CN103468659A - Efficient utilization method of activated sludge - Google Patents

Abstract

The invention discloses a high-efficiency utilization method of activated sludge, comprising the steps of: centrifuging or filtering the activated sludge to remove water in the activated sludge; adding 1-4 times the amount ( w/v) with an extraction solvent containing non-ionic surfactant, after stirring or ultrasonic extraction for 0.5-2 hours, centrifuge or filter to obtain a hydrolase extract; add organic solvents such as ethanol or acetone to the hydrolase extract The concentration is 60%-90%, let stand at 4°C-room temperature for 0.5-1.0 hours, centrifuge, collect the precipitate, and obtain the hydrolase. Through the above method, the present invention can realize resource utilization of activated sludge, reduce environmental pollution, and simultaneously develop a huge amount of natural hydrolytic enzyme resources.

Description

Efficient Utilization Method of Activated Sludge

technical field

The invention relates to the fields of environmental protection and development and utilization of biological resources, in particular to an efficient utilization method of activated sludge.

Background technique

Microbial fermentation is a commonly used sewage treatment method, which decomposes organic waste into CO ₂ and water through the metabolism of microorganisms, and at the same time the microorganisms themselves multiply and grow in large numbers. The sewage treatment process is specifically that microorganisms secrete various extracellular hydrolytic enzymes to hydrolyze macromolecular organic matter into small molecular substances, and small molecular substances can be absorbed and metabolized by microorganisms, so as to achieve the purpose of sewage purification.

During the sewage treatment process, the sewage treatment plant must regularly discharge a large amount of microbial cells, which is called activated sludge or residual activated sludge. With the development of urbanization, urban industrialization and the growth of urban population, the amount of sewage and activated sludge is increasing rapidly, such as activated sludge at a rate of about 10% per year. Activated sludge is mainly composed of bacteria, viruses, fungi, algae, protozoa and the residues of the dead organisms. It is highly cohesive, compressible and rotten, and it is very difficult to deal with. The cost of activated sludge treatment in sewage treatment plants accounts for about 40% of the total investment and operating costs of sewage plants, and activated sludge has become a new source of pollution.

The existing activated sludge treatment methods mainly include direct or fermented fertilizer for crops, landfill or landfill after drying, incineration and throwing into the sea. The advantages and disadvantages of each method are as follows:

Activated sludge contains a large amount of organic nitrogen and rich inorganic salts. It is a good organic fertilizer. However, activated sludge often contains pathogenic bacteria, harmful insect eggs, heavy metals and toxic substances, so it should not be used as fertilizer for farmland. Moreover, the water content of activated sludge is about 80%, and it needs to be dehydrated and concentrated before being applied to the field. During the dehydration process, a large amount of flocculant needs to be added, but the flocculant will cause many adverse effects such as land compaction.

The landfill method is a large project, consumes a lot of land, and is easy to pollute the surrounding environment and groundwater sources.

The incineration method has high investment and operating costs, high energy consumption, and harmful substances such as sulfur dioxide and dioxin are produced during combustion.

The method of throwing into the sea is easy to pollute the seawater, and the throwing of industrial waste and sewage sludge into the sea has been banned internationally.

In addition, for the treatment of activated sludge, a variety of pyrolysis technologies have been developed, such as low-temperature or pressure pyrolysis oil production, microwave high-pressure thermochemical conversion and other technologies. Under the action of catalysts, the organic matter in the sludge is thermally decomposed and converted into Gas, fuel oil and tar, etc., but the pyrolysis technology in the research stage still has problems such as product quality or production cost. In general, none of the current activated sludge treatment methods can effectively solve the treatment of activated sludge.

Contents of the invention

The technical problem mainly solved by the invention is to provide an efficient utilization method of activated sludge, which can prepare hydrolytic enzymes from activated sludge, realize resource utilization of activated sludge, and reduce environmental pollution.

In order to solve the above-mentioned technical problems, a technical scheme adopted by the present invention is: provide a kind of high-efficiency utilization method of activated sludge, comprising the steps of: centrifuging or filtering the activated sludge to remove the moisture in the activated sludge; Add 1-4 times the amount (w/v) of non-ionic surfactant-containing extraction solvent to the activated sludge, stir or ultrasonically extract for 0.5-2 hours, centrifuge or filter to obtain the hydrolytic enzyme extract; Add organic solvents such as ethanol or acetone to the extract to a concentration of 60%-90%, let stand at 4°C-room temperature for 0.5-1.0 hours, then centrifuge, collect the precipitate, and obtain hydrolytic enzymes to realize resource utilization of activated sludge .

