Modelling Nematode Egg Elimination in Wastewater Stabilization Ponds Available to Purchase

The paper analyses data on intestinal nematode egg numbers (N_NE) taken over a 30-month period in a large wastewater stabilization pond system. The retention time of 8-10 days suggested by WHO as the treatment expected to achieve an effluent with less than 1 nematode egg per litre was not supported by the results. A model has been developed to describe the elimination of nematode eggs(N_NE) in ponds. According to this model, 14 days theoretical retention time is required to achieve the above criterion in the Alsamra pond system. The importance of the inflow jet velocity in influencing effluent quality, in terms of N_NE, has been demonstrated.