Papers by Keyword: COD_Cr

Abstract: The effect of a novel amphoteric polymeric flocculant, p (DMC/NVP/FA), was investigated in processing dyeing wastewater. The optimum for flocculant dosage was 55mg/L, and one for pH was 5. Under the optimum conditions, the intrinsic viscosity of flocculant and the removal rates of COD_cr and chroma reached the top (274.425dL/g, 80.1%, 92.6% ) . Analysis dyeing wastewater flocs SEM by calculating the D_f (a symbol stands for fractal dimension) values of fractal dimension with Non-Linear fractional theory. The results of the theorical computationare coordinated with the text.

Abstract: The study used self-made nutshell activated carbon and took catering wastewater as research object. After pretreatment, the catering wastewater was adsorbed by nutshell activated carbon.Throught investigating the adsorption value of methylene blue and iodine,the effect of Peach pit shell activated carbon is higher than others.The optimal conditions are determined: proper time of reaction 4 h, Peach shell activated carbon dosage 30 mg/L, pH 6.0, reaction temperature 30°C. Under this optimum, the removal rate of COD_cr as well as grease can be as high as 92.75% and 87.05%, respectively.

Abstract: When straw pulp papermaking wastewater was treated by the process of coagu-flocculation and nuclear-flocculation, there were still high COD_Cr. UV₂₅₄ can reflect organic pollutants and organic pollutants of unsaturated aromatic ring, carbon-carbon double bond. With the decrease of molecular weight of organic pollutants, absorption of ultraviolet light will decrease. Indirectly, it reflectd that the combination process had a good removal effect on high molecular aromatic hydrocarbons difficult to be biodegraded. Meanwhile it can improve the the biodegradability. It used the activated sludge process as subsequent process of coagulation and-flocculation process. The test results showed that the removal rate of COD_Cr was 24.1%, COD_Cr was the 88.1mg/L. It reached effluent standard.

Abstract: There were still high COD_Cr in straw pulp papermaking waste water, which was dealed with coagulation-combination with nuclear flocculation process. To explore its causes, according to organic qualitative analysis results by GC-MS of the coagulation-flocculation with nuclear process on wastewater treatment and biochemical analysis, this study did the mechanism analysis to the process. It was the main reason, why caused high CODcr, to remain small molecules organic contaminants in the water, such as phthalic acid mono-2-ethylhexyl ester and Diisobutyl phthalate.

Abstract: The laboratory-made dicyandiamide formaldehyde polymer is used to study the effect of the flocculation treatment of simulated wastewater of You Li Su-hong EB. And the influencing factors mainly include flocculant dosage, pH and temperature. The experimental results show that when the dicyandiamide formaldehyde flocculant dosage is 8mL / L and pH is acidic or neutral, COD and color removal rate are the highest that have reached more than 70%. Besides, temperature has little effect on the flocculation treatment, and room temperature is enough to make the treatment effect good. Finally compared with the commonly used flocculant PAC, dicyandiamide formaldehyde polymer treatment effect is better with less addition.

Abstract: Catalytic Wet Air Oxidation (CWAO) is one of advanced oxidation methods about organic wastewater treatment, and the treatment effect of high concentration organic wastewater is remarkable with this method. In this study, the influence factors of the reaction temperature, the reaction pressure and the influent pH were researched on the treatment of the printing and dyeing wastewater with Cu-Fe-La/FSC catalyst, by the single factor experiments and Catalytic Wet Air Oxidation (CWAO) method. Then the catalysts were evaluated by two aspects of the activity and stability. The results show that: with the increase of the reaction temperatures and the reaction pressures, and with the decrease of the influent pH, the COD_Cr removal rate improved and the effluent pH reduced. However, the amount of dissolution catalyst components increased with the improvement of treatment effect and the extension of reaction time. By weighing the activity and stability of the catalysts, the optimized reaction temperature, the reaction pressure and the influent pH are 180 °C, 2.5 MPa and 7.25, respectively. Under the optimized operating conditions, the printing and dyeing wastewater with COD_Cr of 2000 mg/L reaches the COD_Cr removal rate of 78.2%, and the dissolved C[Cu] and C[Fe] of the catalysts are 12.2 and 10.9 mg/L, respectively. Therefore, the catalyst Cu-Fe-La/FSC presents the high activity and stability.

Abstract: Compared microwave-Fenton with Fenton in catalytic oxidation process of Chinese traditional medicine wastewater. The speed of chemical reactions could be improved for more than 10 times by microwave-assisted catalysis. Under microwave irradiation, most of the CODCr removal is concentrated in less than 30s. Radiation power of the microwave affect the removal rate of CODCr, and the best power is related with the water quality.

Abstract: In the present work, acrylonitrile removal from analogue wastewater was investigated using the combined Fe/C microelectrolysis–electro-Fenton. The optimization parameters such as ratio of Fe/C, pH value, the reaction time, the dose of H₂O₂, the voltage, and the stir time on the acrylonitrile removal efficiency were determined by measuring the percentage removal of Chemical Oxygen Demand (CODcr) in the acrylonitrile analogue wastewater. In the Microelectrolysis section, the ratio of Fe/C was 1:1, the pH value was 3.0, and reaction time was 1h. In the electrolyzing Fenton, the optimal conditions of process parameters were the dose of H₂O₂ oxidant (5ml/L), the voltage (2.0 V), electrochemical reaction time (40min), and stir time (20min).Under the optimal conditions, the percentage removal of was 69% in first section and about 35% in the second section. Also, the dose of oxidant (H₂O₂) decreased from 11ml/L to 5ml/L compared with the using single active carbon method.

Abstract: A simulation of the water quality was made in this paper with the help of QUAL2K model for CODCr 、NH3-N in the Le’An river .Based on the results ,The water environmental capacity about CODCr and NH3-N in every function river section of Le’An river was calculated by means of analytic method and section－beginning control mothod.

Abstract: The field in which pure oxygen aeration is applied to sewage treatment is extensive. In actual application it is more suitable for the degradation of industrial sewage. Pure oxygen aeration has unique merit compared with common air aeration. This article introduced the effect by pure oxygen aeration. The study shows pure oxygen aeration is an effective pollutant removal mechanism, and at the same time proposes the best dissolved oxygen is at 3 mg/l. The average removal rates of COD_cr, NH₃-N, TN are 73%, 50%, 55% respectively. The conclusion is that pure oxygen aeration for hospital wastewater the CODcr removing rate is higher than ammonia nitrogen and total nitrogen efficiency.