CN110436749A - The method of accelerating the settling speed of activated sludge by using magnetized micron ferroferric oxide - Google Patents

Abstract

The invention discloses a method for accelerating the settling speed of activated sludge by using magnetized micron ferroferric oxide. The SBR reactor is set up to treat sewage and the sludge is inoculated in the SBR reactor, and then the sludge is continuously acclimated by artificial water distribution. Add magnetized micron ferric oxide and mix thoroughly with the sludge. Through comparative analysis of sedimentation experiments, under the condition that the initial sludge concentration is basically the same, the sedimentation speed of magnetized sludge is faster than that of ordinary sludge, and the SV of magnetized sludge is also smaller than that of ordinary sludge. The sedimentation rate of magnetized sludge with different dosage of magnetic powder is also different. With the increase of magnetic powder dosage, the sedimentation speed of magnetized sludge increases, but the final sedimentation speed and SV are basically the same. The method for accelerating the settling speed of activated sludge by using magnetized micron ferroferric oxide used in the present invention greatly improves the ability of magnetized sludge to treat pollutants in sewage, improves the flocculation ability of sludge, and achieves the purpose of rapid settling.

Description

The method of accelerating the settling speed of activated sludge by using magnetized micron ferroferric oxide

technical field

The invention belongs to the technical field of inorganic materials and water treatment, and in particular relates to a method for accelerating the settling speed of activated sludge by using magnetized micron iron ferric oxide. The method utilizes the magnetized sludge formed by the combination of magnetized micron ferroferric oxide and activated sludge to accelerate its settling and shorten the settling time, so as to achieve an ideal dephosphorization effect.

Background technique

Activated sludge method is a sewage biological treatment method with activated sludge as the main body. Among them, the sludge floc is composed of filamentous bacteria, and the bacteria gelatinous group, other bacteria and other microorganisms and other fine particle impurities are attached to the skeleton, and after a long period of growth and reproduction, a compact floc is formed. If the cohesion and settling properties of the flocs deteriorate due to environmental changes, the sludge will not be able to sink, and the mud and water will be difficult to separate. In severe cases, the activated sludge will expand.

A typical activated sludge process is composed of an aeration tank, a sedimentation tank, a sludge return system and an excess sludge removal system. The mixed solution after activated sludge purification enters the secondary sedimentation tank, where the suspended activated sludge and other solid substances in the mixed solution settle down and separate from the water, and the clarified sewage is discharged from the system as treated water. According to the principle of aerobic phosphorus absorption and anaerobic phosphorus release, the phosphorus in the sludge may be released during the static sedimentation process of the sludge in the secondary sedimentation tank. After the sludge sedimentation process reaches a certain period of time, the phosphorus in the effluent will exceed the standard

With the development of science and technology, some domestic and foreign scholars have realized that the magnetic field can be used to change the physical and chemical properties of water and promote the degradation of pollutants. However, the problems of slow sludge settling speed and poor dewatering performance cannot be solved.

Contents of the invention

The purpose of the present invention is to provide a method for accelerating the settling speed of activated sludge by using magnetized micron ferroferric oxide.

The idea of the present invention: under the premise that the magnetized sludge meets the removal rates of COD and ammonia nitrogen reaching more than 80% and 70% respectively, add the magnetized micron iron tetroxide, fully mix with the sludge for one week, and magnetic powder The surface of the particles is positively charged, while the activated sludge is negatively charged. The activated sludge can be destabilized under the action of the magnetic powder compression double layer, thereby improving the flocculation ability of the sludge and achieving the purpose of rapid settlement.

The specific steps are:

(1) Set up an SBR reactor with a diameter of 20 cm, a height of 50 cm, and a total volume of 10 L; 3 equidistant water outlets are set on the side wall of the SBR reactor, and a sludge discharge port is set at the bottom of the SBR reactor , the SBR reactor uses the bottom blast aeration method, specifically: place two microporous aeration heads at the bottom of the SBR reactor, connect them to the air pump, and use a rotameter to adjust the aeration rate, thereby controlling the DO concentration; A four-blade agitator is set inside the SBR reactor, and the agitation method is used in the anaerobic stage to fully mix the activated sludge for reaction without aeration.

