Water Organic Matter Research Articles

Preozonation on Removal of Organic Matter in Water and Biological Stability

The pollution of drinking water source has become a serious problem facing the world, and it is even more severe in China undergoing rapid development. Statistics show that the total annual emissions in China is 35.3 billion m3, CODMnis about 760 million tons, the treatment rate is only 23.6%, a lot of waste water without being treated in many small towns was discharged directly . It polluted seriously the water supply in many cities and industrial and mining water. According to the survey, among China's seven major river systems, 110 Key Sections, 68% of Water Quality is Ⅲ, Ⅳ, Ⅴ Grade. 90% of the national urban water has been polluted, the most prominent problem is the organic pollution. There are low dissolved oxygen, and the density of ammonia nitrogen, COD, BOD, and TOC in the water is high. Some of the polluted water bodies often appear black smelly serious situation. These organic polluted drinking water source, due to the presence of a large number of organic ozone-depleting substances , by conventional coagulation, sedimentation, filtration and disinfection treatment process, is difficult to achieve the requirements of the national mandatory Standard— "drinking water health standards"(GB 5749-2006) , issued and revised by the national standards committee and Ministry of Health, which there is a new comprehensive index of organic matter - the oxygen consumption is to control trace organic matter in water.

Improvement of the analysis of the biochemical oxygen demand (BOD) of Mediterranean seawater by seeding control

Biochemical oxygen demand (BOD) is a useful parameter for assessing the biodegradability of dissolved organic matter in water. At the same time, this parameter is used to evaluate the efficiency with which certain processes remove biodegradable natural organic matter (NOM). However, the values of BOD in seawater are very low (around 2mgO2L−1) and the methods used for its analysis are poorly developed. The increasing attention given to seawater desalination in the Mediterranean environment, and related phenomena such as reverse osmosis membrane biofouling, have stimulated interest in seawater BOD close to the Spanish coast. In this study the BOD analysis protocol was refined by introduction of a new step in which a critical quantity of autochthonous microorganisms, measured as adenosine triphosphate, is added. For the samples analyzed, this improvement allowed us to obtain reliable and replicable BOD measurements, standardized with solutions of glucose–glutamic acid and acetate. After 7 days of analysis duration, more than 80% of ultimate BOD is achieved, which in the case of easily biodegradable compounds represents nearly a 60% of the theoretical oxygen demand. BOD7 obtained from the Mediterranean Sea found to be 2.0±0.3mgO2L−1 but this value decreased with seawater storage time due to the rapid consumption of labile compounds. No significant differences were found between two samples points located on the Spanish coast, since their organic matter content was similar. Finally, the determination of seawater BOD without the use of inoculum may lead to an underestimation of BOD.

Changes in different organic matter fractions during conventional treatment and advanced treatment

XAD-8 resin isolation of organic matter in water was used to divide organic matter into the hydrophobic and hydrophilic fractions. A pilot plant was used to investigate the change in both fractions during conventional and advanced treatment processes. The treatment of hydrophobic organics (HPO), rather than hydrophilic organicas (HPI), should carry greater emphasis due to HPO's higher trihalomethane formation potential (THMFP) and haloacetic acid formation potential (HAAFP). The removal of hydrophobic matter and its transmission into hydrophilic matter reduced ultimate DBP yield during the disinfection process. The results showed that sand filtration, ozonation, and biological activated carbon (BAC) filtration had distinct influences on the removal of both organic fractions. Additionally, the combination of processes changed the organic fraction proportions present during treatment. The use of ozonation and BAC maximized organic matter removal efficiency, especially for the hydrophobic fraction. In sum, the combination of pre-ozonation, conventional treatment, and O 3-BAC removed 48% of dissolved organic carbon (DOC), 60% of HPO, 30% of HPI, 63% of THMFP, and 85% of HAAFP. The use of conventional treatment and O 3-BAC without pre-ozonation had a comparable performance, removing 51% of DOC, 56% of HPO, 45% of HPI, 61% of THMFP, and 72% of HAAFP. The effectiveness of this analysis method indicated that resin isolation and fractionation should be standardized as an applicable test to help assess water treatment process efficiency.

