The effect of the molecular mass of the organic matter in raw water on the formation of disinfection by-products

2001 ◽  
Vol 50 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Chen-Yu Chang ◽  
Yung-Hsu Hsieh ◽  
Yu-Min Lin ◽  
Po-Yu Hu ◽  
Chin-Chuan Liu ◽  
...  
1999 ◽  
Vol 40 (9) ◽  
pp. 165-172 ◽  
Author(s):  
E. S. Melin ◽  
H. Ødegaard

Treatment of humic water was studied in a pilot-scale ozonation/biofiltration treatment plant. The raw water had TOC and CODMn concentrations of 3.2-5.0 and 4.1-6.6 mgO 1−1, respectively, and colour (410 nm) of 30-50 mgPt 1−1. The effect of biofilter loading rate on removal of organic matter and ozonation by-products was investigated in two upflow biofilters containing expanded clay aggregate (Filtralite) media. The empty bed contact times ranged from 11 to 54 min. The TOC removals varied from 18 to 37% and the CODMn removals from 30 to 48% with ozone dosages from 1.0 to 1.7 mgO3 mgTOC−1. The ozone dosage seemed to have larger effect on removal efficiency than the loading rate. Concentrations of aldehydes (sum of formaldehyde, acetaldehyde, glyoxal and methyl glyoxal) were 41-47 μg 1−1 in ozonated water. Formaldehyde and glyoxal were the only aldehydes detected from the biofilter effluents at concentrations higher than 1 μg 1−1, but their mean concentrations were below 2.1 μg 1−1. The ketoacid concentrations (sum of glyoxylic, pyruvic and ketomalonic acids) ranged from 272 to 441 μg 1−1. Average biofilter effluent concentrations varied from 5.3 (glyoxylic acid) up to 67 μg 1−1 (ketomalonic acid) with steady-state reductions generally over 80%. The aldehydes and ketoacids accounted on average for 16% of the biodegraded TOC. The results show that expanded clay aggregate media is a good alternative as biofilter material.


2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Muhammad Firdaus Kamal ◽  
Euis Nurul Hidayah

Kehadiran NOM menurunkan kualitas air baku untuk air minum dengan mengubah sifat organoleptik, mengganggu sistem pengendapan dan meningkatkan penggunaan koagulan, menyebabkan penyumbatan pada saringan dan distribusi air minum. Komponen NOM, seperti humic acids (HA) dan fulvic acids (FA) yang bereaksi dengan logam berat menyebabkan terbentuknya senyawa toksik dan berkontribusi terhadap pembentukan disinfection by products (DBPs) yang menyebabkan potensi adanya senyawa karsinogenik dalam pengolahan air minum secara konvensional. Salah satu metode penyisihan bahan organik dalam air adalah dengan peningkatan proses koagulasi, dengan pretreatment sebelum proses koagulasi. Tujuan dari penelitian ini adalah mengetahui pengaruh pre-oksidasi dan koagulasi terhadap penyisihan bahan organik pada air Kali Jagir yang digunakan untuk produksi air minum. Berdasarkan hasil analisis, konsentrasi TOC pada air baku sebesar 11,67  mg/liter dan nilai UV absorbansi 254 nm sebesar 0,10895 cm-1, sehingga diperoleh nilai SUVA sebesar 0,934 L/mg/cm, sehingga diketahui karakteristik pada air Kali Surabaya yang cenderung hidrofilik dengan berat molekul rendah dan kebanyakan bukan humik yang mengindikasikan bahwa air tersebut dihasilkan dari kegiatan domestik dan industri. Pada kombinasi pre-oksidasi dan koagulasi, CaOCl2 dengan dosis 25 mg/liter mampu menurunkan TOC dari 11,67 mg/liter menjadi 9,11 mg/liter, sedangkan permanganat dengan dosis 0,8 mg/liter hanya mampu menurunkan TOC dari 11,67 mg/liter menjadi 11,25 mg/liter. Kombinasi pre-oksidasi dan koagulasi mampu menurunkan bahan organik aromatik, ditunjukkan dengan nilai absorbansi UV210 air baku yaitu 1,4983 cm-1 menjadi 1,2720 cm-1 dengan pre-oksidasi KMnO4-koagulan Al2(SO4)3 dan 1,3152 cm-1 pada pre-oksidasi CaOCl2-koagulan Al2(SO4)3. Kata kunci: bahan organik alami, koagulasi, pre-oksidasi. The presence of NOM reduces air quality for drinking water with changes in organoleptic properties, deposition systems and increased use of coagulants, blockages in filters and distribution of drinking water. NOM components, such as humic acid (HA) and fulvic acid (FA) which are printed with heavy metals cause the formation of toxic compounds and contribute to product disinfection (DBPs) which produce potential carcinogenic compounds in conventional drinking water treatment. One method of removing organic matter in water is by increasing the coagulation process, with pretreatment before the coagulation process. The purpose of this study was to determine the effect of pre-oxidation and coagulation on the removal of organic material in Kali Jagir water used for the production of drinking water. Based on the results of the analysis, TOC concentration in raw water is 11.67 mg/liter and UV absorbance value 254 nm is 0.10895 cm-1, so that the SUVA value is 0.934 L/mg/cm, so it is known the characteristics of the Surabaya River water which tend to be hydrophilic with low molecular weight and most not humic which indicates that the water is produced from domestic and industrial activities. In a combination of preoxidation and coagulation, CaOCl2 with a dose of 25 mg/liter was able to reduce TOC from 11.67 mg/liter to 9.11 mg/liter, while permanganate at a dose of 0.8 mg/liter was only able to reduce TOC from 11,67 mg/liter to 11.25 mg/liter. The combination of preoxidation and coagulation is able to reduce aromatic organic matter, indicated by the absorbance value of UV210 of raw water, namely 1.4983 cm-1 to 1.2720 cm-1 with the KMnO4-coagulant Al2(SO4)3 and 1.3152 cm-1 preoxidation in preoxidation CaOCl2-coagulant (SO4)3. Keywords: natural organic matter, coagulation, pre-oxidation.


