scholarly journals Pilot - Plant Experiments For The Removal of Thms, Haas and Doc from Drinking Water by Gac Adsorption- Galatsi Water Treatment Plant, Athens

2013 ◽  
Vol 5 (3) ◽  
pp. 177-184
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Activated Carbon ◽  
Water Treatment ◽  
Dissolved Organic Matter ◽  
Pilot Plant ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Carbon Surface ◽  
Gac Adsorption

A pilot-plant study was carried out with the water supply to Athens water works filtered through a granular activated carbon (GAC) filter- adsorber. The objective of this study was to evaluate the performance of GAC for the removal from drinking water of the two main groups of disinfection by -products (DBPs), trihalomethanes (THMs) and haloacetic acids (HAAs), as well as of dissolved organic matter. The pilot treatment facility is located at the Water Treatment Plant of EYDAP in Galatsi, Athens, and was operated as a rapid gravity filter - adsorber. It was fed with chlorinated water, coming from the overflow of the sedimentation tanks, and operated continuously in parallel with a full-scale sand filter. At regular time intervals water samples were taken from both filters and analysed for THMs, HAAs and DOC. Other parameters were measured too. The operation of the GAC filter-adsorber continued until the GAC adsorption capacity for THMs and HAAs was almost exhausted. The results of the analyses showed that GAC was more effective in removing the dissolved organic matter than the smaller molecules of THMs and HAAs, fact which is in agreement with the relevant literature. GAC was also proved more effective in removing HAAs than removing THMs. The removal of THMs and the most part of the removal of HAAs and DOC must be attributed to adsorption by GAC, while that of a smaller part of DOC and HAAs may be attributed to biological activity in the filter bed, where chlorine had been totally removed by the catalytic action of the activated carbon surface.

scholarly journals Profiles of dissolved organic matter and haloacetic acid formation potential in drinking water treatment by a comprehensive fractionation technique

2013 ◽  
Vol 13 (1) ◽  
pp. 89-95 ◽  
Author(s):  
I. Jo ◽  
S. Echigo ◽  
S. Itoh
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Water Treatment ◽  
Dissolved Organic Matter ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Haloacetic Acid ◽  
Limited Ability ◽  
Treatment Train

A comprehensive fractionation technique was applied to a set of water samples obtained along a real drinking water treatment plant with ozonation and granular activated carbon (GAC) treatment to obtain detailed profiles of dissolved organic matter (DOM) and to evaluate the haloacetic acid (HAA) formation potentials of these DOM fractions. The results indicated that ozonation and GAC treatment showed limited ability to remove hydrophilic fractions (23%), while removal of hydrophobic fractions was 72%. The contribution of hydrophilic fractions to HAA formation increased from 30 to 61% along the treatment train because of better removal for hydrophobic fractions both in concentration and reactivity. Similar trends were also found for trihalomethanes.

scholarly journals Pilot study of the removal of individual trihalomethanes (THMs) from chlorinated drinking water by GAC adsorption - Galatsi water treatment plant, Athens, Greece

2013 ◽  
Vol 15 (4) ◽  
pp. 504-512
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
Water Treatment ◽  
Pilot Study ◽  
Contact Time ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Carbon Surface ◽  
Chlorinated Drinking Water ◽  
Adsorbed Mass

<p>The objective of this pilot study was to evaluate the performance of Powdered Activated Carbon (PAC) for the removal of individual trihalomethanes (THMs) from chlorinated drinking water, Athens, Greece. The pilot treatment facility was located at the Water Treatment Plant of EYDAP (Athens Water Supply and Sewerage Company) in Galatsi, Athens, and consisted of two mixing tanks operating as open batch reactors, which were fed with chlorinated water from the overflow of the sedimentation tanks. Experimental cycles were performed, with different PAC doses ranging from 5 to 50 mg L-1 and with contact times 30 and 60 min for each cycle. Water samples taken at the start of each cycle and after contact with PAC, were analysed for individual THMs and Dissolved Organic Carbon (DOC). Bromide, free residual chlorine, pH and temperature were also measured. From the experimental results, it was shown that all THMs concentrations were decreased after PAC contact, the decrease being higher for higher PAC dose and higher contact time, with few exceptions. This fact probably indicates that adsorption rate plus volatilisation rate of THMs overcame formation rate, in most cases. It was also concluded that volatilisation and possible formation reactions of THMs had probably a more apparent effect to the total removal of most THMs at low PAC doses and low contact time. At higher PAC doses and higher contact time, PAC adsorption probably had an increased contribution to THMs removal, because of the larger carbon surface area and the longer contact time, resulting in higher adsorbed mass according to adsorption theory. By using isotherm results of individual THMs on activated carbon by other researchers, the theoretically adsorbed mass of THMs per g of PAC was roughly estimated and compared with the measured removed mass of THMs per g of PAC at PAC dose 50 mg L-1 and contact time 60 min for most THMs, on the assumption of equilibrium achievement. The removed mass of THMs by PAC appeared much higher than the theoretically adsorbed, especially for the most volatile members. The difference was attributed to volatilisation taking place in the open mixing tanks. In conclusion, the practical results from the application of PAC for the removal of THMs are much better than expected from single adsorption by PAC. Volatility of THMs, especially of chloroform (TCM), substitutes for weak adsorbability and gives increased removal. The influent DOC was almost constant in all experiments. The removal of DOC was generally higher for increased PAC dose and contact time. Although equilibration cannot have happened for DOC, the mass removal of DOC per g of PAC was higher by more than two orders of size than that of the smaller and in lower concentration THMs, as expected.</p>

scholarly journals Pesticide removals in the nitrifying expanded-bed filter at drinking water treatment plant

2020 ◽  
Vol 15 (1) ◽  
pp. 1-13
Author(s):  
Nguyet Thi-Minh Dao ◽  
The-Anh Nguyen ◽  
Viet-Anh Nguyen ◽  
Mitsuharu Terashima ◽  
Hidenari Yasui
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
Water Treatment ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Cost Effective ◽  
Water Treatment Plant ◽  
Field Analysis ◽  
Expanded Bed ◽  
Biological Activated Carbon

The occurrence of pesticides even at low concentrations in drinking water sources might induce potential risks to public health. This study aimed to investigate the removal mechanisms of eight pesticides by the nitrifying expanded-bed filter using biological activated carbon media at the pretreatment of a drinking water plant. The field analysis demonstrated that four pesticides Flutolanil, Buprofezin, Chlorpyrifos, and Fenobucard, were removed at 82%, 55%, 54%, and 52% respectively, while others were not significantly removed. Under controlled laboratory conditions with continuous and batch experiments, the adsorption onto the biological activated carbon media was demonstrated to be the main removal pathway of the pesticides. The contribution of microorganisms to the pesticide removals was rather limited. The pesticide removals observed in the field reactor was speculated to be the adsorption on the suspended solids presented in the influent water. The obtained results highlighted the need to apply a more efficient and cost-effective technology to remove the pesticide in the drinking water treatment process. Keywords: biological activated carbon; drinking water treatment; nitrifying expanded-bed filter; pesticide removal.

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