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Turnover mechanisms of organic conformation on turbidity in drinking water

ZHONG Runsheng, ZHU Chunwei, ZHANG Xihui, GUAN Yuntao

《环境科学与工程前沿（英文）》 2007年第1卷第3期页码 276-279 doi: 10.1007/s11783-007-0046-9

摘要： The turbidity variation in artificial water and samples from a water plant was investigated in the presence of organics with different relative molecular mass. The results show that recessive turbidity existed when water chemical conditions were changing. The formation of turbidity depended on organic relative molecular mass and their conformations on particles. At higher pH and lower ionic strength, the organic chains with a more extended conformation resulted in rising turbidity of the suspension. At lower pH, the reconformation of organics took place due to charge neutralization by the proton, resulting in a decline in turbidity. The addition of NaCl and MgCl at pH 7.00 also resulted in a decrease of turbidity in the suspension. It is believed that the occurrence of recessive turbidity has a significant influence on the stability of water supply quality.

关键词： stability different turbidity occurrence supply

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Turbidity-adaptive underwater image enhancement method using image fusion

《机械工程前沿（英文）》 2022年第17卷第3期 doi: 10.1007/s11465-021-0669-8

摘要： Clear, correct imaging is a prerequisite for underwater operations. In real freshwater environment including rivers and lakes, the water bodies are usually turbid and dynamic, which brings extra troubles to quality of imaging due to color deviation and suspended particulate. Most of the existing underwater imaging methods focus on relatively clear underwater environment, it is uncertain that if those methods can work well in turbid and dynamic underwater environments. In this paper, we propose a turbidity-adaptive underwater image enhancement method. To deal with attenuation and scattering of varying degree, the turbidity is detected by the histogram of images. Based on the detection result, different image enhancement strategies are designed to deal with the problem of color deviation and blurring. The proposed method is verified by an underwater image dataset captured in real underwater environment. The result is evaluated by image metrics including structure similarity index measure, underwater color image quality evaluation metric, and speeded-up robust features. Test results exhibit that the method can correct the color deviation and improve the quality of underwater images.

关键词： turbidity underwater image enhancement image fusion underwater robots visibility

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of black-odorous water using tower bipolar electro-flocculation including the removal of phosphorus, turbidity

Huan He, Qinjin Yu, Chaochao Lai, Chen Zhang, Muhan Liu, Bin Huang, Hongping Pu, Xuejun Pan

《环境科学与工程前沿（英文）》 2021年第15卷第2期 doi: 10.1007/s11783-020-1310-5

摘要： Abstract • An innovative bubble column tower BPE was designed to treat the black-odorous water. • PO43−, S2− and turbidity were removed, and dissolved oxygen was enriched in the BPE. • An aluminum bipolar electrode gave the best oxygen enrichment and pollutant removal. • Changes of microorganisms confirmed the improvement in water quality achieved. The large amount of municipal wastewater discharged into urban rivers sometimes exceeds the rivers’ self-purification capacity leading to black-odorous polluted water. Electro-flocculation has emerged as a powerful remediation technology. Electro-flocculation in a bubble column tower with a bipolar electrode (BPE) was tested in an attempt to overcome the high resistance and weak gas-floatation observed with a monopolar electrode (MPE) in treating such water. The BPE reactor tested had a Ti/Ta2O5-IrO2 anode and a graphite cathode with an iron or aluminum bipolar electrode suspended between them. It was tested for its ability to reduce turbidity, phosphate and sulphion and to increase the concentration of dissolved oxygen. The inclusion of the bipolar electrode was found to distinctly improved the system’s conductivity. The system’s electro-flocculation and electrical floatation removed turbidity, phosphate and sulphion completely, and the dissolved oxygen level improved from 0.29 to 6.28 mg/L. An aluminum bipolar electrode performed better than an iron one. Changes in the structure of the microbial community confirmed a significant improvement in water quality.

