Removal of parasitic particles, protozoa cysts, and thermotolerant coliforms in the integrated aeration lagoon, case study: Iran

Abstract

The aim of this study is to determine the efficiency of integrated aerated lagoon (with sludge recycling) on removal of parasite eggs, protozoan cysts, and thermotolerant coliforms from wastewater of Marivan city in Iran. This descriptive–analytical study was carried out during 6 months and samples were collected at weekly intervals from influent and effluent. The counting of parasite eggs and protozoan cysts carried out using Bailenger method. Thermotolerant coliforms are determined according to standard method. Engelberg index was also surveyed. Statistical analytic was accomplished by SPSS (Kolmogrov Smirnov test and Mann-Whitney u test). No nematode, Trichuris trichiura egg, Ascaris lumbricoides egg, and Entamoeba coli cyst were detected in the effluents of aerated lagoon. The efficiency of process in removing parasite eggs and protozoan cysts was >99%. Aerated lagoon was capable of thermotolerant coliform removal from 88.1% (warm weather) until 80.37% (cold weather). The results of this study indicate that aerated lagoon process can achieve good microbial removal in proper condition. Irrigation with lagoon effluent is saved by parasite not thermotolerant coliform. The outlet effluent quality of in terms of nematode eggs is consistent with Engelberg index. Any correlation between the thermotolerant coliform, protozoa cyst, and parasite egg observed.