Filler for unpowered sand bioreactor and its application

Abstract

The present invention discloses a filler for an unpowered sand bioreactor and an application thereof. One cubic meter of the filler for the unpowered sand bioreactor comprises: 100-300g of a nitrifying bacterial agent, 90-200g of a denitrifying bacterial agent, and the balance is sand; the sand is composed of coarse sand and fine yarn, and the volume ratio of the coarse sand to the fine sand is (17-21):31; the filler of the present invention is specially invented for an unpowered sand bioreactor used for treating rural domestic wastewater and upgrading the tail water of a sewage treatment plant. The filler can enable the unpowered sand bioreactor to be quickly started after construction and achieve the designed treatment effect in a short time. Specifically, by adopting a method of simultaneously carrying out nitrification and denitrification and utilizing the synergistic effect between bacterial species, in particular, by using a preferred commercial bacterial agent, a microbial film is quickly formed on the surface of the sand, thereby enabling the sewage treatment equipment to be quickly started, and effectively solving the problems of poor bacterial species, a large number of miscellaneous bacteria, and slow startup of naturally enriched microorganisms.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, in particular to a filler for an unpowered sand bioreactor and application thereof. Background Art

[0002] Unpowered sand bioreactors are very economical, practical, and effective equipment for treating rural domestic sewage and upgrading wastewater treatment plant tailwater. They use sand with a very large specific surface area to enrich and domesticate microbial flora and enzymes that are beneficial for denitrification and phosphorus removal, as well as digestion of oil and fat in domestic wastewater. This decomposes and digests various pollutants in domestic wastewater, achieving excellent treatment results. However, the microbial flora in unpowered sand bioreactors is currently naturally enriched, which presents the following major problems:

[0003] First, the newly built sand bioreactor lacks microorganisms that can decompose and digest various pollutants in domestic wastewater. It takes a long time for the environment in the sand bioreactor to reach the level required for microorganisms to efficiently digest various pollutants in sewage through natural and slow enrichment. Usually, it takes 15-30 days in the summer and more than a month or even longer in the winter for a sand bioreactor to be put into normal operation. After the sand bioreactor is built and put into use, domestic wastewater will be continuously discharged every day. Therefore, in the early stage of the construction of the sand bioreactor, due to the lack of the required microbial flora, the decomposition and digestion effect cannot be achieved;

[0004] Second, the composition of domestic wastewater is complex. The composition of kitchen wastewater and washing wastewater is different. Kitchen wastewater usually contains a lot of grease, food waste, food residues, kitchen wastewater, etc. Its main components are fat, carbohydrates, etc.; washing wastewater is composed of laundry wastewater and bathing wastewater, and various detergents contain high phosphorus. Domestic wastewater has different types in different occasions. Domestic wastewater in restaurants, farmhouses and other places is mainly kitchen wastewater, while in rural hotels and other places it is mainly washing wastewater. In farmers' households, there are both kitchen wastewater and washing wastewater. Different microbial flora are needed to treat domestic wastewater in different scenarios. Therefore, it is necessary to formulate it according to local conditions;

[0005] Third, naturally enriched microorganisms are not necessarily the most dominant flora and cannot fully meet the microbial flora needs for decomposing and digesting domestic wastewater;

[0006] Fourth, there is a shortage of technical personnel in rural areas, and the fillers of sand bioreactors are very arbitrary. In addition, the combination, enrichment and addition technology of complex microbial flora are difficult to popularize, and they need to be pre-prepared for different types of domestic wastewater.

[0007] Fifth, there is a lack of pre-mixed starter fillers for unpowered sand bioreactors suitable for rural areas. Patent application number 201310597290.8, filed by Li Jincheng, Shi Qin, Mo Deqing, Li Wenwen, and Shen Yuxiang of Guilin University of Technology, describes a bio-activated sand reactor. However, its complex structure requires activated carbon as filler in addition to sand, and it consumes electricity. This makes it suitable for treating urban domestic sewage, making it difficult to promote in rural areas. Currently, most power-hungry, complex domestic sewage treatment facilities in rural areas have been decommissioned.

