Efficient composite sludge reduction biological agent as well as preparation method, use method and application thereof

Abstract

The invention provides an efficient composite sludge reduction biological agent which comprises bacillus coagulans, bacillus altitudinis, bacillus pumilus cellulase and efficient composite COD / NH3-N bacteria, the efficient composite COD / NH3-N bacteria comprise amylolytic bacteria, proteolytic bacteria, plant lactic acid bacteria and nitrifying bacteria, the preservation number of the bacillus coagulans is CGMCC NO.31765, and the preservation number of the bacillus altitudinis is CGMCC NO.31765. The preservation number of the bacillus altitudinis is CGMCC (China General Microbiological Culture Collection Center) NO.29011, and the preservation number of the bacillus pumilus is CGMCC NO.29013. The efficient composite sludge reduction biological agent is directly added into an aeration tank (aerobic tank) in a sludge treatment process, sludge (MLVSS) generated by a system is reduced in the digestion process of organic matters in a biochemical tank, the discharge of residual sludge is reduced, and the sludge age is prolonged.

Description

Technical Field

[0001] The present invention relates to the field of environmental protection technology, and in particular to a highly efficient composite sludge reduction biological agent and a preparation method, a use method and an application thereof. Background Art

[0002] At present, the basic sewage treatment process used by urban sewage treatment plants is the activated sludge method. The generation of residual sludge is inevitable during the sewage treatment and purification process. The activated sludge method is the most widely used sewage biological treatment technology in the world. It has the characteristics of mature technology, diverse processes, strong impact resistance, and stable operation. However, how to deal with residual sludge is a major problem for sewage treatment plants. When the physical or chemical methods currently used to concentrate sludge or reduce sludge production, a large amount of chemical agents and flocculants need to be invested to use machinery to dehydrate the sludge. After the sludge is dehydrated, it needs to be transported, buried or incinerated. There is secondary pollution, high treatment costs, and impacts on the surrounding environment and human health.

[0003] Microorganisms are an important tool for achieving pollutant degradation and resource utilization. Selecting bacteria with specific functions from nature, taming and cultivating them, and then returning them to nature as bio-enhancement can effectively shorten the time that pollution remains undecomposed and achieve resource utilization.

[0004] High-efficiency composite sludge reduction biological agents are separated from environmental samples through primary screening and secondary screening by specific methods, combined with the application and development of microbial technology, and through the screening, combination and cultivation of specific microorganisms, the amount of sludge generated is reduced, the efficiency of sewage treatment is improved, and the dual goals of environmental protection and resource recovery are achieved. With the continuous advancement of technology, the application prospects of sludge reduction bacteria are broad and are expected to play an important role in the field of sewage treatment.

[0005] However, there will be interactions between bacterial communities. How to select bacterial species so that they can establish a mixed competition mechanism through cooperative and antagonistic interactions, form a competitive relationship by competing for shared resources, select those bacterial species that can adapt to specific environmental conditions, and optimize the bacterial community structure to improve the competitiveness of certain bacterial species, so as to inhibit the growth of natural bacteria and slow down the sludge growth rate is itself a technical challenge.

[0006] Therefore, there is an urgent need for an efficient composite sludge reduction biological agent to achieve in-situ sludge reduction technology and effectively solve the problems of large sludge production and high costs in sewage treatment plants and treatment processes. Summary of the invention

[0007] One aspect of the present invention provides a highly efficient composite sludge reduction biological agent, which degrades organic matter, sludge, and aged and dead organisms in water by adding enzymes secreted by special efficient microorganisms in an aerobic tank, thereby degrading and eliminating sludge in water, inhibiting the growth and reproduction of inefficient microorganisms, and thus maintaining high activity and stability of sewage. Another aspect of the present invention provides an application, preparation method and use method of a highly efficient composite sludge reduction biological agent.

[0008] The first aspect of the present invention provides a high-efficiency composite sludge reduction biological preparation, comprising Bacillus coagulans, Bacillus brevis cellulase and high-efficiency composite COD / NH3-N bacteria, wherein the high-efficiency composite COD / NH3-N bacteria include starch-decomposing bacteria, protein-decomposing bacteria, plant lactic acid bacteria and nitrifying bacteria, the preservation number of the Bacillus coagulans is CGMCC NO.31765, the preservation number of the Bacillus brevis is CGMCC NO.29011, and the preservation number of the Bacillus brevis is CGMCC NO.29013.

[0009] For the high-efficiency composite sludge reduction biological agent, preferably, the fermentation broth of the Bacillus coagulans, the fermentation broth of the Bacillus albopictus, the fermentation broth of the Bacillus pumilus and the fermentation broth of the high-efficiency composite COD / NH3-N bacteria are added in a volume ratio of 2:1:1:5.

[0010] The second aspect of the present invention provides an application of the highly efficient composite sludge reduction biological agent for the digestion of excess sludge in sewage treatment and purification processes.

