Browsing by Author "Ayoola Olusegun AKINWOLE"

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    Biodenitrification of Aquaculture Wastewater at Different Drying Times in Water Reuse System
    (2014) Akeem Babatunde DAUDA; Ayoola Olusegun AKINWOLE; Latifat Kehinde OLATINWO
    Introduction of denitrification in water recirculating system to remove nitrate-nitrogen which is produced by nitrification and tend to be toxic at high concentration has been investigated by some researchers but mostly for temperate aquaculture and information on the time for readiness of the system is virtually not available. Therefore this study examined the biodenitrification of aquaculture wastewater from a tropical fish species at different drying times. Aquaculture effluent from monoculture of Clarias gariepinus was passed through nitrifying followed by denitrifying biofilter at three drying times (24, 72 and 144 hours). Water quality parameters; Temperature, Dissolved oxygen (DO), pH, Total ammonia-nitrogen (TAN), Nitrite-nitrogen (NO2-N) and Nitrate-nitrogen (NO3-N) were measured in the filtrates of the nitrification and denitrification column to assess the change in water quality. Denitrification efficiency of the biofilter was determined using Percentage nitrate-nitrogen removed (PNR) and Volumetric nitrate-nitrogen conversion rate (VNR). The result showed that all the water quality parameters were within the range for fish culture but the nitrate-nitrogen in the nitrification is higher than the recommended level for discharge into the environment. The PNR recorded were 33.33±57.74%, 47.87±4.19 % and 59.09±7.87% while the VNR recorded were 3116.88±599.60 mgNO3-N/m3d, 14125.26±746.55, 58775.51±7068.43 mgNO3-N/m3d for the 24, 72 and 144 hours drying time respectively. The study revealed that biodenitrification increases with drying time and prevented NO3-N accumulation in the system. The incorporation of denitrification column in recirculating system will enhance sustainable aquaculture production and save the aquatic environment from eutrophication.