关键词： Black-odorous water Bipolar electrodes Flocculation Floatation Oxygen enrichment Turbidity

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Simultaneous sorption of aqueous phenanthrene and phosphate onto bentonites modified with AlCl3 and CTMAB

ZHU Runliang, ZHU Lizhong, ZHU Jianxi

《环境科学与工程前沿（英文）》 2007年第1卷第1期页码 79-82 doi: 10.1007/s11783-007-0015-3

摘要： The purpose of this work is to synthesize a new type of bentonite sorbent that can simultaneously remove both organic compounds and phosphate from water. Inorganic-organic bentonites (Al-CTMAB-Bent) were synthesized by modifying bentonites with both AlCl3 and cetyltrimethyl ammonium bromide (CTMAB). Simultaneous sorption of aqueous phenanthrene and phosphate onto Al-CTMAB-Bent was examined. Removal rates of phenanthrene and phosphate from water reached 96.3% and 90.2%, respectively, at their respective initial concentrations of 1 mg/L and 5 mg/L and the added amount of Al-CTMAB-Bent was 1.25 g/L. The residual turbidity of the Al-CTMAB-Bent suspension decreased 81.4% compared to that of organobentonite suspension after a 1 h settling time. Thus, inorganic-organic bentonite can be used to treat wastewater containing both organic pollutants and phosphate.

关键词： phenanthrene settling respective residual turbidity Inorganic-organic

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Factors influencing water quality indices in a typical urban river originated with reclaimed water

Jiao Zhang, Zhen Wei, Haifeng Jia, Xia Huang

《环境科学与工程前沿（英文）》 2017年第11卷第4期 doi: 10.1007/s11783-017-0943-5

摘要： The water quality in a typical urban river segment originated with reclaimed water in Beijing was monitored for two years to investigate the evolution of water quality along the river, and statistical analysis was applied to determine factors influencing water quality of such river recharged by reclaimed water. It was found that no significant change in pollutant concentrations (including COD, NH -N, TN and TP) was observed during this time, and their average values were close to those of the original reclaimed water. However, turbidity and algal contents fluctuated temporally in the direction of river flow. Statistical analysis showed that turbidity was strongly positively correlated with algal contents for flow rate<0.1 m·s , whereas it was strongly positively correlated with both algal contents and TOC for flow rate>0.1 m·s . It was observed that diatom was the absolute predominant phyla with as the major species. In terms of algal bloom control, the specific growth rate of algae was strongly correlated to temperature, and was influenced by flow rate as well. Compared with two other rivers originated with reclaimed water and one originated with natural water, the Shannon–Wiener index in the objective river was the lowest, with values between 0.7 and 1.6, indicating a high risk for algal bloom. Statistics showed that Shannon–Wiener index was strongly negatively correlated to nutrient salts and cations.

关键词： Reclaimed water Urban river Turbidity Algae Flow rate

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Particulate matter and metals partitioning in highway rainfall-runoff

Gaoxiang YING, John J. SANSALONE,

《环境科学与工程前沿（英文）》 2010年第4卷第1期页码 35-46 doi: 10.1007/s11783-010-0009-4

摘要： This study investigated the particulate matter (PM) and metals in highway dry deposition and rainfall-runoff as a function of hydrologic transport and settling on an event basis. Events were differentiated as mass-limited (ML) and flow-limited (FL). Results indicate that unique and separate suspended sediment concentration (SSC) relationships with turbidity occurred for ML and FL events. Sixty minutes of quiescent settling produced a single SSC-turbidity relationship for all events. ML events transport higher proportions of settleable and sediment PM while FL events transported relatively higher suspended PM. For batch clarification with one hour of settling, ML events had generally higher treatment efficiencies compared to FL events for the same settling conditions. Highway dry deposition PM was hetero-disperse and coarse ( = 304 µm). Results indicate that the acidic rainfall is not a significant contributor to metals in runoff but is capable of leaching metals from dry deposition PM into runoff. Partitioning in retained runoff resulted in a particulate-bound €predominance €for €most €metals €except Ca and Mg. While the finer fraction of dry deposition PM (<75µm) generates the highest metal concentrations, the highest metal mass is associated with the coarser fraction (>75µm).

关键词： stormwater particulate matter (PM) turbidity suspended sediment concentration (SSC) unit operations metals dry deposition acid rain