阅读说明：本技术 一种新型污泥可降解有机碳doc指标测定方法 (Novel DOC index determination method for degradable organic carbon in sludge ) 是由 郭恰 韩小蒙 马艳 宋姗姗 于 2021-07-29 设计创作，主要内容包括：本发明公开了一种新型污泥可降解有机碳DOC指标测定方法,具体涉及污泥处理处置领域,测定方法包括：步骤S1,将污泥泥样通过重铬酸钾法进行加热消煮,则污泥样品中的有机碳会被过量重铬酸钾硫酸溶液氧化,其中有机质的碳元素会被氧化成二氧化碳,六价铬被还原成三价铬,可以根据有机碳被氧化前后重铬酸离子量的变化计算出有机碳的含量；步骤S2,将实验过程中记录的数据代入到原本用于测定化学需氧量的计算公式中,并将公式中氧的毫摩尔质量参数替换成碳的毫摩尔质量。本发明通过利用化学实验定量测定可降解有机碳的数值,对原有用于计算的经验值参数进行校正,可用于精确核算各污泥处理处置工艺和路线的碳排放量。(The invention discloses a novel method for measuring DOC index of degradable organic carbon in sludge, and particularly relates to the field of sludge treatment, wherein the measuring method comprises the following steps: step S1, heating and digesting the sludge sample by a potassium dichromate method, wherein organic carbon in the sludge sample is oxidized by excessive potassium dichromate sulfuric acid solution, carbon element of organic matter is oxidized into carbon dioxide, hexavalent chromium is reduced into trivalent chromium, and the content of the organic carbon can be calculated according to the change of the amount of dichromate ions before and after the organic carbon is oxidized; and step S2, substituting the data recorded in the experimental process into the original calculation formula for measuring the chemical oxygen demand, and replacing the millimolar mass parameter of oxygen in the formula with the millimolar mass of carbon. The method quantitatively determines the numerical value of the degradable organic carbon by using a chemical experiment, corrects the original empirical value parameters for calculation, and can be used for accurately calculating the carbon emission of each sludge treatment process and route.)

1. A novel DOC index measuring method for degradable organic carbon in sludge is characterized by comprising the following steps: the method comprises the following steps:

step S1: heating and digesting the sludge sample by a potassium dichromate method to obtain the organic matters in the sludge sampleCarbon is oxidized by excessive potassium dichromate sulfuric acid solution, and carbon element in organic matter is oxidized into carbon dioxide and hexavalent chromium (Cr)⁶⁺) Is reduced into trivalent chromium (Cr)³⁺) Titrating the residual potassium dichromate solution by using a ferrous sulfate standard solution, and calculating the content of the organic carbon according to the change of the amount of dichromate ions before and after the organic carbon is oxidized;

step S2: substituting the data recorded in the experimental process into the original calculation formula for measuring the Chemical Oxygen Demand (COD), and replacing the millimolar mass parameter of oxygen in the formula with the millimolar mass of carbon to obtain the following calculation formula: degradable organic carbon

2. The novel method for measuring DOC index of degradable organic carbon in sludge according to claim 1, which is characterized in that: the specific experimental steps of step S1 are as follows:

step S101: taking a certain amount of sludge samples and placing the sludge samples in an oven for drying;

step S102: taking out the dried sample in the step S101, immediately crushing and sieving;

step S103: storing the sludge sample sieved in the step S102 in a wide-mouth bottle, opening the mouth of the wide-mouth bottle, putting the wide-mouth bottle back into a drying box, and continuously drying the wide-mouth bottle;

step S104: taking out a sludge sample from the drying box in the step S103, and then putting the sludge sample into a dryer for cooling;

step S105: weighing a dried and cooled sludge sample, putting the sludge sample into a triangular flask, and adding K of 1/6 weight of the sludge sample₂Cr₂O₇-H₂SO₄Mixing the solution, and uniformly shaking to obtain a suspension;

step S106: placing the mixed suspension prepared in the step S105 in a glycerol bath, keeping the mixed suspension boiling, and taking out until the mixed suspension is completely cooled;

step S107: adding distilled water into the cooled mixed solution, then dripping the o-phenanthroline indicator into the mixed solution, and using standard FeSO₄Solution processTitrating until the sample turns brick red;

step S108: record FeSO consumed when sample turned brick-red₄The number of milliliters of (a) is marked as V, and 5 parallel samples are respectively made for each sample; in addition, a blank is prepared for each sample at the time of measurement, and FeSO used in titration of the blank is used₄The amount of solution used is denoted V₀。