In situ microbial fuel cell-based biosensor for organic carbon

The biological oxygen demand (BOD) may be the most used test to assess the amount of pollutant organic matter in water; however, it is time and labor consuming, and is done ex-situ. A BOD biosensor based on the microbial fuel cell principle was tested for online and in situ monitoring of biodegradable organic content of domestic wastewater. A stable current density of 282 ± 23 mA/m 2 was obtained with domestic wastewater containing a BOD 5 of 317 ± 15 mg O 2/L at 22 ± 2 °C, 1.53 ± 0.04 mS/cm and pH 6.9 ± 0.1. The current density showed a linear relationship with BOD 5 concentration ranging from 17 ± 0.5 mg O 2/L to 78 ± 7.6 mg O 2/L. The current generation from the BOD biosensor was dependent on the measurement conditions such as temperature, conductivity, and pH. Thus, a correction factor should be applied to measurements done under different environmental conditions from the ones used in the calibration. These results provide useful information for the development of a biosensor for real-time in situ monitoring of wastewater quality.

Ultrasound-Enhanced Coagulation Pilot Plant for Micro-Polluted Water of Huaihe River

The method to remove natural organic matter in water at low tempreture of the status of the Huaihe River water was studied .Through 10t/h in a pilot scale, ultrasound-enhanced coagulation treatment was used to simulate the micro-polluted water. For the role of Ultrasound, different pharmaceutical dosage control、the control of different HRT ,select the optimal HRT and the dosage of drugs. Also investigated whether the design parameters is reasonable. The effectiveness of the tested coagulation was evaluated by measurements of turbidity, CODMn, UV254and NH3-N.Results showed that: when accordance with 10t/h processing load operation, settled water turbidity is high, the removal of organic matter was poor results. However, when accordance with 8t/h processing load operation, PAC dosage of 5.4mg/l were added,The removal efficiency of turbidity, NH3-N, CODMnand UV254were respectively 93.29%, 7.91%, 37% and 41.63%.On this basis, when open Ultrasonic mixer, the CODMnand UV254removal rates were increased by 9.12% and 7.86% compared with conventional treatment (PAC 5.4 mg/L)but had little effect on the removal of ammonia.

Content and composition of natural organic matter in water of Lake Pitkjärv and mire feeding Kuke River (Estonia)

The seasonal and spatial changes of content and composition of dissolved organic carbon in water flowing out from bog were studied. Water was sampled from the Kuke River flowing out from Koigi Bog (eastern Saaremaa, Estonia) and in comparison the water samples from the bog lake (Lake Pitkjärv) were analyzed regularly during 18 months. Absorptions of water samples were measured at 250, 254, 285, 365 and 436 nm on UV–Vis spectrophotometer and pH, conductivity and concentration of dissolved organic carbon (DOC) were measured. Specific ultraviolet absorptions (SUVA) and the ratios of absorptions were calculated to characterize the nature of dissolved organic carbons. The significant changes of the concentration of DOC were determined in water sampled from the Kuke River during the dry days, but it was much steadier during rest sampling time. Analysis of water from the Lake Pitkjärv showed relatively high content of macromolecular organic compounds rich in aromatics (SUVA254 = 4.58 L mg−1 m−1), whereas water samples from the Kuke River contained predominantly more homogeneous low-molecular-weight materials poor in aromatics (SUVA254 = 2.96 L mg−1 m−1). Calculated values of SUVA285 confirmed that organic carbon in river water can be also originated from the decomposition of root litter. The values of ratio of UVA250/A365 for water samples from Kuke River indicated the fulvic nature of DOC as conformed by the SUVA254 and SUVA285 values. The values of A254/A436 for river were higher than 14 indicating that the organic matter in water from lake and river contained lots of UV absorbing functional groups.

