Enhanced coagulation under changing alkalinity-hardness conditions and its implications on trihalomethane precursors removal and relationship with UV absorbance

Iriarte‐Velasco, Unai; Álvarez-Uriarte, Jon I.; González‐Velasco, Juan R.

doi:10.1016/j.seppur.2006.12.022

Cited by 44 publications

(18 citation statements)

References 38 publications

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“…The total removal rate of UV 254 is slightly higher than that of DOC, which is in agreement with the result of Ref. [14]. To sum up, it could be concluded that the concentration of DOC in MBW is much higher than that of other three samples.…”

Section: Distribution Of Mw By Uv 254supporting

confidence: 91%

“…In MW<1 kDa range, THMsFP of MFW and MTW account for 76.5% and 64.6% of their total values, which are roughly close to the ratio of DOC, 71.7% and 71.8%. This shows that most of THMsFP is generated by the organic matter with low MW [14] . There is no obvious relationship between MW distribution and THMsFP in each of the MW fraction [25] .…”

Section: Distribution Of Mw By Uv 254mentioning

confidence: 85%

“…The UF has a higher efficiency than flocculating and precipitation process,which presents in MW>30 kDa fraction [14,15] . Due to the high MW NOM showing more hydrophobic [16] and its low polarity characteristics [17] , it tends to be rejected by the membrane.…”

Section: Measurements Of Thmsfp and Haasfpmentioning

confidence: 99%

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Characterization of natural organic matter and disinfection byproducts formation potential in pilot-scale coagulation-ultrafiltration membrane combined process in winter

Zhang

Wang

et al. 2010

Trans. Tianjin Univ.

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Abstract：A pilot-scale ultrafiltration membrane plant was set up for treating Luanhe River water with flocculating and precipitation process of waterworks. The aim is to investigate the variation and characteristics of natural organic matter and disinfection byproducts formation potential in the whole process in winter. The results show that dissolved organic matter (DOM), UV 254 , trihalomethanes formation potential (THMsFP) and haloacetic acids formation potential (HAAsFP) of Luanhe River water were mainly distributed in the range of molecular weight (MW) <1 kDa, so were the membrane feed water and treated water by membrane. Specific UV absorbance, specific THMsFP and specific HAAsFP have the maximal value in the MW fraction of 1-3 kDa, except that specific UV absorbance of membrane feed water is in the range of 3-10 kDa; DOM of membrane backwash water is mainly distributed in the range of MW>30 kDa and MW<1 kDa. It is the DOM in water backwashing in up way that made significant contribution to the higher dissolved organic carbon content in membrane backwash water. However, UV 254 , THMsFP and HAAsFP were mainly distributed in the range of MW<1 kDa. The highest concentrations of specific THMsFP and specific HAAsFP appeared in the MW fraction of 3-10 kDa. CHCl 3 was the major THMs species during MBW chlorination and occupied more than 60% of the total THMsFP. Dichloroacetic acid and trichloroacetic acid were the main components in HAAsFP. The concentration of THMsFP and HAAsFP in MBW was influenced by operation period.The polluted water sources and enhancement of water quality requirements lead to the fact that the traditional treatment process cannot meet the stringent drinking water standards. The ultrafiltration (UF) membrane is regarded as a substitute of traditional drinking water treatment process for its efficient retention of particles and viruses in water [1] . The research on the distribution and characterization of natural organic matter (NOM) and disinfection byproducts formation potential (DBPFP) arouses special attention [2,3] . Variation in the amount and nature of NOM, especially with respect to changes in the aromatic carbon content, has become significant factors for designing water treatment strategies [4] . NOM in water not only produces chromaticity, turbidity and eutrophication, but also produces disinfection byproducts(DBPs), and many of them have been proved to be carcinogenic [5] . At present, most researches regarding the occurrence of chlorinated DBPs in drinking water are on trihalomethanes (THMs) formation and evolution [6] , and a few are on haloacetic acids (HAAs). In order to better remove NOM in the UF process, membrane filtration can be combined with other unit processes, such as coagulation, precipitation and adsorption [7] . Research on the characteristics of NOM in the combined process and the role in forming DBPFP may shed light on more effective solutions to controlling NOM and decreasing DBPs in the treatment process during the period of low temperature and low turbid...

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Section: Distribution Of Mw By Uv 254supporting

confidence: 91%

Section: Distribution Of Mw By Uv 254mentioning

confidence: 85%

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Characterization of natural organic matter and disinfection byproducts formation potential in pilot-scale coagulation-ultrafiltration membrane combined process in winter

Zhang

Wang

et al. 2010

Trans. Tianjin Univ.

