The study examined the removal mechanism of non-acclimated and acclimated aerobic
activated sludge for 29 target organic micropollutants (OMPs) at low concentration. The
selection of the target OMPs represents a wide range of physical-chemical properties
such as hydrophobicity, charge state as well as a diverse range of classes, including
pharmaceuticals, personal care products and household chemicals.
The removal mechanisms of OMPs include adsorption, biodegradation, hydrolysis, and
vaporization. Adsorption and biodegradation were found to be the main routes for OMPs
removal for all target OMPs. Target OMPs responded to the two dominant removal
routes in different ways: (1) complete adsorption, (2) strong biodegradation and weak
adsorption, (3) medium biodegradation and adsorption, and (4) weak sorption and weak
biodegradatio. Kinetic study showed that adsorption of atenolol, mathylparaben and
propylparaben well followed first-order model (R2: 0.939 to 0.999) with the rate
constants ranging from 0.519-7.092 h-1. For biodegradation kinetics, it was found that
benzafibrate, bisphenol A, diclofenac, gemfibrozil, ibuprofen, caffeine and DEET
followed zero-order model (K0:1.15E-4 to 0.0142 μg/Lh-1, R2: 0.991 to 0.999), while
TCEP, naproxen, dipehydramine, oxybenzone and sulfamethoxazole followed first-order
model (K1:1.96E-4 to 0.101 h-1, R2: 0.912 to 0.996).
4
Inhibition by sodium azide (NaN3)and high temperature sterilization was compared, and
it was found that high temperature sterilization will damage cells and change the sludge
charge state.
For the OMPs adaptation removal study, it was found that some of OMPs effluent
concentration decreased, which may be due to the slow adaptation of the sludge or the
increase of certain bacteria culture; some increased due to chromic toxicity of the
chemicals; most of the OMPs had stable effluent concentration trend, it was explained
that some of the OMPs were too difficutl to remove while other showed strong quick
adaptation.
A new module combined of sequencing batch reactor (SBR) and nanofiltration
membrane filtration (NF-MBR) was developed to further study the OMPs removal and to
exam the concept of compounds (CRT). The NF-MBR was proved to be a promising
bioreactor, as OMPs were rejected by NF membrane which leaded to a low OMPs
concentration in permeate water, the apparent removal rate was over 80% for most of the
OMPs.
| Identifer | oai:union.ndltd.org:kaust.edu.sa/oai:repository.kaust.edu.sa:10754/295059 |
| Date | 06 1900 |
| Creators | Wang, Nan |
| Contributors | Amy, Gary L., Biological and Environmental Sciences and Engineering (BESE) Division, Hong, Peiying, Zhang, Tao |
| Source Sets | King Abdullah University of Science and Technology |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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