36 results about "Chemical Oxygen Demand Analysis" patented technology

Methods for measuring chemical oxygen demand, a composition and a kit useful for measuring chemical oxygen demand, a method for calibrating a chemical oxygen demand analysis method, and a method for determining carbonaceous chemical oxygen demand are disclosed.

The invention provides a rainwater collection pool control system. The system runs in a distributed control system. The distributed control system is connected to a rainwater collection pool. The rainwater collection pool control system comprises a control module and a starting module, wherein the control module is used for controlling a chemical oxygen demand analyzer inside the rainwater collection pool to sample rainwater inside the rainwater collection pool, and analyzing a chemical oxygen demand concentration value of the rainwater, the starting module is used for starting a submersible pump inside the rainwater collection pool when the chemical oxygen demand concentration value of the rainwater exceeds the rainwater drainage standard and the liquid level of the rainwater reaches the high liquid level of a liquidometer inside the rainwater collection pool, controlling the submersible pump to pump out the rainwater in the rainwater collection pool, draining the rainwater through an upper water drainage opening of the rainwater collection pool to a wastewater treatment system and closing the submersible pump when the liquid level of the rainwater in the rainwater collection pool reaches the low liquid level set by the liquidometer. The invention further provides a rainwater collection pool control method. According to the rainwater collection pool control system and method, the rainwater can be collected and treated, and environment pollution is prevented.

The invention discloses a method of removing sulfanilamide antibacterials and a COD (chemical oxygen demand) from livestock breeding waste water by using micron zero-valent ferrum-activated persulfate. The method comprises the steps of adding 0.007-0.008mol/L persulfate and 0.2-0.3g/L micron zero-valent ferrum, uniformly stirring, and keeping pH (potential of hydrogen) of a reaction system to be 4.5-5.5 for reaction, wherein a mole ratio of micron zero-valent ferrum to persulfate is 1:(1.40-2.10). The method overcomes the disadvantages of a too high reaction rate, a low utilization ratio and the like of a metal ion catalyst, can quickly, efficiently and persistently remove the sulfanilamide antibacterials and the waste water COD from the livestock breeding waste water; reaction conditions are mild; the treatment time is greatly shortened; the technical cost is lowered; and the method has wide application prospects in degradation and removal of the sulfanilamides antibacterials and the COD in the livestock breeding waste water.

The invention discloses a method for monitoring COD in fluorescent wastewater, wherein a closed tube digestion spectrophotometric method is adopted for monitoring COD in fluorescent wastewater. According to the method for monitoring COD in fluorescent wastewater, the closed tube digestion spectrophotometric method comprises the steps as follows: 1), 2.5-3mL of homogenous mixed water sample is absorbed in a reaction tube, 0.5-1mL of an oxidizing agent solution is added, 4-6mL of a composite catalyst, 0.3-0.5mL of a masking agent is added, and the solution are shaken uniformly; 2), the reaction tube is placed in a digester at the temperature ranging from 160 DEG C to 165 DEG C, a reaction tube cover is covered, and the reaction tube is taken out after digested for 10-15min; 3), the reaction tube is cooled in the air after being taken out, 2.5mL of deionized water is added and uniformly shaken, and water cooling is performed until the room temperature is achieved; and 4), then the solution is poured into a cuvette, absorbance is measured by a spectrophotometer, and finally a COD concentration value is obtained. The closed tube digestion spectrophotometric method is used for monitoring COD in fluorescent wastewater, so that the accuracy of monitored data is guaranteed, the operation environment is more environment-friendly and safer, and damage to human body health due to volatilized harmful substances is prevented.

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.

The invention provides a rainwater collection and processing control method. A rainwater collection and processing system applied by the control method comprises a control module, a sub-station systemand a start module, wherein the control module controls a chemical oxygen demand analyzer in a rainwater collection pool to sample rainwater in the rainwater collection pool, and analyzes a chemicaloxygen demand concentration value of the rainwater; the sub-station system comprises a sub-station controller, a waste flow controller well, a rainwater storage pool, a purifying device, a clean waterstorage pool and a sub-station control system; the start module starts a submerged pump in the rainwater collection pool when a chemical oxygen demand concentration value of the rainwater excesses arainwater emission standard and a rainwater level reaches a high liquid level of a liquidometer in the rainwater collection pool. The invention further provides a rainwater collection pool control method. Rainwater can be collected and processed and environmental pollution can be prevented.

