Implications for physical design: The effect of depth on the performance of waste stabilization ponds
Pearson, H.W.; Silva Athayde, S.T.; Athayde, G.B.; Silva, S.A.
Water Science and Technology a Journal of the International Association on Water Pollution Research 51(12): 69-74
2005
ISSN/ISBN: 0273-1223 PMID: 16114665 Document Number: 592683
Studies on experimental primary facultative ponds showed that varying the depth from 1.25 m to 2.3 m had no effect on the rates of BOD removal. In contrast k values for FC removal rates were higher in the shallower (1.25 m) facultative ponds. The risk of odour release via H2S production was higher in the 2.2 m ponds than the 1.25 m ponds and NH3 removal was much better in the 1.25 m facultative ponds. A comparison of the efficiency of shallow 5-pond series (1.0 m and 0.61 m deep) with a 2.2 m deep series showed that the shallow systems were more efficient at FC removal, but the deeper series actually saved land area for the same FC final effluent quality under tropical conditions. However, efficient nutrient removal (N and P) only occurred in the shallow series and effluent standards for nutrient concentrations are unlikely to be met by 2.2 m deep 5-pond series in contrast to the norms for pathogen removal.