Distribution and Transformation of Molecular Weight of Organic Matters in a Canal Water Treatment Procedure

2012 ◽  
Vol 610-613 ◽  
pp. 2483-2487
Author(s):  
Xiao Dan Zhao ◽  
Chun Hua Wu ◽  
Zhen Zhou

Distribution and transformation of molecular weight of organic matters in canal raw water, primary coagulated water, secondary coagulated water, enhanced coagulated water and water filtered by activated carbon were monitored by ultrafiltration membrane method. The results show that organics on the fraction of molecular weight less than 2kDa has the largest ratio in total organics of outlets of coagulation and activated carbon tank. Removal rate of total organics is about 73% by secondary coagulation, but which of micromolecule organics of molecular weight less than 2kDa is only 10%, which can be removed by activated carbon more than 80%.

2011 ◽  
Vol 366 ◽  
pp. 86-89
Author(s):  
Yi Xin Yang ◽  
Wen Jun Liu

Raw water of Yellow River was treated by ultrafiltration process (UF) combined with powdered activated carbon (PAC) in this study. Experimental results showed that UF is a perfect physical sieving barrier to remove turbidity and algae from water, which is far superior to conventional filter bed. UF is inefficient to dissolved organic matter removal because of its large molecular weight cut-off. Combination of PAC with ultrafiltration membrane can effectively increase the removal rate of CODMn, TOC and UV254.


2017 ◽  
Vol 18 (3) ◽  
pp. 950-955
Author(s):  
Bo Gui ◽  
Qingqing Zhao ◽  
Junxia Liu ◽  
Zhihong Wang ◽  
Huaqiang Chu ◽  
...  

Abstract This study was to assess the effect of powdered activated carbon (PAC) pre-adsorption time on ultrafiltration performance for surface water treatment. Experimental results demonstrated that membrane fouling could be mitigated by extending the pre-adsorption time. The molecular weight (MW) distribution of water samples was determined by liquid chromatography – organic carbon detector (LC-OCD) and results showed that the mechanism of PAC controlling fouling was attributed to a decrease in the low molecular weight (LMW) fraction of raw water via extending the pre-adsorption time. Fouling indexes (FIs) were used to evaluate membrane fouling potential and the results showed that polysaccharides (PS) and proteins (PN) were greatly responsible for membrane fouling. Therefore, prolonging the PAC pre-adsorption time and decreasing the PS and PN content in raw water are the main measurement for the alleviation of membrane fouling when PAC is used as the pretreatment in waterworks.


2020 ◽  
Vol 20 (5) ◽  
pp. 2013-2020
Author(s):  
Hudori Hudori ◽  
Toshiro Yamada ◽  
Yukitaka Suzuki ◽  
Maulana Yusup Rosadi ◽  
Hiroto Tamaoki ◽  
...  

Abstract This research focuses on characterizing the dissolved organic matter found at water treatment plants with closed systems. Recycled water generated as a by-product of water treatment is added to raw water in those systems. The dissolved organic matter in the raw water was found to be higher in summer than in winter, but the water treatment process was able to produce purified water of the similar quality in both seasons. The recycled water contained mostly low molecular weight and protein-like substances, and this composition was different from that of the raw water, which mainly contained humic-like substances. The recycled water did not influence the concentration of humic-like substances or the molecular weight distribution in the influent water.


2000 ◽  
Vol 41 (10-11) ◽  
pp. 43-49 ◽  
Author(s):  
C-N. Chang ◽  
A. Chao ◽  
F-S. Lee ◽  
F-F. Zing

The objective of this study is to investigate how the molecular weight distribution of the organic substances affects their treatment efficiencies and the reduction of disinfection by-products (DBPs) in the various unit operations of a full-scale water treatment plant. The results indicate that the membrane with a smaller molecular weight cut-off is more effective for removing the organic substances and its associated water quality parameters from the raw water. For example, using the membrane with a molecular weight cut-off of 0.5 K (500 daltons), the removal efficiency of DOC from the raw water sample can be as high as 88%. Removal efficiencies of other water quality parameters such as UV254 absorbance, THMFP and AOXFP are generally between 65–69%. When undergoing the various unit operations in the conventional water treatment plant, most organic substances are removed in the coagulation process followed by sedimentation.


