Characterising natural organic matter flocs

2004 ◽  
Vol 4 (4) ◽  
pp. 79-87 ◽  
Author(s):  
P. Jarvis ◽  
B. Jefferson ◽  
S.A. Parsons
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Structural Characteristics ◽  
Floc Size ◽  
Water Characteristics ◽  
Floc Structure ◽  
Floc Characteristics ◽  
Floc Strength ◽  
Settling Column ◽  
One Year

Using a dynamic optical technique and settling column apparatus, natural organic matter floc structural characteristics were monitored and evaluated over a one year period to monitor the seasonal variation in floc structure at optimum coagulation dose and pH. The results show that flocs changed seasonally with different growth rates, size, response to shear and settling rate. Autumn and summer flocs were shown to be larger and less resistant to floc breakage when compared to the other seasons, suggesting reduced floc strength. Floc strength was observed to increase with smaller median floc size. The results of the settling tests indicated that the autumnal flocs were of a more open structure which helped to explain why they settled faster. In summary, the autumnal flocs had significantly different floc characteristics although it was difficult to relate the floc structure with the incoming water characteristics.

scholarly journals Super-bridging Fibrous Materials for Water Treatment: Impacts on Removal of Plastic Particles, Phosphorus and Natural Organic Matter

2021 ◽  
Author(s):  
Mathieu Lapointe ◽  
Heidi Jahandideh ◽  
Jeffrey Farner ◽  
Nathalie Tufenkji
Keyword(s):  
Organic Matter ◽  
Water Treatment ◽  
Natural Organic Matter ◽  
Emerging Contaminants ◽  
Settling Tank ◽  
Process Unit ◽  
Fibrous Materials ◽  
Floc Size ◽  
Sludge Waste ◽  
Treatment Facilities

Aggregation combined with gravitational separation is the most commonly used method to treat water globally, but it carries a significant economic and environmental burden as the chemicals used in the process (e.g., coagulants) generate ~8 million tons of metal-based sludge waste annually. To simultaneously deal with the issues of process sustainability, cost, and efficiency, we developed materials reengineered from pristine or waste fibers to serve as super-bridging agents, adsorbents, and ballast media. This study shows that these sustainable fiber-based materials considerably increased the floc size (~6630 µm) compared to conventional physicochemical treatment using a coagulant and a flocculant (~520 µm). The fiber-based materials also reduced coagulant (up to 40%) and flocculant usage (up to 60%). Moreover, the unprecedented size of flocs produced using fiber-based materials (up to ~13 times larger compared to conventional treatment) enabled easy floc removal by screening, thereby eliminating the need for a settling tank, a large and costly process unit. Our results show that fiber-based materials can be effective solutions at removing classical (e.g., natural organic matter (NOM) and phosphorus) and emerging contaminants (e.g., microplastics and nanoplastics). Due to their large size (> 3000 µm), some Si-grafted and Fe-grafted fiber-based materials can be easily recovered from settled/screened sludge and reused multiple times for coagulation/flocculation. Our results also show that these materials could be used in synergy with coagulants and flocculants to improve settling in existing water treatment processes. Furthermore, these reusable materials combined with separation via screening could allow global water treatment facilities to reduce their capital and operating costs as well as their environmental footprint.

Ozonation of natural organic matter and aquatic humic substances: the effects of ozone on the structural characteristics and subsequent trihalomethane formation potential

2020 ◽  
Vol 55 (2) ◽  
pp. 155-166
Author(s):  
Mehrnaz Sadrnourmohammadi ◽  
Kenneth Brezinski ◽  
Beata Gorczyca
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Structural Characteristics ◽  
Aromatic Rings ◽  
Formation Potential ◽  
Trihalomethane Formation Potential ◽  
Vis Spectroscopy ◽  
Reflectance Ftir ◽  
Main Components ◽  
Humic Fractions

