Verification of automatic coagulant dosage control technology based on aluminum concentration at a water purification plant

2014 ◽  
Vol 15 (1) ◽  
pp. 26-33 ◽  
Author(s):  
Y. Sangu ◽  
H. Yokoi ◽  
H. Tadokoro ◽  
T. Tachi
Keyword(s):  
Water Quality ◽  
Water Purification ◽  
Aluminum Concentration ◽  
Feed Water ◽  
Control Technology ◽  
Control Logic ◽  
Water Quality Control ◽  
Water Turbidity ◽  
Coagulant Dosage ◽  
Purification Plant

An automatic coagulant dosage control technology for water purification plants was developed to deal with rapid changes of feed water quality. Control logic was developed to decide coagulant dosage based on aluminum concentration in the mixing tanks. A coagulant-sedimentation process apparatus was installed in December 2010 in a water purification plant, and the coagulant dosage control test using feed water was started. The developed system was confirmed to be effective for managing settled water turbidity and adequacy of coagulant dosage. For actual changes of feed water quality at the water purification plant over more than one year, the developed system was able to maintain settled water turbidity at less than 1.0 mg-kaolin/L in the period of high feed-water turbidity.

Development of automatic coagulant dosage control technology for rapid change of raw water quality parameters

2012 ◽  
Vol 12 (6) ◽  
pp. 918-925 ◽  
Author(s):  
Y. Sangu ◽  
H. Yokoi ◽  
H. Tadokoro ◽  
T. Tachi
Keyword(s):  
Water Quality ◽  
Pilot Scale ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Control Technology ◽  
Raw Water ◽  
Control Logic ◽  
Water Turbidity ◽  
Coagulant Dosage ◽  
Raw Water Quality

An automatic coagulant dosage control technology for water purification plants was developed to deal with rapid changes of raw water quality parameters. Control logic was developed to decide coagulant dosage based on aluminum concentration in rapid mixing tank water based on results of semi-pilot scale experiments. This logic enabled quick feedback on the excess or lack of coagulant. It was found that the aluminum residual rate, which was proposed as an indicator of coagulation reactions, could be given as a function of coagulant dosage and turbidity. The effectiveness of the control logic was verified in semi-pilot scale experiments. Settled water turbidity was within ±0.5 NTU of target value even when raw water turbidity increased rapidly up to 100 NTU.

Yangtze River Water Treatment by Spiral UF Membrane with Coagulation Pretreatment

2010 ◽  
Vol 113-116 ◽  
pp. 1524-1528
Author(s):  
Yan Chen ◽  
Guo Zhen Zhang ◽  
Zi Wen Xiao
Keyword(s):  
Water Quality ◽  
Pressure Difference ◽  
Yangtze River ◽  
Operating Efficiency ◽  
Feed Water ◽  
Sand Filtration ◽  
Water Value ◽  
Coagulant Dosage ◽  
In Trans ◽  
Filtration Flux

To further determine the effects of operational condition on water quality and to prepare a integrated unit for waterworks on a small or medium-sized in future, an experiment using Yangtze River source water(site in Zhenjiang) as raw water was carry out to run continuously for six months by applying the in-line microflocculation/sand filtration/ spiral UF membrane process. The results show that the coagulant dosage of 3~5 mg/L(as Fe), the sand filtration at a speed of 19.5m/h and the filtration flux at 1m3/m2.d can efficient in discharging the most suspensions, and a part of organics from water can de removed. The turbidity in sand-filtration treated water value of 3~10 NTU may cause little change in trans-membrane pressure difference and increase operating efficiency, while turbidity value is less than 2 NTU , much change is observed in the trans-membrane pressure difference. Although the wash pressure and membrane feed water quality have effect on the trans-membrane pressure difference, the wash pressure is not an important influencing the trans-membrane pressure difference.

Natural organic matter fouling and chemical cleaning of nanofiltration membranes

2004 ◽  
Vol 4 (5-6) ◽  
pp. 245-251 ◽  
Author(s):  
Q. Li ◽  
M. Elimelech
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Calcium Ions ◽  
Ionic Composition ◽  
Solution Chemistry ◽  
Feed Water ◽  
Cleaning Efficiency ◽  
Chemical Cleaning ◽  
Water Quality Control

Fouling and subsequent chemical cleaning are two important issues for sustainable operation of nanofiltration (NF) membranes in water quality control applications. Because fouling strongly depends on the feed water quality, especially the ionic composition, chemical cleaning solutions should be chosen to target the solution chemistry that is most responsible for the formation of a compact, high resistance fouling layer. In this study, the effect of solution chemistry on natural organic matter (NOM) fouling of two NF membranes with different surface properties was investigated. Compared to monovalent cations, divalent cations were found to greatly enhance NOM fouling by complexation. Moreover, calcium ions caused a much greater fouling rate than magnesium ions, presumably due to the intermolecular bridging formed among NOM molecules through the calcium ions. Various chemical cleaning solutions were evaluated for water flux recovery efficiency. Although both deionized water and dilute NaOH solution were found effective in cleaning membranes fouled in the absence of calcium ions, efficient chemical cleaning in presence of calcium was achieved only when the calcium ion bridging was eliminated. The cleaning efficiency was shown to be highly dependent on solution pH and the concentration of the chemical cleaning agent.

scholarly journals Molecular Characterization of the Bacterial Communities in the Different Compartments of a Full-Scale Reverse-Osmosis Water Purification Plant

2008 ◽  
Vol 74 (17) ◽  
pp. 5297-5304 ◽  
Author(s):  
L. A. Bereschenko ◽  
G. H. J. Heilig ◽  
M. M. Nederlof ◽  
M. C. M. van Loosdrecht ◽  
A. J. M. Stams ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Reverse Osmosis ◽  
Water Purification ◽  
Full Scale ◽  
Feed Water ◽  
Water Origin ◽  
Ro Membrane ◽  
Biological Methods ◽  
Purification Plant

ABSTRACT The origin, structure, and composition of biofilms in various compartments of an industrial full-scale reverse-osmosis (RO) membrane water purification plant were analyzed by molecular biological methods. Samples were taken when the RO installation suffered from a substantial pressure drop and decreased production. The bacterial community of the RO membrane biofilm was clearly different from the bacterial community present at other locations in the RO plant, indicating the development of a specialized bacterial community on the RO membranes. The typical freshwater phylotypes in the RO membrane biofilm (i.e., Proteobacteria, Cytophaga-Flexibacter-Bacteroides group, and Firmicutes) were also present in the water sample fed to the plant, suggesting a feed water origin. However, the relative abundances of the different species in the mature biofilm were different from those in the feed water, indicating that the biofilm was actively formed on the RO membrane sheets and was not the result of a concentration of bacteria present in the feed water. The majority of the microorganisms (59% of the total number of clones) in the biofilm were related to the class Proteobacteria, with a dominance of Sphingomonas spp. (27% of all clones). Members of the genus Sphingomonas seem to be responsible for the biofouling of the membranes in the RO installation.

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