Spectroscopic and elemental investigation of microbial decomposition of aquatic fulvic acid in biological process of drinking water treatment

Abstract

As humic substances left in treated water tend to form trihalomethans during chlorination, their removal in water treatment processes is a significant concern for drinking water supplies. One of the removal technologies, the biofilm reactor is studied for the microbial decomposition of aquatic fulvic acid (AFA). The AFA is characterized by elemental analysis. UV-Vis, 13C-NMR, and IR spectroscopic methods. The spectroscopic and elemental investigation was capable of characterizing the microbial decomposition of AFA. Biologically treated fulvic acid was in a more oxidized state; its spectra displayed a higher degree of condensation of aromatic constituents than influent fulvic acid. Microbial degradation of AFA was more active in the low molecular weight fractions and intensively occurred in the aliphatic fraction.

Degradation and Transformation of Aquatic Humic Substances by Laccase-producing FungiCladosporium cladosporioides andPolyporus versicolor

“…A microbial degradation of aquatic HS has been repeatedly reported [3,24,25]. Despite of this, only little knowledge exists about the microorganisms and possible mechanims involved in the process.…”

Interactions between Humic Substances and Microorganisms and Their Implications for Nature-like Bioremediation Technologies

“…A large variety of bacterial consortia capable of degrading HSs were isolated from soil [ 9 , 13 , 14 , 93 , 94 ], coal [ 20 ], or aquatic environments [ 2 , 95 , 96 , 97 , 98 ], including marine and estuarine waters [ 6 , 99 , 100 ]. According to the data presented by Yanagi and coauthors [ 14 ], the population of total bacteria that were capable of degrading soil HAs varied from 0.1 × 10 6 to 2.8 × 10 6 CFU g −1 of soil, forming 0.2–3.5% of the total microbe density.…”

“…Bacterial and fungal utilization of HSs results in the alteration of HS properties, including a decrease in molecular weight [ 96 , 147 , 148 , 154 , 155 , 174 ], a loss of carbohydrates [ 13 , 175 ], a loss of aliphatics and an increase in aromatics [ 13 , 38 , 73 , 96 , 176 , 177 , 178 , 179 ], increased aromaticity [ 147 ], utilization of the polysaccharides [ 180 , 181 ], a loss of peptides [ 40 , 180 ], alteration of the C/N ratio [ 9 , 13 , 40 , 54 ], and oxidation [ 96 ]. Peroxidase and phenoloxidase enzymes, which are excreted by microorganisms to utilize HSs, can catalyze not only oxidative polymerization of phenolic moieties of HSs but also the oxidative coupling of phenol and aniline pollutants [ 182 ].…”

Biological filtration is resilient to wildfire ash-associated organic carbon threats to drinking water treatment

“…Biological filtration preferentially removes low molecular weight (LMW) compounds 41,42 that may be present in wildfireimpacted source waters. 14 Accordingly, it may offer treatment resilience in buffering elevated source water DOM after wildfire.…”

“…Substantial reductions in UVA254 across the biofilters were not expected because (i) UVA254 reflects both DOC concentration and aromaticity, 68 (ii) WEOM is typically more aromatic when an impact of wildland fire on source water DOM is observed, 14 and (iii) aromatic DOC is less biodegradable than more aliphatic DOC. 41,42,69 Thus, while the biofilters were able to reduce UVA254 somewhat, the extent of removal diminished as more of the influent UVA254 was derived from wildfire ash addition (i.e., higher ash content). Importantly, the biofilter DOC, UVA254, and LC-OCD removal data collectively demonstrate that while the biofilters were not designed to mimic all aspects of full-scale biofiltration (especially not operational aspects such as headloss accumulation), they provided representative and therefore reasonable indication of the biodegradation capabilities of biological filtration processes.…”