[0011] The third aspect of the present invention provides a method for preparing the highly efficient composite sludge reduction biological agent, comprising the following steps:

[0012] Fermentation and cultivation to obtain fermentation broth of Bacillus coagulans, fermentation broth of Bacillus albopictus, fermentation broth of Bacillus pumilus cellulase and fermentation broth of high-efficiency composite COD / NH3-N bacteria;

[0013] The fermentation broth of Bacillus coagulans, the fermentation broth of Bacillus altaica, the fermentation broth of Bacillus pumilus cellulase and the fermentation broth of high-efficiency composite COD / NH3-N bacteria are mixed in proportion to obtain a sludge reduction composite biological bacterial agent.

[0014] In the method for producing the highly efficient composite sludge reduction biological agent, preferably, the fermentation broth of the Bacillus coagulans, the fermentation broth of the Bacillus albopictus, the fermentation broth of the Bacillus pumilus and the fermentation broth of the highly efficient composite COD / NH3-N bacteria are mixed in a ratio of 2:1:1:5.

[0015] In the method for preparing the highly efficient composite sludge reduction biological preparation, preferably, the conditions for mixing the fermentation broth of Bacillus coagulans, the fermentation broth of Bacillus albopictus, the fermentation broth of Bacillus pumilus cellulase and the fermentation broth of the highly efficient composite COD / NH3-N bacteria are: temperature of 35-45°C, rotation speed of 150-250r / min, and constant temperature culture for 8-12h.

[0016] The fourth aspect of the present invention provides a method for using a high-efficiency composite sludge reduction biological agent for sludge reduction, wherein the high-efficiency composite sludge reduction biological agent in claim 1 or 2 is put into a process for treating sewage by an activated sludge method, and the activated sludge in the biochemical pool degrades organic matter and pollutants in the sewage to eliminate the sludge generated by the sewage treatment process.

[0017] The beneficial effects are:

[0018] 1. The high-efficiency composite sludge reduction biological agent of the present invention can be directly added to the aeration tank (aerobic tank) in the sludge treatment process to reduce the generation of excess sludge during the digestion of organic matter in sewage, and the sludge reduction amount can reach 51%.

[0019] 2. After use, the high-efficiency composite sludge reduction biological agent of the present invention can change the activity state of sludge, reduce and eliminate dead sludge and aged sludge, increase the activity of sludge and extend the sludge age, and increase the sludge age by more than 50%.

[0020] 3. After the use of the high-efficiency composite sludge reduction biological agent of the present invention, the sedimentation performance (SV30) of the sludge is improved, the large particles and bacterial flocs in the activated sludge are more, the structure is tighter, and the sedimentation speed is faster, which is increased by more than 60% compared with before use.

[0021] 4. After the use of the high-efficiency composite sludge reduction biological agent of the present invention, the biological population in the sludge is richer, and in the different physical structure layers and distributions formed by the sludge, different dominant microbial communities have a more suitable living environment, thereby promoting the function of activated sludge.

[0022] 5. After the use of the high-efficiency composite sludge reduction biological agent of the present invention, the activated sludge has a stronger impact ability, and inhibits the massive reproduction and outbreak of filamentous bacteria, thereby improving the effective removal rate of activated sludge.

[0023] The present invention uses microorganisms to treat sludge, utilizes biological lysis technology, and utilizes the technology of strengthening the predation of micro-animals on bacteria by the action of food chain, strengthens the composition and function of microorganisms in activated sludge, promotes the decomposition of organic pollutants and the continuous decomposition of dead microbial cells, greatly reduces the amount of residual sludge generated, reduces the subsequent residual sludge treatment, and realizes the control of the amount of residual sludge generated in sewage treatment plants from the source, and finally reduces the sludge production itself, so that the sludge disposal is transferred from "end treatment" to "source control", which is a green technology for realizing sludge source treatment.

[0024] The microbial enhancement process of the present invention only changes the microbial composition and function of the activated sludge, does not change the process and operating conditions of the sewage treatment plant, has good adaptability, and is the development direction of the residual sludge source reduction technology. Therefore, it is of great significance to the operation of the sewage treatment plant to effectively reduce the sludge production by adding some specific microbial strains. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structure of the test system in Example 4;

[0026] Figure 2 is the variation trend of MLSS in Example 4;

[0027] Figure 3-1 It is a comparison chart of the COD of the inlet and outlet water in Example 4;

[0028] Figure 3-2 This is a comparison chart of the inlet and outlet NH3-N in Example 4;

[0029] Figure 4-1 SV on April 18 in Example 4 30 Comparison chart of

[0030] Figure 4-2 SV on May 6 in Example 4 30 Comparison chart of

[0031] Figure 4-3 SV on May 25 in Example 4 30 Comparison chart of

[0032] Figure 5-1 The biological microscopic examination of barrel No. 1 in Example 4;

[0033] Figure 5-2 The biological microscopic examination of barrel No. 2 in Example 4;

[0034] Figure 6-1 This is a usage status diagram of bucket A and bucket B in Example 5;

[0035] Figure 6-2 It is a top view of the use state of barrel A and barrel B in Example 5;

[0036] Figure 6-3 This is the sludge concentration change curve in Example 5.

