The performance of an innovative tropical experimental waste stabilisation pond system operating at high organic loadings

In this study on the experimental pond complex at the Federal University of Paraiba in NE Brazil the organic loadings were were more than doubled to investigate the effect on pond performance. The results emphasise the tolerance of the pond system at high loadings without odour production or significant loss of efficiency in terms of BOD removal and bacterial pathogen removal, although nutrient removal by the maturation ponds was reduced. At high organic loadings baffled maturation ponds were more efficient at faecal coliform removal (FC). A minimum of 3 ponds in series are required to ensure maximum BOD removal. Shallow maturation ponds were also more efficient at FC removal although the depth of the facultative ponds had limited effect on BOD removal efficiency.