Flocculation kinetics mechanism and floc formation prepared by poly aluminum chloride coupled with polyacrylamide for ship ballast water

2016 ◽  
Vol 74 (1) ◽  
pp. 57-64 ◽  
Author(s):  
Zhimin Zhou ◽  
Sha Liu ◽  
Linan Jia

The performance of flocculants prepared by poly aluminum chloride (PAC) and polyacrylamide (PAM) on treating ballast water collected at the Dalian new port area, the evaluation depending on the values of reaction parameters, and kinetics mechanism of flocculation were investigated in this study. Accordingly, the flocculants of 0.1 g·L−1, prepared by mixing PAC of 10% with PAM of 2.0‰, enabled the removal rate of zooplankton and phytoplankton to reach 91% in ballast water at 20 °C. Based on flocculation kinetics mechanism analysis, the efficient vortex size during stirring should be larger than the floc particles, and gradient of fluctuating velocity provide the impetus for turbulence flocculation. The results of this study could be relevant to understanding particle–floc interactions during developmental flocculation, and during application of ballast water treatment.

2021 ◽  
Vol 825 (1) ◽  
pp. 012010
Author(s):  
CHEN Wen-xiang ◽  
ZHU Fa-xin ◽  
TENG Xian-bin ◽  
Yang He-wu ◽  
DING Kong-xing ◽  
...  

2003 ◽  
Vol 40 (01) ◽  
pp. 49-60
Author(s):  
Michael G. Parsons

Investigations are currently underway to establish effective primary and secondary ballast water treatment methods to minimize the potential for the introduction of additional nonindigenous aquatic species into the Great Lakes and other U.S. coastal waters. This treatment could be used in place of mid-ocean ballast exchange currently required by the U.S. Coast Guard for all vessels entering the Great Lakes in ballast from beyond the Exclusive Economic Zone (EEZ). Primary and secondary treatment could provide environmental protection for both Ballast On Board (BOB) vessels, which are required to perform mid-ocean ballast exchange before entering the Great Lakes, and No Ballast On Board (NOBOB) vessels, which are currently exempt from any ballast exchange requirements. Primary treatment using some form of mechanical separation to 100 urn or 50 um followed by secondary treatment using 254 nm UV irradiation or some form of chemical treatment are currently leading candidates. Over the past six years, the Great Lakes Ballast Technology Demonstration Project (GLBTDP) has undertaken the full-scale evaluation of 340 m3/h (1500 U.S. gpm) ballast water mechanical separation using an automatic backwashing screen filter, hydrocyclone, and automatic backwashing disk filter. This experience provides the basis for the investigation of various ballast system design issues that must be considered in the selection and design of the primary ballast water treatment. This investigation is based upon the ballast system of a typical Seaway size bulk carrier using port and starboard 2000 m3/h (8800 U.S. gpm) main ballast pumps. A discrete multicriterion optimization tradeoff study using the Analytical Hierarchy Process (AHP) is also presented to illustrate a rational method for determining the best choice for primary ballast water treatment for such a Seaway size bulk carrier.


2014 ◽  
Vol 998-999 ◽  
pp. 414-417
Author(s):  
Jun Wang

Biological invasions caused by Ballast water is always one of the diffcult problems of marine environmental protection, and the technology of ballast water treatment is an effective way to solve biological invasion. This article introduce many equipments of ballast water treatment, introduce physical ballast water treatment, chemical treatment and comprehensive treatment, then describes the advantages and disadvantages of these metheods.


2017 ◽  
Author(s):  
Seungshic Yum ◽  
Bong Gil Hyun ◽  
Kitae Rhie ◽  
Kyoungsoon Shin

Rapid and simple analytical methods for viable microorganism detection in ballast water are required to evaluate the efficiency of ballast water treatment system. During the course of systematic investigation of the cytotoxicity and apoptosis assays, it was found that the adenosine triphosphate (ATP) and luminescence based cell viability assay, in other word, an ATP assay was the most sensitive and applicable to ballast water management (BWM). The assay was applied to cultured microalgae samples, and it could detect the existence of 5 viable cells in 100 μl. Comparably low luminescent values were detected in two cultured diatom species than in cultured dinoflagellates. This result might be caused by the small cell volume in diatom species. Following a regression model between ATP concentration and cell volume, an ATP guideline (876 – 109246 relative luminescence units: RLU) was developed for the evaluation of treated ballast water. ATP assay was also applied to the evaluation of ballast water treatment system (BWTS). The luminescence value which obtained from the ATP assay also showed a good correlation with the presence of living natural plankton cells with comparably low luminescence values than the cultured species. The low ATP concentration in natural plankton cells may reflect a decline in their biological activity because of extended exposure to dark conditions. ATP assay could be a suitable method for the monitoring of ballast water management compliance even though the results of this study need further validation.


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