[0008] Sixth, the Ministry of Ecology and Environment recently issued the "Guiding Opinions on Further Promoting Rural Domestic Wastewater Treatment," which mandates timely optimization and adjustment of technical routes for inappropriate technologies (e.g., overly complex processes, excessive operating costs, and incompatibility with rural realities). Currently, many energy-intensive wastewater treatment plants in rural areas are out of service, primarily due to overly complex processes, high electricity and maintenance costs, and incompatibility with rural realities. Furthermore, the wastewater treatment process generates new carbon emissions.

[0009] Therefore, the activated sand bioreactor with pre-mixed microbial agents is a practical technology with low carbon, low operating cost and sustainable operation.

[0010] In view of this, the present invention is proposed. Summary of the Invention

[0011] The purpose of the present invention is to provide a filler for an unpowered sand bioreactor and its application. The filler for the unpowered sand bioreactor of the present invention can quickly start the unpowered sand bioreactor after it is built by introducing microbial agents, and achieve the designed treatment effect in a short time.

[0012] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted:

[0013] A first aspect of the present invention provides a filler for an unpowered sand bioreactor, wherein 1 cubic meter of the filler for the unpowered sand bioreactor comprises:

[0014] 100-300g of nitrifying bacteria agent, 90-200g of denitrifying bacteria agent, and the balance is sand;

[0015] The sand consists of coarse sand and fine yarn, and the volume ratio of the coarse sand to the fine sand is (17-21):31.

[0016] Preferably, 1 cubic meter of the filler for the unpowered sand bioreactor further includes 50 to 300 g of a functional bacterial agent;

[0017] The functional bacterial agent is selected from at least one of a phosphorus removal bacterial agent, an oil removal bacterial agent and a high-salt bacterial agent.

[0018] Preferably, the coarse sand particle size is 3.46-4.75 mm; the fine sand particle size is 0.5-1 mm;

[0019] The sand is natural sand and / or machine-made sand, the loss on ignition of the sand is not more than 0.8%, and the density of the sand is less than 2g / cm 3 The light matter content is not more than 0.22%.

[0020] Preferably, the number of viable bacteria in the nitrifying bacteria agent is not less than 200 million cfu / g.

[0021] Preferably, the number of viable bacteria in the denitrifying bacteria agent is not less than 3 billion cfu / g.

[0022] Preferably, the number of viable bacteria in the phosphorus removal bacterial agent is not less than 3 billion cfu / g; the number of viable bacteria in the oil removal bacterial agent is not less than 3 billion cfu / g; and the number of viable bacteria in the high-salt bacterial agent is not less than 3 billion cfu / g.

[0023] A second aspect of the present invention provides an application of the filler for the unpowered sand bioreactor in sewage treatment.

[0024] Preferably, the sewage includes domestic sewage and / or tail water from a sewage treatment plant.

[0025] Preferably, the type of functional bacterial agent is selected according to the type of sewage. For example, if the sewage contains phosphorus, the functional bacterial agent includes a phosphorus removal agent; if the sewage contains oil and salt, the functional bacterial agent includes an oil removal agent and a high-salt bacterial agent.

[0026] The third aspect of the present invention further provides a sewage treatment method, which comprises the following steps:

[0027] (a) loading the unpowered sand bioreactor filler into the sand pool of the unpowered sand bioreactor and allowing it to stand for 20 to 30 hours;

[0028] (b) regulating the pH value of the sewage to 7.0-8.0 and the carbon-nitrogen ratio to between (5-8):1, and then introducing the sewage into an unpowered sand bioreactor for treatment.

[0029] Preferably, the step of loading the filler for the unpowered sand bioreactor according to any one of claims 1 to 6 into the sand pool of the unpowered sand bioreactor specifically comprises:

[0030] First, the denitrifying bacteria agent, nitrifying bacteria agent and functional bacteria agent are prepared into an aqueous solution and left for a period of time to obtain a microbial solution;

[0031] Then, 25% to 35% of the microbial solution is sprayed on the coarse sand and mixed to obtain coarse activated sand; then, the remaining microbial solution is sprayed on the fine sand and mixed to obtain fine activated sand;

[0032] Subsequently, if the unpowered sand bioreactor is fed with water from the middle or upper middle part, the coarse activated sand is loaded into the sand pool at the top and the fine activated sand is loaded at the bottom; if the unpowered sand bioreactor is fed with water from the bottom, the coarse activated sand is loaded into the sand pool at the bottom and the fine activated sand is loaded at the top.

