Author(s): Nguyen Quang Lich; Martin Kumar; Balaji Seshadri; Nanthi Bolan
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Keywords: Shrimp effluent; Wastewater treatment; Nutrient; Seaweed
Abstract: This study explored the potential of Gracilaria verrucosa, one of the most common seaweed species in Tam Gang lagoon in order to determinethe nutrient removal efficiency over eight days of treatment of wastewater in an intensive shrimp farm. 1000 liters of wastewater from intensive shrimp farming after enhancing dissolved oxygen (DO) level and removing ammonia (NH 3) toxicity by splash board treatment over three hours was transferred into the treatment tank. The tank was stocked with 500 g of Mugil cephalus and 200 g of Cerithidea obtuse for biodegradation of organic matter. After 84 hours of biodegradation of organic matter, the wastewater was moved into four different treatment tanks (250 L) that were stocked with three different levels of G. verrucosa biomass: 300 g/m 3 (G-300), 400 g/m 3 (G-400) and 500 g/m 3 (G-500) and a control (CT). The removal efficiency of total ammonium nitrogen (TAN) increased with increasing seaweed biomass and ranged from 300-500 g/m 3. The final TAN removal rates were 89%, 95.6%and 98.1%in treatment G-300, G-400 and G-500, respectively. The removal of total nitrogen (TN) increased from 40.3%to 64.1%with increasing G. verrucosa biomass from300-500 g/m3. The PO4-P decreased from 0.91 mg/L to<0.42 mg/L in all G. verrucosa biomass treatments. The highest total phosphorus (TP) stripping was achieved in treatment G-500 (72.5%), followed by treatment G-400 (66.5%) and G-300 (59.8%). The study demonstrated that the seaweed, G. verrucosa treatment significantly reduced both N and P concentration in shrimp wastewater and the nutrient removal efficiency increased with increasing seaweed biomass level.
Year: 2014