[0037] In the figure:

[0038] 1. Water bucket; 2. Aeration device; 3. Sewer pipe; 4. Water inlet pipe. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0040] Bacillus Coagulans is deposited in the China Microbiological Culture Collection Administration, Institute of Microbiology, Chinese Academy of Sciences, with the deposit number CGMCC No.31765 and the deposit date August 27, 2024. The address is: Institute of Microbiology, Chinese Academy of Sciences.

[0041] Bacillus altitudinis is deposited in the China Microbiological Culture Collection, Institute of Microbiology, Chinese Academy of Sciences, with the deposit number CGMCC No.29011 and the deposit date November 14, 2023. The address is: Institute of Microbiology, Chinese Academy of Sciences.

[0042] Bacillus pumilus is deposited in the China Microbiological Culture Collection, Institute of Microbiology, Chinese Academy of Sciences, with the deposit number CGMCC No.29013 and the deposit date November 14, 2023. The address is: Institute of Microbiology, Chinese Academy of Sciences.

[0043] Example 1 Selection of bacterial strains

[0044] In this example, activated sludge from a domestic sewage plant was used to conduct a bacterial sludge digestion test to verify the effects of three bacterial species, Bacillus coagulans ZTSHEM-2401, Bacillus brevis and Bacillus pumilus, in sludge digestion.

[0045] 1. Experimental design

[0046] 1.1. Preparation of test materials

[0047] 1.1.1 Test materials

[0048] The sludge comes from the sludge produced by the belt desludging machine in a sewage treatment plant.

[0049] 1.1.2 Instruments and Equipment

[0050] EHEIM air-1000 aeration pump, flow rate 1000l / h, purchased from JD.com;

[0051] SS-10Z sludge concentration meter (MLSS meter), Japan Kasari KRK Co., Ltd.;

[0052] Hach 40D (DO, PH, ORP, conductivity), D2600 instrument, Hach Water Quality Analysis Instrument (Shanghai) Co., Ltd.;

[0053] 5000ml beaker, 1000ml measuring cylinder, etc., Sanfeng Precision Measuring Instrument (Shanghai) Co., Ltd.;

[0054] Aeration tube and one-to-five air stones (aeration head) were purchased from JD.com.

[0055] 2. Test methods

[0056] Use five 5-liter beakers, numbered 1 to 5, add 500 g of solid wet sludge (80% water content) into each beaker, then add tap water to the 4500 ml mark, add 200 ml each of Bacillus coagulans, Bacillus highlandii, Bacillus brevis, high-efficiency composite COD / NH3-N bacteria and tap water to beakers 1 to 5, and the sludge concentrations in beakers 1 to 5 are measured to be 22000 mg / L, 22100 mg / L, 21800 mg / L, 22600 mg / L and 221000 mg / L, respectively. Then, use air stone aeration to make the dissolved oxygen in beakers 1 to 5 above 2 mg / L. Aerate continuously for one week to detect the sludge concentration in the five beakers, control the liquid level in the five beakers at 4700 ml, and make up the evaporation with tap water.

[0057] 3. Test results

[0058] Through a week of uninterrupted testing, the dissolved oxygen in the beaker was monitored every day and controlled by a valve between 2-4 mg / L. The liquid level was replenished at 4700 ml with tap water every day to compensate for the evaporation of water. After one week, the sludge concentration in the beaker was tested, as shown in Table 1.

[0059] Table 1 Sludge concentration in beaker

[0060] Serial number Before the test One week later Removal rate No. 1 (Bacillus coagulans) 22000mg / L 16700mg / L 29% No. 2 (Bacillus aegypti) 22100mg / L 18200mg / L 22% No. 3 (Bacillus brevis) 21800mg / L 17900mg / L 18% <![CDATA[No. 4 (Efficient Composite COD / NH3-N Bacteria)]]> 22600mg / L 18700mg / L 17% No. 5 (blank control group) 22100mg / L 19000mg / L 14%

[0061] 4. Results and Analysis

[0062] By comparing the No. 1 to No. 5 beaker tests, it was confirmed that the spore-forming agent had a significant impact on the original activated sludge microbial flora, and the addition of Bacillus could digest the sludge in the biochemical system.

[0063] Among them, bacteria No. 1 (Bacillus aeruginosa) has the strongest ability in producing enzymatic hydrolysates to decompose organic matter and dead mud in sludge in water, with a degradation rate of 29%;

[0064] Bacteria No. 2 and No. 3 also had degradation effects relative to the blank group (No. 5);

[0065] No. 4 (high-efficiency composite COD / NH3-N bacteria) has a strong enzymatic reaction to decompose COD and NH3-N in sludge, and also reduces the amount of whole sludge.