[0033] Compared with the prior art, the beneficial effects of the present invention include at least:

[0034] The filler for the unpowered sand bioreactor of the present invention is specially invented for an unpowered sand bioreactor used for treating miscellaneous domestic drainage in rural areas and upgrading the tailwater of sewage treatment plants. The unpowered sand bioreactor can be quickly started up after construction and achieve the designed treatment effect in a short time. Specifically, by simultaneously carrying out nitrification and denitrification and utilizing the synergistic effect between bacterial strains, in particular, through the use of preferred commercial bacterial agents, a microbial film is quickly formed on the surface of the sand, thereby enabling the sewage treatment equipment to be quickly started up. This can effectively solve the problems of poor bacterial strains, a large number of miscellaneous bacteria, and slow startup of naturally enriched microorganisms.

[0035] In addition, the present invention targets sewage of different characteristics. During the installation phase after the equipment is built, the construction personnel will load the fillers for the unpowered sand bioreactor into the unpowered sand bioreactor to achieve rapid startup and achieve the designed treatment effect in a short time. Since the microorganisms have the ability to self-reproduce, they do not need to be added again after the equipment is operating normally, which facilitates the user's management and reduces the user's management costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly describes the drawings required for the specific embodiments or the description of the prior art. Similar elements or parts are generally identified by similar reference numerals throughout the drawings. Elements or parts in the drawings are not necessarily drawn to scale.

[0037] Figure 1 This is a line graph of the effluent COD index in the experimental example of the present invention.

[0038] Figure 2 This is a line graph of the effluent SS index in the experimental example of the present invention;

[0039] Figure 3 This is a line graph of the total nitrogen index in the effluent water in the experimental example of the present invention;

[0040] Figure 4 This is a line graph of the b index of the effluent vegetable oil in the experimental example of the present invention. DETAILED DESCRIPTION

[0041] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore only used as examples and cannot be used to limit the scope of protection of the present invention.

[0042] It should be noted that, unless otherwise specified, the technical or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0043] The raw materials used in the following examples are as follows:

[0044] Nitrifying bacteria agent: The number of viable bacteria is not less than 200 million cfu / g, from BioFeng;

[0045] Denitrifying bacteria agent: The number of viable bacteria is not less than 3 billion cfu / g, sourced from BioFeng;

[0046] Phosphorus removal agent: The number of viable bacteria is not less than 3 billion cfu / g, from BioFeng;

[0047] Degreasing agent: The number of viable bacteria is not less than 3 billion cfu / g, sourced from BioFeng;

[0048] High-salt bacterial agent: The number of viable bacteria is not less than 3 billion cfu / g, derived from BioFeng.

[0049] Example 1

[0050] This embodiment is a filler for an unpowered sand bioreactor. One cubic meter of the filler for the unpowered sand bioreactor includes:

[0051] 100g of nitrifying bacteria agent, 200g of denitrifying bacteria agent, and the balance is sand;

[0052] The sand is composed of coarse sand and fine sand, the volume ratio of the coarse sand to the fine sand is 17:31, wherein the particle size of the coarse sand is 3.46-4.75 mm; the particle size of the fine sand is 0.5-1 mm;

[0053] The sand is quartz sand, with a loss on ignition of 0.6% and a density of less than 2g / cm 3 The light matter content is 0.17%.

[0054] Example 2

[0055] This embodiment is a filler for an unpowered sand bioreactor. One cubic meter of the filler for the unpowered sand bioreactor includes:

[0056] 300g of nitrifying bacteria agent, 90g of denitrifying bacteria agent, and the balance is sand;

[0057] The sand is composed of coarse sand and fine sand, the volume ratio of the coarse sand to the fine sand is 21:31, wherein the particle size of the coarse sand is 3.46-4.75 mm; the particle size of the fine sand is 0.5-1 mm;

[0058] The sand is quartz sand, with a loss on ignition of 0.6% and a density of less than 2g / cm 3 The light matter content is 0.17%.

