Assessment of the new generation aeration systems efficiency and water current flow rate, its relation to the cost economics at varying salinities for Penaeus vannamei culture

Abstract

The selection of aerators and correct numbers can play an essential role in reducing the cost of production in aquaculture. The new generation aerators, namely spiral leaf, air‐jet, submersible and impeller, used in aquaculture, were assessed for its aeration efficiency and energy cost compared with the commonly used paddle wheel aerator. Of the aerators tested, the impeller had the highest aeration efficiency of 2.098 kg O2/kW hr, followed by paddle wheel with 1.436 kg O2/kW hr at 20‰ salinity. The spiral and air‐jet aerators had maximum aeration efficiency of 1.326 and 1.419 kg O2/kW hr, respectively, at 35‰ salinity. The submersible aerator was not efficient as its maximum efficiency was 0.380 kg O2/kW hr. The water flow by paddle wheel was 3 ft/sec and also provides better coverage than other types of aerators. The efficiency of aerators was high in optimum salinities (20‰ and 35‰) than the low or high saline condition. The average energy cost of shrimp pond aeration per hectare was lowest for impeller, followed by paddle wheel aerator. The study provided economic comparisons of vannamei culture using different aeration systems by keeping a uniform set of economic assumptions. Shrimp farms with impellors can give 14%–25% high returns across salinities, whereas spiral leaf can provide 5% high returns at 35‰ salinity. The combination of the type of aerators and the calculated use based on the salinity of the culture systems can result in energy‐saving and also a reduction in the production cost.

Aerator energy use in shrimp farming and means for improvement

“…Several recent reports have suggested new methods of aerating shrimp ponds such as wave (surge) aeration (Guan, Liu, Song, & Zhang, 2012), microbubble aeration (Liu, 2017), on‐site oxygen generation and pure oxygen contact systems with aeration control by dissolved oxygen sensors (Nguyen & Matsuhashi, 2019; Tien, Matsuhashi, & Chan, 2019), solar‐powered aerators (Chaithanakulwat, 2019), and submersible impeller aerators (Marappan et al, 2020). These systems have yet to be perfected for use in shrimp ponds.…”

Effect of some Protein Sources on White Shrimp Production under Lake Qarun Condition

“…It accounts for over 90 per cent of total world production of shrimp and is commonly farmed in many countries around the world. Growth in aquaculture has been possible thanks to scientific advances in culture technology, intensive cultivation practices under controlled environmental conditions (Marappan et al, 2020).…”

Enhanced Oxygen Volumetric Mass Transfer in a Geometrically Constrained Vortex

“…These high oxygen transfer rates are a consequence of the aforementioned combination of high area-to-volume ratios and possibly enhanced turbulence close to the interface. On the other hand, the SOTR values (up to 0.5 kg/h) [12] are comparable to air jet system and lower than those reported for impeller and paddle systems (between 1.0 and 2.5 kg/h) [12]. This is due to the short hydraulic retention times in the hyperbolic funnel (typically less than a minute).…”

“…Figure 4 shows K L a and SOTR values dependent also as a function of flow rate. Average K L a values (for 20 °C) for air jet, impellers and paddle aerators [12] are shown for comparison. The plot shows that the K L a values obtained with the free surface vortex in a hyperbolically shaped funnel are considerably higher than those of the three commercial systems used for comparison, especially in the twisted regime.…”

“…For practical applications the specific energy demand of such a cascade can be estimated as follows: The hyperbolic funnel tested in this work has a specific energy demand of 0.01 kWh/kg O 2 (see Appendix A for calculation details). In comparison, the specific energy demands of mechanical aerators range from 0.42 to 0.83 kWh/kg O 2 [13] and the specific energy demands of air jets range from 0.74 to 1.0 kWh/kg O 2 [12]. However, the industrial applicability of this system depends on its scalability to higher flow rates in larger funnels on the one hand, and on the possibility to achieve the described regimes with liquids of different viscosities as found in wastewater streams on the other.…”