scholarly journals Sorption Characteristics and Removal Efficiency of Organic Micropollutants in Drinking Water Using Granular Activated Carbon (GAC) in Pilot-Scale and Full-Scale Tests

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 2053
Author(s):  
Oksana Golovko ◽  
Luana de Brito Anton ◽  
Claudia Cascone ◽  
Lutz Ahrens ◽  
Elin Lavonen ◽  
...  

Granulated active carbon (GAC) is commonly used as a chemical barrier for the removal of organic micropollutants (OMPs) in drinking water treatment plants (DWTPs). However, little is known about the impact of dissolved organic carbon (DOC) and its long-term performance with regard to OMP removal efficiency. This study examined the performance of two GAC types (Norit 830W and Filtrasorb 400) in the removal of OMPs and DOC from natural lake water, in pilot-scale and full-scale tests run for almost one year. Potential early warning indicators of the exhaustion of GAC sorption capacity were also evaluated. The seven OMPs investigated (carbamazepine, lamotrigine, cetirizine, fexofenadine, oxazepam, fluconazole and N,N-diethyl-meta-toluamide (DEET)) all showed decreasing removal efficiencies after ~20,000 bed volumes (BV) in the pilot-scale Norit 830W and Filtrasorb 400 columns. However, columns with an 18-min empty bed contact time (EBCT) showed better performances than columns with 6-min EBCT. DEET was the OMP adsorbed most weakly. We found that DOC concentrations, methylene blue sorption kinetics, UV and fluorescence did not sufficiently explain the OMP breakthrough in the GAC columns. We concluded that carbamazepine, lamotrigine and fexofenadine can be used as indicators of decreasing GAC adsorption performance, due to their later breakthrough. Based on the results, UV and fluorescence removal could be used for the early detection of declining DOC removal, and online solid-phase extraction (SPE)–liquid chromatography–tandem mass spectrometry (SPE-LC-MS/MS) could be used for the early detection of OMPs in drinking water.

2006 ◽  
Vol 41 (3) ◽  
pp. 296-306 ◽  
Author(s):  
Souleymane Ndiongue ◽  
William B. Anderson ◽  
Abhay Tadwalkar ◽  
John Rudnickas ◽  
Margaret Lin ◽  
...  

Abstract Pilot tests were conducted to investigate the removal of geosmin and 2-methylisoborneol (MIB) by new and semi-exhausted granular activated carbon (GAC) extracted from full-scale filters located in the City of Toronto's drinking water treatment facilities. Four pilot filters containing core-sampled GAC and new sand were fed with settled water from a full-scale plant and operated under conditions similar to those employed at full-scale. None of the pilot filters appeared to be capable of reducing geosmin and MIB concentrations to below the commonly cited threshold odour limits of 4 ng/L for geosmin and 9 ng/L for MIB at the influent levels tested. When operated at a 5-min empty bed contact time (EBCT) with geosmin influent concentrations in the range of about 70 to 110 ng/L, removals ranged from 10 to 38% in filters with 25 to 30 cm of used GAC. In the filter with 25 cm of new GAC, removal was 83%. When operated with a 7.5-min EBCT, the filter containing 95 cm of used bituminous GAC removed 78% of the geosmin present in the influent. For both geosmin and MIB, the effluent concentration and the amount removed increased as influent concentration increased, as was expected. In general, geosmin was better removed than MIB.


2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Maria Yu ◽  
Elin Lavonen ◽  
Agneta Oskarsson ◽  
Johan Lundqvist

Abstract Background Bioanalytical tools have been shown to be useful in drinking water quality assessments. Here, we applied a panel of in vitro bioassays to assess the treatment efficiency of two pilot-scale treatments: ozonation and granular activated carbon (GAC) filtration at a drinking water treatment plant (DWTP). The pilot-scale systems were studied alongside a full-scale treatment process consisting of biological activated carbon (BAC) filtration, UV disinfection, and monochloramine dosing. Both systems were fed the same raw water treated with coagulation/flocculation/sedimentation and sand filtration. The endpoints studied were oxidative stress (Nrf2 activity), genotoxicity (micronuclei formations), aryl hydrocarbon receptor (AhR) activation, as well as estrogen receptor (ER) and androgen receptor (AR) activity. Results Nrf2, AhR, and ER activities and genotoxic effects were detected in the incoming raw water and variability was observed between the sampling events. Compared to most of the samples taken from the full-scale treatment system, lower Nrf2, AhR, and ER bioactivities as well as genotoxicity were observed in all samples from the pilot-scale systems across all sampling events. The most pronounced treatment effect was a 12-fold reduction in Nrf2 activity and a sixfold decrease in micronuclei formations following ozonation alone. GAC filtration alone resulted in sevenfold and fivefold reductions in Nrf2 activity and genotoxicity, respectively, in the same sampling event. Higher bioactivities were detected in most samples from the full-scale system suggesting a lack of treatment effect. No androgenic nor anti-androgenic activities were observed in any sample across all sampling events. Conclusions Using effect-based methods, we have shown the presence of bioactive chemicals in the raw water used for drinking water production, including oxidative stress, AhR and ER activities as well as genotoxicity. The currently used treatment technologies were unable to fully remove the observed bioactivities. Ozonation and GAC filtration showed a high treatment efficiency and were able to consistently remove the bioactivities observed in the incoming water. This is important knowledge for the optimization of existing drinking water treatment designs and the utilization of alternative treatment technologies.


