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Reactor type BOD rapid measuring method and measuring instrument

A rapid determination and measurement method technology, applied in the field of environmental pollution monitoring, can solve the problems of biofilm thickness, large mass transfer resistance, and fragility, and achieve the requirements of simple activation and storage methods, lower precision, and avoid large attenuation Effect

Inactive Publication Date: 2010-02-03
TSINGHUA UNIV
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Problems solved by technology

Therefore, this measurement method not only requires a good measurement environment, but also needs the support of a very high-precision dissolved oxygen meter, which makes the overall rapid detector higher in price and poor in instrument performance stability.
[0015] (2) Large mass transfer resistance: The biofilm BOD measurement method is not only restricted by the metabolism of the microorganism itself, but also largely controlled by the mass transfer of the porous membrane of the immobilized microorganism, resulting in a linear range of measurement Narrow, generally only tens of mg / L, most samples need to be diluted before measurement
[0016] (3) There are some defects in the biofilm itself: the mechanical strength of the biofilm is poor, it is easy to break, the biomass is not easy to control, and the replacement of the biofilm is difficult
[0017] (4) There is an irreconcilable contradiction between microbial biomass and biofilm thickness: Generally speaking, the sensitive materials used in the rapid biofilm BOD determination method are fixed in the film. From the perspective of mass transfer, it is hoped that the thinner the biofilm, the more Good; but considering the stability of the measurement, it is desirable to have more biomass, but this will lead to thicker biofilms, increased mass transfer resistance, and serious attenuation of dissolved oxygen signals
[0020] (1) The microorganisms used in it need to be provided on site: Therefore, it is generally only used for the determination of BOD concentration in sewage treatment plants, and cannot meet the monitoring of natural water bodies far away from sewage treatment plants
[0021] (2) Frequent replacement of biometric materials will lead to the lack of a unified benchmark for measurement due to inconsistent microbial activity states

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  • Reactor type BOD rapid measuring method and measuring instrument

Examples

Experimental program
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Effect test

Embodiment 1

[0053] Use this experimental device to measure standard BOD samples.

[0054] Standard GGA solutions with BOD concentrations of 5 mg / l, 20 mg / l, 50 mg / l, 100 mg / l, and 200 mg / l were respectively prepared for measurement. The test conditions are: water bath 30±1°C, aeration rate 500ml / min. The GGA standard solution with a BOD value of 5 mg / l took the shortest time to reach equilibrium, which took 5 minutes, and the GGA standard solution with a BOD value of 200 mg / l took the longest time to reach equilibrium, which was 13 minutes.

[0055] The test results show that the detection range of the instrument is 5-200mg / l, and the linear correlation coefficient achieved by the measurement is 0.996, which meets the requirements of rapid BOD measurement (such as figure 1 shown).

Embodiment 2

[0057] Rapid Determination of BOD Using Carrageenan Immobilized Activated Sludge Granules

[0058] (1) Weigh 2.0 g of carrageenan, mix it with 100 mL of deionized water, heat it in a water bath until it dissolves, and then cool it to normal temperature to obtain a carrageenan solution;

[0059] (2) Centrifuge the activated sludge from Gaobeidian Sewage Treatment Plant, discard the supernatant, wash the sludge three times with normal saline (0.9% NaCl solution), and prepare with 100mL according to step (1). Carrageenan solution mixed to obtain a mixed solution;

[0060] (3) Add 1g chitosan to 100mL 2% KCl solution to obtain a crosslinking agent solution;

[0061] (4) Use a 0.40mm ID syringe to add the mixed solution in (2) dropwise to the crosslinking agent solution cooled to 35°C to form microbial particles with a diameter of about 3mm, soak them for 5h, and then use physiological saline washing immobilized microbial particles;

[0062] (5) Using the immobilized microbial p...

Embodiment 3

[0064] Detection of BOD Value of Domestic Sewage Using Immobilized Microbial Particles

[0065] (1) Centrifuge the activated sludge from Gaobeidian Sewage Treatment Plant, discard the supernatant, wash the sludge 3 times with normal saline (0.9% NaCl solution), and place it in a refrigerator for subsequent use;

[0066] (2) heating and melting 15% (w / v) PVA and 1% (w / v) sodium alginate as a material for embedding immobilized microorganisms;

[0067] (3) uniformly mixing the above-mentioned thickened sludge with the cooled embedding material prepared in step (2) according to the ratio of 1:2 (v / v);

[0068] (4) Preparation of 50% NaNO 3 and 1% CaCl 2 The mixed solution is used as a cross-linking solution;

[0069] (5) Add the mixed solution obtained in step (3) dropwise to the cross-linking solution prepared in step (4) with a syringe, let it stand for 3 hours, and obtain microbial particles with a diameter of 3 ~ 5mm. Use physiological saline (0.9% NaCl solution) rinsed an...

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Abstract

The invention discloses a reactor type BOD rapid measuring method and a measuring instrument, belonging to the field of environmental pollution monitoring. The measuring instrument comprises a hybridbiochemical reactor, an aeration system connected therewith, a dissolved oxygen converter and a computer data processing system, wherein, a dissolved oxygen electrode and an aeration pipe are arrangedin the hybrid biochemical reactor. Sewage and immobilized microorganism particles to be measured are mixed, stirred and aerated in a measuring chamber, heating and temperature control are carried out, thereby leading the immobilized microorganism particles to degrade biodegradable organic pollutants in a water body, constantly reducing the concentration of dissolved oxygen and then calculating the BOD value of a water sample to be measured through a standard curve according to the difference value of the dissolved oxygen between two stable states. The measuring instrument solves the problemsof instability, poor reproducibility of the measurement result and the like of the traditional biological membrane type BOD rapid measuring instrument. The reactor type BOD rapid measuring instrumenthas the advantages of good stability, wide linear range of measurement, good reproducibility, low requirement on precision of a dissolved oxygen instrument and the like.

Description

technical field [0001] The invention belongs to the field of environmental pollution monitoring, and relates to a reactor-type BOD rapid measurement method and a measuring instrument for rapid monitoring of water body organic pollution. Specifically, in a measurement chamber composed of a completely mixed reactor, immobilized microbial particles are used as the biometric components of the BOD rapid detector to replace the biofilm used in the current BOD rapid detector, with the purpose of improving the stability of the measurement results and reproducibility, and prolong the life of biometric components. Background technique [0002] Biochemical oxygen demand (Biochemical Oxygen Demand, BOD) refers to the amount of dissolved oxygen consumed by organic matter in water under the action of microbial oxidation. The unit is mg / L, which can represent the pollution degree of biodegradable organic pollutants in water. [0003] At present, foreign and domestic (GB7488-87) mainly ado...

Claims

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Application Information

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IPC IPC(8): G01N33/18
CPCG01N33/1866
Inventor 王建龙
Owner TSINGHUA UNIV
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