Removal of humic substances by chitosan

2004 ◽  
Vol 4 (5-6) ◽  
pp. 121-129 ◽  
Author(s):  
C. Vogelsang ◽  
D.O. Andersen ◽  
A. Hey ◽  
T. Håkonsen ◽  
T.G. Jantsch ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Humic Substances ◽  
Surface Waters ◽  
Laboratory Tests ◽  
Uv Absorbance ◽  
Raw Water ◽  
Triggering Mechanism ◽  
Particle Content ◽  
Reduced Dose ◽  
Maximum Removal

Results from laboratory tests, conducted to study different aspects regarding the removal of humic substances by the environmentally friendly cationic biopolymer chitosan, are presented. Chitosan was shown to be an efficient remover of the high molecular weight humic substances, significantly reducing the colour and UV absorbance in typical humus-rich Norwegian surface waters with low particle content. By adding small amounts of Fe3+ together with a reduced dose of chitosan, it was possible to significantly improve the removal of the medium molecular weight humic substances. The highest charged (low Fa) chitosans were the most efficient coagulants, indicating that charge neutralisation was the triggering mechanism for the coagulation. Surface charge measurements of coagulated raw water gave strong indications in the same direction. However, net positive surface potentials of flocs after neutralisation indicated that excess chitosan participated in the build-up of flocs, suggesting that bridging or electrostatic patch flocculation could be important mechanisms during flocculation. However, the molecular weight of chitosan had no significant influence on the maximum removal of the humic substances.

NOM control options: the next generation

2004 ◽  
Vol 4 (4) ◽  
pp. 139-145 ◽  
Author(s):  
D.A. Fearing ◽  
J. Banks ◽  
D. Wilson ◽  
P.H. Hillis ◽  
A.T. Campbell ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Exchange Process ◽  
Uv Absorbance ◽  
Raw Water ◽  
Ion Exchange Process ◽  
Control Options ◽  
The Times ◽  
Magnetic Ion

Seasonal periods of high rainfall have been shown to cause elevated natural organic matter (NOM) loadings at treatment works. These high levels lead to difficulties in removing sufficient NOM to meet trihalomethane (THM) standards, and hence better alternative treatments are required. Here three options for the removal of NOM either by optimising current coagulation and pre- or post-coagulation have been studied. NOM can be isolated into fractions distinguished by their hydrophobic and hydrophilic characteristics. Previous studies have shown that certain fractions are more recalcitrant to treatment during the times of high loadings. By optimising coagulation for these fractions a staged coagulation is proposed, the results of which found that although no significant dissolved organic carbon (DOC) or UV absorbance at 254 nm (UV254) was observed filter run times were significantly increased. Secondly a novel magnetic ion exchange process (MIEX®) developed specifically for the removal of NOM was trialled and the results of a combination of ferric coagulation and MIEX® showed that although the final DOC of the water was not significantly reduced the THM formation potential (THMFP) was reduced by more than 50% for the lower molecular weight (MW) compounds that are known to be untreated by conventional coagulation. Finally the addition of a range of adsorbents including carbons, hydroxides and clays to both the raw water and the isolated low MW fraction showed that an increase in DOC and UV254 removal was achievable. The findings of the three trials showed that at the difficult to treat times of the year, optimised removal for the low MW fractions could prove to be vital if legislation is changed.

A Perspective on Low Molecular Weight Heparins in the Management of Thrombosis

1993 ◽  
Vol 13 (S 01) ◽  
pp. S5-S11 ◽  
Author(s):  
Debra Hoppensteadt ◽  
Jeanine Walenga ◽  
A Ahsan ◽  
O Iqbal ◽  
W Jeske ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Mechanism Of Action ◽  
Manufacturing Process ◽  
Laboratory Tests ◽  
Low Molecular Weight ◽  
Low Molecular Weight Heparins ◽  
Pharmacological Management

SummaryThe introduction of low molecular weight heparins has added a new dimension to the pharmacological management of thrombotic disorders. Because of different chemical and pharmacological characteristics, due to the manufacturing process, each LMWH should be considered as a distinct entitity and only be used for its given indication. A list of commercially available LMWHs is included. The mechanism of action of the LMWHs and their use in various disorders are discussed. Available laboratory tests for monitoring LMWHs are presented and their limitations pointed out.