The invention provides a biochemical oxygen demand detection method which comprises the following steps: a) subjecting a water sample containing microbes to microbiological culture so as to obtain a microbial membrane; b) allowing a target water sample and air to pass through the microbial membrane obtained in step a ) to detect chemical oxygen demand of the target water sample which has been degraded by the microbes; c) calculating difference of the chemical oxygen demands of the target water sample based on initial water chemical oxygen demand and the chemical oxygen demand obtained step b) of the target water sample; and d) calculating biochemical oxygen demand of the target water sample according to a predetermined standard curve and the chemical oxygen demand of the target water sample obtained in step c), wherein the standard curve in step d) is a relation curve between the chemical oxygen demand difference and the biochemical oxygen demand of the target water sample. According to the invention, the key technology of treating sewage with a biological membrane is used to provide sufficient air for degradation of organic compounds, which enables efficiency of non-selective degradation of organic matters by microbes to be enhanced, thereby improving the accuracy of detection results.

The invention provides a method for rapid determination of chemical oxygen demand (COD) in an environmental water sample. The method comprises the following steps: respectively carrying out photo-catalytic oxidation on a diluent of a to-be-determined water sample and on a COD standard solution under the conditions that the concentration of MnO4<-> is 2 mmol/L, usage amount of a catalyst is 5 g/L, the pH value of a reaction solution is 3.0, reaction temperature is 80 DEG C and illumination time is 30 min, wherein the catalyst is 5-SA_Fe2O3-GO-TiO2 with a modification degree of 90%; subjecting resultant solutions to high speed centrifugation at a rotating speed of 14000 rpm, respectively taking out supernatants and determining absorbance values of the supernatants at a wavelength of 525 nm by using spectrophotometry; and drafting a calibration curve and querying corresponding COD concentration of the diluent of the to-be-determined water sample from the calibration curve based on the absorbance values. The method provided by the invention not only overcomes problems in conventional photo-catalytic oxidation methods for determination of COD in environmental water samples, but also has the advantage of rapid, easy, convenient and sensitive determination.

The invention provides a simple efficient pretreatment method for shielding chlorine ion interference, which can perform mass determination and has the characteristic of wide application range. The method is suitable for determining the chemical oxygen demand (CDO) of wastewater in which the chlorine ion concentration is less than 20000 mg/L and the COD is greater than 20 mg/L. The measuring method comprises the following steps: 1. measuring the chlorine ion concentration in a wastewater sample by silver nitrate titrimetry (GB/T 11896-1989), and preparing a water solution with the same chlorine ion concentration as the wastewater sample as a quality control water sample or taking added standard recovery quality control measures; 2. respectively taking the wastewater sample and quality control water sample, mixing with equal volume of a mercuric sulfate solution, carrying out pretreatment (innovative point), and standing for some time until the chlorine ions and mercury ions form a stable mercury tetrachloride complex, thereby shielding the chlorine ions in wastewater; and 3. transferring the pretreated water sample in the step 2 into a prefabricated test tube, and carrying out an SM5220D process to obtain the measuring result of COD.

The invention relates to a method for determining chemical oxygen demand (COD) of titanium dioxide production waste water, which belongs to the field of titanium dioxide production and comprises the steps of A neutralizing titanium dioxide waste water through alkali; B determining the chemical oxygen demand of neutralized titanium dioxide waste water through a potassium dichromate method, wherein the reaction time for heating return flow is 10-30 minutes; C enabling the titanium dioxide waste water with unqualified chemical oxygen demand to repeat the step of A. By means of the method for determining a value of the COD, under the premise of an accurate test value, the operation is simple and easy to implement and the analysis process is fast and effective. Therefore, the method can be widely applied to the detection of the COD of the titanium dioxide waste water.