Behavior of Dissolved Organic Matter in Coral Reef Waters in Relation with Biological Processes

Behavior of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in coral reef waters in relation with biological processes was studied with incubation experiments and field observations in May 2008 and 2009 at the fringing reef of Sesoko Island, Okinawa, Japan. Reef sea water (RSW) and coral mucus added RSW collected from Acropora digitifera (AcrRSW) and Montipora digitata (MonRSW) were incubated for one day in situ and then for 77 days in the laboratory under dark condition. The results indicated that the behavior of DON was different compared to that of DOC in RSW and mucus added (AcrRSW and MonRSW) during dark incubation. Concentration of DON increased from 8.3 µM to 11.8 µM for AcrRSW and 4.0 µM to 15.4 µM for MonRSW during dark incubation period. The increasing rates for DON in AcrSRW and MonRSW were 0.05 µM day-1 and 0.1 µM day-1 respectively. On the other hand DOC concentration decreased from 129.0 µM to 75.0 µM for AcrRSW and 75.1 µM to 64.7 µM for MonRSW, with decreasing rates of 0.7 µM day-1 and 0.1 µM day-1 respectively. We assume that the increase of DON may be determined by difference between rates of inputs of organic matter mainly from mucus and rate of degradation of dissolved organic matter in the water column. These results suggest that recycling of DON is slow than that of DOC in coral reef ecosystem.

PIV characterisation of flocculation dynamics and floc structure in water treatment

Particle flocculation with chemical flocculant addition is an essential step in water treatment. The performance of flocculation and the property of the flocs formed affect the overall results of the treatment process. In addition to particulate impurities, the presence of organic matter in water, such as natural organic materials (NOM), also influence the effectiveness of chemical flocculation. In this paper, the PIV system was employed to investigate the flocculation dynamics for different flocculants in different model waters. With the PIV and image analysis, the change in particle size distribution could be well recorded. Using the sequence of flocculation, shear breakage and re-flocculation on a jar-test device together with the PIV system, the rate of floc formation, the strength of the flocs, the recovery of broken flocs, and the morphological and structural features of the flocs were characterized. The results indicated that the adsorption of HA on the particle will stabilized the particles, hence hindered the flocculation process. Sweep flocculation using a higher chemical coagulant dosage was an effective means of process enhancement for the removal of particulates and associated organic matter. The dynamics of A–B–R process was characterized by particle size distribution (PSD) measurement with PIV setup. The particle strength and reversibility capability were examined. Strength index showed the HA flocs have comparable strength, while recovery index indicated a less recovery capability with the increasing of HA concentration after exposure to a higher shear, especially for ferric HA flocs. It appears that the bonds holding HA flocs together are not purely physical bonds given the limited regrowth seen. Finally, evolution of floc structure during A–B–R process was analysed by investigated the fractal dimension D b . The results were generally consistent with previous PSD measurements. It suggested that the structure of flocs in breakage became more compact with little permeability. An increase in floc compaction provides a further explanation for the limited regrowth for most of flocs. According to the performances of alum and ferric, it can be noticed that HA flocs have different properties dependent on which chemical coagulant is used. Alum produced larger HA flocs which endured a higher recovery capability after exploring higher shear, hence, compared to ferric, it could be preferred to using in the practical enhanced coagulation unit.

Simultaneous removal of chlorpyrifos and dissolved organic carbon using horizontal sub-surface flow pilot wetlands

Rural areas of developing countries require low-cost treatment systems to purify wastewater which is contaminated with pesticides and organic matter. This work evaluated for six months the simultaneous removal of chlorpyrifos and dissolved organic matter in water using four horizontal sub-surface flow constructed wetlands (SSFCW) at a pilot scale, that were planted with Phragmites australis at 20 ± 2 °C water temperature. In each wetland, three concentrations of chlorpyrifos and three of dissolved organic carbon (DOC) were tested by liquid chromatography and an organic carbon analyzer respectively. The pesticide and DOC were added to the wetlands in synthetic wastewater. For the experiments, four wetlands of equal dimensions were used, with granular material of igneous rocks, 3.9–6.4 mm in diameter and at a depth of 0.3 m with a layer of water 0.2 m deep. For each treatment, regular sampling was carried out for the influent and effluents. As a supporting feature NH 4 +, NO 3 − and PO 4 3− were quantified and in situ measurements of dissolved oxygen (DO), pH, electrical conductivity, water temperature and redox potential were taken. The overall removal of the chlorpyrifos (92.6%) and DOC (93.2%) was high, as was DOC removal as a function of pesticide concentration in the influent. The minimum magnitude (92.0%) was reached with 425.6 μg L −1 of chlorpyrifos and, with the highest pesticide removal (96.8%). At lower concentrations of the agrochemical, DOC removal increased. The removals were possibly due to mineralization processes, biological decomposition and sorption in plants. These findings demonstrate that SSFCW are capable of simultaneously removing dissolved organic matter and organophosphate pesticides such as chlorpyrifos, which indicate that chlorpyrifos did not interfere with the removal of organic material.

