I have heard that it can take up to 8 months to form granular sludge in a new Upflow Anaerobic Sludge Blanket (UASB). Are there any common methods that work, even with relatively unfavorable waste waters such as petroleum and dairy?
Ca2+ and Fe2+, enhance granulation, check the references below:
Grotenhuis et al., 1991; Kosaric and Blaszczyk, 1990; Mahoney et al., 1987; Schmidt and Ahring, 1993
Hi Tyler and colleagues,
A state-of-the-art UASB reactor (low-medium up-flow velocity) - as opposed to an EGSB one (high up-flow velocity) - does NOT need granular sludge. UASB's operates very well on dense flocculating sludge which is far less delicate to grow and maintain than the pure granular sludge needed in EGSB's. Methanogenic activity of the biosludge is far more important than its physical shape.
I agree with Evangelos that calcium and ferrous iron are important for all high-rate AD reactors. However even more important is adequate equalization, hydrolysis, pre-acidification and conditioning upstream of the UASB reactor along with effective process controls.
I /we designed, realized and commissioned over hundred UASB based high-rate AD plants worldwide including several in California, USA. If interested, I can send you more info via email.
Hi Tyler
you can used old or granulated sludge from other UASB already under operation as a source for granulated anaerobic bacteria with high activity
best wishes
randa
Hi. I agree with Randa, the easiest solution is to use granular sludge from an existing full-scale facility, preferably one treating a similar substrate of what you want to digest. Making granular sludge from scratch is possible and can be hastened but it can't be explained in 2-3 sentences here. Among other parameters, the substrate used and the upflow velocity of your digester becomes critical. Good luck !
Pay attention to the calcium concentration that you add in your system. You can obtain larger granules but also a detrimental effect for biological activity of anaerobic microorganisms (especially methanogens).
Yu, H. Q., Tay, J. H., & Fang, H. H. P. (2001). The roles of calcium in sludge granulation during UASB reactor start-up. Water Research, 35(4), 1052–1060. http://doi.org/10.1016/S0043-1354(00)00345-6
Dang, Y., Zhang, R., Wu, S., Liu, Z., Qiu, B., Fang, Y., & Sun, D. (2014). Calcium effect on anaerobic biological treatment of fresh leachate with extreme high calcium concentration. International Biodeterioration & Biodegradation, 95, 76–83. http://doi.org/10.1016/j.ibiod.2014.05.016
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