Coagulation performance and floc properties of Microcystis aeruginosa in the presence of humic acid

2014 ◽  
Vol 15 (2) ◽  
pp. 339-347
Author(s):  
Peixia Cheng ◽  
Fei Ge ◽  
Xingwang Liu ◽  
Xiaoshuang Zeng ◽  
Biao Chen
Keyword(s):  
Humic Acid ◽  
Microcystis Aeruginosa ◽  
Removal Efficiency ◽  
High Concentration ◽  
Polyaluminum Chloride ◽  
Charge Neutralization ◽  
Low Concentration ◽  
Chl A ◽  
Coagulation Performance ◽  
Floc Properties

Coagulation removal of algae in raw water could be significantly affected by humic acid (HA). A series of jar-tests were conducted to investigate the coagulation performance with polyaluminum chloride and floc properties of Microcystis aeruginosa, a unicellular cyanobacteria, in the presence of HA. Meanwhile the coagulation mechanism was explored through the measurement of zeta potential of the supernatant. The results showed that an optimal removal efficiency of chlorophyll-a (Chl-a) was obtained at pH 8.0 with a low concentration of HA (2 mg/L) and at pH 6.0 with a high concentration of HA (8 mg/L). The floc structure was more compact and bigger-sized and the calculated fractal dimension (Df) was larger at maximum coagulation efficiency. The variation of Df was consistent with that of Chl-a removal efficiency under the same coagulation conditions. Charge neutralization was inferred to be the dominant mechanism to remove algal cells with low concentration of HA, while charge neutralization, gathering and the bridging process worked together to remove algal cells with a high concentration of HA. These results provide insight on how to achieve an optimal removal efficiency of algae in the presence of different concentrations of HA in water treatment.

scholarly journals Start-up Strategies for Anaerobic Ammonia Oxidation (Anammox) in In-Situ Nitrogen Removal from Polluted Groundwater in Rare Earth Mining Areas

2021 ◽  
Vol 13 (8) ◽  
pp. 4591
Author(s):  
Shuanglei Huang ◽  
Daishe Wu
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Ex Situ ◽  
High Concentration ◽  
Low Concentration ◽  
Start Up ◽  
Anammox Activity

The tremendous input of ammonium and rare earth element (REE) ions released by the enormous consumption of (NH4)2SO4 in in situ leaching for ion-adsorption RE mining caused serious ground and surface water contamination. Anaerobic ammonium oxidation (anammox) was a sustainable in situ technology that can reduce this nitrogen pollution. In this research, in situ, semi in situ, and ex situ method of inoculation that included low-concentration (0.02 mg·L−1) and high-concentration (0.10 mg·L−1) lanthanum (La)(III) were adopted to explore effective start-up strategies for starting up anammox reactors seeded with activated sludge and anammox sludge. The reactors were refrigerated for 30 days at 4 °C to investigate the effects of La(III) during a period of low-temperature. The results showed that the in situ and semi in situ enrichment strategies with the addition of La(III) at a low-concentration La(III) addition (0.02 mg·L−1) reduced the length of time required to reactivate the sludge until it reached a state of stable anammox activity and high nitrogen removal efficiency by 60–71 days. The addition of La(III) promoted the formation of sludge floc with a compact structure that enabled it to resist the adverse effects of low temperature and so to maintain a high abundance of AnAOB and microbacterial community diversity of sludge during refrigeration period. The addition of La(III) at a high concentration caused the cellular percentage of AnAOB to decrease from 54.60 ± 6.19% to 17.35 ± 6.69% during the enrichment and reduced nitrogen removal efficiency to an unrecoverable level to post-refrigeration.

