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Artificial aeration system for aquaculture ponds becomes essential to meet the oxygen requirement posed by the aquatic species. The performance of an aerator is generally measured in terms of standard aeration efficiency (SAE), which is significantly affected by the different geometric and dynamic parameters of the aerator. Therefore, to enhance the aeration performance of an aerator, these parameters need to be optimized. In the present study, a perforated pooled circular stepped cascade (PPCSC) aerator was developed, and the geometric and dynamic parameters of the developed aerator were optimized using the hybrid ANN-PSO technique for maximizing its aeration efficiency. The geometric parameters include consecutive step width ratio (Wi-1/Wi) and the perforation diameter to the bottom-most radius ratio (d/Rb), whereas the dynamic parameter includes the water flow rate (Q). A 3–6-1 ANN model coupled with particle swarm optimization (PSO) approach was used to obtain the optimum values of geometric and dynamic parameters corresponding to the maximum SAE. The optimal values of the consecutive step width ratio (Wi-1/Wi), the perforation diameter to the bottom-most radius ratio (d/Rb), and the water flow rate (Q) for maximizing the SAE were found to be 1.15, 0.002 7 and 0.016 7 m3/s, respectively. The cross-validation results showed a deviation of 3.07 % between the predicted and experimental SAE values, thus confirming the adequacy of the proposed hybrid ANN-PSO technique.

Aeration experiments were conducted in a masonry tank to study the effects of operating parameters on the standard aeration efficiency (SAE) of a propeller diffused aeration (PDA) system. The operating parameters included the rotational speed of shaft (N), submergence depth (h), and propeller angle (α). The response surface methodology (RSM) and an artificial neural network (ANN) were used for modelling and optimizing the standard aeration efficiency (SAE) of a PDA system. The results of both approaches were compared for their modelling abilities in terms of coefficient of determination (R2), root mean square error (RMSE), and mean absolute error (MAE), computed from experimental and predicted data. ANN models were proved to be superior to RSM. The results indicate that for achieving the maximum standard aeration efficiency (SAE), N, h and α should be 1,000 rpm, 0.50 m, and 12°, respectively. The maximum SAE was found to be 1.711 kg O2/ kWh. Cross-validation results show that best approximation of the optimal values of input parameters for maximizing SAE is possible with a maximum deviation (absolute error) of ±15.2% between the model predicted and experimental values. HIGHLIGHTS Aeration characteristics of a propeller diffused aerator (PDA) were evaluated.; The response surface methodology (RSM) and an artificial neural network (ANN) were used for modelling and optimizing the standard aeration efficiency (SAE) of a PDA system.; The results of RSM and ANN were compared for their modelling abilities in terms of coefficient of determination (R2), root mean square error (RMSE) and mean absolute error (MAE), computed from experimental and predicted data.

The growing intensive aquaculture system around the world maintains a high stocking density, wherein it is essential to increase and sustain the optimum dissolved oxygen concentration (DO) through the provision of artificial aeration systems. The selection of an aerator is a crucial aspect of aquaculture operations. The selected aerator must be economically efficient and should be able to fulfill the requirement of oxygen supply in the pond water. The present study provides an extensive literature review on the importance of artificial aeration in aquaculture, the standard method of test for performance evaluation of an aerator, various aeration systems and their mechanisms, method to determine the numbers of aerator requirement, comparative studies of different type of aerators, and economic consideration in selection of aerators. In addition, a thorough analysis has been done to suggest the type of aerator that is economically viable and efficient for different pond volumes based on the performance data reported in the reviews. Therefore, this study may help the end-users (fish farmers) to select the best aerator based on their requirements.

The performance of the perforated tray aerator (PTA) was evaluated by conducting experiments in a tank of size 4 m × 4 m × 1.5 m. Based on the dimensional analysis, non-dimensional numbers related to geometric variables, viz. numbers of trays (n), ratio of consecutive width of tray to total height of aerator , ratio of perforation diameter to total height of aerator and ratio of the volume of water in the tank to total height of aerator were developed. Experiments were conducted with different numbers of trays (n): 1, 2, 3 and 4, keeping = 0.33, = 2.5 × 10−4, = 2,500 and pump flow rate (Q) = 0.010 m3/s as constants. The optimum number of perforated trays was found to be 3. Response surface methodology (RSM) and central composite rotatable design (CCRD) were used to further optimize the geometric variables with combinations of non-dimensional geometric variables , and . The flow rate (Q) of 0.013 m3/s and number of trays (n) as 3 were kept as constants. The optimum performance of PTA was obtained at = 0.665, = 1.85 × 10−4 and = 312.50 with the maximum non-dimensional standard aeration efficiency (NDSAE) and standard aeration efficiency (SAE) of 35.58 × 10−3 and 1.45 kgO2/kWh.

Selection of aerator is a very important aspect in aquaculture operations. The selected aerator must be economically efficient and should be able to fulfil the requirement of oxygen supply in the pond water. In the present study, economic feasibility of nine different types of aerators, namely, perforated pooled circular stepped cascade (PPCSC), pooled circular stepped cascade (PCSC), circular stepped cascade (CSC), paddle wheel (PWA), spiral aerator (SA), propeller-aspirator-pump (PAA), submersible (SUBA), impeller aerator (IA) and air-jet aerator (AJA) was assessed based on capitalization method, a life cycle costing (LCC) approach. The results revealed that the PPCSC aerator can be considered as the most suitable aerator when dissolved oxygen (DO) content in the pond water is less than equal to 3 mg/L, and pond water volume (V) is less than 2100 m3. In other situations, mostly when pond water volume is more, IA proves to be the most suitable aerator, followed by PWA, PPCSC, and other available aerators. The sensitivity analysis conducted by using varying stocking density and capital cost also showed the same trend with regard to selection of aerators. This life cycle costing approach for selection of aerator can be implemented for any types of cultured species at any prevailing environmental conditions.

In this study, the performance of a spiral aerator, a modified design of the paddlewheel aerator, was evaluated to determine its applicability in aquaculture ponds. The aeration characteristics of the spiral aerator were determined by conducting aeration experiments in a cement concrete tank of dimension 5 × 5 × 1.5 m. Nondimensional numbers related to oxygen transfer (E) and power consumption (Ne) were proposed and expressed as functions of geometric (number of handles per shaft, n) and dynamic (Froude and Reynolds number) parameters. Simulation equations for oxygen transfer and power consumption based on the Froude criterion were developed. The maximum brake power standard aeration efficiency was achieved at n = 13. Finally, an economic analysis was performed assuming a typical Indian major carp culture pond to determine the optimum rotational speed of the aerator at different pond volumes and dissolved oxygen concentration present in the pond at which the aeration cost is minimized. The results showed that the least aeration cost is achievable when rotational speed of the spiral aerator is only 70 rpm for pond volumes up to 700 m3 and from 120 to 220 rpm for pond volumes exceeding 700 m3.