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“…More importantly, NOM is the precursor for health concerning disinfection by-products (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs). The US Environmental Protection Agency (USEPA) has proposed more stringent maximum contaminant levels (MCLs) of 80 and 60 g/L for THMs and HAAs, respectively in finished drinking water [1,2]. Removal of NOM in an effective way is one of the major challenges in modern drinking water industry.…”

Section: Introductionmentioning

confidence: 99%

Effect of polyaluminum chloride on enhanced softening for the typical organic-polluted high hardness North-China surface waters

Yan

Wang

et al. 2008

Separation and Purification Technology

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a b s t r a c tThe treatment of organic-polluted high hardness surface water by enhanced softening via precipitation using various coagulants, such as FeCl 3 , AlCl 3 and polyaluminum chloride (PACl), was investigated in bench scale experiments. Higher removal of natural organic matter (NOM) (UV 254 removal reaches about 50%) is achieved by enhanced softening with coagulant addition conditions as compared with conventional coagulation at natural pH or by softening alone without coagulation. It is found that PACl could enhance the formation of Mg(OH) 2 precipitate to remove NOM efficiently at relative lower pH range (pH <10). Under this circumstance, the pH for enhanced softening can be decreased significantly into the practical pH range for treatment plant operation. The efficiency of enhanced softening is affected significantly not only by pH, coagulant type and dose, but also by raw water quality such as NOM characteristics, magnesium content and hardness. NOM with more hydrophobic content and higher molecular weight may be removed more easily in some situations. For water with higher content of Mg 2+ , the inflexion pH for favorable UV 254 removal is lower. It is of practical value for organic-polluted water with high content of magnesium to be treated by enhanced softening with PACl.

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“… Decreasing NOM levels in source water using coagulation and settling, filtering, and oxidation (Iriarte-Velasco et al, 2007;Xiao et al, 2010;Gerrity et al, 2009;Ghernaout and Boucherit, 2015;Ghernaout et al, 2014;2015a, b).  Utilizing sorption on granulated activated carbon to eliminate DOC (Fabris et al, 2008;Drikas et al, 2008;Tan et al, 2008).…”

Section: Strategies For Monitoring Dbpsmentioning

confidence: 99%

Disinfection and DBPs removal in drinking water treatment: A perspective for a green technology

Ghernaout

2018

Int. j. adv. appl. sci.

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The generation, monitoring, and health impacts of disinfection by-products (DBPs) in potable water are problems of worldwide worry. Several nations, besides the World Health Organization, possess regulations and/or guidelines on bearable levels of DBPs in water. Since drinking water is frequently remediated using a chemical killing agent, DBPs are pollutants to which several humans are unprotected. On account of the health impacts linked to subjection to chlorinated water and/or some DBPs, the water manufacturing has performed great endeavors to equilibrate killing pathogens and DBP monitoring. Large survey has been realized on rising DBPs of health and regulatory worry. In spite of the fact that the attention on DBPs was previously on chlorine-and bromine-containing carbonaceous DBPs, appearing DBPs comprise iodine-containing species, also halogenated and non-halogenated nitrogenous DBPs. In addition, latest toxicity experimentation has proposed that certain of the more recent PBPs are of more elevated toxicity than some of the regulated chemical products. Therefore, survey has been realized to better comprehend how to costeffectively monitor a large interval of regulated and appearing DBPs. This comprises the usage of advanced remediation and killing pathogens methodologies. This paper shows certain of the newest research works at comprehending these significant DBP-related problems. Disinfection is killing microorganisms present in water; but, it is as well killing human beings drinking water by poisonous DBPs. Using chemicals for water treatment is finally a lost cause.

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Enhanced coagulation under changing alkalinity-hardness conditions and its implications on trihalomethane precursors removal and relationship with UV absorbance

Cited by 44 publications

References 38 publications

Characterization of natural organic matter and disinfection byproducts formation potential in pilot-scale coagulation-ultrafiltration membrane combined process in winter

Characterization of natural organic matter and disinfection byproducts formation potential in pilot-scale coagulation-ultrafiltration membrane combined process in winter

Effect of polyaluminum chloride on enhanced softening for the typical organic-polluted high hardness North-China surface waters

Disinfection and DBPs removal in drinking water treatment: A perspective for a green technology

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