[0066] Through the above analysis, since Bacillus coagulans, Bacillus altissima, Bacillus pumilus, and high-efficiency composite COD / NH3-N bacteria are mainly used in the biochemical pool of sewage treatment plants, and the most basic requirement for sewage treatment is to meet water quality standards, the main focus in the formulation determination process is to remove pollutants (COD / NH3-N) in water, and simultaneously eliminate the generation of residual sludge during the treatment process. Therefore, the formula ratio of the high-efficiency composite sludge reduction biological agent is determined as follows: fermentation broth of Bacillus aerogenes: fermentation broth of Bacillus altissima: fermentation broth of Bacillus pumilus: fermentation broth of high-efficiency composite COD / NH3-N bacteria, the volume ratio = 2:1:1:5 is mixed and used as a preferred sludge reduction bacteria for the next round of experimental verification.

[0067] Example 2 Preparation method of high-efficiency composite sludge reduction biological agent

[0068] A method for preparing a highly efficient composite sludge reduction biological agent comprises the following steps:

[0069] Step S1: fermentation culture to obtain fermentation broth of Bacillus coagulans, fermentation broth of Bacillus albopictus, fermentation broth of Bacillus pumilus cellulase and fermentation broth of high-efficiency composite COD / NH3-N bacteria.

[0070] Wherein, step S1 also includes step S11, step S12 and step S13.

[0071] Step S11: Preparation of culture medium.

[0072] The solid culture medium includes 1% soluble starch, 2g / L peptone, 1g / L beef extract, 8g / L molasses, 8g / L cellulose, 0.1g / L ammonium chloride, 0.1g / L sodium sulfate, 15g-20g agar powder, pH 7.4-7.5, and the above culture medium is sterilized at 121°C for 30 minutes in an autoclave, then poured into a plate, cooled and set aside. The solid culture medium is used for the purification, preservation and separation of oligotrophic bacteria.

[0073] The liquid culture medium includes 2% starch, 2g / L peptone, 8g / L molasses, 5g / L beef extract, 0.1g / L sodium chloride, and pH 7.0. After intermittent stirring culture at 38°C and 160r / min for 24h, it is changed to intermittent stirring culture at 37-40°C and 140r / min for 4 days.

[0074] Step S12: Preparation of highly efficient composite sludge reduction biological agent.

[0075] Seed culture: inoculate the slant-preserved Bacillus coagulans strain into liquid culture medium and culture at 38°C and 160 r / min with intermittent stirring for 24 h.

[0076] Fermentation culture: The seeds were inoculated into the fermentation liquid culture medium in three stages, with the inoculation amount of 10% and 1% being gradually expanded. The culture was carried out at a constant temperature of 37-40℃ and a speed of 140r / min with intermittent stirring. The fermentation concentration OD 600 Reaching 0.8-0.9, the fermentation broth of Bacillus coagulans, the fermentation broth of Bacillus albopictus, the fermentation broth of Bacillus pumilus cellulase and the fermentation broth of high-efficiency composite COD / NH3-N bacteria were obtained.

[0077] Step S2: The fermentation broth of Bacillus coagulans, the fermentation broth of Bacillus albus, the fermentation broth of Bacillus pumilus cellulase and the fermentation broth of high-efficiency composite COD / NH3-N bacteria obtained in step S1 are mixed in proportion to obtain a composite biological agent for sludge reduction.

[0078] The fermentation broth of Bacillus coagulans, the fermentation broth of Bacillus altaica, the fermentation broth of Bacillus pumilus cellulase and the fermentation broth of high-efficiency composite COD / NH3-N bacteria are mixed in a volume ratio of 2:1:1:5 and cultured at a constant temperature of 40°C and a rotation speed of 200r / min for 8-12h to obtain a high-efficiency composite sludge reduction biological agent.

[0079] Example 3 Highly efficient composite sludge reduction biological agent

[0080] A highly efficient composite sludge reduction biological agent comprises Bacillus coagulans, Bacillus altitudinis, Bacillus pumilus cellulase and highly efficient composite COD / NH3-N bacteria, wherein the highly efficient composite COD / NH3-N bacteria comprises starch decomposing bacteria, protein decomposing bacteria, plant lactic acid bacteria and nitrifying bacteria.

[0081] in,

[0082] The Bacillus Coagulans is deposited at: China Microbiological Culture Collection Administration, Institute of Microbiology, Chinese Academy of Sciences, with the deposit number CGMCC No.31765, the deposit date is August 27, 2024, and the address is: Institute of Microbiology, Chinese Academy of Sciences.

[0083] The Bacillus altitudinis is deposited at: China Microbiological Culture Collection Administration, Institute of Microbiology, Chinese Academy of Sciences, with the deposit number CGMCC No.29011, the deposit date is November 14, 2023, and the address is: Institute of Microbiology, Chinese Academy of Sciences.

[0084] The Bacillus pumilus is deposited at: China Microbiological Culture Collection Administration, Institute of Microbiology, Chinese Academy of Sciences, with the deposit number CGMCC No.29013, the deposit date is November 14, 2023, and the address is: Institute of Microbiology, Chinese Academy of Sciences.

