Pretreatment of concentrated leachate by the combination of coagulation and catalytic ozonation with Ce/AC catalyst

2015 ◽  
Vol 73 (3) ◽  
pp. 511-519 ◽  
Author(s):  
Hangdao Qin ◽  
Honglin Chen
Keyword(s):  
Size Distribution ◽  
Membrane Separation ◽  
Oxygen Demand ◽  
Molecular Size ◽  
Apparent Molecular Weight ◽  
Catalytic Ozonation ◽  
Cod Removal ◽  
Distribution Analysis ◽  
Molecular Size Distribution ◽  
Ozonation Process

A raw concentrated leachate produced from membrane bioreactor-nanofiltration (MBR-NF) was taken from Chengdu Chang'an Waste Landfill Site, China. The major fraction of this concentrated leachate was large refractory humic substances. A coagulation–ozonation process was applied to treat this leachate, aiming at enhancing chemical oxygen demand (COD) removal efficiency and increasing its biodegradability. Meanwhile the molecular size distribution of the leachate, before and after coagulation and ozonation treatment, was analyzed by using ultrafiltration membrane separation. Coagulation pretreatment effectively removed varieties of large molecules in the raw concentrated leachate. The addition of Ce/AC greatly improved the oxidative ability of O3 in COD removal in the ozonation of coagulated leachate. The biochemical oxygen demand (BOD5)/COD ratio increased from 0.011 for the untreated concentrated leachate to 0.30 for the effluent of the coagulation–catalytic ozonation process, which indicated that a subsequent biological treatment could be readily conducted. The stability test demonstrated that the Ce/AC catalyst was effective and stable in the catalytic ozonation process. According to the results of molecular size distribution analysis, a direct correlation was observed between the increase of BOD5/COD and the decrease of apparent molecular weight.

Determination of the Size Distribution of Dissolved Organics in Effluents

1973 ◽  
Vol 8 (1) ◽  
pp. 1-15 ◽  
Author(s):  
L.A. Addie ◽  
K.L. Murphy ◽  
J.L. Robertson
Keyword(s):  
Size Distribution ◽  
Biological Treatment ◽  
Oxygen Demand ◽  
Molecular Size ◽  
Monitoring Systems ◽  
Clean Surface ◽  
Sephadex Column ◽  
Dissolved Organics ◽  
Molecular Size Distribution

Abstract The importance of removing the small amounts of residual organics is increasing as the sources of clean surface water decrease. Knowledge of the nature of these soluble residual organics will be needed in order to assess the type of treatment required for their removal. Residual organics in three different biological treatment plants were analyzed and compared. An attempt was made to characterize these organics by a molecular size distribution on a Sephadex column monitored by differential ultraviolet and refractive index detectors. The organic carbon and chemical oxygen demand of the fractions collected from the column was also determined. An investigation of some of the problems inherent in the monitoring systems was conducted.

Characterization of Landfill Leachates by Molecular Size Distribution, Biodegradability, and Inert Chemical Oxygen Demand

2009 ◽  
Vol 81 (5) ◽  
pp. 499-505 ◽  
Author(s):  
Míriam C. S. Amaral ◽  
Cynthia F. A. Ferreira ◽  
Liséte Celina Lange ◽  
Sérgio F. Aquino
Keyword(s):  
Chemical Oxygen Demand ◽  
Size Distribution ◽  
Oxygen Demand ◽  
Molecular Size ◽  
Landfill Leachates ◽  
Molecular Size Distribution

scholarly journals Application of heterogeneous catalytic ozonation process for treatment of high toxic effluent from a pesticide manufacturing plant

2020 ◽  
Vol 7 (2) ◽  
pp. 79-88
Author(s):  
Mina Ghahrchi ◽  
Edris Bazrafshan ◽  
Behruz Adamiyat Badan ◽  
Yousef Dadban Shahamat ◽  
Fariba Gohari
Keyword(s):  
Reaction Time ◽  
Treatment Process ◽  
Catalyst Concentration ◽  
Oxygen Demand ◽  
Catalytic Ozonation ◽  
Cod Removal ◽  
Heterogeneous Catalytic ◽  
Removal Efficiencies ◽  
Ozonation Process ◽  
Maximum Removal

Background: The discharge of untreated wastewater containing toxic and resistant compounds into the environment is a serious threat for ecosystems. Therefore, this study was conducted to evaluate the treatment of poison production factory wastewater using heterogeneous catalytic ozonation process (COP). Methods: Magnetic carbon nanocomposite was used as a catalyst at concentrations of 1, 2, and 4 g/L. Its effect on improving the treatment process was evaluated at reaction time of 30, 60, 90, and 120 minutes. At the end of each experiment, parameters including total organic carbon (TOC), chemical oxygen demand (COD), biological oxygen demand (BOD5 ), pH, electrical conductivity (EC), and turbidity were measured. Results: It was revealed that in single ozonation process (SOP), the maximum removal efficiencies of TOC, COD, and BOD5 were achieved at reaction time of 120 minutes as 56%, 40%, and 11.7%, respectively. By adding the catalyst to the wastewater, the treatment process was improved, so that the maximum removal efficiencies of COD (91%), TOC (73%), and BOD5 (74%) were obtained at catalyst concentration of 4 g/L. Under this condition, BOD5 /COD ratio increased from 0.22 to 0.64. Also, the results of analysis of ozone consumption per each mg of reduced COD showed that its amount sharply decreased from 2.1 mgO3 / mg COD removal in the SOP, to 0.34 mgO3 /mg COD removal in the COP. The results of kinetic reaction analysis also revealed that the rate constant increased from 0.007 to 0.02 min-1. Conclusion: According to the results, it can be concluded that the COP at a catalyst concentration of 4 g/L, by decomposing resistant compounds and increasing the biodegradability, can be used as a suitable pretreatment method for biological processes.

Molecular size distribution analysis of human gingival glycosaminoglycans in cyclosporin- and nifedipine-induced overgrowths

2003 ◽  
Vol 38 (2) ◽  
pp. 182-189 ◽  
Author(s):  
Rita C. L. Martins ◽  
Claudio C. Werneck ◽  
Lia A. G. Rocha ◽  
Eduardo J. Feres-Filho ◽  
Luiz-Claudio F. Silva
Keyword(s):  
Size Distribution ◽  
Molecular Size ◽  
Distribution Analysis ◽  
Molecular Size Distribution
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