Abstract:
The objective of this research is to study comparatively between the result of using ozone and using chlorine (65% Calcium hypochlorite) as disinfectant in storage tank for water quality improvement before use in Black Tiger Shrimp pond, including the determination of some toxic compounds which may result from the ozone treatment. The experiment was performed for studying the growth and the survival rate for Black Tiger Shrimp at nauplius phase until postlarva phase. Black Tiger Shrimp were farmed in two plastic ponds of 3 m3 in capacity for 23 day by using water from 2 storage tanks. One was treated with ozone at concentration of 0.898 mg/L and the other was calcium hypochlorite treated at concentration of 67 mg/L. The water quality from 2 ponds during the farming period were analyzed comparatively. The experimental results indicated that the ozone treatment was able to reduce TSS, turbidity, BOD, COD, Total Plate Count, Vibrio sp. and Vibrio harveyi more than the chlorine treatment, comparing with the quality of original water before treatment with ozone and chlorine. Shrimp survival rate was 90 %( 225,000 shrimps) for ozone treatment pond, but in the chlorine treatment pond, shrimp survival rate was 76 %(189,200 shrimps ). The cost comparison for 100,000 shrimps between ozone treatment pond and chlorine treatment pond were 3,600 baths and 4,200 baths respectively. The profit from ozone treatment pond was about 3,380 baths/pond higher than that of the chlorine treatment. Moreover, the quantitative level of toxicants(bromate and iodate ions) found in the ozone treatment pond were not dangerous for shrimps.