Water Coagulation Using Electrostatic Patch Coagulation (EPC) Mechanism

Coagulation of fine particles to form large flocs is an essential step to reach efficient dewatering of wet materials. The electrostatic patch coagulation (EPC) mechanism was applied in this study to remove turbidity and natural organic matters in water using four different dosing-mixing schemes. Sufficient rapid mixing and slow mixing or applying two-stage coagulation benefit removal of turbidity. The EPC mechanism could only efficiently remove organic matters of molecular weight of 7500–10,000 Da. Only sufficient rapid mixing is relevant to organic matter removal. The mechanisms for natural organic matters (NOM) removal are proposed to be complexation of ions and NOM to form insoluble aggregates to be separated by membrane filtration.

Determination of haloacetic acids in human urine by headspace gas chromatography–mass spectrometry

Haloacetic acids (HAAs) are water disinfection byproducts (DBPs) formed by the reaction of chlorine oxidizing compounds with natural organic matter in water containing bromine. HAAs are second to trihalomethanes as the most commonly detected DBPs in surface drinking water and swimming pools. After oral exposure (drinking, showering, bathing and swimming), HAAs are rapidly absorbed from the gastrointestinal tract and excreted in urine. Typical methods used to determine these compounds in urine (mainly from rodents) only deal with one or two HAAs and their sensitivity is inadequate to determine HAA levels in human urine, even those manual sample preparation protocols which are complex, costly, and neither handy nor amenable to automation. In the present communication, we report on a sensitive and straightforward method to determine the nine HAAs in human urine using static headspace (HS) coupled with GC–MS. Important parameters controlling derivatisation and HS extraction were optimised to obtain the highest sensitivity: 120 μl of dimethylsulphate and 100 μl of tetrabutylammonium hydrogen sulphate (derivatisation regents) were selected, along with an excess of Na 2SO 4 (6 g per 12 ml of urine), an oven temperature of 70 °C and an equilibration time of 20 min. The method developed renders an efficient tool for the precise and sensitive determination of the nine HAAs in human urine (RSDs ranging from 6 to 11%, whereas LODs ranged from 0.01 to 0.1 μg/l). The method was applied in the determination of HAAs in urine from swimmers in an indoor swimming pool, as well as in that of non-swimmers. HAAs were not detected in the urine samples from non-swimmers and those of volunteers before their swims; therefore, the concentrations found after exposure were directly related to the swimming activity. The amounts of MCAA, DCAA and TCAA excreted from all swimmers are related to the highest levels in the swimming pool water.

Removal of less biodegradable dissolved organic matters in water by superconducting magnetic separation with magnetic mesoporous carbon

Less biodegradable dissolved organic matters in water as typified by humic substances are known as precursors of carcinogenic trihalomethanes, and are removed about 60% by current advanced water treatments. However, further increase of the removal ratio is demand. In this study, magnetic mesoporous carbon (MMPC), which can adsorb the substances physically and be efficiently collected by using superconducting high gradient magnetic separation (HGMS), has been synthesized with coconut-shell-based activated carbon and ferric nitrate solution by the gas activation method. The MMPC has the maximum magnetization value of 30.7emu/g and an adsorption ability of 87% to 10mg/L humic acid in a short time. The standard MMPC having a magnetization of 6.43emu/g was able to be separated at magnetic field of 2T. Used MMPC regained the adsorption ability to 93.1% by N2 reactivation heat treatment. These results show promise for application of current water treatments by superconducting HGMS, which is suitable for high-speed water treatment without secondary wastes.