2011 ◽  
Vol 255-260 ◽  
pp. 2686-2690
Author(s):  
Gui Qing Gao ◽  
Hai Yan Ju ◽  
Du Wang Li

The pilot-scale experiment of air flotation was carried out for reservoir water treatment of Shenzhen in order to provide reference for waterplant. The results show the turbidity of raw water is higher or lower than 15NTU, the optimum dosage of poly aluminum chloride (PAC) is 1.65mg/L and 1.25mg/L respectively. When the turbidity of raw water is between 3NTU and 32NTU, the amount of algae is less than 1.08×107unit/L, the removal rate of air flotation for turbidity and algae is 89.3% and 92.7% respectively; besides, the average removal rate of air flotation on CODMn is 32.6%, 21.2% of TOC is removed at least. Air flotation has preferable treatment effect on high–algae and low-turbidity water, adapts to treat micro-polluted water in South China.


2019 ◽  
Vol 280 ◽  
pp. 03007 ◽  
Author(s):  
Toshiro Yamada ◽  
Maulana Yusup Rosadi ◽  
Hudori ◽  
Yukitaka Suzuki ◽  
Eri Ito ◽  
...  

Dissolved organic matter (DOM) needs to be characterized todetermine the ability of a water treatment unit to reduce organic matter andits relationship to the levels of chlorine required for disinfection. Weinvestigated water quality parameters, including DOM, in a waterpurification plant and distribution pipes located in central Japan. Thedissolved organic carbon (DOC) concentration decreased from 0.73 mg/Lin raw water to 0.50 mg/L in purified water by conventional treatmentprocesses. The DOC of purified water decreased slightly in the pipesdownstream of the plant. The three-dimensional excitation-emission matrixfluorescence spectra showed some specific peaks for humic-like substancesand protein-like substances in all water samples, and the compositions ofDOM in purified water were close to those in raw water. However, therewas a peak of protein-like substances in purified and returned water, whichwas not observed for raw water. The fluorescence intensities of humic-likesubstances in purified water decreased downstream of the plant, while thefluorescence intensities of protein-like substances increased in the pipes. The measured molecular weight distributions of DOM in water presentedsome specific peaks, and DOM with a smaller molecular weight was noteasily removed by water treatment processes. There were positiverelationships between decreases in the intensities of some peaks andresidual chlorine decay.


2008 ◽  
Vol 58 (5) ◽  
pp. 1129-1135 ◽  
Author(s):  
D. Simazaki ◽  
J. Fujiwara ◽  
S. Manabe ◽  
M. Matsuda ◽  
M. Asami ◽  
...  

Removal property of nine pharmaceuticals (clofibric acid, diclofenac, fenoprofen, gemfibrozil, ibuprofen, indomethacin, ketoprofen, naproxen and propyphenazone) by chlorination, coagulation–sedimentation and powdered activated carbon treatment was examined by laboratory-scale experiments under the conditions close to actual drinking water treatment processes. Indomethacin and propyphenazone were completely degraded by chlorination within 30 minutes, but others remained around 30% (naproxen and diclofenac) or more than 80% of the initial concentration after 24 hours. A couple of unidentified peaks in a chromatogram of the chlorinated samples suggested the formation of unknown chlorination by-products. Competitive adsorption was observed when the mixed solution of the target pharmaceuticals was subjected to batch adsorption test with powdered activated carbon. Clofibric acid and ibuprofen, which were relatively less hydrophobic among the nine compounds, persisted around 60% of the initial concentration after 3 hours of contact time. Removal performance in actual drinking water treatment would become lower due to existence of other competitive substances in raw water (e.g. natural organic matter). Coagulation–sedimentation using polyaluminium chloride hardly removed most of the pharmaceuticals even under its optimal dose for turbidity removal. It is suggested that the most part of pharmaceuticals in raw water might persist in the course of conventional drinking water treatments.


2010 ◽  
Vol 03 (03) ◽  
pp. 213-216 ◽  
Author(s):  
RONG-MIN WANG ◽  
FANG-YING LI ◽  
XIAO-JIE WANG ◽  
QUAN-FANG LI ◽  
YU-FENG HE ◽  
...  

In this paper, stable and homogeneous feather keratin was effectively extracted from feathers. Its molecular weight is 20kDa with low dispersivity. The extracted feather keratin (FK) and its derivatives (FK-ET) were used as natural polymer flocculants. It was a new kind of effective and innoxious flocculant for the COD removal of potato starch wastewater. The removal rate of COD was up to 75% under the following optimal condition: 100mL of initial wastewater (COD = 7380), T = 20°C, [FK-ET] = 0.4g/L, [Bent] = 4g/L, pH = 8.0. Compared with traditional flocculants, keratin flocculants are innoxious natural polymers. Their sludge is easy to be treated, and there is no further pollution. Also, the flocculating constituents, which containing keratin, starch, saccharide, protein and other solubility substances from wastewaters, should be reutilized. It has practical application value in water treatment as a kind of natural polymer flocculant.


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