1] / 4
TN (mg L-1) / 15 / 4
TP (mg L-1) / 10 / 4
Cl- (mg L-1) / 300 / 4
Oils (mg L-1) / 5 / 4
Zn (mg L-1) / 1[2] / 2
Cu (mg L-1) / 0.1 / 2
Pb (mg L-1) / 0.15 / 2
Cd (mg L-1) / 0.01 / 2
Hg (mg L-1) / 0.05 / 2
Cr (mg L-1) / 0.1 / 2
Ni (mg L-1) / 0.2 / 2
B (mg L-1) / 13 / 2
Faecal coliforms 100 m L-1 / 504 / 4
Faecal parasites eggs / 0 / 4
Residual Cl (mg L-1) / 15 / 4
pH / 6.5 – 8.5 / 4
Toxicity / 75% of samples must comply with the following:6
Bioluminescence inhibition TU50<1
and/orTU20<1.5
Immobilization for Daphnia TU50<1
Growth inhibition for algae TU50<1 / 1

Table S2

Cluster / Error / F / Sig.
Mean Square / df / Mean Square / df
Zscore: log[Temperature] / 64.129 / 1 / 0.833 / 379 / 76.945 / 0.000
Zscore: log[pH] / 120.154 / 1 / 0.683 / 376 / 175.895 / 0.000
Zscore: log[TP] / 22.550 / 1 / 0.837 / 132 / 26.949 / 0.000
Zscore: log[TN] / 10.138 / 1 / 0.932 / 134 / 10.880 / 0.001
Zscore: log[BOD] / 31.096 / 1 / 0.551 / 67 / 56.455 / 0.000
Zscore: log[COD] / 183.019 / 1 / 0.471 / 344 / 388.676 / 0.000
Zscore: log[TSS] / 39.955 / 1 / 0.891 / 359 / 44.819 / 0.000
Zscore: log[Conductivity] / 327.159 / 1 / 0.137 / 378 / 2385.505 / 0.000
The F tests should be used only for descriptive purposes because the clusters have been chosen to maximize the differences among cases in different clusters. The observed significance levels are not corrected for this, and thus, cannot be interpreted as tests of the hypothesis that the cluster means are equal.

Table S3

Cluster / Error / F / Sig.
Mean Square / df / Mean Square / df
Zscore[Temperature] / 4.849 / 1 / 0.989 / 335 / 4.905 / 0.027
Zscore[pH] / 283.957 / 1 / 0.137 / 328 / 2067.743 / 0.000
Zscore[TP] / 27.555 / 1 / 0.800 / 133 / 34.429 / 0.000
Zscore[COD] / 166.104 / 1 / 0.487 / 322 / 340.900 / 0.000
Zscore[TSS] / 193.502 / 1 / 0.395 / 318 / 490.315 / 0.000
Zscore[NO3] / 107.055 / 1 / 0.220 / 136 / 486.207 / 0.000
The F tests should be used only for descriptive purposes because the clusters have been chosen to maximize the differences among cases in different clusters. The observed significance levels are not corrected for this, and thus, cannot be interpreted as tests of the hypothesis that the cluster means are equal.

Table S4

Cluster / Error / F / Sig.
Mean Square / df / Mean Square / df
Zscore[Temperature] / 104.896 / 1 / 0.729 / 384 / 143.804 / 0.000
Zscore[pH] / 23.187 / 1 / 0.941 / 374 / 24.649 / 0.000
Zscore[TP] / 88.510 / 1 / 0.608 / 223 / 145.678 / 0.000
Zscore[TN] / 83.449 / 1 / 0.630 / 223 / 132.400 / 0.000
Zscore[NO3] / 327.334 / 1 / 0.078 / 354 / 4188.475 / 0.000
Zscore[BOD5] / 4.678 / 1 / 0.947 / 69 / 4.941 / 0.030
Zscore[COD] / 194.216 / 1 / 0.471 / 365 / 412.661 / 0.000
Zscore[TSS] / 164.043 / 1 / 0.546 / 359 / 300.532 / 0.000
Zscore[Conductivity] / 357.287 / 1 / 0.062 / 380 / 5725.514 / 0.000
The F tests should be used only for descriptive purposes because the clusters have been chosen to maximize the differences among cases in different clusters. The observed significance levels are not corrected for this, and thus, cannot be interpreted as tests of the hypothesis that the cluster means are equal.

[1]For STP B 1700 μS/cm.

[2] For STP A 0.1 mg/L.