Hi
I've been trying to get UASB start up on a tannery landfill leachate a few months ago .
We have been inoculating sludge from septic tanks and anaerobic lagoons once a week for 4 months now and there has not been enough response from the UASB.
The UASB has 65m3 and we are currently treating 10 m3 a day of landfill leachate, to increase the HTR in the UASB tank. Perhaps biodegradable organic matter is missing, we are already dosing phosphoric acid. Who could help us with these questions for a susscefully of the start-up?
What would be the best readily biodegradable organic material to add to the leachate, thus stimulating the growth of microorganisms?
Thanks for feed backs.
Lots of unknown variables here, but I can throw out a few questions. Do you have any information on concentration of key parameters in the leachate? Typically we might look at carbon, nitrogen as well as phosphorus, which it sounds like you are already taking into account. You might also look to see if you have any inhibitory conditions, particularly the pH or cold temperatures (depending on location at this time of year,) as anaerobic treatment tends to work best at >30 deg C.
Would be happy to have an additional conversation to see if I can be of further help.
- Something appeares to poison your microbes. What chemicals does the tannery use? Chromium (III)? Aluminium? Polyphenol? Isn't it present in the leachate at a toxic level?
- As @Henry C. Croll noted, pH is critical. Please check the pH of the inoculant + substrate solution.
- What is your inoculation rate (activated sludge/leachate)? In our lab, the start-up is done at a very high inoculation rate, then we gradually increase the substrate concentration, until just below the toxic level.
- If organic carbon is the bottleneck, you can always use simple alcools or sugar industrial residues for the start-up. If the inoculant + substrate solution is alkaline, acetate is just as good. But please check first the COD and BOD5 of the leachate. If the COD is at least a few hundred mg/l, and at least 1/3rd of it is BOD5, you normally should not need any extra carbon source.
Hello colleagues Gábor Z. Szelényi Henry C. Croll
Thank you very much for answering my question.
The process has physical chemical treatment, UASB reactor, MBBR reactor and reverse osmosis.
After the processes, the NH4 and Boron parameters were not met. The UASB reactor is still in its infancy, with no suspended solids and a very low gas production of 0.001 m3/day.
The main parameters of the raw effluent are (mg/l):
COD: 5000, BOD: 2000, NH4: 1200, NO2: 0.15, NO3: 430, PO4: 5.0, Alkalinity: 11,000, Boron: 13, Hexavalent chromium: 0.9, Toluene: 50, ethylbenzene: 13,chloroform: 30 and sulfide: 60. The temperature is 25 Celsius degrees.
As two parameters (NH4 and Boron), still remain outside the legislation, I think that if I can successfully start the UASB, these parameters would also be reduced. Thank you very much for the feedbacks.
Elisangela Franciscon Yes, the biodegradable carbon concentration itself seems fair enough, but you have too much of NH4-N => the C:N ratio is too narrow for the start-up. (And the pH in the UASB is probably too high, too...) Once the UASB is operational, you can expect an extra NH4-removal through anamox metabolism; till then, you will have to add extra carbon source.
Is the MBBR for aerobic treatment?
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