2011 ◽  
Vol 383-390 ◽  
pp. 3719-3723
Author(s):  
Yan Fang Liu ◽  
Qi Shan Wang ◽  
Shang Chao Yue ◽  
Si Si Li

This study compared the differential absorbance spectroscopy of the raw water oxidized with chlorine and chlorine dioxide to explore the reactions between oxidants and natural organic matter in disinfection by-products (DBPs) formation. The correlations between the differential absorbance at 272 nm (ΔA272) and 254 nm (ΔA254) and DBPs formation in chlorinated water were also examined, respectively. The intensity of the differential absorbance increased with increasing doses for both chlorine and chlorine dioxide. The sites in natural organic matter oxidized with chlorine and chlorine dioxidate are different. Unlike the well defined band at 272 nm and 254 nm in differential spectra of water oxidized with chlorine, a well defined band at 220 nm was found in water oxidized with chlorine dioxide. The behavior of -ΔA272 during chlorination process was determined to be strongly correlated with DBPs concentrations quantified by linear equations with R2 values > 0.95. A weak correlation (R2 value 254, indicating the formation of DBPs independent of destruction in UV-absorbing sites.


2020 ◽  
Vol 55 (2) ◽  
pp. 184-197
Author(s):  
Saeideh Mirzaei ◽  
Beata Gorczyca

Abstract In this study, diffused aeration was applied to remove trihalomethane (THM) compounds from chlorinated, treated water containing high dissolved organic carbon (DOC) of 6.8 ± 1.2 mg/L. Increasing air-to-water volumetric ratio (rA/W) from 16 to 39 enhanced total THM (TTHM) removal from 60 to 70% at 20 °C and from 30 to 50% at 4 °C. Although bromodichloromethane has lower Henry's law constant than chloroform (CF), it was removed by a higher degree than CF in some aeration trials. Albeit obtaining high removals in aeration, TTHM reformed, and their concentration surpassed the Canadian guideline of 100 ppb in about 24 hours at 20 °C and 40 hours at 10 °C in all attempted air-to-water ratios. The water age in the system investigated in this study varied from 48 hours in midpoint chlorine boosting stations to 336 hours in the nearest endpoint. This study showed that THM removal by aeration is not a viable solution to control the concentration of these disinfection by-products in high-DOC treated water and in distribution systems where water age exceeds 24 hours; unless, it is going to be installed at the distribution endpoints.


2013 ◽  
Vol 316-317 ◽  
pp. 323-326
Author(s):  
Chao Jie Zhang ◽  
Si Bo Li ◽  
Qian Chen ◽  
Qi Zhou

Dissolved organic matter (DOM) may do harms to human beings. After disinfected by chlorine (amine), DOM can form disinfection by-products (DBPs) which can be mutagenic, teratogenic and carcinogenic. Characterization and source of trihalomethane precursors in the secondary effluent by sequencing batch reactors were investigated. CHCl3 was the primary DBPs. The results showed that the precursors of CHCl3 were mainly strongly hydrophobic DOM, while CHCl2Br and CHClBr2 were mainly formed from hydrophilic DOM. The effects of different powder media (activated carbon, zeolite) on removal of DOM were compared. The results showed that the dosing of powder media can promote the removal of DOM and the DBPs precursors.


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