Water Treatment Considerations–Aquatic Humus

1983 ◽  
Vol 15 (S2) ◽  
pp. 95-101 ◽  
Author(s):  
E T Gjessing
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Humic Substances ◽  
Health Effects ◽  
Surface Waters ◽  
Cold Climate ◽  
Treatment Processes ◽  
Aquatic Humus ◽  
Treatment Considerations

For several reasons the surface waters in cold climate areas are coloured due to humic substances. There are two major objections against humus in drinking water, the first is concerned with aesthetical and practical problems and the second is due to indirect negative health effects. There are essentially three different methods in use today for the removal or reduction of humus colour in water: (1) Addition of chemicals with the intention of reducing the “solubility”, (2) Addition of chemicals in order to bleach or mineralize the humus, and (3) Filtration with the intention of removal of coloured particles and some of the “soluble” colour. The treatment processes are discussed.

scholarly journals Characterization of Soil Organic Matter Individual Fractions (Fulvic Acids, Humic Acids, and Humins) by Spectroscopic and Electrochemical Techniques in Agricultural Soils

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1067
Author(s):  
Aleksandra Ukalska-Jaruga ◽  
Romualda Bejger ◽  
Guillaume Debaene ◽  
Bożena Smreczak
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Humic Substances ◽  
Humic Acids ◽  
Agricultural Soils ◽  
Fulvic Acids ◽  
Sorption Properties ◽  
Aliphatic Chains

The objective of this paper was to investigate the molecular characterization of soil organic matter fractions (humic substances (HS): fulvic acids-FAs, humic acids-HAs, and humins-HNs), which are the most reactive soil components. A wide spectrum of spectroscopic (UV–VIS and VIS–nearIR), as well as electrochemical (zeta potential, particle size diameter, and polydispersity index), methods were applied to find the relevant differences in the behavior, formation, composition, and sorption properties of HS fractions derived from various soils. Soil material (n = 30) used for the study were sampled from the surface layer (0–30 cm) of agricultural soils. FAs and HAs were isolated by sequential extraction in alkaline and acidic solutions, according to the International Humic Substances Society method, while HNs was determined in the soil residue (after FAs and HAs extraction) by mineral fraction digestion using a 0.1M HCL/0.3M HF mixture and DMSO. Our study showed that significant differences in the molecular structures of FAs, Has, and HNs occurred. Optical analysis confirmed the lower molecular weight of FAs with high amount of lignin-like compounds and the higher weighted aliphatic–aromatic structure of HAs. The HNs were characterized by a very pronounced and strong condensed structure associated with the highest molecular weight. HAs and HNs molecules exhibited an abundance of acidic, phenolic, and amine functional groups at the aromatic ring and aliphatic chains, while FAs mainly showed the presence of methyl, methylene, ethenyl, and carboxyl reactive groups. HS was characterized by high polydispersity related with their structure. FAs were characterized by ellipsoidal shape as being associated to the long aliphatic chains, while HAs and HNs revealed a smaller particle diameter and a more spherical shape caused by the higher intermolecular forcing between the particles. The observed trends directly indicate that individual HS fractions differ in behavior, formation, composition, and sorption properties, which reflects their binding potential to other molecules depending on soil properties resulting from their type. The determined properties of individual HS fractions are presented as averaged characteristics over the examined soils with different physico-chemical properties.

Removal of humic substances from surface waters with recycled fluidized bed sand

2021 ◽  
pp. 1-16
Author(s):  
Joni Lehto ◽  
Juha Heikkinen ◽  
Anna Riikka Nickull ◽  
Vesa Junnikkala ◽  
Janne Soimasuo
Keyword(s):  
Humic Substances ◽  
Fluidized Bed ◽  
Surface Waters

scholarly journals Identification and management of microbial contaminations in a surface drinking water source

2007 ◽  
Vol 5 (S1) ◽  
pp. 67-79 ◽  
Author(s):  
J. Åström ◽  
T. J. R. Pettersson ◽  
T. A. Stenström
Keyword(s):  
Drinking Water ◽  
Water Intake ◽  
Surface Waters ◽  
Microbial Contamination ◽  
Water Source ◽  
Drinking Water Source ◽  
Raw Water ◽  
Indicator Organisms ◽  
E Coli ◽  
The City

Microbial contamination of surface waters constitutes a health risk for drinking water consumers which may be lowered by closing the raw water intake. We have evaluated microbial discharge events reported in the river Göta älv, which is used for raw water supply to the city of Göteborg. Elevated levels of faecal indicator bacteria were observed during periods of closed raw water intake. High bacteria levels were, however, also occasionally detected during periods of open intake, probably as a result of microbial discharge far upstream in the river which may be difficult to predict and manage by closing the intake. Accumulated upstream precipitations, resulting in surface runoff and wastewater contaminations in the catchment, correlated positively with the levels of total coliforms, E. coli, intestinal enterococci and sulfite-reducing clostridia. Levels of faecal indicator organisms were negatively correlated to the water temperature due to enhanced survival at lower temperatures. Wastewater discharges from a municipality located just upstream of the water intake resulted in elevated E. coli concentrations downstream at the raw water intake for Göteborg. To improve the prediction of microbial contaminations within the river Göta älv, monitoring data on turbidity and upstream precipitation are of particular importance.

scholarly journals Molecular Weight Characterization of Humic Substances by MALDI-TOF-MS

2004 ◽  
Vol 52 (1) ◽  
pp. 29-32 ◽  
Author(s):  
Toshiyuki SHINOZUKA ◽  
Mitsuhiro SHIBATA ◽  
Tatsuaki YAMAGUCHI
Keyword(s):  
Molecular Weight ◽  
Humic Substances ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms
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