3. The novel DOC index measuring method for the degradable organic carbon in the sludge according to claim 2, which is characterized in that: the calculation parameters obtained in the specific experimental steps are respectively as follows:

V₀the volume of the ferrous sulfate standard solution consumed in titration of the blank, mL;

v is the volume of the ferrous sulfate standard solution consumed in titrating the sample, mL;

mc-the millimolar mass of carbon, with an Mc of 1/4 of 0.003 g/mmol;

m is the concentration of ferrous sulfate standard solution, mol/L;

w-oven dried sample mass, g.

4. The novel DOC index measuring method for the degradable organic carbon in the sludge according to claim 2, which is characterized in that: in step S101, the temperature in the oven is adjusted to 60 ℃ and the sample is dried for 12 hours.

5. The novel method for measuring DOC index of degradable organic carbon in sludge according to claim 4, which is characterized in that: in step S102, the sample is pulverized and sieved to select 20^#And (4) screening.

6. The novel DOC index measuring method for the degradable organic carbon in the sludge according to claim 5, which is characterized in that: in step S103, the screened sample is stored in a jar, and the jar is opened and dried in a drying oven at 60 ℃ for 2 hours.

7. The novel sludge degradable agent as claimed in claim 6The machine carbon DOC index measuring method is characterized by comprising the following steps: in step S105, 0.07g of the dried and cooled sample is weighed into a 250mL triangular flask, and 20mL of K with a concentration of 0.4mol/L and a weight of 1/6 of the sludge sample is added₂Cr₂O₇-H₂SO₄The solution was mixed and shaken well.

8. The novel DOC index measuring method for the degradable organic carbon in the sludge according to claim 7, which is characterized in that: in step S106, the sample is placed in a glycerol bath heated to 185-195 ℃ and kept boiling at 170-180 ℃ for 5 minutes.

9. The novel DOC index measuring method for the degradable organic carbon in the sludge according to claim 8, which is characterized in that: in step S107, 120mL of distilled water was added, and 3 drops of the o-phenanthroline indicator were added dropwise.

Technical Field

The invention relates to the technical field of sludge treatment and disposal, in particular to a novel method for measuring DOC index of degradable organic carbon in sludge.

Background

China proposes to strive for carbon dioxide emission to reach a peak value in 2030 years before 9 months in 2020, and carbon neutralization is realized in 2060 years before. Various industries need to actively respond to calls, and reduce the existing emission by means of reforming and updating the routes, processes and equipment of the prior art and the like. As an effective method and basis for controlling and reducing carbon emission, the accounting analysis of the carbon emission generated in various fields has received wide attention at home and abroad. Particularly in the sludge industry, carbon emission of different sludge treatment processes is greatly different on accounting boundaries, and the most widely used model in carbon emission accounting in all current large sewage plants is a default value model proposed in 1996 by IPCC (inter-government Climate Change on Climate Change, IPCC for short) no matter what process route is adopted. But IPCC was originally proposed according to the model of sanitary landfill of solid waste, and is not specific to sludge treatment and disposal process, and the parameters involved therein are derived from the empirical values of IPCC, i.e. the global average.

Although the sludge is a solid waste, the sludge has a great difference in characteristics from general solid waste. The municipal solid waste refers to industrial waste, commercial waste and domestic waste generated by human activities, including daily life, production and construction, and is in a solid and semi-solid state. The main components of the solid waste are solid particles, garbage, furnace slag, damaged vessels, animal carcasses, deteriorated food, sludge, human and animal excreta and the like. The sludge of the municipal sewage plant can be classified into three major types, namely water supply sludge, domestic sewage sludge and industrial wastewater sludge, according to the source classification. The municipal sludge has complex components and is mainly characterized by high water content, large volume, fine contained granular substances, extremely strong rheological property, high organic matter content, easy degradation, odor generation, and great toxicity and environmental pollution.