Cleanroom Mats: An Investigation of Particle Removal

1996 ◽  
Vol 39 (4) ◽  
pp. 19-27
Author(s):  
W. Whyte ◽  
T. Shields ◽  
T. Prvan
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Removal Efficiency ◽  
Adhesive Strength ◽  
Particle Removal ◽  
High Concentration ◽  
Low Concentration

The variables that influence the particle removal efficiency of cleanroom mats were investigated. The removal efficiency was generally found to be greater if the mat was of a softer type, the particles smaller, the particle size distribution more homogeneous, the distance between the particles greater, and the adhesive strength of the mat surface greater. One application of a mat surface was sufficient to remove a low concentration of similarly sized particles from a surface but it could require up to four mat surfaces to remove a high concentration of heterogeneously sized particles. It was found with heterogeneously sized particles that larger particles were removed first, thus allowing access to the smaller particles which could then be removed. If the mat was soft, it allowed larger particles to sink into it and smaller particles than normal to be picked up.

The performance of enhanced coagulation for treating slightly polluted raw water combining polyaluminum chloride with variable charge soil

2014 ◽  
Vol 70 (12) ◽  
pp. 1907-1912 ◽  
Author(s):  
Z. L. Zhang ◽  
C. D. Wu ◽  
Y. J. Wang ◽  
J. C. Tang ◽  
Y. P. Liu
Keyword(s):  
Heavy Metals ◽  
Main Mechanism ◽  
Raw Water ◽  
Polyaluminum Chloride ◽  
Enhanced Coagulation ◽  
Charge Neutralization ◽  
Variable Charge ◽  
Coagulation Performance ◽  
Removal Efficiencies ◽  
Variable Charge Soil

The feasibility and effectiveness of treating pollutants in slightly polluted raw water by variable charge soil and polyaluminum chloride (PAC) was investigated. Removal efficiencies of turbidity, phenol, aniline, algae and heavy metals (Cu2+, Zn2+ and Pb2+) were used to evaluate the coagulation performance. The results indicated that the addition of variable charge soil as a coagulant aid is advantageous due to the improvement of removal efficiencies. The tests also demonstrated that the presence of variable charge soil increased the removal of turbidity rather than adding residuary turbidity. The use of variable charge soil produced settleable flocs of greater density and bigger size. The main mechanism involved in the PAC coagulation was supposed to be sweep flocculation as well as charge-neutralization. Variable charge soil played a promoted aid role by adsorption in the enhanced coagulation process. It is concluded that the enhanced coagulation by PAC and variable charge soil, as coagulant and adsorbent, is more effective and efficient than traditional coagulation.

Optimization of the Coagulation Process for Kaolin and Humic Acid Removal Using Polymeric Aluminum Ferric Sulfate

2015 ◽  
Vol 1088 ◽  
pp. 353-357 ◽  
Author(s):  
Zhen Zhen Jiang ◽  
Yang Chen ◽  
Jun Ren Zhu
Keyword(s):  
Humic Acid ◽  
Removal Efficiency ◽  
Mixing Time ◽  
Ferric Sulfate ◽  
Single Factor ◽  
Mixing Speed ◽  
Rapid Mixing ◽  
Coagulation Process ◽  
Coagulation Performance ◽  
Slow Mixing

In the paper, the optimization of the coagulation process for Kaolin and humic acid removal using polymeric aluminum ferric sulfate (PAFS) was studied. In order to obtain the maximum turbidity and humic acid removal efficiency of Kaolin and humic acid simulated wastewater, the optimum coagulation conditions was investigated with the factors of mixing speed and time. Furthermore, mixing speed and time including parameters affecting the coagulation performance such as rapid mixing speed, rapid mixing time, slow mixing speed and slow mixing time using single factor and orthogonal array L9 (34) analysis were examined. The results showed that the optimum single factor of mixing speed and time indicated rapid mixing speed of 350 rpm, rapid mixing time of 1.0 min, slow mixing speed of 60 rpm and slow mixing time of 20 min. Then the orthogonal optimization experiment of mixing speed and time indicated maximum HA removal efficiency was 97.5% at rapid mixing speed of 350 rpm, rapid mixing time of 1.25 min, slow mixing speed of 60 rpm, and slow mixing time of 20 min.