[0085] High-efficiency composite sludge reduction biological agents screen for microorganisms that can secrete bioactive enzymes such as amylase, protease, and hydrolase during sewage treatment. The mechanism of action is as follows: sludge is mainly composed of biological cell bodies. These single-cell bacteria have a layer of cell membrane on the surface. The main component of the cell membrane is extracellular polymers (EPS), which protect the cell body. 99% of the cells are water. Therefore, through the secretion of extracellular enzymes by microorganisms in high-efficiency composite sludge reduction biological agents, this layer of cell membrane can be hydrolyzed, causing the cells to rupture, dissolve, and metabolize, thereby reducing the generation of sludge. This allows the new cells and dead cells in the system to reach a certain balance, and the sludge concentration to stabilize within a certain range, thereby reducing the discharge of sludge or even stopping the discharge of sludge, thereby achieving the purpose of sludge reduction.

[0086] Example 4 Application of high-efficiency composite sludge reduction biological agent

[0087] A pilot test was conducted at the Capital Airport Wastewater Treatment Plant (domestic sewage treatment plant). Two buckets with an effective volume of 1,000 liters were used as aeration tanks to simulate the SBR state for a sewage treatment sludge reduction test. Finally, the sludge reduction effect of the KO biological agent was determined by measuring the MLSS concentration.

[0088] 1. Experimental design

[0089] 1.1 Preparation of test materials

[0090] 1.1.1 Test materials

[0091] Activated sludge, from the oxidation ditch activated sludge of a sewage treatment plant at the Capital Airport;

[0092] Sewage, from the fine screen effluent of a sewage treatment plant at the Capital Airport;

[0093] The D2600 instrument supporting reagents such as COD, P, ammonia nitrogen, total nitrogen, phosphorus, etc. were purchased from Hach Water Quality Analysis Instruments (Shanghai) Co., Ltd.

[0094] 1.1.2 Instruments and equipment

[0095] 1 HC-30S rotary fan, Zhangqiu Fengyuan Machinery Co., Ltd.;

[0096] 2 sets of TM-1000LIMPIO aeration heads, TMコ-ポレ-ション Co., Ltd.;

[0097] 2 PE1000L buckets, Tianjin Chuangxin Yuanda Plastic Products Co., Ltd.;

[0098] A set of automatic control system (including liquid level controller and time relay);

[0099] SS-10Z sludge concentration meter (MLSS meter), Japan Kasari KRK Co., Ltd.;

[0100] Hach 40D (DO, PH, ORP, conductivity), D2600 instruments, Hach Water Quality Analysis Instruments (Shanghai) Co., Ltd.;

[0101] Olympus BX43 microscope, Olympus Corporation;

[0102] Beaker 500ml, measuring cylinder 1000ml, etc., Mitutoyo Precision Measuring Instruments (Shanghai) Co., Ltd.

[0103] 1.1.3 Experimental plan

[0104] 1) Establish a test system

[0105] like Figure 1As shown, two 1000-liter PE water barrels 1 are used to simulate the SBR process for the sludge reduction test of sewage treatment. An aeration device is installed at the bottom of the barrel, wherein the aeration head of the aeration device is connected to the rotary fan, a submersible pump is installed at the 500-liter position, and the outlet is connected to the sewer pipe 3. The test sewage is taken from the rear end of the fine screen of a sewage plant in Beijing Airport. A submersible pump is installed in the pool at the rear end of the fine screen to connect the water inlet pipeline and enter the two 1000-liter PE barrels respectively. The submersible pump and solenoid valve at the water inlet end are controlled by the PLC program in the control cabinet to realize automatic water inlet. The liquid level controller and PLC program control are installed in the experimental barrels. The control program realizes automatic water inlet, automatic start of the aeration fan, and control of the aeration time by the time relay, start and stop of aeration. After the system sedimentation is completed, the supernatant is discharged through the submersible pump in the barrel. When the supernatant is discharged to the set liquid level, the water inlet submersible pump is started again to inlet water, and a new round of experiments begins in this cycle.

[0106] After 3 days of operation and debugging, the water intake, discharge volume and sludge settling time all met the process design requirements. On April 9, the test group (hereinafter referred to as Bucket 1) added 0.5% of the pool volume of the high-efficiency composite sludge reduction biological agent prepared in Example 3, totaling 5 liters (added in two days), and the other bucket as the control group (hereinafter referred to as Bucket 2) added tap water totaling 5 liters (added in two days).

[0107] The average water quality COD of the fine screen inlet is 450mg / L, the inlet water volume is 500L / cycle, and it is circulated every 12 hours, that is, 1000L / day. The initial sludge concentration (MLSS) is 8000mg / L. No sludge is discharged from barrels 1 and 2 during the test, and the dissolved oxygen DO is controlled at 2-6mg / L at room temperature.

