Abstract
Background: Conventional wastewater treatment is a combination of physical and biological processes designed to remove organic matter from solution. Waste sludge drawn from these processes is thickened and processed for ultimate disposal wastewater contains various kinds of infectious agents, such as bacteria, viruses, fungi and parasites. Correct treatment in wastewater treatment plants is important for preservation of environment and also from economic point of view. Present study was conduced for determination of protozoan cyst and helminth ova in sludge and effluent of the Kerman central prison wastewater treatment plant.
Methods: This study - that lasted from April to October 2002, sampling was accomplished in eleven stages. Three samples of effluent, wet sludge, and dewatered sludge were selected in any stage and were transferred to the laboratory in plastic vessels. Each sample was tested for different kinds of cysts of Amoeba, Giardia, and also Helminths ova, such as Ascaris, Teania, Schistosoma, Toxocara and Hymenolepis nana.
Results: Results showed that the mean total number of the cysts and helminthes ova was 15 and the most contamination occurred with cysts of Amoeba and Giardia in wet sludge stage. In dried sludge stages, the mean total number of the cysts and helmiths ova was 1.2. The results showed that the mean total number of the cysts and helminth ova was 6 and the most contamination occurred with Amoeba cysts in effluent stage.
Conclusion: Totally, the number of cysts and helminthes ova was higher than the standard in wastewater effluent and dewatered sludge. Therefore, it is essential to control operation of wastewater treatment plant more carefully, especially if its effluent is used for irrigation purposes.