Efficiency of removal in stabilization ponds II. Statistical analysis of K values

The analytical values obtained from five WSP systems located in different ecoclimatic zones in the centre and South of Portugal, were subjected to a statistical analysis of K and K₂₀ values (as used in the van Hoff-Arrhenius equation) utilizing an analysis of variance and a vectorial analysis of principal components. Significant differences between K and K₂₀ values in facultative, maturation ponds and in the whole system were verified. The projection of the first principal components of eigenvectors made possible the classification of the stations, showing the existence of similarities and discrepancies in their removal BOD kinetics behaviour. The K₂₀ value must be estimated and taken into account for the design of waste stabilization ponds.