Factors Influencing the Formation of Trihalomethanes and Haloacetic Acids in Source Water

2011 ◽  
Vol 183-185 ◽  
pp. 347-351 ◽  
Author(s):  
Gai Mei Guo

Humic acid and aromatic organic compounds (AOCs) detected generally in source water recently could react with chlorine during drinking water treatment process to generate disinfection by-products (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs). To simulate the real contaminated water, in the samples containing humic acid, 1,3-benzenediol, 1,4-benzenediol, 1,2-benzenediol, phenol and benzoic acid as representative AOCs were added to conduct chlorination test in order to analyze the impacts of some factors on the formation of THMs and HAAs. The research results indicated that THMs concentration increased with pH but HAAs concentration decreased with pH, and chlorine time, temperature and chlorine dosage all had the functional relationships with the formation of THMs and HAAs. These results could provide the valuable information for the effective control of DBPs during drinking water treatment operation.

2012 ◽  
Vol 10 (2) ◽  
pp. 324-336 ◽  
Author(s):  
Walter Q. Betancourt ◽  
Kristina D. Mena

Three drinking water treatment plants (DWTPs) differing in source water and treatment capacity were investigated for the potential passage of waterborne protozoan (oo)cysts through conventional processing. DWTP I (15,000 L/s), DWTP II (7,500 L/s) and DWTP III (4,300 L/s) provide drinking water for approximately 2.7 million inhabitants of the Metropolitan District of Caracas (Venezuela). The US Environmental Protection Agency Method 1623 for detection of Cryptosporidium and Giardia was used to analyze raw water and finished drinking water samples collected from the three plants. (Oo)cyst recovery efficiencies varied between 23 and 84%. The concentration of confirmed (oo)cysts detected in raw water samples ranged between 1 and 100 per 100 L. (Oo)cyst levels in finished water samples ranged from 2 to 25 per 100 L. These data indicated that the conventional treatment process to produce finished water at two filtration plants was not effective in preventing the passage of protozoan (oo)cysts. Monitoring strategies that include multiple microbial indicators and waterborne pathogens are strongly recommended for accurate source water characterization and for verification of the effectiveness of treatment process barriers to microbial breakthrough in the finished water.


2017 ◽  
Vol 5 (2) ◽  
pp. 168-179
Author(s):  
M. Farhaoui

Water management is a key pillar of sustainable development. Indeed, the rational use of water has become a condition for new investments in the water sector as many sectors. Optimizing the production of drinking water is one aspect. This optimization involves not only the choice of water resource use but also the management of by-products of the water treatment process to manage sustainably the exploited water resources. The city of Meknes is watered from two sources and a set of holes (14), the turbidity of water sources can vary depending on rainfall recorded in the region. A water treatment plant (600 l/s) was performed for the purification of water sources. Through this study, we focus on modeling of sludge volume produced by this plant.  The objective is to design a model for calculating the sludge volume from the actual data recorded in the plant. The model ca be used by the operator to predict the sludge volume and can be used also by the designers. The results of this study demonstrated that the volumes calculated from the model constructed considering the data recorded at the station perfectly match the volumes produced with a determination coefficient of 100%. The application of this model can not only provide the operator with an effective tool for managing of the station by-products but also to provide designers with a formula to prevent over/under design of structures. Therefore, these measures help to optimize the cost of production of drinking water and will play an important role in the sustainable development of water resources.


2013 ◽  
Vol 7 (1) ◽  
pp. 145-153

Since discovery of harmful disinfection by products (DBPs) like trihalomethanes (THMs) and haloacetic acids (HAAs) in chlorinated waters the removal of organic DBPs precursors gained priority in drinking water treatment. Historically, coagulation process was arranged to remove turbidity, typically related to pathogens occurrence, but nowadays it is usually optimized/enhanced for total organic carbon (TOC) reduction. This work dealt with the removal of TOC and turbidity by means of enhanced coagulation process using Al2(SO4)3⋅18 H2O and FeCl3⋅6H2O as coagulants for jar test without pH adjustment according to USEPA procedure. 15% of TOC removal required by USEPA D/DBPs rule (1998) was achieved using 30-50 mg l-1 of both coagulants. On the other hand, for compliance with more stringent MCL for total THMs in Italy (30 μg l-1) higher TOC removal (>30%) which needed of higher coagulants doses (80 mg l-1), was obviously required. Those high coagulant doses were also to be used for the compliance with the turbidity standard (<1NTU).


1999 ◽  
Vol 48 (5) ◽  
pp. 177-185 ◽  
Author(s):  
O. Griffini ◽  
M. L. Bao ◽  
D. Burrini ◽  
D. Santianni ◽  
C. Barbieri ◽  
...  

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