بررسي تعداد تخم نماتودها در فاضلاب ورودي و پساب خروجي از تصفيه خانه فاضلاب خانه فاضلاب شهرك شوش تهران در سال 79-1378

nvestigation into the Removal of Nematods Eggs in Influent and Effluent of Shoosh Wastewater Treatment Plant

The reuse of reclaimed wastewater has been increasing over the past decade, especially in arid and semiarid regions where reclaimed wastewater is used to conserve valuable potable water supplies. Careful consideration must be given to the hazards to health that may arise from the reuse of sewage, the hazards to health can be reduced by the treatment of sewage before use in agriculture. Conventional wastewater treatment processes such as activated sludge are generally very effective at removing nematodes eggs by sedimentation. WHO guidelines stated that the wastewater treatment system should produce an effluent with less or equal to one intestinal nematode egg per litre and less or equal to 1000 faecal coliforms per 100 ml to permit its reuse in unrestricted irrigation. In this research the efficiency of Shoosh Wastewater Treatment Plant (SWTP) in removal of nematods Eggs was investigatigated for eleven months during the years of 2000-2001. SWTP operates on activated sludge process and the grab samples of raw wastewater and effluent of system were taken daily every morning. Intestinal nematode eggs were counted according to standard method (APHA, 1995). The mean concentration of nematode eggs namely, Ascaris lumbricoides, Trichuris churia, Enterobios vermicularis and Hook worms were 4.4, 0.5 , 0.9 and 1.1 eggs per litre, in raw sewage respectively. The concentration of total nematode eggs in raw sewage was 6.8 eggs per litre. The results of research showed that no nematode eggs were present in the final effluent throughout the period. Thus the effluent quality suitable for reuse in unrestricted irrigation. The results showed that activated sludge processes may remove 100 percent of influent intestinal nematode eggs.