MONTAJE Y VALIDACIÓN DEL MÉTODO DE ANÁLISIS POR COMBUSTIÓN Y DETECCIÓN POR INFRARROJO NO DISPERSIVO PARA DETERMINACIÓN DE CARBONO ORGÁNICO TOTAL (COT) EN AGUA

The combustion analysis technique and non-dispersive infrared (NDIR) detection was validated for the determination of organic matter in water, quantified as total organic carbon (TOC). Previously, the elimination of inorganic carbon (IC) of the sample with an optimum time of 1.5 min and an acid ratio of 5% was optimized. A linear dynamic range (LDR) between 3 and 20 mg/L of TOC was established, in which the regression line met the parameters that credited its linearity as analyzed by the least squares method, showing a correlation coefficient of 0,

DRINKING WATER QUALITY: Better Biomarker of DBP Exposure

DRINKING WATER QUALITY: Better Biomarker of DBP Exposure

Rapid Fractionation of Natural Organic Matter in Water Using a Novel Solid‐Phase Extraction Technique

This paper introduces a novel natural organic matter (NOM) fractionation technique using solid-phase extraction cartridges. The new technique requires only 6 hours of fractionation time, which is much faster than traditional fractionation techniques (24 hours). It uses three Bond Elute ENV cartridges (Varian, Inc., Lake Forest, California), one Strata X-C cartridge (Phenomenex, Torrance, California), and one Strata X-AW cartridge (Phenomenex) in series and was tested by using to fractionate NOM from Suwannee River, Georgia (SRNOM) and Red River, Minnesota (RRNOM). Hydrophobic acid was a major fraction and accounted for 66 to 70% and 36% of SRNOM and RRNOM, respectively. The NOM fractions obtained from the developed method were characterized using Fourier transformed infrared spectroscopy and 13C nuclear magnetic resonance. The acid fractions of SRNOM mainly consisted of carboxylic acids. An application of this new technique was demonstrated by using it to investigate the effectiveness of water treatment processes in removing different NOM fractions.

Formation of chloroform during chlorination of alanine in drinking water

Currently, dissolved nitrogenous organic matters in water, important precursors of disinfection by-products (DBPs), are of significant concern. This study was to explore the formation of chloroform (CF) during chlorination of alanine (Ala), an important nitrogenous organic compound commonly present in water sources. Our results indicated that the CF yield reached a maximum value of 0.143% at the molar ratio of chlorine atom to nitrogen atom (Cl/N) = 1.0 over a Cl/N range of 0.2–5.0 (pH = 7.0, reaction time = 5 d, and initial Ala = 0.1 mM). At an acidic–neutral condition (pH 4–7), the formation of CF was suppressed. However, the highest CF yield (0.227%) occurred at weakly alkaline condition (pH 8.0) (initial Ala = 0.1 mM, and Cl/N = 1.0). The increase of Br − in water can increase total trihalomethanes (THMs) and bromo-THMs. However, the bromo-THMs level reached a plateau at Br −/Cl > 0.04. Finally, based on the computation of frontier electron density and identification and measurement of key intermediates during Ala chlorination, we proposed a formation pathway of CF from Ala chlorination: Ala → monochloro- N-alanine (MC-N-Ala) → acetaldehyde (AAld) → monochloroacetaldehyde acetaldehyde (MCAld) → dichloroacetaldehyde (DCAld) → trichloroacetaldehyde (TCAld) → CF.

Utilization of oligo- and polysaccharides at microgram-per-litre levels in freshwater byFlavobacterium johnsoniae

To obtain a bacterial strain that can be used to quantify biodegradable polysaccharides at concentrations of a few micrograms per litre in freshwater. Flavobacterium johnsoniae strain A3 was isolated from tap water supplemented with laminarin, pectin or amylopectin at 100 microg C l(-1) and river Rhine water. The organism utilized 14 of 23 oligo- and polysaccharides, and 1 of 9 monosaccharides, but none of the sugar acids, sugar alcohols, carboxylic acids or aromatic acids tested at 10 microg C l(-1). Amino acids promoted growth of strain A3, but not in coculture with assimilable organic carbon (AOC) test strain Pseudomonas fluorescens P17, which utilized these compounds more rapidly than strain A3. Compounds released by strain P17 and AOC test strain Spirillum sp. NOX grown on acetate promoted the growth of strain A3 at N(max) values of > or = 2 x 10(5) CFU ml(-1) of strain P17 and > or = 5 x 10(5) CFU ml(-1) of strain NOX. Significant growth of strain A3 was observed in surface water and in tap water in the presence of strain P17 (N(max) P17 < 2 x 10(5) CFU ml(-1)). Strain A3 utilizes oligo- and polysaccharides at microgram-per-litre levels. In surface water and in tap water, the organism was able to utilize compounds that were not utilized by strain P17. These compounds may include oligo- and/or polysaccharides. Phytoplanktonic and bacterial polysaccharides can constitute an important biodegradable fraction of natural organic matter in water and may promote growth of heterotrophic bacteria during water treatment and drinking water distribution. Strain A3 can be used to quantify a group of compounds that includes oligo- and polysaccharides at microgram-per-litre levels in freshwater.

