Document Type : Original Article
Authors
1
Department of Environmental Science,, Faculty of Natural Resources and Environment, Science and Research Branch, Islamic Azad University, Tehran, Iran.
2
Department of Fisheries, Natural Resources Faculty, University of Tehran, Karaj, Iran.
Abstract
Due to the development of intensive aquaculture systems that is associated with increased environmental impacts and the use of chlorine compounds due to their availability, efficiency and cost, the present study aimed to investigate the effect of chlorination on the physicochemical parameters of aquaculture effluent including nitrate, phosphate, TDS, TOC, ORP, BOD, COD, pH, EC and MPN. For this study, 200 liters of rainbow trout farms’ effluent were collected from the lowest outlet of Karaj Mahi-sara farm in Bilqan, Karaj and transferred to Sheikh Bahai Laboratory, Islamic Azad University Science and Research Branch. The effluent was designed in a control group and four treatments of chlorine with different levels, including 30, 20, 10, 40 mg/L liquid hypochlorite (3 times in 5-liter containers for 24 hours with shaker). After this period, 100 ml samples were taken from each container and qualitative indices were analyzed. The results showed that with increasing chlorine, bacterial BOD, COD, TDS, TOC, EC, nitrate and MPN parameters decreased tha highest difference (P<0.05) third treatment with control one in TDS and with 4th treatments with other parameters indicated. ORP increased with increasing chlorine content, but increasing chlorine level did not have significant effect on pH and phosphate indices. The results showed that with increasing chlorine content, water and wastewater quality and biological indices improved to environmental standards. Based on the results, the fourth treatment with 40 mg / L had the best performance in improving the physicochemical parameters of the wastewater and the BOD, COD and TOC indices showed the highest response in this study.
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