Therefore, the calculation result of the default model and the empirical average value is not necessarily in accordance with the actual situation. In addition, considering the difference of sludge quality and environment between developing countries and developed countries and regional areas, the calculation is directly carried out by using empirical values, and the discharge amount of carbon dioxide and methane obtained by sewage plants with daily treated sludge amount of several hundred tons can be greatly changed.

Disclosure of Invention

In order to overcome the defects in the prior art, the embodiment of the invention provides a novel DOC index measuring method for degradable organic carbon in sludge, which is used for accurately calculating the carbon emission of each sludge treatment process and route by quantitatively measuring the numerical value of the degradable organic carbon through a chemical experiment and correcting the original experience value parameters for calculation. The disadvantages and the advantages of the sludge treatment processes in the aspect of carbon emission reduction are obtained, and the corresponding sludge treatment processes are selected for sludge treatment, so that the purpose of carbon emission reduction in the sludge treatment process is achieved, and contribution is made to the achievement of the carbon neutralization target.

In order to achieve the purpose, the invention provides the following technical scheme: a novel DOC index measuring method for degradable organic carbon in sludge comprises the following steps:

step S1: heating and digesting the sludge sample by a potassium dichromate method, so that organic carbon in the sludge sample is oxidized by excessive potassium dichromate sulfuric acid solution, and carbon element of organic matter is oxidized into carbon dioxide and hexavalent chromium (Cr)⁶⁺) Is reduced into trivalent chromium (Cr)³⁺) Titrating the residual potassium dichromate solution by using a ferrous sulfate standard solution, and calculating the content of the organic carbon according to the change of the amount of dichromate ions before and after the organic carbon is oxidized;

step S2: substituting the data recorded in the experimental process into the original calculation formula for measuring the Chemical Oxygen Demand (COD), and replacing the millimolar mass parameter of oxygen in the formula with the millimolar mass of carbon to obtain the following calculation formula: degradable organic carbon

In a preferred embodiment, the specific experimental steps of step S1 are as follows:

step S101: taking a certain amount of sludge samples and placing the sludge samples in an oven for drying;

step S102: taking out the dried sample in the step S101, immediately crushing and sieving;

step S103: storing the sludge sample sieved in the step S102 in a wide-mouth bottle, opening the mouth of the wide-mouth bottle, putting the wide-mouth bottle back into a drying box, and continuously drying the wide-mouth bottle;

step S104: taking out a sludge sample from the drying box in the step S103, and then putting the sludge sample into a dryer for cooling;

step S105: weighing a dried and cooled sludge sample, putting the sludge sample into a triangular flask, and adding K of 1/6 weight of the sludge sample₂Cr₂O₇-H₂SO₄Mixing the solution, and uniformly shaking to obtain a suspension;

step S106: placing the mixed suspension prepared in the step S105 in a glycerol bath, keeping the mixed suspension boiling, and taking out until the mixed suspension is completely cooled;

step S107: adding distilled water into the cooled mixed solution, then dripping the o-phenanthroline indicator into the mixed solution, and using standard FeSO₄Titrating the solution until the sample turns brick red;

step S108: record FeSO consumed when sample turned brick-red₄The number of milliliters of (a) is marked as V, and 5 parallel samples are respectively made for each sample; in addition, a blank is prepared for each sample at the time of measurement, and FeSO used in titration of the blank is used₄The amount of solution used is denoted V₀。

In a preferred embodiment, the calculation parameters obtained in the specific experimental steps are respectively:

V₀the volume of the ferrous sulfate standard solution consumed in titration of the blank, mL;

v is the volume of the ferrous sulfate standard solution consumed in titrating the sample, mL;

mc-the millimolar mass of carbon, with an Mc of 1/4 of 0.003 g/mmol;

m is the concentration of ferrous sulfate standard solution, mol/L;

w-oven dried sample mass, g.

In a preferred embodiment, in step S101, the temperature in the oven is adjusted to 60 ℃ to dry the sample for 12 hours.

In a preferred embodiment, in step S102, the sample isPulverizing, sieving, and selecting 20^#And (4) screening.

In a preferred embodiment, in step S103, the screened sample is stored in a jar, and the jar is dried in a drying oven for 2 hours at 60 ℃ with the mouth open.

