CN102180574A - Surplus sludge reduction method combining ultrasonic treatment with microfauna ingestion - Google Patents

Abstract

The invention relates to a method for reducing excess sludge in an urban sewage treatment plant, which belongs to the technical field of environmental engineering. The invention utilizes low-energy ultrasonic treatment to reduce the particle size of the sludge to be suitable for micro-animals to feed, and then uses the micro-animals' feeding to reduce the excess sludge. The kind of miniature animal that the present invention adopts is erythema erythematosus and rotifer, in order to improve the density of microfauna to improve the feeding efficiency of microfauna to surplus sludge, adopt the porous elastic carrier (being polyurethane that is suitable for the growth of these two types of microfauna foam material) and maintain a certain concentration of dissolved oxygen. By adopting the method of the invention, the population density of the erythema erythema and the rotifer are increased by 5-6 times, the sludge reduction efficiency is increased by 46.2-60.1%, and the COD removal rate is increased by 23.6-41.5%. Therefore, the method can not only increase the population density of micro-animals, but also benefit the micro-animals to feed and utilize excess sludge and increase the efficiency of excess sludge reduction, and can also improve the purification effect on water quality.

Description

A Method for Reducing Excess Sludge Combining Ultrasonic Treatment and Micro-animal Ingestion

technical field

The invention relates to a method for reducing excess sludge in urban sewage treatment plants, and belongs to the technical field of environmental engineering.

Background technique

With the improvement of urban sewage biological treatment rate and treatment capacity, how to deal with and dispose of the excess sludge produced in the process of sewage biological treatment. The moisture content of excess sludge is generally above 95%, and the organic matter content is 60-70%. It also contains harmful components such as pathogenic bacteria, parasite eggs, viruses and heavy metals. The traditional disposal methods of surplus sludge include landfill and throwing into the sea. The throwing into the sea has been banned by more and more countries due to the serious harm to ocean water quality, and the landfilling method may not only pollute the soil but also cost a lot. Therefore, exploring New methods for cost-effective disposal of excess sludge have received increasing attention.

There are many literatures and patents related to the reduction method of excess sludge. These methods can be roughly divided into two categories, one belongs to physical and chemical methods, and the other belongs to biological or ecological methods. For example, the Chinese patent application numbers are CN200810180021.0, CN200910227265.4, etc., all of which use physical and chemical methods to reduce excess sludge.

The method of using micro-animals to feed on sludge to achieve the purpose of reducing excess sludge is in line with ecological principles, and has the characteristics of low energy consumption and no secondary pollution. However, the effect of this method on excess sludge reduction is restricted by some factors: first, the growth of micro-animals in the excess sludge system is not stable, and the population density is not high; second, the feeding efficiency of micro-animals to sludge related to sludge particle size. Microfauna mainly rely on their mouthparts to feed on sludge, and only sludge with a particle size smaller than its mouthparts can be ingested by microfauna. The current research tends to stabilize the growth of microanimals, that is, to design special microanimal reactors, such as patents CN200310115721.9, CN200610010265.5, etc. If the excess sludge can be pretreated, the utilization efficiency of micro-animals to excess sludge can be improved by reducing its particle size, and at the same time, the growth and reproduction of micro-animals in the excess sludge reduction system can be strengthened, which can effectively improve the residual sludge. Mud reduction efficiency.

Contents of the invention

The purpose of the present invention is to reduce the particle size of the sludge by ultrasonic treatment of the excess sludge, and at the same time add a carrier in the sludge reduction system, while stabilizing the growth of micro-animals and increasing the population density of micro-animals, strengthen the micro-animals The feeding efficiency of sludge is of great significance to reduce the amount of excess sludge discharged in order to achieve a higher sludge reduction efficiency.

The present invention is a method for reducing the amount of excess sludge combined with ultrasonic treatment and micro-animal feeding, which is characterized in that it has the following processes and steps:

a. Treat a certain concentration of excess sludge with ultrasonic waves to reduce the particle size of the sludge to a level suitable for micro-animal feeding; the appropriate concentration of excess sludge is 1-12g/L; the particle size is 5-30μm; The ultrasonic energy density is 0.05~0.1W/ml; the action time is 5~15min;

b. Introduce the above-mentioned treated sludge into the treatment system, inoculate suitable micro-animals in the sludge, and put it into a porous elastic carrier that is conducive to its attachment and growth; at the same time, the concentration of aerated dissolved oxygen in the system Controlled at 2-4mg/L; the micro-animals are Cystia erythematosus and/or Rotifer.

The porous elastic carrier on which the miniature animal attaches and grows is a polyurethane foam material with a pore diameter of 1-2mm.

The sludge is the remaining sludge in the sedimentation tank of the urban sewage treatment plant, or the return sludge.

The micro-animals can also be other flatworms and perifilariae micro-animals.

