Use of GAC after enhanced coagulation for the removal of natural organic matter from water for purification

2009 ◽  
Vol 9 (2) ◽  
pp. 173-180 ◽  
Author(s):  
I. García ◽  
L. Moreno
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Environmental Protection Agency ◽  
Organic Matter Content ◽  
The United States ◽  
Matter Content ◽  
Protection Agency ◽  
Enhanced Coagulation ◽  
Water Plant ◽  
Anionic Charge

Filtration with granular activated carbon (GAC) after an enhanced coagulation (EC) process was evaluated in order to determine the effectiveness of GAC in the reduction of natural organic matter (NOM), which should result in much lower formation of trihalomethane in the disinfection step. The results show that a combination of EC and GAC considerably reduces the organic matter content, which is mainly fulvic acid. This type of organic matter is removed with high coagulant dosages which neutralize their high anionic charge. A further reduction of NOM is achieved due the adsorption of NOM by GAC. As a result, the average trihalomethane (THM) concentration was only 14.5±5 μg L−1. Enhanced coagulation alone decreased the NOM concentration by 50%, but the remaining NOM reacted in the chlorination step and a higher average THM concentration was found (38±23 μg L−1). An average THM concentration of 73.8±41.2 μg L−1 was found at the drinking water plant of Boaco when conventional treatment was used. This THM concentration sometimes exceeds the maximum contaminant level of 80 μg L−1 established by the United States Environmental Protection Agency (USEPA), but not the Nicaraguan threshold of 460 μg L−1.

scholarly journals Optimization of the coagulation–flocculation process for the removal of natural organic matter fractions present in drinking water sources

2016 ◽  
Vol 51 (2) ◽  
pp. 153-166
Author(s):  
Oswaldo Cerón Alfaro ◽  
Alejandra Martín Domínguez ◽  
Fotis Rigas ◽  
Myriam Solís-López ◽  
Rosa-María Ramírez-Zamora
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Natural Organic Matter ◽  
Membrane Fouling ◽  
Environmental Protection Agency ◽  
Influence Factors ◽  
Weight Ratio ◽  
The United States ◽  
Operating Conditions ◽  
Organic Matter Fractions

We used an experimental design to determine the best coagulation–flocculation mechanism and the optimal operating conditions for the maximum removal of the natural organic matter fractions (hydrophobic acid (HPOA) and hydrophilic neutral (HPIN)), which are the main factors responsible for irreversible membrane fouling and the generation of disinfection by-products (DBPs). Charge neutralization and sweep mechanisms (SM) were studied using the jar test experiment, and synthetic waters prepared with different hydrophobic/hydrophilic (HPO/HPI) weight ratios by adding model compounds to represent the dissolved organic matter (DOM) fractions. Significant influence factors were identified for both coagulation mechanisms. The SM was the best one for DOM removal independent of the HPO/HPI weight ratio. The SM removed HPOA and HPIN fractions with efficiencies of 87.5–90.5% and 73.6–89.8%, respectively. The dissolved organic carbon (DOC) values of all met the recommendation proposed by the United States Environmental Protection Agency (2 mg total organic carbon (TOC)/L or 1.8 mg DOC/L) for DBPs (<100 μg/L). Furthermore, all effluents met the DOC and silt density index recommended values by membrane suppliers (<3 mg DOC/L and <5%/min, respectively) to minimize fouling potential and to extend the membrane life.

Dissipation of Herbicides at Three Soil Depths

Weed Science ◽  
1969 ◽  
Vol 17 (1) ◽  
pp. 27-31 ◽  
Author(s):  
C. I. Harris ◽  
E. A. Woolson ◽  
B. E. Hummer
Keyword(s):  
United States ◽  
Organic Matter ◽  
Puerto Rico ◽  
Soil Organic Matter ◽  
Organic Matter Content ◽  
The United States ◽  
Vertical Movement ◽  
Matter Content ◽  
Soil Organic Matter Content ◽  
Positive Correlation

Twelve locations in the United States and Puerto Rico were the sites for determining the loss of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) and 2,3,6-trichlorophenylacetic acid (fenac) from soil. The herbicides were contained in tubes (1.88 by 6 inches) placed at depths of 3, 9, and 15 inches in the field. The samples were placed horizontally to minimize losses due to vertical movement of water from the tubes. After at least 3 months in the soil, the samples were returned to Beltsville and analyzed. Average recoveries showed 61% more atrazine and 41% more fenac from the 15-inch depth than from the 3-inch depth. Five northern samples contained more than twice as much atrazine and fenac residue as four southern samples. A positive correlation existed between fenac retention and soil organic matter content. Increasing soil organic matter and depth of placement, and decreasing temperature, tended to make the herbicides more persistent. However, the data were quite variable and the variations were often unexplainable.