In a preferred embodiment, in step S105, 0.07g of the dried and cooled sample is weighed into a 250mL triangular flask, and 20mL of K with a concentration of 0.4mol/L and a weight of 1/6 of the sludge sample is added₂Cr₂O₇-H₂SO₄The solution was mixed and shaken well.

In a preferred embodiment, in step S106, the sample should be placed in a glycerol bath heated to 185-195 ℃ and kept boiled for 5 minutes at 170-180 ℃.

In a preferred embodiment, 120mL of distilled water is added and then 3 drops of the o-phenanthroline indicator are added in step S107.

The invention has the technical effects and advantages that:

compared with the prior art, the novel DOC index measuring method for the degradable organic carbon in the sludge utilizes chemical experiments to quantitatively measure the numerical value of the degradable organic carbon, can be used for accurately accounting the carbon emission of each sludge treatment process and route by correcting the original empirical value parameters for calculation, and contributes to realizing the carbon neutralization target.

Drawings

FIG. 1 is a flow chart of the steps of the DOC index determination method of the degradable organic carbon in sludge according to the invention;

FIG. 2 is an experimental procedure of the DOC index determination method of the degradable organic carbon in the sludge.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

FIG. 1 is a flow chart of steps of a novel method for determining DOC index of degradable organic carbon in sludge according to the invention; as shown in figure 1, the novel method for measuring DOC indexes of degradable organic carbon in sludge comprises the following steps:

step S1: heating and digesting the sludge sample by a potassium dichromate method, so that organic carbon in the sludge sample is oxidized by excessive potassium dichromate sulfuric acid solution, and carbon element of organic matter is oxidized into carbon dioxide and hexavalent chromium (Cr)⁶⁺) Is reduced into trivalent chromium (Cr)³⁺) Titrating the residual potassium dichromate solution by using a ferrous sulfate standard solution, and calculating the content of the organic carbon according to the change of the amount of dichromate ions before and after the organic carbon is oxidized;

step S2: substituting the data recorded in the experimental process into the original calculation formula for measuring the Chemical Oxygen Demand (COD), and replacing the millimolar mass parameter of oxygen in the formula with the millimolar mass of carbon to obtain the following calculation formula: degradable organic carbon

FIG. 2 is a flow chart of experimental steps of a novel method for determining DOC index of degradable organic carbon in sludge according to the present invention; as shown in FIG. 2, the novel method for measuring DOC index of degradable organic carbon in sludge comprises the following experimental steps:

step S101: taking a certain amount of sludge samples and placing the sludge samples in an oven for drying;

step S102: taking out the dried sample in the step S101, immediately crushing and sieving;

step S103: storing the sludge sample sieved in the step S102 in a wide-mouth bottle, opening the mouth of the wide-mouth bottle, putting the wide-mouth bottle back into a drying box, and continuously drying the wide-mouth bottle;

step S104: taking out a sludge sample from the drying box in the step S103, and then putting the sludge sample into a dryer for cooling;

step S105: weighing a dried and cooled sludge sample, putting the sludge sample into a triangular flask, and adding K of 1/6 weight of the sludge sample₂Cr₂O₇-H₂SO₄Mixing the solution, and uniformly shaking to obtain a suspension;

step S106: placing the mixed suspension prepared in the step S105 in a glycerol bath, keeping the mixed suspension boiling, and taking out until the mixed suspension is completely cooled;

step S107: adding distilled water into the cooled mixed solution, then dripping the o-phenanthroline indicator into the mixed solution, and using standard FeSO₄Titrating the solution until the sample turns brick red;

step S108: record FeSO consumed when sample turned brick-red₄The number of milliliters of (a) is marked as V, and 5 parallel samples are respectively made for each sample; in addition, a blank is prepared for each sample at the time of measurement, and FeSO used in titration of the blank is used₄The amount of solution used is denoted V₀。

The invention is further illustrated below by means of an embodiment:

example of the implementation

China is wide in territory, and sludge produced in different areas under different geographic environments and economic environments has certain difference in sludge quality. The sewage quantity in China is characterized by more south and less north, more south and less north and more west and north. The sewage in northern cities has high concentration of influent pollutants, the annual concentration distribution of COD, BOD and SS in the influent water is in a biased distribution, and TKN and TP are in a normal distribution; higher concentration of organic contaminants, BOD₅250.8 mg/L; has better biodegradability, about 38 percent of BOD₅The COD is between 0.2 and 0.4, while the COD is greater than 0.4 and accounts for 62 percent. In contrast, the southern wastewater had a lower concentration of organics, total BOD₅The COD can reach about 0.5; the nitrogen and phosphorus content in the sewage is high. The difference of the water quality of the sewage from south to north also determines the difference of sludge quality in south to north and different regions of China.