[0059] Example 3

[0060] This embodiment is a filler for an unpowered sand bioreactor. One cubic meter of the filler for the unpowered sand bioreactor includes:

[0061] 240g of nitrifying bacteria agent, 200g of denitrifying bacteria agent, and the balance is sand;

[0062] The sand is composed of coarse sand and fine sand, the volume ratio of the coarse sand to the fine sand is 19:31, wherein the particle size of the coarse sand is 3.46-4.75 mm; the particle size of the fine sand is 0.5-1 mm;

[0063] The sand is quartz sand, with a loss on ignition of 0.6% and a density of less than 2g / cm 3 The light matter content is 0.17%.

[0064] Example 4

[0065] This embodiment is a filler for an unpowered sand bioreactor. One cubic meter of the filler for the unpowered sand bioreactor includes:

[0066] 120g nitrifying bacteria agent, 100g denitrifying bacteria agent, 250g functional bacteria agent, and the balance is sand;

[0067] The sand is composed of coarse sand and fine sand, the volume ratio of the coarse sand to the fine sand is 19:31, wherein the particle size of the coarse sand is 3.46-4.75 mm; the particle size of the fine sand is 0.5-1 mm;

[0068] The sand is quartz sand, with a loss on ignition of 0.6% and a density of less than 2g / cm 3 The light matter content is 0.17%;

[0069] The functional bacterial agents include 100g of phosphorus removal bacterial agent, 80g of oil removal bacterial agent and 70g of high-salt bacterial agent.

[0070] Example 5

[0071] This embodiment is a filler for an unpowered sand bioreactor. One cubic meter of the filler for the unpowered sand bioreactor includes:

[0072] 120g nitrifying bacteria agent, 100g denitrifying bacteria agent, 150g functional bacteria agent, and the balance is sand;

[0073] The sand is composed of coarse sand and fine sand, the volume ratio of the coarse sand to the fine sand is 19:31, wherein the particle size of the coarse sand is 3.46-4.75 mm; the particle size of the fine sand is 0.5-1 mm;

[0074] The sand is quartz sand, with a loss on ignition of 0.6% and a density of less than 2g / cm 3 The light matter content is 0.17%;

[0075] The functional bacterial agents are 80g of degreasing bacterial agent and 70g of high-salt bacterial agent.

[0076] Example 6

[0077] This embodiment is a filler for an unpowered sand bioreactor. One cubic meter of the filler for the unpowered sand bioreactor includes:

[0078] 120g nitrifying bacteria agent, 100g denitrifying bacteria agent, 100g functional bacteria agent, and the balance is sand;

[0079] The sand is composed of coarse sand and fine sand, the volume ratio of the coarse sand to the fine sand is 19:31, wherein the particle size of the coarse sand is 3.46-4.75 mm; the particle size of the fine sand is 0.5-1 mm;

[0080] The sand is quartz sand, with a loss on ignition of 0.6% and a density of less than 2g / cm 3 The light matter content is 0.17%;

[0081] The functional bacterial agent is 100g of phosphorus removal bacterial agent.

[0082] Example 7

[0083] This embodiment is a method for treating tail water from a sewage treatment station. Before treatment, the COD of the tail water is 220 mg / L, the ammonia nitrogen is 30 mg / L, the carbon-nitrogen ratio is 7.33, and the pH is 7.5. There is no need to adjust the carbon-nitrogen ratio and the pH. The sewage treatment method comprises the following steps:

[0084] (a) The method of loading the filler for the unpowered sand bioreactor of Example 3 into the sand pool of the unpowered sand bioreactor specifically comprises:

[0085] First, the denitrifying bacteria agent and the nitrifying bacteria agent are prepared into an aqueous solution at a mass ratio of 1:20 and left for a period of time to obtain a microbial solution;

[0086] Then, 30% of the microbial solution is sprayed on the coarse sand and mixed to obtain coarse activated sand; then, the remaining microbial solution is sprayed on the fine sand and mixed to obtain fine activated sand;

[0087] The unpowered sand bioreactor is fed with water from the middle and upper part, and the coarse activated sand is placed on top and the fine activated sand is placed on the bottom. The sand pool is then left to stand for 20 to 30 hours.