scholarly journals Studi Pendahuluan Pengolahan Air Payau Menjadi Air Bersih Dengan Metode Kombinasi Elektrokoagulasi Dan Adsorpsi Menggunakan Karbosil

2014 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Eny Heriani R.N. ◽  
Wasinton Simanjuntak ◽  
Ilim .
Keyword(s):  
Electrical Conductivity ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Brackish Water ◽  
Adsorption Process ◽  
Organic Matter Content ◽  
Matter Content ◽  
Homogeneous Surface ◽  
Pyrolysis Method ◽  
Electrocoagulation Process

This study was carried out to investigate treatment of brackish water using a combination of electrocoagulation and adsorption using carbosil prepared from rice husk with pyrolysis method. Electrocoagulation was applied with the aim to remove natural organic matter in the sample, using aluminim as electrodes, with the particular purpose to study the effect of potenstials.For this purpose, electrocoagulation experiments were conducted at potential of 4, 6, and 8 volt at fixed contact time of 60 minutes.The performance of the method was defined in term of absorbance reduction at the wavelengths of 254 and 285 nm, since the absorbance at these two wavelenghts was found to correlate well with the amount of organic matter in the water samples. The treated water was then subjected to adsorption process at different contac times of 5. 10, and 15 minutes, and the performance of the process was evaluated in term of electrical conductivity reduction.The results obtained indicate that for electrocoagulation process, the higest reduction of natural organic matter content was achieved using potential of 8 volt, and adsorption porcess of 15 minutes was found to result in reduction of electrical conductivity from 15.13 mS/cm to 10.10 mS/cm.Characterization of the carbosil using SEM/EDX technique revealed that the carbosil has practically homogeneous surface and able to adsorb salt and several other elements from the brackish water. Key words : adsorption, brackish water, carbosil, electrocoagulation

THE ESTIMATED NUMBER OF NEMAS IN THE SOILS OF MANITOBA

1934 ◽  
Vol 11 (5) ◽  
pp. 594-601
Author(s):  
E. H. J. Marchant
Keyword(s):  
United States ◽  
Organic Matter ◽  
Organic Matter Content ◽  
The United States ◽  
Matter Content ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Number Of Species ◽  
Moisture Equivalent

Samples of soil, taken from 29 different sections of the arable portions of Manitoba, have been analyzed. Twelve species of eight genera of nematodes have been identified. No species of the genus Heterodera were found.An endeavor has been made, first, to determine the approximate degree of infestation, and second, to correlate such factors as hydrogen ion concentration, moisture equivalent, and organic matter content with the nema counts.The nematode population is somewhat higher in the soils of Manitoba than in those of many parts of the United States, but considerably lower than in those of North China.The number of species seems to be limited.The degree of infestation appears to be negatively affected by either hydrogen ion concentration or moisture equivalent, but is decidedly influenced by organic matter content.

Soil Properties Influence Saflufenacil Phytotoxicity

Weed Science ◽  
2014 ◽  
Vol 62 (4) ◽  
pp. 657-663 ◽  
Author(s):  
Travis W. Gannon ◽  
Adam C. Hixson ◽  
Kyle E. Keller ◽  
Jerome B. Weber ◽  
Stevan Z. Knezevic ◽  
...  
Keyword(s):  
Organic Matter ◽  
Regression Analysis ◽  
Soil Properties ◽  
Texture Classification ◽  
Organic Matter Content ◽  
The United States ◽  
Exchange Capacity ◽  
Matter Content ◽  
Crop Tolerance ◽  
Wide Range

Saflufenacil, a pyrimidinedione herbicide, is used for contact and residual broadleaf weed control in various crops. Bioactivity of saflufenacil in soil was tested in greenhouse and laboratory studies on 29 soils representing a wide range of soil properties and geographic areas across the United States. A greenhouse bioassay method was developed using various concentrations of saflufenacil applied PPI to each soil. Whole canola plants were harvested 14 d after treatment, and fresh and dry weights were recorded. Nonlinear regression analysis was used to determine the effective saflufenacil doses for 50% (ED50,), 80% (ED80), and 90% (ED90) inhibition of total plant fresh weight. Bioactivity of saflufenacil in soil was strongly correlated to soil organic (R= 0.85) and humic matter (R= 0.81), and less correlated to cation exchange capacity (R= 0.49) and sand content (R= −0.32). Stepwise regression analysis indicated that organic matter was the major soil constituent controlling bioactivity in soil and could be used to predict the bioactivity of saflufenacil. Saflufenacil phytotoxicity was found to be dependent on soil property; therefore, efficacy and crop tolerance from PRE and PPI applications may vary based on soil organic matter content and texture classification.

