Biogenic Nanoscale Colloids in Wastewater Effluents

Abstract

The size, surface area, metal complexation capacity, organic pollutant sorption potential, reactivity with disinfectants, and elevated nitrogen content of biogenic organic nanoscale material (BONM) can potentially affect aquatic environments. BONM in effluents from 11 full-scale wastewater treatment plants (WWTPs), which use a range of biological processes, were characterized in two ways. First, BONM was measured by hydrodynamic size-exclusion chromatography coupled with an online organic carbon and UV detector. Second, BONM was isolated from the wastewater using rotary evaporation and dialysis and then characterized by elemental analysis, transmission electron microscopy, and Fourier transform infrared spectroscopy. The wastewaters contained 6-10 mg/L of dissolved organic carbon (DOC). BONM accounted for 5%-50% of the DOC in wastewater effluent organic matter, and the largest size fraction (>10 kDa) of organic carbon correlated with the organic carbon content determined after rotary evaporation and dialysis. Membrane bioreactor WWTPs had the lowest fraction of BONM (<10% of the DOC), followed by conventional activated sludge (10% to 30% of the DOC), with other processes (e.g., trickling filters, aerated lagoons) containing larger BONM percentages. BONM had a lower carbon to nitrogen ratio (6.2 ± 1.7) compared with the literature values for humic or fulvic acids, exhibited chemical bonds that were indicative of amides and polysaccharides, and contained fibril entangled networks. This work has important implications for operations efficiency of WWTPs, including controlling membrane fouling and release of organic nitrogen into sensitive environments.

Understanding and Control of Biopolymer Fouling in Ultrafiltration of Different Water Types

“…This trend confirms the phenomenon reported in a previous study [24]. Although detailed reason has not been explored thoroughly, several factors such as temperature shock, availability of food and nutrients can affect the living condition of bacteria, and thus the secretion of SMP [7,8,33]. Under such challenging conditions, bacteria alter the production of SMP and/or EPS to adapt to the situation and protect their metabolism process [8].…”

“…This process is feasible because protein content in biopolymers originating from SE and SW is quantitatively quite different. For instance, some investigations on the EfOM biopolymers show that this fraction contains relatively high protein-like material, indicated by the ratio of carbon to nitrogen (C:N ratio) in the range of 6.2 ± 1.7 [7]. This C:N ratio indicator is consistent with the Redfield ratio (C:N:P = 106:16:1) [14].…”

“…SE biopolymers are the macromolecular fraction of effluent organic matter (EfOM). They are mostly solvable microbiological products (SMP) secreted by microorganisms during metabolism and/or related to extracellular polymeric substances (EPS) [6][7][8]. Using advanced characterization technologies, the presence of proteins and polysaccharides in this fraction are clearly identified [2].…”

Transformation in Bulk and Trace Organics during Ozonation of Wastewater

“…The distribution can be broadly divided into three groups, high, medium and low, corresponding to colloidal organics above 10,000 Da, from 1000 to 10,000 Da, and from 100 to 1000 Da. Compounds in the high-molecularweight range are predominantly colloidal matter (Song et al, 2010). These compounds are responsible for membrane fouling and can sorb micropollutants such as PPCPs.…”

Cell-Free DNA: An Underestimated Source of Antibiotic Resistance Gene Dissemination at the Interface Between Human Activities and Downstream Environments in the Context of Wastewater Reuse

“…Putting these observations together, the implication of MVs in the dissemination of ARGs in WWTPs and downstream environments is likely but its incidence remains to be elucidated. With this respect, structures once known as "biological colloids" or "liposomes-like biogenic materials, " probably MVs, have already been described in wastewater effluents and sometime reported to affect the operation and the quality of treatment processes (Song et al, 2010;Barry et al, 2014;Toyofuku et al, 2015). Second, considering that WWTP combines both MV forming bacteria and stressing molecules (e.g., antibiotics), it is of prime importance to determine: (i) whether the induction of MV formation can occur during the wastewater treatment processes, (ii) where it occurs during the process, (iii) whether a given advanced treatment process could eliminate or retain MVs in the final effluents, and finally (iv) the fate of the MVs discharged from WWTPs in downstream (aquatic and terrestrial) environments.…”