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The effect of different water circulation speeds on the microbial treatment of wastewater in a recirculating system for Huso huso culture
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Mehran Avakh Keysami   , Masoud Sattari , Hojatlah Zamani , Mohsen Pourasadi |
| 1- Department of Fisheries and Aquatics, Agricultural Research and Education Center and Natural Resources of Guilan Province, Agricultural Research, Education and Extension Organization, Rasht, Iran |
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Abstract: (74 Views) |
This study aimed to investigate the effect of a suspension of bacteria (Bacillus, Corynebacterium, Nitrosomonas, and Nitrobacter) at a concentration of 107 cells/mL and a control treatment without bacterial inoculation with water circulation once a day, under different water circulation speeds, on the physicochemical variables of water, fish growth, and bacterial density in water and the digestive tract of fish in the aquaculture laboratory of Mirza Kuchak Khan Fisheries Training Center in Gilan. Three treatments and one control (each with 3 replications) were carried out in aquariums (50×50×160), with a water intake volume of 0.4 cubic meters and a density of 10 sturgeon fry, including the first treatment of 0.004 liters per second with water circulation once a day, the second treatment of 0.008 liters per second with water circulation twice a day, and the third treatment of 0.012 liters per second with water circulation three times a day. The control treatment was also provided with a flow rate of 0.004 liters per second with water circulation once a day, from the treated wastewater of the biofilters in a recirculated system. After adding water and 10 pieces of sturgeon fry (65.58±3.13g) to the culture tanks, feeding was carried out as usual with mild aeration, and after 4 days, a mixture of 4 bacteria (Bacillus, Corynebacterium, Nitrosomonas, and Nitrobacter) in the form of a suspension at a ratio of 107 Cfu/ml was inoculated into the biofilters of the 3 experimental treatments, which were placed at the effluent outlet of these tanks. pH, oxygen, temperature, were measured daily and ammonia, nitrite and nitrate levels were measured weekly. The weight of all sturgeon fry in the tanks was measured and recorded once a week to determine daily and weekly feed intake. The results of the 4-week rearing period with three treatments T1, T2 and T3 and control treatment C showed significant differences in terms of water quality and body weight gain, specific growth rate, feed conversion ratio and survival rate between the control and the treatments (P<0.05). Therefore, based on the results obtained in this experiment, each of the experimental treatments 1 and 2 can be considered for treating and improving the quality of the effluent, for the purpose of reusing and returning the water to sturgeon farms.
Reuse water system, water quality, Huso huso, growth indices.
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Article number: 2 |
| Keywords: Reuse water system, water quality, Huso huso, growth indices. |
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Full-Text [PDF 747 kb]
(27 Downloads)
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Type of Study: Research |
Subject:
Special
Received: 2025/07/7 | Accepted: 2025/10/29 | Published: 2025/10/29
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