ADSORPTION, KINETICS, AND EQUILIBRIUM STUDIES ON REMOVAL OF 4,4-DDT FROM AQUEOUS SOLUTIONS USING LOW-COST ADSORBENTS

The removal of a chlorinated pesticide (4,4-DDT) from aqueous solutions by a batch adsorption technique using different low-cost adsorbents was investigated. Two adsorbents, wood sawdust (A) and cork wastes (B), were used to determine adsorption efficiency. The influence of the adsorbent particle size and the organic matter of water (humic acids) on the removal process was studied. The obtained results were compared to those obtained with a commercial powdered activated carbon (PAC, F400, Chemviron) (C). Kinetic studies were performed to understand the mechanistic steps of the adsorption process. The rate of the adsorption kinetics of 4,4-DDT on the low-cost adsorbents was found best fitted with a pseudo-second-order kinetic model. This is in contrast to the rate of the adsorption kinetics of the PAC F400, which was best fitted with the Lagergren model. The application of the Morris-Weber equation showed that the adsorption process of 4,4-DDT on these adsorbents was complex. Both the adsorption on the surface and the intraparticle diffusion were the rate-controlling mechanisms. Langmuir and Freundlich adsorption isotherms were applicable to the adsorption process and their constants were evaluated. The adsorption capacity (qm) calculated from the Langmuir isotherm (69.44 mg·g−1, 19.08 mg·g−1, and 163.90 mg·g−1, respectively, for A, B, and C) showed that the process is highly particle size dependent, that the organic matter influenced the adsorption process negatively, and that wood sawdust is the most effective adsorbent for the removal of 4,4-DDT from aqueous solutions. The adsorbents studied exhibited a possible application in water decontamination, as well as in treatment of industrial and agricultural waste waters.

Reduction of natural organic matter by nanofiltration process

The objectives of this investigation were to characterize natural organic matter (NOM) in Kin-men raw water, to evaluate the performance of the nanofiltration (NF) membrane process for NOM removal, and to determine the good engineering practice (GEP) of the NF 270 membrane filtration performance. Three different samples: (1) raw water collected from the Tai Lake in Kin-men, Taiwan; (2) ultrafiltration (UF) pre-treated water; and (3) sand filtration (SF) treated water after the coagulation and sedimentation processes were employed in this study. The hydrophobic component (58%) was the predominant NOM fraction, and the NOM molecular weight was distributed broadly, i.e., lower than 1 kDa (30%), 1–5 kDa (32%) and larger than 5 kDa (38%). Hydrophobic NOM easily accumulated on the NF membrane surface and resulted in flux decline. The SF–NF was the proposed treatment process because it can reduce the NOMs effectively with lower energy consumption than UF–NF. It was noted that the dissolved organic carbon (DOC) rejection ratio was not affected by changing cross-flow velocity. However, at lower cross-flow velocity (0.15 m s −1), the reduction of organic matter in water sample was higher than that at higher cross-flow velocity (0.30 m s −1). By integrating the experimental results, it was concluded that a transmembrane pressure of 690 kPa and a cross-flow velocity of 0.30 m s −1 exhibited the GEP, yielding about 94% of both DOC and UV 254 reduction.

Regularities of Corg distribution in bottom sediments of the Russian part of the Sea of Azov

The principal regularities were ascertained for the spatiotemporal distribution of organic carbon in the water and bottom sediments of the Russian part of the Sea of Azov. The relationships between allo- and autochthonous organic matter in water and bottom sediments from different parts of the sea aquatic area were found. The behavior of organic carbon in the water-bottom sediments system was characterized as the effect of the variability of hydrochemical, biological, and hydrological factors ad processes.