According to different regional characteristics and sludge quality differences in different regions of China, sludge inlet samples of different sewage treatment plants of Heilongjiang jackwood, Jiangsu Zhenjiang, Hunan Changsha and Yunnan Lijiang are respectively collected for experimental detection.

The method for measuring the DOC content of the sludge by adopting a potassium dichromate method is mainly based on the principleWhen the sludge sample is heated and digested by the potassium dichromate method, organic carbon in the sludge sample is oxidized by excessive potassium dichromate sulfuric acid solution, and carbon element of organic matter is oxidized into carbon dioxide and hexavalent chromium (Cr)⁶⁺) Is reduced into trivalent chromium (Cr)³⁺) And titrating the residual potassium dichromate solution by using a ferrous sulfate standard solution, and calculating the content of the organic carbon according to the change of the amount of dichromate ions before and after the organic carbon is oxidized.

The potassium dichromate method was originally used to determine the Chemical Oxygen Demand (COD), and the molar mass of oxygen used in the calculation, i.e., 8g/mol, was calculated. However, in the calculation of the degradable organic carbon DOC, the carbon content needs to be considered, so that the calculation of the degradable organic carbon DOC content can be performed by replacing the millimolar mass of oxygen with the millimolar mass of carbon. The specific calculation formula is as follows: degradable organic carbon

In the formula:

V₀the volume of the ferrous sulfate standard solution consumed in titration of the blank, mL;

v is the volume of the ferrous sulfate standard solution consumed in titrating the sample, mL;

mc-the millimolar mass of carbon, with an Mc of 1/4 of 0.003 g/mmol;

m is the concentration of ferrous sulfate standard solution, mol/L;

w-oven dried sample mass, g;

the specific experimental operating method (see the attached figure 2) is as follows: firstly, taking a certain amount of samples to be placed in an oven, adjusting the temperature to 60 ℃ and drying for 12 hours; ② taking out the dried sample to immediately crush and pass through 20^#Screening; thirdly, storing the screened sample in a wide-mouth bottle, opening the bottle mouth, putting the wide-mouth bottle back into a drying box, and continuously drying the wide-mouth bottle for 2 hours at the temperature of 60 ℃; taking out the sample from the drying box and then putting the sample into a dryer for cooling; fifthly, 0.07g of dried and cooled sample is weighed and put into a 250mL triangular flask, and 20mL of 1/6K with the concentration of 0.4mol/L is added₂Cr₂O₇-H₂SO₄Mixing the solution, and uniformly shaking; sixthly, placing the mixture on a heated state to 185-195Boiling in glycerol bath at 170-180 deg.C for 5min, and cooling; seventhly, 120mL of distilled water is added, then 3 drops of o-phenanthroline indicator are dropped, and standard FeSO is used₄Titrating the solution until the sample turns brick red; record FeSO consumed by sample to become brick red₄The number of milliliters of (a) is marked as V, and 5 parallel samples are respectively made for each sample; in addition, a blank is prepared for each sample at the time of measurement, and FeSO used in titration of the blank is used₄The amount of solution used is denoted V₀。

Substituting the experimental data into a calculation formula to obtain the degradable organic carbon in the sludge of different sewage treatment plants, wherein the specific numerical values are shown in table 1:

TABLE 1 actual measurement proportions of decomposition of Degradable Organic Carbon (DOC) in sludge from different sewage treatment plants

In conclusion, the novel DOC index measuring method for the degradable organic carbon in the sludge is used for measuring and calculating the degradable organic carbon in different sludge to obtain specific accounting parameters, so that the carbon emission accounting result is more accurate, evaluation on the disadvantages and superiority of each sludge treatment process in the aspect of carbon emission reduction is facilitated, the purpose of reducing the carbon emission in the sludge treatment process is achieved, and the carbon neutralization target is facilitated.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Modifications and variations can be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the present invention. Therefore, the scope of the invention should be determined from the following claims.