(2) Domesticate the sludge with the help of the SBR reactor set in (1), adopt the operation mode of intermittent water intake and intermittent drainage, and directly use the one-time water injection method to enter the water, according to the water intake-aeration-stirring-sedimentation-drainage - Idle working conditions; the start-up period is set to 8 hours, respectively: 6 hours of aeration, 1 hour of sedimentation and 1 hour of idle water, 3 cycles per day, each discharge is half of the reaction solution, from The water outlet of the SBR reactor is discharged, take the required fine particle sludge, discard the upper layer impurities and the lower layer larger matter, then put the microporous aeration head into the sludge, and turn on the air pump to aerate the sludge 1 ~2 days, after the stuffy exposure, let stand for 2 hours to make all the sludge settle, then discharge the supernatant, inoculate the sludge in the SBR reactor, and then use artificial water distribution to continuously domesticate the sludge to maintain the SBR reaction The MLSS of the sludge in the tank is 3000~4000mg/L. Under the condition of influent COD of 400±1 mg/L and ammonia nitrogen of 40±0.1mg/L, the removal rate of COD and ammonia nitrogen reaches 80% and 80% respectively. More than 70%, so far the domestication of sludge is over.

(3) After acclimating the sludge, take the sludge mixed solution from the SBR reactor described in (1) and put it into the container, and add magnetized micron iron tetroxide to it, and fully mix with the sludge mixed solution After mixing for one week, the rapid sedimentation of activated sludge can be realized.

The artificial water distribution preparation method is as follows: C ₆ H ₁₂ O ₆ is used as a carbon source, ammonium chloride is used as a nitrogen source, and potassium dihydrogen phosphate is used as a phosphorus source, and the mass ratio of carbon source: nitrogen source: phosphorus source is 100:5: 1 for preparation, and adding trace elements manganese sulfate and calcium chloride, utilizing sodium bicarbonate to regulate the pH of artificially distributed water.

The advantage of the inventive method:

In the magnetized activated sludge used in the method of the present invention, the spherical bacteria on the surface of the magnetized sludge are obviously more than the spherical bacteria on the surface of ordinary sludge, and the flocculation ability of the sludge is improved on the basis of greatly improving the ability of the magnetized sludge to treat pollutants. To achieve the purpose of rapid settlement.

Description of drawings

Fig. 1 is a schematic structural diagram of the device used in the embodiment of the present invention.

Marks in the figure: 1- agitator; 2- aerator; 3- mud outlet; 4- water outlet; 5- air pump.

Fig. 2 is a graph showing the variation of sludge volume with settling time in the embodiment of the present invention.

Fig. 3 is a graph showing the variation of sludge layer height with settling time in the embodiment of the present invention.

Detailed ways

Example:

The activated sludge used in this example is taken from the activated sludge in the aeration tank of a certain sewage treatment plant in Guilin City. The screened sludge is continuously domesticated, and the MLSS of the sludge in the reactor is kept at 3000-4000 mg/L. The appearance and physical properties of activated sludge are as follows: the color is dark brown, and some earthy smell can be felt in the sense of smell.

The physical and chemical properties of the above-mentioned artificial water distribution are shown in Table 1.

Table 1 Water quality indicators of simulated urban sewage

(1) Set up an SBR reactor with a diameter of 20 cm, a height of 50 cm, and a total volume of 10 L. Three equidistant water outlets are set on the side wall of the SBR reactor. A sludge outlet is set at the bottom of the SBR reactor. The SBR reactor uses the bottom blast aeration method, specifically: place two microporous aeration heads at the bottom of the SBR reactor, connect them to the air pump, and use a rotameter to adjust the aeration rate to control the DO concentration. A four-blade agitator is set inside the SBR reactor, and the agitation method is used in the anaerobic stage to fully mix the activated sludge for reaction without aeration.

(2) process sewage by means of the SBR reactor that step (1) sets (fully mix sewage and activated sludge by agitator 1, open air pump 5 and aerator 2 simultaneously, adopt rotameter to adjust aeration rate. Test process Measure the concentration change of each pollutant in the effluent water every day), adjust the operating parameters, adopt the operation mode of intermittent water intake and intermittent drainage, and directly use the one-time water injection method to enter the water, according to the water intake-aeration-stirring-sedimentation -Drain-idle operation. The operation period of the start-up phase is set to 8 hours, which are: aeration for 6 hours, sedimentation for 1 hour and effluent idle for 1 hour, and 3 cycles per day. Each water discharge is half of the reaction liquid, and is discharged from the water outlet 4 of the SBR reactor.

