Converting to Polyaluminum Chloride to Address Water Treatment Challenges in New England—A Case Study with Operational Implications

2001 ◽  
Author(s):  
David S. Pines ◽  
Scott Simard ◽  
David J. Pernitsky
2009 ◽  
Vol 7 (1) ◽  
pp. 83-104 ◽  
Author(s):  
Phitsamay Uy

In the world of K–12 education, the growing numbers of dropouts are a major concern. This article examines the dropout rates of Chinese and Vietnamese high school students. Using logistic regression analysis, this article examines the influence of ethnicity, gender, and socioeconomic status (SES) on dropout rates. The distinct contribution of this analysis lies within the intraethnic comparisons within the Asian American student population and its use of longitudinal data. The results of the study support existing research that gender and SES are related to dropout rates. Moreover, an interesting interaction between ethnicity and SES exists.


Author(s):  
Zheng-Qian Liu ◽  
Bang-Jun Han ◽  
Gang Wen ◽  
Jun Ma ◽  
Sheng-Jun Wang ◽  
...  

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1367
Author(s):  
Izabela Krupińska

In topic-related literature pertaining to the treatment of water, there is a lack of information on the influence of iron ions in highly basic polyaluminum chlorides on the efficiency of purifying water with increased contents of organic substance. The aim of this work was to determine the changes in the content of organic substances as well as iron compounds in water intended for human consumption following unit treatment processes with particular attention paid to the coagulation process. As coagulants, polyaluminium chloride PAXXL10 with an alkalinity of 70%, as well as polyaluminium chloride PAXXL1911 with an alkalinity of 85% the composition of which also contained iron, were tested. The analysis of the obtained results showed that iron compounds and organic substances were removed to the greatest extent by the coagulation process, which also had a significant influence on the final efficiency of water treatment. The effectiveness of water treatment was determined by the type of tested polyaluminum chloride, which influenced the formation of iron-organic complexes. The reason behind the formation of colored iron-organic complexes during coagulation using PAXXL1911 coagulant was the high pH (approx. 8), at which the functional groups of organic substances, due to their dissociation, are more reactive in relation to iron, and possibly the fact of introducing additional iron ions along with the coagulant.


2012 ◽  
Vol 65 (10) ◽  
pp. 1895-1902 ◽  
Author(s):  
Rita Hilliges ◽  
Eberhard Steinle ◽  
Bernhard Böhm

The two-staged WWTP ‘Gut Grosslappen’ has a capacity of 2 mio. PE. It comprises a pre-denitrification in the first stage using recirculation from the nitrifying second stage. A residual post-denitrification in a downstream sand filter is required in order to achieve the effluent standards. Presently the process water from sludge digestion is treated separately by nitrification/denitrification. Due to necessary reconstruction of the biological stages, the process water treatment was included in the future overall process concept of the WWTP. A case study was conducted comparing the processes nitritation/denitrititation and deammonification with nitrification/denitrification including their effect on the operational costs of the planned main flow treatment. Besides the different operating costs the investment costs required for the process water treatment played a significant role. Six cases for the process water treatment were compared. As a result, in Munich deammonification can only be recommended for long-term future developments, due to the high investment costs, compared with the nitritation/denitritation alternative realizable in existing tanks. The savings concerning aeration, sludge disposal and chemicals were not sufficient to compensate for the additional investment costs. Due to the specific circumstances in Munich, for the time being the use of existing tanks for nitritation/denitritation proved to be most economical.


Desalination ◽  
2007 ◽  
Vol 202 (1-3) ◽  
pp. 318-325 ◽  
Author(s):  
C.C. Chien ◽  
C.M. Kao ◽  
C.D. Dong ◽  
T.Y. Chen ◽  
J.Y. Chen
Keyword(s):  

2021 ◽  
Vol 141 ◽  
pp. 110766
Author(s):  
Steffi Olesi Muhanji ◽  
Clayton Barrows ◽  
Jordan Macknick ◽  
Amro M. Farid
Keyword(s):  

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