[0088] (b) The sewage is introduced into an unpowered sand bioreactor for treatment.

[0089] Example 8

[0090] This embodiment is a method for treating domestic sewage. In addition to high ammonia nitrogen content, the domestic sewage also contains high levels of oil, fat, salt, and phosphorus. The sewage treatment method includes the following steps:

[0091] (a) The method of loading the filler of the unpowered sand bioreactor of Example 4 into the sand pool of the unpowered sand bioreactor specifically comprises:

[0092] First, a denitrifying bacteria agent, a nitrifying bacteria agent and a functional bacteria agent are prepared into an aqueous solution at a mass ratio of 1:20 and allowed to stand for a period of time to obtain a microbial solution;

[0093] Then, 30% of the microbial solution is sprayed on the coarse sand and mixed to obtain coarse activated sand; then, the remaining microbial solution is sprayed on the fine sand and mixed to obtain fine activated sand;

[0094] The unpowered sand bioreactor is bottom-influent, and the coarse activated sand is placed at the bottom and the fine activated sand is placed at the top in the sand pool and left to stand for 24 hours.

[0095] (b) The sewage is introduced into an unpowered sand bioreactor for treatment.

[0096] Experimental example

[0097] This experimental example is a comparative study of different microbial agent addition methods under the same conditions:

[0098] Under the same conditions, three different ways of adding microbial agents were compared and the test results are as follows:

[0099] 1. Same test conditions

[0100] 1. Use fiberglass sand filter tanks with the same shape and volume, with a tank volume of 2.5 cubic meters.

[0101] 2. The uniform filling material is 2.0 cubic meters, including 0.764 cubic meters of coarse sand with a diameter of 3.46-4.75 mm and 1.236 cubic meters of fine sand with a diameter of 0.5-1.0 mm. The coarse sand is at the bottom and the fine sand is at the top, with water entering from the bottom and out from the top.

[0102] 3. Unified water source. For rural domestic sewage from the same village, the amount and time of adding water to the sand filter tank are consistent. On the first day, 1.0 cubic meter of domestic sewage is added to the sand filter tank. Thereafter, 0.25 cubic meter of domestic sewage is added every day. The original water quality is shown in Table 1:

[0103] Table 1

[0104] index original COD (mg / L) 198.5 SS (mg / L) 86.3 Total nitrogen (as N) 49.5 Total vegetable oilsb 19.2

[0105] 4. The uniform water temperature is 26℃-30℃.

[0106] 5. The test period is 10 days.

[0107] 6. Water quality test cycle: test once every other day and take samples from the water outlet of the equipment.

[0108] 2. Different control factors

[0109] 1. Sand filter tank A was pre-prepared with microbial agents. The pre-preparation method was strictly in accordance with the preparation method in Example 8 of the present invention. The microbial agents and fillers were pre-prepared in advance and then placed in rural domestic sewage at the same time as the other two control groups. The types and quantities of microbial agents added were as follows:

[0110] (1) 215g of commercial nitrifying bacteria agent, the effective viable bacterial count (CFU) of the bacteria agent was tested to be ≥ 2 billion cells / g;

[0111] (2) 185 g of commercial denitrifying bacteria agent, with the effective viable bacterial count (CFU) of the agent being ≥ 3 billion cells / g;

[0112] (3) 115g of commercial degreasing agent, the effective viable bacterial count (CFU) of the agent was tested to be ≥3 billion / g;

[0113] 2. Sand filter tank B is the control tank with post-addition of bacterial agent

[0114] First, fill the sewage according to the unified standard, and then add the same type and quantity of microbial agents as those added to the sand filter tank A, add water and pour it into the sand filter tank.

[0115] 3. Sand filter tank C is the control group without adding microbial agents.

