Qualitative analysis of activated sludge using FT-IR technique

Abstract

The ability to measure and control the composition of activated sludge is an important issue, aiming at evaluating the effectiveness of changes occurring in the sludge, what determines its usefulness to treat wastewater. In this research, diffuse reflectance infrared Fourier transform (FTIR–DRIFT) technique was used, which relies on measuring the reflectance of the powdered substance’s surface layer and capturing spectra in range of infrared wave. First, spectra correlation table of the substances mostly occurring in wastewater was developed to assess the main components of the tested samples of activated sludge. The simplest compounds containing functional groups characteristic for particular chemical classes were chosen: peptides (peptone and albumin), fats (glycerin and fatty acids), carbohydrates (glucose and sucrose), nitrogen compounds (NaNO3 and NH4SO4), sulfur compounds (Na2SO4 and Na2S2O3), silicate, etc. The spectra of those substances were captured and characteristic absorption bands for respective bonds in the function groups were assigned. Second, samples of activated sludge from lab-scale membrane bioreactors (MBRs), which purifies petroleum wastewater, were taken. Samples were properly prepared (lyophilization and homogenization) and their spectra were captured. During spectra analysis, previously developed correlation table was used. In obtained spectra of activated sludge, absorption bonds characteristic for amides, peptides, carbohydrates, fats, and aliphatic was identified. The spectra profile of the sludge sample from MBR feed with petroleum wastewater was slightly different from the control MBR sample’s spectra. Intensity of bands in the area characteristic for aliphatic compounds and phenols was clearly higher. This study proves the usefulness of FT-IR technique to observe changes in the chemical composition of activated sludge.

Synthesis and Cytotoxicity Study of Magnetite Nanoparticles Coated with Polyethylene Glycol and Sorafenib–Zinc/Aluminium Layered Double Hydroxide

“…The appearance of these bands indicates that the main phase of the synthesized drug-loaded magnetic nanoparticles is superparamagnetic iron oxide nanoparticles. In the FTIR spectra, the vibrational band for the hydroxy groups was also observed, but this is due to the high moisture absorption on the sample [ 43 , 44 ].…”

Biodiesel-Derived Glycerol Obtained from Renewable Biomass—A Suitable Substrate for the Growth of Candida zeylanoides Yeast Strain ATCC 20367

“…For instance, the high-pitched peak situated at 1741 cm −1 indicated the presence of C=O bonds specific to carboxylic acids or esters of fatty acids. The band at 1560 cm −1 showed the presence of COO ― groups particular to soaps or salts, which, in this case, may have been attributed to the catalyst involved in the transesterification reaction [54,55].…”

Photocatalytic degradation of swine wastewater on aqueous TiO2 suspensions: optimization and modeling via Box-Behnken design

“…As inset, the spectra of untreated SWW is also shown for comparison. Peaks at 3300 cm À1 and 2927 cm À1 could be attributed to -NH 2 or -OH compounds and to the stretching vibration of C-H bond, respectively, and probably relate either to OH bending vibrations of absorbed water molecules or peptides, polyalcohols, and carbohydrates present in the wastewater [37]. Other peaks signals can also be identified in the regions near 1645 cm À1 and 1540 cm À1 , which may reflect asymmetrical vibrations of COO À and symmetrical vibrations of NH þ bonds.…”