[0108] 2) Experimental process

[0109] like Figure 1 As shown, the same sludge (activated sludge from the secondary sedimentation tank) is added to the two barrels, and the MLSS concentration is adjusted (8000 mg / L) using the MLSS meter. The automatic water inlet and outlet of the automatic control system is turned on, and debugging begins to ensure the accuracy of the time relay. The system sewage treatment time is 12 hours, including 10 hours and 55 minutes of aeration, 1 hour of standing, and 5 minutes of water inlet and outlet.

[0110] 3) Experimental plan

[0111] The test data were recorded on April 10. Every morning at 7:30 and evening at 19:30, the on-duty personnel took the supernatant after precipitation for inspection. Every day at 10:00 and 14:30, the technical personnel tested the two groups of tests, and tested and recorded the MLSS, PH, DO, SV30, temperature data and other data.

[0112] The sludge from the experimental group and the control group was taken regularly for microscopic examination (eyepiece 16 times, objective lens 10 times) to observe the biological phase, mud phase, filamentous fungi, metazoa, protozoa, etc. in the sludge.

[0113] Patrol personnel were arranged every day to inspect the test equipment every 2 hours to ensure the stability of the test process. The sludge reduction effect of the high-efficiency composite sludge reduction biological agent prepared in Example 3 was determined by measuring the MLSS concentration data for 2 months, and the final test conclusion statistics were made.

[0114] 2. Test process

[0115] The test started on March 25, 2024 with the installation of the test equipment, on-site commissioning, sludge inoculation and other preparatory work. 300 kg of system activated sludge with a sludge concentration of about 10,000 mg / L was added to barrels 1 and 2 respectively, and water was added to the 1,000 liter position of the PE barrel. After 2 hours of aeration, the sludge concentration MLSS of barrel 1 was 8,100 mg / L and that of barrel 2 was 7,900 mg / L.

[0116] On April 9, 3 liters of the high-efficiency composite sludge reduction biological agent prepared in Example 3 was added to Bucket 1, with an addition amount of 0.3%, and the high-efficiency composite sludge reduction biological agent prepared in Example 3 was acclimated and cultured; only 3 liters of tap water was added to Bucket 2 of the control group, and both systems were in aeration (i.e., aeration was carried out 24 hours a day).

[0117] On April 10, the automatic control program system was started to run automatically, 500L of water was added to barrels 1 and 2 respectively, 2L of the high-efficiency composite sludge reduction biological agent prepared in Example 3 was added to barrel 1 again, 2L of tap water was added to barrel 2, and the test data began to be recorded.

[0118] On April 11, the system started to stop aeration at 7:00 a.m. every morning according to the scheduled time, and the sludge mixture in the barrel began to settle. At 8:00, the drainage pump started to discharge the supernatant, and at 8:04 the drainage motor was shut down; at 8:05, the water supply valve was opened, the water supply pump started to start water intake, and at the same time, the fan started aeration. After 3 minutes, the liquid level in barrels 1 and 2 reached the set value, and the level meter gave a signal to stop water intake and close the valve. At 19:00 in the afternoon, the aerator stopped working and began to settle. At 20:00, the drainage pump started to discharge the supernatant, and at 20:04 the drainage motor was shut down; at 20:05, the water supply valve was opened, the water supply pump started to start water intake, and at the same time, the fan started aeration. After 3 minutes, the liquid level in barrels 1 and 2 reached the set value, and the level meter gave a signal to stop water intake and close the valve. The water inflow and outflow volume was 500L / cycle each time, and it was operated in this cycle twice a day.

[0119] During the test, sampling personnel, inspection personnel and test technicians ensured the normal operation of the system. Sampling personnel sampled the precipitated supernatant at 7:30 and 19:30 every day and handed it over to the laboratory for testing; technicians tested the operating system and sludge indicators at 10:00 and 14:30 every day. No residual sludge was discharged during the operation of the test device. During the test, the relevant data of barrels 1 and 2 (MLSS, PH, DO, SV30, temperature) were observed, and DO (dissolved oxygen) was controlled. The aeration gas volume was controlled by the discharge valve on the fan, and the DO concentration in the system was controlled at 4mg / L.

[0120] 3. Experimental results and discussion

[0121] 3.1 Changes in sludge concentration (MLss)

[0122] From April 10 to May 31, the water quality and sludge index of the inlet and outlet water were tested. The changes in the sludge concentration (MLSS) in barrels 1 and 2 are shown in Figure 2 At the beginning of the test on April 10, the sludge in barrels 1 and 2 did not change much in the first week. After a week of domestication, cultivation and proliferation, they gradually became dominant bacteria and multiplied rapidly. The growth rate of the excess sludge in barrel 1 slowed down significantly. The spore bacteria in the high-efficiency composite sludge reduction biological agent prepared in Example 3 secreted a large amount of enzymes and began to rapidly decompose the original aged sludge. It showed a downward trend for a month. After one month, this trend slowed down. Compared with the barrel 1 device that added the high-efficiency composite sludge reduction biological agent prepared in Example 3, the growth rate of the excess sludge in the barrel 2 device that did not add the high-efficiency composite sludge reduction biological agent prepared in Example 3 was significantly increased, and the sludge concentration increased rapidly.