The invention provides a biochemical pretreatment method of coal chemical industry wastewater, which solves the problems of small biochemical oxygen demand/chemical oxygen demand ratio and poor biodegradability in the coal chemical industry wastewater. The method comprises the following steps: injecting coal chemical industry wastewater into a reaction tank, irradiating the reaction tank under ultraviolet light with the radiation intensity of higher than 0.01W/m<2>, and adding an acidic solution to regulate the pH value of the mixed solution to 3-3.5; adding a ferrous salt solution and an oxydol solution into the reaction tank to react, discharging all the solution into a filter tank, and adding an alkaline solution into the filter tank to regulate the pH value of the mixed solution in the filter tank to 9-10 and generate a ferric precipitate; and filtering out the precipitate in the filter tank to obtain the solution capable of biochemical treatment. The method enhances the biochemical oxygen demand/chemical oxygen demand ratio of the coal chemical industry wastewater, and achieves the goal of enhancing the biodegradability of the coal chemical industry wastewater, so that the quality of the water subjected to biochemical treatment can easily satisfy the discharge standard.

The invention discloses a poison-free quick COD (chemical oxygen demand) detection method. The poison-free quick COD detection method specifically comprises the following steps of 1, preparing regeneration liquid, standard liquid and electrolyte, enabling a main computer to control the action of a pump, and sending a sample, the regeneration liquid, the standard liquid and the electrolyte into a measuring bin by the pump; 2, enabling a working electrode to generate hydroxyl radical in the measuring bin at overvoltage, and enabling the hydroxyl radical to oxidize an organic matter to degrade the electrode potential; 3, producing measuring current in the measuring bin, so as to calculate the COD value through the measuring current. The poison-free quick COD detection method has the advantages that by adopting a poison-free and pollution-free reagent, the secondary pollution is avoided, and the hazard to human body health is avoided; the measuring speed is high, a result can be measured within 3min, the main computer is used for controlling, the automation degree is high, the frequent replacing of reagent is not needed, a detection instrument does not need to be calibrated, and the use cost is reduced; the accuracy of the measuring result obtained by the method is high, the method is suitable for complicated and variable water samples, and the use effect is good.

The invention discloses a method for determination of chemical oxygen demand in water, wherein the method comprises the following steps: a, carrying out acidification treatment of a water sample withhydrochloric acid with the volume concentration of 1-10%, to obtain an acidified water sample; b, taking 20 [mu]L-2.5 mL of the acidified water sample and carrying out high temperature combustion at the temperature of 600-1200 DEG C, taking 20 [mu]L-2.5 mL of the acidified water sample and carrying out low temperature combustion at the temperature of 100-300 DEG C; c, determining the composition and content of gas generated in high temperature combustion and low temperature combustion respectively; and d, calculating the chemical oxygen demand. The method has simple test steps; the reagent amount is low, only needs 40 [mu]L-5 mL and is far lower than 50-120 mL in the traditional test method; and moreover, the test method is green and environmentally friendly and has no need of use of potassium dichromate, potassium permanganate, mercury sulfate, silver sulfate, concentrated sulfuric acid and other reagents which can produce secondary pollution.

A provided method for measuring chemical oxygen demand by using a gaseous molecular absorption spectrum process is characterized in that the chemical oxygen demand of a to-be measured sample is determined according to the residual amount of a strong oxidant after being used to oxidize the to-be measured sample, wherein the residual amount is obtained by employing gas-phase molecular absorption spectroscopy. The finally detected substance of the method is a gaseous substance, the method is completely not influenced by water body color and turbidity, and accordingly, the precision of a measurement result is guaranteed.

The invention belongs to the field of detection equipment and discloses preparation methods and rapid detection device of a nitrite detection electrode and a chemical oxygen demand detection electrode. The nitrite detection electrode, the chemical oxygen demand detection electrode, a reference electrode, a counter electrode, a light source and a stirring paddle are arranged in a sample pool; the nitrite detection electrode and the chemical oxygen demand detection electrode are connected with an electrochemical workstation; the reference electrode, the counter electrode and the electrochemicalworkstation are connected; the light source is connected in series with a direct current power supply; the stirring paddle is driven to operate by a micro motor; the micro motor is connected in serieswith the direct current power supply; the electrochemical workstation is connected with a USB (Universal Serial Bus) driving module in a portable computer; the portable computer further comprises a nitrite analysis module, a chemical oxygen demand analysis module and an alarm system. The device disclosed by the invention is rapid in detection result and high in detection accuracy, can detect nitrite detection content and a chemical oxygen demand of one piece of samples, and can be widely applied to rapid field detection in the food field and the environment field.

