Production and use of ozone : Case study in biological treatment of black tiger shrimp pond

Supawan Tirawanichakul, Asst. Prof., D. of Chemical Eng., F. of Eng., PSU.
Yutthana Tirawanichakul, Asst. Prof., D. of Physics, F. of Sci., PSU.
Poonsin Parnichsuke, National Institute of Coastal Aquaculture, Songkhla

Presented : "Regional Symposium on Chemical Engineering 1999", Nov. 22-29, 1999, B.P. Smila Beach Hotel, Songkhla, Thailand
Key words : plasma discharges, disinfection by ozone and black tiger shrimp

Ozone is powerful oxidizing gas and has proven to be effective against microorganisms. Its use was restricted mainly to water and wastewater treatment because of its complex nature since the reaction takes place in the plasma state. So the plasma ozonizer (PZUO3-1) was designed and con-structed with a compact type, using ripple AC high voltage supply produced ozone from dried air. The ozone production was in range of 0.1-2 mg/l of water depending on power supply.

This was a preliminary study to investigation to evaluate the water treatment efficiency of ozone in marine prawn pond at National Institute of Coastal Aquaculture (Thailand). The experiment was semi-batch since the ozonized air was diffused into the blck tiger shrimp (Penaeus monodon) pond by bubbling. The total dissolved time was fixed at 18 hours each day with volumetric flow rate 5.66 m3/min. The main objective of this project was to present the effect of shrimp growht, Total bacteria control and Vibrio sp. control during period of ozone treatment. From the result was shown that Total bacteria was affected by ozone disinfection. And NH4- was a few increased compare to referenced pond while the oxides of nitrogen (NO₂, NO₃) were reduced and DO was not changed. The marine prawn growth was proportional to ozone dosage in water.

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