Johnny Lee

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Questions related from Johnny Lee

How can we measure the biological oxygen uptake rate correctly?

For any wastewater treatment aeration tank, the paper presents an interesting technique to deal with oxygen uptake rate (OUR) measurements. Aerobic metabolism rates are frequently reflected in...

06 October 2024 9,649 3 View

Is measurement of oxygen uptake rate dependent on the DO concentration in the sample?

One problem w the BOD bottle type of OUR measurement is that it can only be used in a system that is not DO limited (typically assumed about 2 mg/l or more). If the system is running at low DO and...

02 July 2024 1,709 2 View

Would modification of two-film theory's equation to account for microbial respiration result in a different equation? Rd=KLa(Cs-C)-Ru?

Oxygen transfer in the activated sludge system involves physical mass transport across a two-film layer that consists of a gas film and a liquid film. For gases with limited solubility such as...

23 June 2024 5,083 0 View

What is effect of biochemical reactions on the oxygen transfer rate in a wastewater aeration tank for activated sludge treatment?

activated sludge treatment plant treatment process

20 March 2024 10,035 4 View

How do we solve the gas-liquid transfer equation dC/dt = K1 (K2 - c) where K1 and K2 are arbitrary constants?

We all know that in any gas-liquid dissolution interactions, under a constant rate of gas supply, the basic equation is given by: dC/dt = K1 (K2 - C) where K1 and K2 are arbitrary constants, dC/dt...

16 December 2023 6,453 9 View

If the oxygen mass transfer rate in a tank of water is X kg/hr at 10 degC, what will it be at 20C?

temperature correction factor is requested

04 February 2023 8,808 3 View

Is the oxygen uptake rate in a WWTP or a fermenter dependent on oxygen availability?

According to ASCE guidelines, measuring the OUR under oxygen limiting conditions is extremely difficult, although the principle of respirometry is remarkably simple—-the slope of the decline curve...

22 November 2019 2,813 11 View

How to measure microbial respiration rate (oxygen uptake rate) in a WWTP aeration basin?

The Current standards and guidelines do not recommend the steady-state method to estimate oxygen transfer rate because of difficulties measuring the oxygen uptake rate. Is there a way to measure...

07 November 2019 2,823 0 View

Is there such a thing as "cellular economy principle" when microbial cells consume less oxygen in anticipation of an impending oxygen deficiency?

Garcia et al. (2009) in their paper "Bioreactor scale-up and oxygen transfer rate in microbial processes:an overview" explained an anomaly in their data in the experiments to measure the oxygen...

14 August 2017 1,205 0 View

Rd = Kla (Cs – C) – Ru I’m happy with dC/dt = Kla (Cs – C) – Ru Stating that transfer rate = dissolution rate – uptake rate feels like a mistake?

One could argue that when R = KLaf ( Cs - C), the fugacity (the maximum transferable rate) has been reached and so the OTR or Rd is zero at that gas flow rate representing the energy input....

01 January 1970 6,597 1 View

Why does the gas-phase mass flowrate increase as it encounters resistance towards the transfer rate?

Einstein’s mass-energy equivalence principle applied to the dissolved gas transfer to microbial cells can be explained as follows: The formula for relativistic kinetic energy (Ek) of a massive...

01 January 1970 5,268 1 View

The confusion about oxygen transfer rate and oxygen uptake rate in submerged bubble aeration.

Many people have expressed concerns about my recent Forum paper, such as this one: "You're confusing oxygen transfer mechanisms with respiration. The respiration determines the OTR which is...

01 January 1970 9,381 0 View