How can you get a representative sample of AGS out of a laboratory SBR for VSS/TSS measurement. The granules are not evenly distributed through the SBR during aeration, i.e. there are more granules in the bottom of the reactor. Does the sample need to be taken from the settled sludge bed?
Is there a method/protocol available in the literature?
Thanks
Mario
I suggest you try the sieving method.
I have summarized the experimental protocol for your reference as follows.
Protocol
1. Measure the total wet weight of a sample.
2. Mount the sieves vertically one on top of the other in increasing order of mesh opening (from bottom to top) so that the coarsest mesh is at the top.
3. Pour the granule sample onto the sieves.
4. Wash each sieve successively to allow the granules to move from one sieve to the next.
5. Filter the liquid (which has trickled through all the sieves) in order to collect particles smaller than 0.3 mm.
6. Backwash each sieve to retain each granule fraction in a separate beaker.
7. Determine the wet weight, and if needed the dry weight (TSS), the ash content and the VSS of each fraction, which will result in the theoretical percentage of each class size.
The screening can be performed with sieves with mesh openings of, i.e. 2.0, 1.0, 0.5 and 0.3 mm, making it possible to cover the most common granule size range.
Thanks.
Hello Fenghao,
thanks for your answer, but the problem is the sampling itself. How do you get a representative sample before starting with step 1.
Mario
It depends on your reactor size.
I have no distribution problems when using a small lab-scale reactor (2.5L). The granular sludge was evenly distributed in the reactor by high-intensity aeration (3 L/min).
In a large-scale pilot plant (10 m3), we may have an issue as you described. In this case, we sampled the settled sludge and measured the settled volume in the reactor. The VSS concentration (g/m3) of the settled sludge multiplied by the settled volume (m3) can be considered as the mass of the sludge in the reactor.
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