Evaluation of centrifugal ultrafilters for size fractionation of total mercury and methylmercury in freshwaters

2013 ◽  
Vol 10 (4) ◽  
pp. 323 ◽  
Author(s):  
David Kocman ◽  
Scott C. Brooks ◽  
Carrie L. Miller ◽  
Xiangping L. Yin
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Total Mercury ◽  
Organic Matter Content ◽  
Matter Content ◽  
Contaminated Water ◽  
Size Fractionation ◽  
East Fork Poplar Creek ◽  
Total Hg ◽  
Nominal Molecular Weight

Environmental context Although mercury associated with colloids is an important part of the aquatic Hg cycle, there is currently no fast and reliable method to separate complexes smaller than traditional filter pore sizes. We test commercially available centrifugal ultrafilters for their applicability to size fractionation of total Hg and methylmercury in freshwaters. Sorption of Hg onto the filters precludes their use for fractionation of inorganic Hg, the approach proved to be very suitable for methylmercury fractionation regardless of sample organic matter content. Abstract Amicon Ultra-15 centrifugal filters with nominal molecular weight cut-offs of 100, 30 and 3kDa, were tested for separating Hg complexes in freshwaters. Experiments used Hg-contaminated water from East Fork Poplar Creek (EFPC) and laboratory-prepared Hg solutions containing Suwannee River natural organic matter (SR-NOM). Investigations focussed on Hg and dissolved organic carbon blank levels, Hg sorption and leaching, Hg mass balance closure and spike recoveries of inorganic and methylmercury (MeHg). Hg spike recoveries for EFPC samples were low (57±16%, n=30) due to sorption. MeHg recovery averaged 87±9% (n=15) suggesting it was less affected by sorptive losses. SR-NOM samples yielded similar dissolved organic matter (DOM) and MeHg size fractionation patterns with ~20% of the MeHg found in the less than 3-kDa fraction. Overall, the distribution of MeHg followed a pattern similar to the DOM, indicating the importance of both sample DOM quantity and quality for MeHg partitioning in aquatic systems. Although the use of these ultrafilters for inorganic Hg in freshwater samples is not recommended, they were successfully used for MeHg in EFPC where the majority of MeHg was found to be either dissolved or associated with phases smaller than 3kDa.

scholarly journals Natural organic matter (NOM) removal in a typical North-China water plant by enhanced coagulation: Targets and techniques

2009 ◽  
Vol 68 (3) ◽  
pp. 320-327 ◽  
Author(s):  
Mingquan Yan ◽  
Dongsheng Wang ◽  
Jinren Ni ◽  
Jiuhui Qu ◽  
Wenjin Ni ◽  
...  
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
North China ◽  
Enhanced Coagulation ◽  
Water Plant

scholarly journals Impact of Polyelectrolytes on the Effectiveness of Treatment of Groundwater with Increased Natural Organic Matter Content

2018 ◽  
Vol 28 (3) ◽  
pp. 17-29
Author(s):  
Izabela Krupińska
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Organic Matter Content ◽  
Matter Content ◽  
Ionic Character ◽  
Organic Substances ◽  
Groundwater Treatment ◽  
Anionic Polyelectrolyte ◽  
Coagulation Process ◽  
Water Treatments

Abstract The article discusses effectiveness of treatment of groundwater with increased natural organic matter content with the use of organic polyelectrolytes. The effects of water treatments were determined by the ionic character of the polyelectrolyte and its dose. Due to the amount of removed general ferric and coloured matters a greater usefulness of anionic and non-ionic polyelectrolytes was shown, while due to decreased turbidity and TOC, cationic flocculants proved more useful. Using the Praestol 2540 semi-anionic polyelectrolyte as the substance aiding the coagulation process decreased the effectiveness of groundwater treatment, especially in terms of the removal of iron and organic substances when using the PIX-112 coagulating agent.

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