[0123] The change in MLSS can be calculated to show that the sludge concentration in barrel 1 was reduced by 51% compared with that in barrel 2. After the test, the sludge level in barrels 1 and 2 increased from the initial 12 cm to 13 cm in barrel 1 and 2 to 20 cm in barrel 2. The total amount of sludge in barrel 1 was reduced by 87.5% compared with that in barrel 2.

[0124] 3.2 Outlet water quality

[0125] During the test, the water quality indicators of the effluent from barrels 1 and 2 all met the Beijing Landmark B standard (except for element P) of the Pollutant Discharge Standard for Urban Wastewater Treatment Plants (DB11 / 890-2012). From April 28 to May 29, we focused on testing the water quality of the effluent from barrel 1 twice a day. The test results are as follows: Figure 3-1 and Figure 3-2 As shown, COD and NH3-N are both below the standard values, complying with the emission standards of Beijing Landmark B.

[0126] 3.3 Sludge settling ratio (SV30)

[0127] like Figure 4-1 , Figure 4-2 and Figure 4-3 As shown in the figure, through the detection of SV30 during the experiment, the SV30 settling ratios in barrels 1 and 2 were both 40% at the beginning. After April 18, the SV30 of barrel 1, which was added with the high-efficiency composite sludge reduction biological agent prepared in Example 3, was 30%, and it was very stable at about 30%-35% in the later period, and the settling speed was also relatively fast. The SV30 of barrel 2 (control group) has been rising since the beginning of the experimental record on April 10. On May 25, the SV30 of barrel 1 was 32%, and the SV30 of barrel 2 was 66%.

[0128] 3.4 Microscopic examination of sludge

[0129] like Figure 5-1 and Figure 5-2 As shown, by observing the types and numbers of microorganisms in the sludge under a microscope, the activity of the sludge and the treatment effect of the activated sludge can be evaluated. The laboratory conducted microscopic analysis of the sludge in barrels 1 and 2. The sludge in barrel 1 was yellow-brown, with large sludge flocs, clear edges, and a tight structure. It precipitated quickly and had good concentration performance. The biological population in the sludge was relatively rich and active. It contained abundant shield ciliates, a large number of bell worms, rough whipworms (protozoa), a small number of sessile organisms and creeping organisms such as coccinella, and no free bacteria. It can be concluded that the activated sludge has a high activity. On the contrary, the sludge in barrel 2 had a loose floc structure, small flocs, and a grayish-white sludge color. There were a small number of live bacterial species under microscopic examination, fewer biological species, and lower activity, more dead sludge, and many coccinella (metazoa) and flagellates with large bodies. There were no protozoa, and the activated sludge was in an aging state.

[0130] 4. Conclusion

[0131] During the verification test of removing sludge by the high-efficiency composite sludge reduction biological agent prepared in Example 3, the test device did not discharge sludge externally, the supernatant was discharged from the activated sludge 1 hour after sedimentation, and then an equal amount of sewage was injected into the system. The sludge concentration changes, sludge settling performance and other data between the experimental group and the control group were compared to demonstrate the role of sludge reduction bacteria in the in-situ degradation of sludge in the aeration tank. At the beginning of the test, the sludge concentration in barrel No. 1 of the experimental group slowly increased for 5 days, and then began to show sludge reduction characteristics. In the later period, the reduction trend tended to be flat. On May 23, the sludge concentration (MLSS) of barrel No. 1 was 6400 mg / L; SV30 was 34%, and the sludge settled rapidly, showing a yellow-brown color. The sludge flocs were large, with clear edges and a tight structure. The sludge was in the later period of the experiment. In barrel No. 2 of the control group, the sludge concentration showed an upward trend since the beginning of the experiment, and the sludge settling rate slowed down. On May 23, the sludge concentration (MLSS) of barrel No. 2 was 13100 mg / L, and SV30 was 63%. The sludge structure was loose, the flocs were small, and the sludge color was grayish white.

[0132] Through the experimental comparison between barrel No. 1 and barrel No. 2, it was confirmed that the high-efficiency composite sludge reduction biological agent prepared in Example 3 had a significant impact on the original activated sludge microbial flora after being added to the sewage treatment system. The addition of the high-efficiency composite sludge reduction biological agent prepared in Example 3 can reduce the discharge of residual sludge in the biochemical system, reduce the amount of activated sludge in the entire sewage treatment system, improve the treatment efficiency and load capacity of the system, and reduce the power consumption and operation cost of the sewage treatment plant; the experiment verified that the amount of sludge generated and the discharge of sludge can be reduced in situ by biodegradation. Compared with the back-end dehydration and drying process, it is more competitive in the market and more environmentally friendly, and truly achieves the goal of efficient utilization and recycling of resources. It takes "reduction, reuse, and resource utilization" as the principle, and is characterized by closed-loop material circulation and cascaded energy use, and operates in accordance with the material circulation and energy flow mode of the natural ecosystem.

