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Activated sludge solubleness COD measuring method

A technology of chemical oxygen demand and measurement method, which is applied in the field of determination of activated sludge dissolved chemical oxygen demand, can solve the problem of accurate evaluation of cell lysis technology, difficult membrane filtration, and accurate determination of dissolved chemical oxygen demand, etc. problem, to achieve the effect of reliable principle, simple preparation and large amount of information

Active Publication Date: 2009-04-29
江苏乐尔环境科技股份有限公司
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  • Application Information

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Problems solved by technology

However, when the sludge is lysed by various technologies, especially the long-term ultrasonic treatment, the sludge flocs are greatly dispersed, and a large number of sludge fine particles and cell fragments are suspended in the solution. Even the sludge solution after high-speed centrifugation It is also difficult to perform 0.45um membrane filtration
Therefore, the traditional method of using 0.45um membrane filtration to prepare a solution without sludge particles is very difficult, which affects the accurate determination of dissolved chemical oxygen demand and the accurate evaluation of various lysis techniques

Method used

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  • Activated sludge solubleness COD measuring method
  • Activated sludge solubleness COD measuring method
  • Activated sludge solubleness COD measuring method

Examples

Experimental program
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Effect test

Embodiment 1

[0034] Take 1L of excess sludge with a water content of 98.5% from a sewage plant, adjust the pH to 10.0 with sodium hydroxide (NaOH), and treat it with a tank-type ultrasonic wave with a frequency of 25kHz and a power of 50W for 30min. Then take 4 parts of 50ml lysed sludge and centrifuge respectively at 5000g for 5min, 8min, 10min and 15min at a centrifugal acceleration, take out the upper suspension and measure the light transmittance at a detection wavelength of 630nm, then use the potassium dichromate titration method Analyze the chemical oxygen demand (COD) data of the suspension, and plot the light transmittance and COD in the Excel software (such as figure 2 ), according to the data, use the Excel linear regression function to perform linear regression to obtain a linear equation:

[0035] COD=2919.9-25.62T (5)

[0036] Then use equation (5) to calculate the chemical oxygen demand when the light transmittance is 100%, which is 358.4mg / L. This data is the dissolved c...

Embodiment 2

[0038] With embodiment 1. The difference is that the pH of the sludge is 11.0, the ultrasonic treatment is 60 minutes, and two parts of 50ml volume of lysed sludge are centrifuged at the centrifugal accelerations of 5000g and 8000g for 10min respectively. Use Excel software to plot the data (such as figure 2 shown), and utilize Excel software to carry out linear regression to obtain the linear equation of light transmittance and chemical oxygen demand:

[0039] COD=3954-25.83T (6)

[0040] According to equation (6), the dissolved chemical oxygen demand when the light transmittance is 100% is 1371mg / L, while the corresponding value of 0.45um membrane filtration method is 1425mg / L, and the relative error is 3.8%.

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Abstract

The invention relates to a method for determining the soluble chemical oxygen demand of activated sludge. The detection wavelength of a spectrophotometer is preset as 630nm, and the light transmittance of deionized water is taken as 100 percent; after the sludge is subjected to wall breaking and lysing treatment, at least two portions of certain volume of cell-lysing sludges are taken respectively, and are centrifugated for fixed time at different centrifugal accelerations, or are centrifugated for different time at a fixed centrifugal acceleration, and chemical oxygen demand (COD) values of a suspension of the sludge are determined under different centrifugal conditions according to the analysis of a standard potassium dichromate titration method; and in a rectangular coordinate system, horizontal coordinates are taken as values of the light transmittance of a solution, longitudinal coordinates are taken as the chemical oxygen demand values of the suspension, then an Excel software is adopted to perform linear regression to data and extrapolate until the light transmittance is 100 percent, and a corresponding COD value is a soluble chemical oxygen demand (SCOD) value of the solution without sludge particles after the sludge is lysed. Compared with a soluble chemical oxygen demand value determined in a solution prepared by the filtration of a film with the aperture of 0.45mu m, the relative error of an analysis and determination result of the method is less than 5 percent.

Description

technical field [0001] The invention relates to a method for measuring the soluble chemical oxygen demand (SCOD) in the sludge supernatant when the sludge particles are small and difficult to filter in the process of excess sludge treatment, and belongs to the field of sewage treatment and solid waste treatment Sludge treatment technology is a method for determining the dissolved chemical oxygen demand of activated sludge. Background technique [0002] With the development of social economy and the acceleration of urbanization, the amount of urban sewage and its sludge has increased rapidly. The annual production of wet sludge in my country has reached 12 million tons, with an annual growth rate of 10-15%. Because the cost of sludge treatment accounts for about 50% of the treatment cost of sewage treatment plants, the cost is very high, so many sewage treatment plants in my country often only treat sewage and avoid sludge treatment, mainly landfill and stack, causing seriou...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/59
Inventor 刘勇张书廷郝赟
Owner 江苏乐尔环境科技股份有限公司
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