Effect of microbubble aerator innovation on dissolved oxygen, carrying capacity and performance of red tilapia (Orechromis sp.) in the RAS system
Rustadi (a*), Eny Heriyati (b), Alim Isnansetyo (a), Bambang Triyatmo (a), Indah Istiqomah (a), Deendarlianto (c) and Wiratni (d)

(a)Department of Fisheries, Faculty of Agriculture, UGM, Yogyakarta Indonesia.
(b)Marine Science Program study, Kutai Timur Agricultural College School Indonesia
(c)Department of Mechanical Engineering, Faculty of Engineering, UGM, Yogyakarta, Indonesia.
(d)Department of Chemical Engineering, Faculty of Engineering, UGM, Yogyakarta, Indonesia.

Abstract

This research was conducted to examine microbubble aerator compared to conventional aeration (blower) in formation of dissolved oxygen (DO), to measure standard oxygen transfer rate (SOTR) and standard aeration efficiency (SAE) as well as to consider the oxygen consumption of red tilapia in order to predict the optimum stocking density. The results showed that microbubble aerator produced DO 6.58 ppm higher (p<0.05) than that of blower with DO value of 5.59 ppm under air discharge of 3 L/min. The values of SOTR and SAE on microbubble aerator were 0.007 kg O2/h and 0.09 kg O2/KW/h, respectively, higher than those of SOTR and SAE on blower approximately 0.002 kgO2/h and 0.02 kgO2/KW/h respectively. This experiment also tested DO value on recirculation medium with air discharge of 0.03 L/sec, in which DO value of microbubble aerator was 7.44 ppm higher (p<0.05) than those of blower aerator of 6.51, and no aeration as control of 5.35 ppm. Microbubble aerator was capable of increasing 62% higher stocking density than blower aerator in recirculation system. It was concluded that microbubble aerator had higher DO value, transferred much oxygen and more saved the energy compared to blower aerator, and the prediction of stocking density using microbubble aerator was 62% higher than blower. Fish biomass was higher in microbubble aerator, with high survival and growth rate, and a lower FCR value, those indicating good culture performance.

Keywords: DO, microbubble aerator, RAS, red tilapia, stocking density

Topic: Sustainable Aquaculture and Fisheries