Abstract The effect of ozonation on the structural and chemical characteristics of natural organic matter (NOM) and its isolated humic fractions, humic acid (HA) and fulvic acid, were studied using Fourier transform infrared coupled to attenuated total reflectance (FTIR-ATR), ultraviolet/visible (UV/Vis) spectroscopy, and synchronous scanning fluorescence (SSF) spectroscopy. The results were linked to the effect of ozonation on trihalomethane formation potential (THMfp) reduction for water standards with high THM precursors. Results showed that ozonation at a dose of 1 mg ozone/mg dissolved organic carbon (DOC) was capable of reducing DOC, UV absorbance at 254 nm (UV254), and THMfp by up to 42%, 95%, and 89% for the HA water standard, respectively. The study of UV/Vis, FTIR-ATR, and SSF revealed trends showing that ozone can alter the composition of DOC in the water standards, causing a significant reduction in aromaticity. The reduction of UV254 for each ozonated sample also affirms that ozone mainly targets aromatic moieties contained in NOM. FTIR-ATR results showed that the reduction of unsaturated functional groups, including aromatic rings and C = C bonds in the water standards tested, were the main components impacted by ozone application. SSF results also revealed that ozonation decreases the fluorescence intensity of the maximum peak – as well as the whole spectra.

Understanding effects of water characteristics on natural organic matter treatability by PACl and a novel PACl-chitosan coagulants

2013 ◽  
Vol 263 ◽  
pp. 718-725 ◽  
Author(s):  
Mega Ng ◽  
Sanly Liu ◽  
Christopher W.K. Chow ◽  
Mary Drikas ◽  
Rose Amal ◽  
...  
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Water Characteristics

scholarly journals Lability of natural organic matter in freshwater: a simple method for detection using hydrogen peroxide as an indicator

2018 ◽  
Author(s):  
Isabela Carreira Constantino ◽  
Amanda Maria Tadini ◽  
Marcelo Freitas Lima ◽  
Lídia Maria de Almeida Plicas ◽  
Altair Benedito Moreira ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Organic Matter ◽  
Organic Carbon ◽  
Natural Organic Matter ◽  
Water Samples ◽  
Ultrapure Water ◽  
Model Compounds ◽  
Simple Method ◽  
The Difference ◽  
One Year

Abstract. Natural organic matter (NOM) is an important component for understanding the behavior of pollutants in the environment. A fraction of NOM is considered labile, fresh and less oxidized. In this work, a simple method was developed to distinguish between labile (LOM) and recalcitrant (ROM) organic matter in freshwater samples. Pyruvate, lignin and fulvic acid were chosen as model compounds of labile and recalcitrant NOM. The samples were submitted to kinetic monitoring experiments using hydrogen peroxide. Pyruvate was the best standard for the quantification of LOM (for concetrations up to 2.9 mg L−1). ROM was quantified by measuring the difference between total organic carbon (TOC) and LOM concentrations. Curves obtained with 0.5 to 5.0 mg L−1 TOC (pyruvate) in freshwater or ultrapure water samples did not indicate the existence of a matrix effect. This simple method was applied to water samples that were collected monthly for one year; the resulting LOM concentrations ranged from 0.47 to 2.1 mg L−1 and the ROM concentrations ranged from 0.08 to 3.5 mg L−1. Based on this results we concluded that hydrogen peroxide kinetics can be used as a simple method to quantify LOM and ROM concentrations in freshwater samples.

scholarly journals Characterisation of floc size, effective density and sedimentation under various flocculation mechanisms

2020 ◽  
Vol 82 (7) ◽  
pp. 1261-1271
Author(s):  
Yuping Fan ◽  
Xiaomin Ma ◽  
Xianshu Dong ◽  
Zeyu Feng ◽  
Yingdi Dong
Keyword(s):  
Settling Velocity ◽  
Structural Characteristics ◽  
Effective Density ◽  
Floc Size ◽  
Floc Structure ◽  
Trivalent Cations ◽  
Coal Tailings ◽  
Better Than ◽  
Flocculation Mechanisms

Abstract Floc structure plays an important role in the separation of coal wastewater. In this study, a camera-based method is used to evaluate quantitatively the structural characteristics of flocs generated by different coagulants and flocculants. The correlations between particle size, settlement velocity and effective density of coal tailings flocs are analysed. The results show that the statistical settling velocity increases linearly with floc size, while the effective density decreases with increase in floc size. Different flocculation mechanisms lead to diverse growth abilities of flocs. When the flocculant is used alone, the quality of the flocs generated by the flocculants, cationic polyacrylamide (CPAM) and non-ionic polyacrylamide (NPAM), is better than that generated by anionic polyacrylamide (APAM). However, the combination of trivalent cations and APAM yields a much better effect than that obtained using CPAM and NPAM. Flocs become larger and more compact when treated with a coagulant combined with a flocculant.