The invention provides a treatment method for waste liquid produced by a permanganate titration COD (chemical oxygen demand) online determination instrument. The treatment method for the waste liquid produced by the permanganate titration COD online determination instrument is characterized by comprising the following steps: firstly, preparing a transforming agent solution, wherein concentration of Na2C2O4 in the transforming agent solution is 1-50g/L, concentration of Na2S2O3.5H2O is 0-100g/L, concentration of FeSO4 is 0-27g/L, concentration of FeCl2 is 0-23g/L, concentration of ethyl alcohol is 0-24g/L and concentration of phenol is 0-24g/L; secondly, adding the transforming agent solution into the waste liquid which is produced by the permanganate titration COD online determination instrument, heating, stirring and performing reaction; thirdly, adding alkaline into the waste liquid after the reaction in the step two is finished, stirring and performing reaction, standing after the reaction is finished, separating supernate from sediment, and regulating pH value of the supernate to be 7.0-8.0, so that treated waste liquid is obtained. By adopting the treatment method for the waste liquid produced by the permanganate titration COD online determination instrument, the waste liquid produced by COD online determination by adopting a national standard method can be rapidly and comprehensively treated, and solution which is difficult to store and has high toxicity can be transformed into solid which is easy to store and transport and has low toxicity.

The invention discloses a method for determining a chemical oxygen demand of electrolyzed high chlorine waste water. The method successively comprises the following steps of: collecting a water sample to be detected or a diluted water sample to be detected, and placing the water sample to be detected into a closed vessel, and adjusting the pH value of the sample to be less than 3 by using concentrated sulfuric acid; aerating the water sample, vacuumizing the water sample by using a vacuum pump, ensuring a display pressure value of a pressure meter to be 0.05MPa to 0.07MPa, wherein the aeration flow rate is 1 to 3 L/min, the relationship between an aeration time t and a volume L of the water sample to be detected is as follows: t=L*(0.5 to 1) min/10ml, and maintaining the pH value to be less than 3; and stopping the aeration, taking the water sample as a sample, and analyzing the sample according to the high-chlorine wastewater-determination of chemical oxygen demand-chlorine emendation method (HJ/T-70-2001). The method has the advantages that the chlorine gas generated by hypochlorous acid can be reduced, and low determination result of the chemical oxygen demand (COD) caused by the chlorine gas can be avoided.

The invention provides a determination method for the chemical oxygen demand (COD) of waste water. The determination method includes the steps that step A, a waste water sample and sulfuric acid are mixed in a digestion tube and heated in the open, and chloride ions are volatilized in the form of hydrogen chloride to obtain a water sample with the chloride ion content below 1000mg/L; and Step B, amasking agent, a digesting agent and a catalyst are directly and sequentially added into a mixture of the waste water and the sulfuric acid obtained in step A, and a closed catalytic digestion methodis used for determining the COD. The sample of the method avoids the problem that the COD in the diluted sample is less than the method detection limit and cannot be determined due to the dilution ina traditional method.

The invention belongs to the technical field of ground engineering of oil and gas fields and in particular relates to a process for removing refractory CODs (chemical oxygen demands) in produced waterof a high-sulfur-content gas field. Aiming at situations that refractory COD components in produced water of a high-sulfur-content gas field and CODs in fed water after pretreatment are generally 1000mg/L and are refractory CODs, and to achieve resource recycling of the produced water of the high-sulfur-content gas field, the invention discloses the process applicable to removal of refractory CODs in produced water of the high-sulfur-content gas field, a treatment process of "Fenton oxidation+ozone ultraviolet photocatalytic oxidation+micro/ultrafiltration membrane+reverse osmosis membrane" is adopted, and organic components such as refractory CODs and volatile phenols in the produced water of the high-sulfur-content gas field can be degraded and removed. In a situation that the CODs of produced water are less than or equal to 1000mg/L, the process is adopted for treatment, and CODs of an effluent after treatment qualification are less than or equal to 50mg/L.

The present invention provides a method for reducing chemical oxygen demand (COD) and colority of sewage plant effluent. The method comprises: adopting high purity oxygen as a gas source to generate high concentration ozone; adopting the high concentration ozone to carry out a high-grade oxidation treatment for the sewage plant effluent to reduce the COD and the colority. The purpose of the present invention is to reduce the colority and the COD of the sewage. In addition, with properly adjusting the effluent flow and the ozone production rate, the effective controls of the COD removal rate and the colority removal rate can be implemented.