[0116] 4. Except for the different methods of adding microorganisms, all other conditions in the three test tanks were the same.

[0117] 3. The test results are displayed in four line graphs

[0118] The corresponding line graphs of effluent COD, ss, total nitrogen, and vegetable oil b at different treatment days are as follows Figures 1 to 4 As shown, Figure 1 It is the line chart of effluent COD index. Figure 2 It is the line chart of water output SS indicator. Figure 3 This is the line chart of the total nitrogen index in the effluent. Figure 4 It is the line chart of the b indicator of the effluent vegetable oil;

[0119] according to Figures 1 to 4 The experimental results and GB18918-2002 "Pollutant Discharge Standards for Urban Wastewater Treatment Plants" are shown in Table 2, which lists the time for each control group to reach the first-level standard, the second-level standard, and the third-level standard.

[0120] Table 2

[0121]

[0122] As shown in Table 2, all indicators of the pre-mixed microbial agent group are significantly better than those of the post-addition microbial agent group and the group without microbial agent. Not only are all indicators of the post-addition microbial agent group and the group without microbial agent lagging behind the pre-mixed microbial agent group, but more importantly, the water quality of the post-addition microbial agent group and the group without microbial agent is far from the discharge standard at the initial stage of water addition, which is a pollution to the water body.

[0123] 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 above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A sewage treatment method, characterized in that: The steps include: (a) The filler for the unpowered sand bioreactor is loaded into the sand pool of the unpowered sand bioreactor and allowed to stand for 20 to 30 hours; 1 cubic meter of the filler for the unpowered sand bioreactor includes: 100-300g of nitrifying bacteria agent, 90-200g of denitrifying bacteria agent, and the balance is sand; The sand consists of coarse sand and fine sand, and the volume ratio of the coarse sand to the fine sand is (17-21):31; (b) regulating the pH value of the wastewater to 7.0-8.0 and the carbon-nitrogen ratio to (5-8):1, and then introducing the wastewater into an unpowered sand bioreactor for treatment; The method of loading the filler for the unpowered sand bioreactor into the sand pool of the unpowered sand bioreactor specifically comprises: First, the denitrifying bacteria agent and the nitrifying bacteria agent are prepared into an aqueous solution and left for a period of time to obtain a microbial solution; Then, 25% to 35% of the microbial solution is sprayed on the coarse sand and mixed to obtain coarse activated sand; then, the remaining microbial solution is sprayed on the fine sand and mixed to obtain fine activated sand; Subsequently, if the unpowered sand bioreactor is fed with water from the middle or upper middle part, the coarse activated sand is loaded into the sand pool at the top and the fine activated sand is loaded at the bottom; if the unpowered sand bioreactor is fed with water from the bottom, the coarse activated sand is loaded into the sand pool at the bottom and the fine activated sand is loaded at the top.

2. The sewage treatment method according to claim 1, characterized in that: 1 cubic meter of the filler for the unpowered sand bioreactor also includes 50-300g of functional bacterial agent; The functional bacterial agent is selected from at least one of a phosphorus removal bacterial agent, an oil removal bacterial agent and a high-salt bacterial agent.

3. The sewage treatment method according to claim 1, characterized in that: The particle size of the coarse sand is 3.46~4.75mm; the particle size of the fine sand is 0.5~1mm; The sand is natural sand and / or machine-made sand, the loss on ignition of the sand is not more than 0.8%, and the density of the sand is less than 2g / cm 3 The light matter content is not more than 0.22%.

4. The sewage treatment method according to claim 1, characterized in that: The number of viable bacteria in the nitrifying bacteria agent is not less than 200 million cfu / g.

5. The sewage treatment method according to claim 1, characterized in that: The number of viable bacteria in the denitrifying bacteria agent is not less than 3 billion cfu / g.

6. The sewage treatment method according to claim 2, characterized in that: The number of live bacteria in the phosphorus removal bacterial agent is not less than 3 billion cfu / g; the number of live bacteria in the oil removal bacterial agent is not less than 3 billion cfu / g; the number of live bacteria in the high-salt bacterial agent is not less than 3 billion cfu / g.

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