Wherein, after obtaining the hydrolase extract, the hydrolase extract can also be membrane-concentrated to precipitate the hydrolase.

Wherein, the obtained hydrolase is dried or dissolved to make powder hydrolase preparation or liquid hydrolase preparation. The drying method is freeze drying, vacuum drying or spray drying.

The nonionic surfactant in the extraction solvent of the present invention is 0.5%-2% TritonX-100.

The invention can recycle the organic solvent, specifically after obtaining the hydrolytic enzyme precipitation, carry out vacuum distillation on the centrifuged supernatant to recover the organic solvent therein.

The beneficial effects of the present invention are: different from the existing activated sludge treatment technology, the present invention uses activated sludge as a resource utilization method, and can extract hydrolytic enzymes from activated sludge, specifically dehydrating activated sludge first , adding an extraction solvent containing a non-ionic surfactant to the dehydrated activated sludge, stirring or ultrasonically extracting, centrifuging or filtering to obtain a hydrolytic enzyme extract, then adding an organic solvent to the hydrolytic enzyme extract, and statically Centrifuge after placing to obtain hydrolytic enzyme precipitate. Through the above method, the present invention can realize resource utilization of activated sludge, reduce environmental pollution, and simultaneously develop a huge amount of natural hydrolytic enzyme resources.

Description of drawings

Fig. 1 is a schematic flow sheet of an embodiment of the activated sludge treatment method of the present invention;

Fig. 2 is the activity analysis of protease in the hydrolase of different concentration organic solvent precipitation in the embodiment shown in Fig. 1;

Fig. 3 is the activity analysis of esterase in the hydrolase of different concentration organic solvent precipitation in the embodiment shown in Fig. 1;

Figure 4 is an analysis of protease activity in different biological materials.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

Example 1

Please refer to Fig. 1. Fig. 1 is a schematic flow chart of an embodiment of the activated sludge utilization method of the present invention. As shown in Fig. 1, the utilization method of the activated sludge is to extract the hydrolytic enzyme therein to realize the resource utilization of the activated sludge. Before the hydrolytic enzyme is extracted from the activated sludge, it is dehydrated by centrifugation or filtration. Then, add 1-4 times the amount (w/v) of extraction solvent to the dehydrated activated sludge, stir or ultrasonically extract for 0.5-2 hours, centrifuge or filter to obtain a hydrolytic enzyme extract.

Wherein, the extraction solvent contains a nonionic surfactant. In this embodiment, the extraction solvent is an aqueous solution containing 0.5%-2% Triton X-100.

Add organic solvents such as ethanol or acetone to the hydrolytic enzyme extract to a concentration of 60%-90%, leave it at room temperature or on ice for 0.5-1.0 hours and then centrifuge to obtain hydrolytic enzyme precipitates.

In other embodiments, ammonium sulfate can be used to precipitate the hydrolase.

In other embodiments, the hydrolytic enzyme extract can be concentrated by membrane first, and then precipitated.

The precipitated hydrolase can be dried to obtain a powder hydrolase preparation; or dissolved to obtain a liquid hydrolase preparation.

Wherein, the drying method may be freeze drying, vacuum drying or spray drying.

In this embodiment, the centrifuged supernatant can also be distilled under reduced pressure to recover the organic solvent therein.

Wherein, under the condition that the temperature is not limited, the operation of this embodiment is usually carried out at 4° C. to room temperature.

In this example, the obtained hydrolase activity was tested.

As shown in Figure 2, Fig. 2 is the activity analysis of protease in the hydrolase of different concentration organic solvent precipitation in the embodiment shown in Fig. 1, and wherein, 1 is the protease activity of activated sludge hydrolase extraction solution, and 2-8 is different Protease activity obtained by ethanol precipitation of hydrolytic enzyme extracts. The analysis method adopts neutral casein hydrolysis method and polyacrylamide electrophoresis gel autographic method containing 0.1%-0.5% gelatin to measure protease activity.

Fig. 3 is the activity analysis of esterase in the hydrolase of different concentration organic solvent precipitation in the embodiment shown in Fig. 1, as shown in Figure 3, 1-6 is the esterase activity of different concentration organic solvent precipitation, 7-10 is as contrast , is the esterase activity in peanuts precipitated with different concentrations of organic solvents. The analysis method adopts p-nitrophenol method and Fast Blue RR salt-stained polyacrylamide electrophoresis gel autographic method to determine esterase activity.