The advantage of the inventive method is as follows:

The invention is a method for reducing excess sludge in urban sewage treatment plants. Its advantages are: only need to perform ultrasonic treatment on excess sludge, low strength, low energy consumption, and the selected carrier-porous elastic material is generally easy to obtain and low in cost. , good effect, no secondary pollution, can significantly improve the reduction effect of micro-animal feeding on excess sludge and water quality. By using the method of the invention, the sludge reduction efficiency is increased by 46.2-60.1%, and the COD removal rate is increased by 23.6-41.5%. The present invention is also applicable to the use of returning sludge and other micro-animals of worms and rotifers in a sludge reduction system.

Description of drawings

Figure 1 shows the growth of micro-animals in different sludges after ultrasonic treatment at 0.05 W/ml by the method of the present invention.

Figure 2 shows the growth of micro-animals in different sludges after ultrasonic treatment at 0.1 W/ml by the method of the present invention.

Detailed ways

Specific embodiments of the present invention are now described in the following:

Example 1: Treat excess sludge with a sludge concentration of 9710 mg/L and an average particle size of 20.13 μm, an ultrasonic sound energy density of 0.05 W/mL, and an action time of 10 min. After treatment, the residual sludge concentration was reduced to 9510mg/L, and the average particle size was reduced to 8.32μm. In this sludge, add 3ind micro-animal density in every 5mL sludge to inoculate C. erythematosus and rotifer, and add the poroelastic carrier suitable for its attached growth, keep the dissolved oxygen concentration at 2-4mg/L, through During the 25-day contact reaction, the growth of C. erythematosus and rotifer were observed regularly, and the concentration of remaining sludge and the change of sludge COD concentration were measured. The results showed that C. erythematosus and rotifers grew well in the excess sludge treated with ultrasonic treatment and added with carrier, and the population density was significantly higher than that of the control group without ultrasonic treatment and added carrier, which was about 6 times. The excess sludge after ultrasonic treatment can be better ingested and utilized by the erythema erythematosus and rotifers. The sludge reduction effect is significantly improved, and the sludge reduction rate is increased by 60.1%. At the same time, the organic load has not been negatively affected. The COD removal rate increased by 41.5%.

Example 2: To treat excess sludge with a sludge concentration of 8930 mg/L and an average particle size of 21.16 μm, the ultrasonic sound energy density is 0.1 W/mL, and the action time is 10 min. After treatment, the residual sludge concentration was reduced to 8620mg/L, and the average particle size was reduced to 6.17μm. In this sludge with the density of 3ind/5ml to inoculate Cystoma erythematosus and rotifer, and add the porous elastic carrier suitable for its attached growth, keep dissolved oxygen concentration as 2-4mg/L, through 25 days of contact reaction, During the period, the growth of C. erythematosus and rotifer were observed regularly, and the concentration of remaining sludge and the change of sludge COD concentration were measured. The results showed that P. erythematosus and rotifers grew well in the excess sludge treated with ultrasonic treatment and added with carriers, and the population density was significantly higher than that of the control group without ultrasonic treatment and added carriers, which was about 5 times that. The excess sludge after ultrasonic treatment can be better ingested and utilized by the erythema erythematosus and rotifers. The sludge reduction effect is significantly improved, and the sludge reduction rate is increased by 46.2%. At the same time, the organic load has not been negatively affected. COD removal rate increased by 23.6%.

Claims (4)

1. a ultrasonication and the microfauna excess sludge reduction method of ingesting and combining is characterized in that having following process and step:

A. certain density excess sludge is utilized ultrasonication earlier, make the mud granule particle diameter be decreased to the degree that suitable microfauna is ingested; The suitable concn of excess sludge is 1～12g/L; Grain diameter 5～30 μ m ultrasonic energy density are 0.05～0.1W/ml; Be 5～15min action time;

B. above-mentioned treated mud is introduced in the treatment system, the suitable microfauna of inoculation in described mud, and put into and help the poroelasticity carrier that it adheres to and grows; Aeration dissolved oxygen concentration in system is controlled at 2～4mg/L simultaneously; Described microfauna is erythema Piao body worm and/or places rotifer.

2. excess sludge or decrement method that a kind of ultrasonication as claimed in claim 1 and microfauna are ingested and combined is characterized in that described microfauna adheres to and the poroelasticity carrier of growing is a polyurethane foamed material, and its aperture is 1～2mm.

3. excess sludge or decrement method that a kind of ultrasonication as claimed in claim 1 and microfauna are ingested and combined is characterized in that described mud is the excess sludge of municipal sewage plant's settling tank, or returned sluge.

4. excess sludge or decrement method that a kind of ultrasonication as claimed in claim 1 and microfauna are ingested and combined, it is characterized in that described microfauna also can be other coil worm and week silk rotifers microfaunas.

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