Impact of Humic Acid on the Charge Behavior and Coagulation of TiO2 Nanoparticles Suspension

2013 ◽  
Vol 726-731 ◽  
pp. 2384-2388 ◽  
Author(s):  
Feng Gong ◽  
Li Zhu Zhang ◽  
Li Wang
Keyword(s):  
Humic Acid ◽  
Zeta Potential ◽  
Removal Efficiency ◽  
Ph Value ◽  
Fate And Transport ◽  
High Concentration ◽  
Water Treatment Process ◽  
The Stability ◽  
The Impact ◽  
Nanoparticles Suspension

In order to understanding of the fate and transport of TiO2 nanoparticles (Nps) in the water treatment process, this study focused on the impact of humic acid (HA) on the aggregation and charge behavior of TiO2 Nps, and investigated the removability of TiO2 Nps stabilized by HA during the coagulation process. Malvern Zetasizer nanoZS measured the changes of size and zeta potential of HA capped TiO2 Nps (HA-TiO2). Uv-vis spectrometer examined the aggregation behavior of TiO2 and HA-TiO2 NPs at different pH value. Jar tests were conducted to evaluate the removal efficiency of TiO2 NPs. HA adsorbed on the surface of TiO2 Nps could decrease the zeta potential values and enhance the stability of TiO2 Nps. TiO2 Nps could be effectively removed by aluminum sulfate (AS) under favorable condition. HA could influence the removal of TiO2 Nps during the coagulation processes. Low concentration of HA rejected the removal efficiency of TiO2 Nps, however, high concentration of HA promoted removing effectiveness.

The dye or humic acid water treatment and membrane fouling by polyaluminum chloride composited with sodium alginate in coagulation–ultrafiltration process

2013 ◽  
Vol 67 (10) ◽  
pp. 2202-2209 ◽  
Author(s):  
Yan Wang ◽  
Feng Zhang ◽  
Yongbao Chu ◽  
Baoyu Gao ◽  
Qinyan Yue
Keyword(s):  
Humic Acid ◽  
Water Treatment ◽  
Sodium Alginate ◽  
Removal Efficiency ◽  
Membrane Fouling ◽  
Ultrafiltration Membrane ◽  
Acid Water ◽  
Polyaluminum Chloride ◽  
Modified Fouling Index ◽  
Ultrafiltration Process

Composite flocculants have been extensively studied and applied in recent years in order to improve the water treatment efficiency. In this study, a new composite flocculant prepared by polyaluminum chloride (PAC) and sodium alginate (SA) was used to treat dye and humic acid water in the coagulation–ultrafiltration process. The subsequent effects of PAC/SA on ultrafiltration membrane fouling were investigated by calculating the Modified Fouling Index (MFI). The results showed that the application of PAC/SA could not only restrict the membrane fouling but also improve the removal efficiency of the coagulation–ultrafiltration process. MFI of PAC/SA was the lowest, followed by PAC and the raw water for coagulated effluents filtered by ultrafiltration membrane. For example, MFI of PAC/SA was 0.40 s mL−2 for reactive blue KGL (denoted as RB-KGL) treatment, while that of PAC was 2.26 s mL−2. The removal efficiencies were improved as coagulation was used as pretreatment of ultrafiltration membrane. And PAC/SA could form the higher removal efficiency than PAC, especially for RB-KGL. The color removal efficiency of PAC/SA was 96.36% for RB-KGL treated by coagulation–ultrafiltration process, which was higher than that of PAC (85.62%).

Study on Switch from High-concentration to Low-concentration Tacalcitol during Concomitant Use of Bath-PUVA Therapy

2007 ◽  
Vol 69 (6) ◽  
pp. 660-664
Author(s):  
Maki IWAKIRI ◽  
Noriko YASAKA ◽  
Kotaro ITO ◽  
Yuichi YOSHIDA ◽  
Yumiko KUBOTA ◽  
...  
Keyword(s):  
Puva Therapy ◽  
High Concentration ◽  
Low Concentration
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