Johnny Lee

11 Questions 58 Answers 0 Followers

Questions related from Johnny Lee

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 1,115 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 4,919 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 9,878 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 6,375 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 8,738 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 2,725 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 2,767 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 1,148 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 6,546 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 5,209 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 9,330 0 View