I'm running a pilot plant doing lime treatment for pH correction and reduction of sulphates through the precipitation of gypsum. The results so far they show that my pilot plant is working well to reduce sulphates, now I want to add a 4th tank to do aeration to try and deal with my COD biologically. My system consists of :
I want to put an earation tank just before coagulation.
Hello Hopewell,
The answer is relatively simple; however, the monitoring and the end-results are in your hands.
1. Know the pumping rate of your stirrer (e.g. 'a' ltr/min). Pumping is proportional to the rotation rate.
2. Divide the reactor volume (ltr) by the pumping rate, This gives you the the turn-over time, (min)
3. insert a tube over the pumping device into the reactor content (keep both ends of the tube open); otherwise, increase the rotation rate of the pumping device until a vortex forms that sucks the air through its center.
4. The pumping device should pump enough air into the sludge to get to air-saturation.
5. It will take about 4 turn-over times to obtain about 99% of air- saturation.
6. The length of reaction of the sludge with the air depends also on the addition rate of the coagulant and its reaction rate with the sludge. Slow coagulant addition at the beginning may yield larger final sludge- particles.
You may already be quite familiar with what I wrote down. I am hoping that others may add additional suggestions.
Wishing you good success, Ingo
It would be worth to estimate the oxygen mass-transfer coefficient, KLa, for the aeration tank to be considered. The following references may possibly be found helpful:
H.T. Luong, B. Voleski, "Mechanical power requirements of gas-liquid agitated systems", AIChE Journal, 25(5), 1979, pp. 893-895.
Gary B. Tatterson, "Fluid Mixing and Gas Dispersion in Agitated Tanks", McGraw-Hill, 1991, 2nd printing: 2003.
M.M.C.G. Warmoeskerken, "Gas-liquid dispersing characteristics of turbine agitators", PhD thesis. University of Delft, 1986.
I have shown that the KLa coefficient can be estimated on-line and in real-time by applying the recursive least squares algorithm with forgetting factor:
Thesis Controlo do Oxigénio Dissolvido em Fermentadores para Minimi...
- Badges
- Science topic
- Similar topics
- Engineering
- Chemical Engineering