Name: Thermodynamic Analysis of a Venturi Injector for Oxygenation of Wastewater
Start: 2026-09-17T14:00:00-0600
End: 2026-09-17T14:30:00-0600

Thermodynamic Analysis of a Venturi Injector for Oxygenation of Wastewater

Thursday September 17, 2026 2:00pm - 2:30pm MDT

Lombardy

Conventional municipal wastewater aeration relies heavily on the activated sludge method, in which blowers or compressors force air through small bubble diffusers at the bottoms of aeration basins. These bubbles slowly rise to the surface, transferring oxygen in the process, and allow microorganisms to digest the carbonaceous matter in the waste stream. Recently, a new technology is being developed, termed a Confined Tube Aerator (CTA). Here, a pump draws water from a basin and forces it through a Venturi aspirator, where air may be naturally entrained. This multiphase mixture then travels to a coiled tube where oxygen may be transferred without stratification. The proposed technology has strong potential for cold‑climate operation, smaller physical footprint, and reduced operational requirements, making treatment feasible where conventional, lagoon-based systems are impractical.
The efficiency of a CTA system is highly dependent on the losses in the Venturi aspirator itself. Typically, assessment of Venturi aeration efficiency relies on testing, where Dissolved Oxygen (DO) content and pump power draw are used to evaluate standard metrics such as Standard Oxygen Transfer Rate (SOTR) and Standard Aeration Efficiency (SAE). However, these tests are time consuming and costly, and a new metric is proposed herein to use thermodynamic principles to gauge relative improvements in Venturi injector performance. This metric, called the Venturi Efficacy (VE), relies on motive water flow rate, inlet and outlet Venturi pressure, and ingested air flow rates, along with statistical measurements of bubble sizes to provide a relative measurement of the ratio of interfacial surface area flux to entropy generation within the Venturi injector.
The goal of this study is to compare calculated Venturi Efficacy measurement with SAE measurements using aeration tests. To perform each test, sodium sulfite is used to scrub a large 1000L tank of water of oxygen. Then, aeration is performed to saturated levels using a CTA assembly, with varying pump speeds and outlet valve position, the latter drastically affecting back pressure and hence, air injection. SOTR and SAE measurements were obtained for each test and compared in a relative manner to VE calculations.
Preliminary results show that system parameters including bubble size, air and water flow rates, and thermodynamic analysis of entropy generation can be used to assess a Venturi injector performance, relative to a baseline. This approach has the potential to decrease CTA system testing costs as compared to traditional aeration testing.

Speakers

Erin Shapiro

Undergraduate Research Assistant, Carleton University

I am an undergraduate research assistant at Carleton University. I am currently in my 4th year of my bachelor's of engineering, conducting research to improve waste water treatment

Thursday September 17, 2026 2:00pm - 2:30pm MDT
Lombardy 2nf Floor, Delta Hotel

Wastewater Treatment

WCW26

Erin Shapiro

Get help with the event

WCW26

Erin Shapiro

Sign up or log in to save this to your schedule, view media, leave feedback and see who's attending!

Get help with the event