(3) Take 5 parts of 1.5 L sludge mixture from the SBR reactor described in (2) into 5 containers, and add 0, 0.2, 0.5, 0.7 and 1 g/L of magnetized micron Fe3O4, fully mixed with sludge for one week. Take 500mL ordinary sludge and magnetized sludge into a 500mL graduated cylinder (diameter 5 cm, height 25.5 cm), and compare the sedimentation process of ordinary sludge and magnetic sludge respectively. Since the sludge descended faster during the free sedimentation and flocculation sedimentation in the first 15 minutes, the sludge volume was recorded once every minute. After 15 minutes, the sludge descending speed obviously slows down, and the volume of sludge is recorded every 5 minutes. Organize the data table, take the sludge volume as the ordinate, and take the time as the abscissa, draw the curve of the sludge volume and the height of the sludge layer over time, as shown in Figures 2 and 3, during the entire settling cycle, the magnetized sludge The volume of mud and the height of sludge layer decreased faster than that of ordinary sludge. The results showed that under the condition that the initial sludge concentration was basically the same, the sedimentation speed of magnetized sludge was faster than that of ordinary sludge, and the SV of magnetized sludge was also smaller than that of ordinary sludge. The sedimentation rate of magnetized sludge with different dosage of magnetic powder is also different. With the increase of magnetic powder dosage, the sedimentation speed of magnetized sludge increases, but the final sedimentation speed is the same, and the SV is also basically the same.

Claims (1)

1. a method utilizing magnetized micron ferroferric oxide to accelerate the settling speed of activated sludge, is characterized in that concrete steps are: (1) Set up an SBR reactor with a diameter of 20 cm, a height of 50 cm, and a total volume of 10 L; 3 equidistant water outlets are set on the side wall of the SBR reactor, and a sludge discharge port is set at the bottom of the SBR reactor , the SBR reactor uses the bottom blast aeration method, specifically: place two microporous aeration heads at the bottom of the SBR reactor, connect them to the air pump, and use a rotameter to adjust the aeration rate, thereby controlling the DO concentration; A four-blade agitator is installed inside the SBR reactor, and the agitation method is used in the anaerobic stage to make the activated sludge fully mix and react without aeration; (2) Domesticate the sludge with the help of the SBR reactor set in (1), adopt the operation mode of intermittent water intake and intermittent drainage, and directly use the one-time water injection method to enter the water, according to the water intake-aeration-stirring-sedimentation-drainage - Idle working conditions; the start-up period is set to 8 hours, respectively: 6 hours of aeration, 1 hour of sedimentation and 1 hour of idle water, 3 cycles per day, each discharge is half of the reaction solution, from The water outlet of the SBR reactor is discharged, take the required fine particle sludge, discard the upper layer impurities and the lower layer larger matter, then put the microporous aeration head into the sludge, and turn on the air pump to aerate the sludge 1 ~2 days, after the stuffy exposure, let stand for 2 hours to make all the sludge settle, then discharge the supernatant, inoculate the sludge in the SBR reactor, and then use artificial water distribution to continuously domesticate the sludge to maintain the SBR reaction The MLSS of the sludge in the tank is 3000~4000 mg/L. Under the condition of influent COD of 400±1 mg/L and ammonia nitrogen of 40±0.1mg/L, the removal rate of COD and ammonia nitrogen reaches 80% respectively. and more than 70%, so far the domestication of sludge is over; (3) After acclimating the sludge, take the sludge mixed solution from the SBR reactor described in (1) and put it into the container, and add magnetized micron iron tetroxide to it, and fully mix with the sludge mixed solution After mixing for one week, the rapid sedimentation of activated sludge can be realized; The artificial water distribution preparation method is as follows: C ₆ H ₁₂ O ₆ is used as a carbon source, ammonium chloride is used as a nitrogen source, and potassium dihydrogen phosphate is used as a phosphorus source, and the mass ratio of carbon source: nitrogen source: phosphorus source is 100:5: 1 for preparation, and adding trace elements manganese sulfate and calcium chloride, utilizing sodium bicarbonate to regulate the pH of artificially distributed water.