[0133] Example 5 Application of high-efficiency composite sludge reduction biological agent

[0134] like Figure 6-1 , Figure 6-2 and Figure 6-3 As shown, a pilot test was conducted at Handan West Wastewater Treatment Plant, where sludge and sewage from the oxidation ditch were taken to simulate the SBR process, with 500 liters of water discharged per day, 250 liters per time, and automatic discharge twice a day.

[0135] The experimental equipment of this embodiment is the same as that in Embodiment 4. The difference from Embodiment 4 is that the sizes of barrels A and B are different from the sizes of barrels 1 and 2.

[0136] The sludge concentration of barrels A and B was about 10000 mg / L, and the high-efficiency composite sludge reduction biological agent prepared in Example 3 was added to barrel B at a dosage of 0.3% for acclimatization and cultivation. No supernatant was discharged during the sludge cultivation process. No excess sludge was discharged during the operation of the test device. During the test, the relevant data of barrels A and B (MLSS, PH, DO, SV30, temperature) were observed, and DO (dissolved oxygen) was controlled. During the aeration treatment process, the DO concentration was controlled at 2-3 mg / L. The high-efficiency composite sludge reduction biological agent prepared in Example 3 was added to the B barrel, and after one week of acclimation, cultivation, and proliferation, it gradually became the dominant bacterial community in the activated sludge microbial flora, and then began to rapidly decompose the original aged sludge. After one week, the growth rate of the excess sludge in the B barrel was significantly slowed down. The dominant bacterial community formed by the high-efficiency composite sludge reduction biological agent prepared in Example 3 in the water formed a dynamic balance between the influent load, which reduced the growth rate of the excess sludge. Compared with the device B barrel to which the high-efficiency composite sludge reduction biological agent prepared in Example 3 was added, the growth rate of the excess sludge in the A barrel device without adding the high-efficiency composite sludge reduction biological agent prepared in Example 3 was significantly increased, and the sludge concentration increased rapidly. After one month, the sludge reduction in the device B barrel to which the high-efficiency composite sludge reduction biological agent prepared in Example 3 was added was 61.6%.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A highly efficient composite sludge reduction biological agent, characterized in that: The invention comprises Bacillus coagulans, Bacillus altissima, Bacillus pumilus cellulase and high-efficiency composite COD / NH3-N bacteria, wherein the high-efficiency composite COD / NH3-N bacteria comprises starch-decomposing bacteria, protein-decomposing bacteria, plant lactic acid bacteria and nitrifying bacteria. The deposit number of the Bacillus coagulans is CGMCC NO.31765, the deposit number of the Bacillus altissima is CGMCC NO.29011, and the deposit number of the Bacillus pumilus is CGMCC NO.29013.

2. The highly efficient composite sludge reduction biological agent according to claim 1, characterized in that: The added volume ratio of the fermentation liquid of Bacillus coagulans, the fermentation liquid of Bacillus albopictus, the fermentation liquid of Bacillus pumilus and the fermentation liquid of the high-efficiency composite COD / NH3-N bacteria is 2:1:1:

5.

3. An application of the highly efficient composite sludge reduction biological agent according to claim 1 or 2, characterized in that: Used for digestion of residual sludge in sewage treatment and purification process.

4. A method for preparing the highly efficient composite sludge reduction biological agent of claim 1 or 2, characterized in that: The steps include: Fermentation and cultivation to obtain fermentation broth of Bacillus coagulans, fermentation broth of Bacillus albopictus, fermentation broth of Bacillus pumilus cellulase and fermentation broth of high-efficiency composite COD / NH3-N bacteria; The fermentation broth of Bacillus coagulans, the fermentation broth of Bacillus altaica, the fermentation broth of Bacillus pumilus cellulase and the fermentation broth of high-efficiency composite COD / NH3-N bacteria are mixed in proportion to obtain a sludge reduction composite biological bacterial agent.

5. The method of preparing a highly efficient composite sludge reduction biological agent according to claim 4, characterized in that: The mixing ratio of the fermentation liquid of Bacillus coagulans, the fermentation liquid of Bacillus albopictus, the fermentation liquid of Bacillus pumilus and the fermentation liquid of the high-efficiency composite COD / NH3-N bacteria is 2:1:1:

5.

6. The method of producing a highly efficient composite sludge reduction biological agent according to claim 5, characterized in that: The conditions for mixing the fermentation broth of Bacillus coagulans, the fermentation broth of Bacillus altissima, the fermentation broth of Bacillus pumilus cellulase and the fermentation broth of the high-efficiency composite COD / NH3-N bacteria are: temperature of 35-45°C, rotation speed of 150-250r / min, and constant temperature culture for 8-12h.

7. A method for using a highly efficient composite sludge reduction biological agent for sludge reduction, characterized in that: The high-efficiency composite sludge reduction biological agent in claim 1 or 2 is put into a process of treating sewage by an activated sludge method, and the activated sludge in the biochemical pool degrades organic matter and pollutants in the sewage to eliminate the sludge generated by the sewage treatment process.

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