Aeration efficiency influenced by venturi aerator arrangement, liquid flow rate and depth of diffusing pipes

Abstract

The effect of aerator module configuration, liquid flow rate and diffuser submergence on oxygen transfer efficiency was examined in a surface aeration system with venturi injectors using the clean water test. Six venturi aerator modules were evaluated and the results indicated that better aeration efficiencies could be achieved by simply changing the way the venturi aerators were connected. Among all the configurations examined (modules a-f), two and three aerators connected in parallel (modules d, e and f) were able to bring more oxygen into water than the others. An increase in liquid flow rate led to an enhancement of the oxygen transfer coefficients, but the improvement was reduced if the liquid flow rate was too high. The oxygen transfer coefficient was found to have a relationship with the depth of diffusing pipes (surface aeration depth) for the surface aeration system and an optimal depth of around 40 cm was obtained from this study.

Characterization of the performance of venturi-based aeration devices for use in wastewater treatment in low-resource settings

“…9 were discarded from the final models, as its effect was not found to be significant. This runs contrary to what was reported in Dong et al (2012), who found that a depth of 40 cm was optimal while aerating a lagoon with their venturi device. It is possible that the shallow overall depth of the reactor used in this study, combined with the strength of the water jets, allowed for similar mixing of the water column to occur for all tested depths, which may have drowned out its effect.…”

“…For example, values of SOTR reported by Zhang et al (2007) for that type of aerator vary from 0.15 to 0.42 kg/h, which represents a 4-to 11-fold increase from the current study's result. Dong et al (2012) also found similar performances for their own venturibased apparatus (0.141 to 0.306 kg/h).…”

“…However, questions remain as to what factors must be considered when designing venturi-based aerators. Dong et al (2012) have provided some answers to this problem by demonstrating that venturi nozzles connected in parallel have a higher aeration efficiency than nozzles connected in series, and by describing changes in aeration efficiency when the venturi nozzles were placed at different depths inside the water column.…”

Application of an Innovative Venturi Type Aeration Array as Part of the Restoration and Upgrading of an Obsolete Wastewater Treatment Plant

“…Vanturi (Bernoulli Effect) Type aerators are used for fish pond aeration (in a water cannon scheme), as mixing aspirators for laboratory use and for other such tasks; usually with a water stream, which draws air into itself [7]. The temperature of steam systems is commonly regulated by Venturi mixer that draws water into a steam jet.…”

Influence of Smooth Constriction on Microstructure Evolution during Fluid Flow through a Tube

“…Flow through a contraction or expansion is a classical problem in fluid dynamics and its numerical modelling has a lot of applications such as nozzles (Xiong et al 2015;Allamaprabhu et al 2016), diffuser (Rosa and Pinho 2006;Mariani et al 2010) and throttling valves (Jin et al 2013). Other applications, with both combined geometries, are encountered in Venturi devices (Dong et al 2012;Maqableh et al 2012) and hemodynamics (Ikbal et al 2009;Ponalagusamy and Selvi 2013;Mandal et al 2011). Regardless of the nature of the problem, when a fluid passes a contraction, it experiences a loss in pressure but an increase in kinetic energy.…”