Fig. 4 is the activity analysis of protease in different biological materials, as shown in Fig. 4, 8 is protease activity in activated sludge, 10 is protease activity in papaya.

Example 2

Add 400ml of extraction solvent to 100g of activated sludge from a sewage treatment plant, stir and extract for 1 hour, and centrifuge to obtain a hydrolytic enzyme extract. Add acetone to the hydrolytic enzyme extract until the final concentration of acetone is 80%, put it in a refrigerator at 4°C for 1 hour, centrifuge to obtain a hydrolytic enzyme precipitate, and obtain a liquid hydrolytic enzyme preparation after the precipitate dissolves, or obtain a high-activity hydrolytic enzyme after freeze-drying Preparation powder.

The protease activity of the liquid and powder hydrolytic enzyme preparations prepared by separation was determined by casein hydrolysis and polyacrylamide electrophoresis gel autography containing 0.1% gelatin, and the polypropylene was stained by p-nitrophenol method and fast blue RR salt The esterase activity was measured by amide electrophoresis gel autographic method, and the extraction and recovery rates of protease and esterase were high.

Using the above method to extract and prepare the enzyme preparation, 30,000 enzyme activity units of neutral protease and 38.2 enzyme activity units of esterase can be obtained per kilogram of activated sludge. Or 13 grams of powdered enzyme preparation can be prepared per kilogram of activated sludge, containing 800 enzyme activity units of neutral protease and 11.6 enzyme activity units of esterase in each gram of enzyme powder. Or every gram of protein contains 6800 enzyme activity units of neutral protease and 94 enzyme activity units of esterase.

In summary, the activated sludge utilization method of the present invention can turn the activated sludge discharged from the sewage treatment plant into treasure, fundamentally solve the environmental hazards caused by the sludge, and also develop a huge amount of natural hydrolysis Enzyme resources have good economic and social benefits. The advantages of this method are as follows:

A. It is the first time to use activated sludge to extract and prepare high activity hydrolytic enzyme preparation.

B. The protease activity extracted and prepared from activated sludge is higher than the protease activity extracted from papaya, a commonly used plant material. Activated sludge is a high-quality resource for the preparation of hydrolytic enzymes such as high-activity proteases, which contain a large number of hydrolytic enzymes that degrade macromolecular organic substances such as proteins, polysaccharides, and oils.

C. The method for extracting hydrolytic enzymes from activated sludge of the present invention has less investment in equipment, simple operation, low production cost, and is convenient for large-scale production.

D. The invention makes efficient use of activated sludge, turns waste into treasure, fundamentally solves the environmental hazards caused by activated sludge discharged from sewage treatment plants, and has huge economic and social benefits.

E. The organic solvent used to precipitate the hydrolytic enzyme can be completely recycled and reused, and the production process is safe and environmentally friendly, and no pollutants are produced.

The above is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in other related technologies fields, all of which are equally included in the scope of patent protection of the present invention.

Claims (6)

1. An active sludge efficiently utilize method, it is characterized in that, comprise the following steps:

   Active sludge is carried out to centrifugal or filtration treatment to remove the moisture in active sludge;

   In active sludge after dehydration, add 1-4 doubly measure (w/v) containing the extraction solvent of nonionic surface active agent, stir or after ultrasonic extraction 0.5-2 hour, centrifugal or filter to obtain the lytic enzyme extracting solution;

   Adding ethanol or acetone and other organic solvent to its concentration in the lytic enzyme extracting solution is 60%-90%, centrifugal after the standing 0.5-1.0 of 4 ℃-room temperature hour, gets its precipitation, obtains lytic enzyme, realizes the recycling treatment of active sludge.
2. 2. method according to claim 1, is characterized in that, after the step of described acquisition lytic enzyme extracting solution, the lytic enzyme extracting solution carried out to membrane concentration.
3. 3. according to claim 1, the described method of 2 any one, it is characterized in that, after the step of described acquisition lytic enzyme, described lytic enzyme is carried out to drying or dissolving, to make powder lytic enzyme preparation or liquid hydrolysis zymin.
4. 4. method according to claim 3, is characterized in that, the drying mode of described lytic enzyme is lyophilize, vacuum-drying or spraying drying.
5. 5. method according to claim 4, is characterized in that, the Triton X-100 that the nonionic surface active agent in described extraction solvent is 0.5%-2%.
6. 6. method according to claim 5, is characterized in that, after described acquisition lytic enzyme step, described supernatant liquor after centrifugal carried out to underpressure distillation to reclaim organic solvent wherein.

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