Structural controls on floc strength and transport

2004 ◽  
Vol 31 (4) ◽  
pp. 569-578 ◽  
Author(s):  
Ian G Droppo
Keyword(s):  
Extracellular Polymeric Substances ◽  
Correlative Microscopy ◽  
Floc Size ◽  
Biochemical Processes ◽  
Structural Controls ◽  
Floc Structure ◽  
Physical Chemical ◽  
Combined Sewer ◽  
Size Stability ◽  
Floc Strength

An examination of how floc structure (internal and external) influences floc strength and transport is described. Samples were collected from both a natural river and a combined sewer outfall to provide significantly different structures for comparison. Regardless of floc type, the internal matrix was observed to be mediated by a dynamic microbial community. Microbial secretions of fibrilar extracellular polymeric substances (EPS) were found to be interwoven within the floc forming a framework and providing structural stability. This continually changing framework (due to floc physical, chemical, and biological activity) is shown to have extending influence over floc transport by modifying floc size, stability, density, porosity, and biochemical processes. This paper uses correlative microscopy to assess floc structure and behaviour in terms of the transport of sediments and associated contaminants. A conceptual model is provided which links floc strength to sediment transport (deposition and erosion) in the water column and at the sediment water interface.Key words: flocculation, bacteria, extracellular polymeric substances, stability, transport, structure.

Super-bridging Fibrous Materials for Water Treatment: Impacts on Removal of Plastic Particles, Phosphorus and Natural Organic Matter

2021 ◽  
Author(s):  
Mathieu Lapointe ◽  
Heidi Jahandideh ◽  
Jeffrey Farner ◽  
Nathalie Tufenkji
Keyword(s):  
Organic Matter ◽  
Water Treatment ◽  
Natural Organic Matter ◽  
Emerging Contaminants ◽  
Settling Tank ◽  
Process Unit ◽  
Fibrous Materials ◽  
Floc Size ◽  
Treatment Processes ◽  
Large Size

To deal with issues of process sustainability, cost, and efficiency, we developed materials reengineered from fibers to serve as super-bridging agents, adsorbents, and ballast media. These sustainable fiber-based materials considerably increased the floc size (~6630 µm) compared to conventional physicochemical treatment using a coagulant and a flocculant (~520 µm). The materials also reduced coagulant usage (up to 40%) and flocculant usage (up to 60%). These materials could be used in synergy with coagulants and flocculants to improve settling in existing water treatment processes and allow facilities to reduce their capital and operating costs as well as their environmental footprint. Moreover, the super-sized flocs produced using fiber-based materials (up to ~13 times larger compared to conventional treatment) enabled easy floc removal by screening, eliminating the need for a settling tank, a large and costly process unit. The materials can be effective solutions at removing classical (e.g., natural organic matter (NOM) and phosphorus) and emerging contaminants (e.g., microplastics and nanoplastics). Due to their large size, Si- and Fe-grafted fiber-based materials can be easily recovered from sludge and reused multiple times.

Evaluation of Sludge Properties at an Activated Sludge Plant

1992 ◽  
Vol 25 (6) ◽  
pp. 251-265 ◽  
Author(s):  
Leif Eriksson ◽  
Inga Steen ◽  
Marta Tendaj
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Extracellular Polymers ◽  
Filtration Resistance ◽  
Water Composition ◽  
Floc Structure ◽  
History Of ◽  
Floc Strength ◽  
Sludge Properties ◽  
One Year

Composition of pre-settled water, sludge properties in two different lines of an activated sludge plant, and suspended solids (SS) content in outgoing water were followed three times a week during one year. Sludge characteristics were: settling properties, residual turbidity, floc strength, filtration resistance, amount of extracellular polymers, microscope appearance and total length of filamentous organisms. The outgoing SS could be related to residual turbidity and sludge volume. These factors depended on the floc structure and the filament length. These were determined by sludge load or sludge age, water composition and the hydrodynamic history of the sludge. On basis of these and earlier findings a general model for properties of flocs built by floc-forming organisms in activated sludge is proposed.

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