2006 ◽  
Vol 6 (2) ◽  
pp. 169-176 ◽  
Author(s):  
T. Okuda ◽  
W. Nishijima ◽  
M. Okada

The removal efficiency of conventional drinking water for picophytoplankton and the contribution of picophytoplankton to AOC were investigated in this research. The removal ratio during coagulation–sedimentation step was determined by jar test using PAC (poly-aluminium chloride). Lower coagulation pH showed better picophytoplankton removal in coagulation–sedimentation. The optimum coagulant dosage for picophytoplankton was twice or more than that for turbidity. The removal efficiency of picophytoplankton was 44–60% at lowest pH in water quality standard (5.8) and at an optimum coagulant dosage for turbidity. The removal ratio of picophytoplankton in rapid sand filtration was determined by pilot scale column experiments with sand and anthracite. The average removal percentage was 16.3% without PAC addition and chlorination before sand filtration; on the other hand it was 51.5% with PAC and chlorination. AOC increased by the chlorination of picoplankton including 6,800 cells/L of picophytoplankton was 21 μg-acetateC/L at 0.1 mg/L of residual free chlorine. The AOC was increased by the increase of residual chlorine concentration, and leveled off at 0.3 mg-Cl/L. From the result, the AOC originating from picoplankton (maximum AOC from picophytoplankton) could increase up to 155 μg-acetateC/L in this reservoir. It indicates that the removal of picoplankton (picophytoplankton) in drinking water treatment process is important from the viewpoint of AOC control.


2019 ◽  
Vol 148 ◽  
pp. 535-545 ◽  
Author(s):  
Vittorio Albergamo ◽  
Bastiaan Blankert ◽  
Emile R. Cornelissen ◽  
Bas Hofs ◽  
Willem-Jan Knibbe ◽  
...  

2014 ◽  
Vol 700 ◽  
pp. 542-546
Author(s):  
Shan Chao Yue ◽  
Le Jun Zhao ◽  
Xiu Duo Wang ◽  
Qi Shan Wang ◽  
Feng Hua He

The present study was implemented to investigate the trihalomethanes formation potential (THMFP) in drinking water treatment and to determine the impact of preozonation on the reduction of Trihalomethanes (THMs). The full-scale examination was carried out, using Luan River as the raw water. Two different preoxidation methods, prechlorination and preozonation were performed. THMFP and THM species were analyzed. The investigation indicated that 18.72% of THMFP was removed during preozonation. Further study on the distribution of THM species showed a significant reduction of Chloroform and bromodichloromethane, 20.62% and 17.39% during preozonation, respectively. The result suggested that the application of preozonation process is an effective method for reducing THMs generation in drinking water treatment. In the final effluent, the total removal rates of THMFP were 47.49% after preozonation and 55.67% after prechlorination.


Author(s):  
Malin Ullberg ◽  
Elin Lavonen ◽  
Stephan J. Köhler ◽  
Oksana Golovko ◽  
Karin Wiberg

Conventional drinking water treatment is inefficient in removing a large fraction of known organic micropollutants (OMPs). Ozonation in combination with granular activated carbon is a promising approach for addressing this issue.


2006 ◽  
Vol 6 (2) ◽  
pp. 125-130
Author(s):  
C.-H. Hung ◽  
K.-H. Tsai ◽  
Y.-K. Su ◽  
C.-M. Liang ◽  
M.-H. Su ◽  
...  

Due to the extensive application of artificial nitrogen-based fertilizers on land, groundwater from the central part of Taiwan faces problems of increasing concentrations of nitrate, which were measured to be well above 30 mg/L all year round. For meeting the 10 mg/L nitrate standard, optimal operations for a heterotrophic denitrification pilot plant designed for drinking water treatment was investigated. Ethanol and phosphate were added for bacteria growing on anthracite to convert nitrate to nitrogen gas. Results showed that presence of high dissolved oxygen (around 4 mg/L) in the source water did not have a significantly negative effect on nitrogen removal. When operated under a C/N ratio of 1.88, which was recommended in the literature, nitrate removal efficiency was measured to be around 70%, sometimes up to 90%. However, the reactor often underwent severe clogging problems. When operated under C/N ratio of 1.0, denitrification efficiency decreased significantly to 30%. Finally, when operated under C/N ratio of 1.5, the nitrate content of the influent was almost completely reduced at the first one-third part of the bioreactor with an overall removal efficiency of 89–91%. Another advantage for operating with a C/N ratio of 1.5 is that only one-third of the biosolids was produced compared to a C/N value of 1.88.


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