Sewage treatment agent as well as preparation method and application thereof

Abstract

The invention discloses a sewage treatment agent as well as a preparation method and application thereof. The sewage treatment agent comprises a microbial agent, modified diatomite, silicic acid, sodium alginate and modified soluble starch. The preparation process of the sewage treatment agent comprises the following steps: adding a microbial agent into a modified diatomite aqueous solution, uniformly stirring to uniformly load the microbial agent inside and on the surface of the modified diatomite, and drying until the moisture content is less than or equal to 4% to obtain a material I; and adding the first material, silicic acid and modified soluble starch into a reactor with stirring magneton and a sodium alginate aqueous solution for reaction to obtain the sewage treatment agent. According to the invention, microorganisms are adopted to degrade ammonia nitrogen compounds in sewage, meanwhile, suspended substances in water can be subjected to flocculating settling, the microorganisms are reasonably proportioned to realize maximum flocculating settling and degradation of the ammonia nitrogen compounds, and the microorganisms are mutually matched and coordinated and symbiotic, so that dominant bacterial communities can be formed when the microorganisms are put into the sewage; the ammonia nitrogen index in the sewage is rapidly reduced, and the effect is rapid and remarkable.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and specifically relates to a sewage treatment agent and a preparation method and application thereof. Background Art

[0002] With the development of industry and agriculture and the improvement of people's living standards, the discharge of nitrogen-containing wastewater has increased dramatically and has become a major source of environmental pollution, attracting much attention.

[0003] The pathways of nitrogen-containing substances entering the water environment mainly include natural processes and human activities. The natural sources and processes of nitrogen-containing substances entering the water environment mainly include precipitation and dust, non-urban runoff and biological nitrogen fixation. Human activities are also an important source of nitrogen in the water environment, mainly including untreated or treated urban domestic and industrial wastewater, various leachates and surface runoff. Artificially synthesized chemical fertilizers are the main source of nitrogen nutrients in water bodies, and a large amount of nitrogen compounds that are not used by crops are mostly carried into groundwater and surface water by farmland drainage and surface runoff.

[0004] With the development of industries such as petroleum, chemical, food and pharmaceutical, and the continuous improvement of people's living standards, the content of ammonia nitrogen in urban domestic sewage and landfill leachate has increased sharply.

[0005] In recent years, with the development of economy, the indiscriminate discharge of more and more nitrogen-containing pollutants has caused great harm to the environment.

[0006] Nitrogen in wastewater exists in the form of organic nitrogen, ammonia nitrogen (NH 4+ -N), nitrate nitrogen (NO3--N) and nitrite nitrogen (NO2--N), and ammonia nitrogen is one of the main forms of existence. Ammonia nitrogen in wastewater refers to nitrogen in the form of free ammonia and ionized ammonium, which mainly comes from the decomposition of nitrogen-containing organic matter in domestic sewage, industrial wastewater such as coking and synthetic ammonia, and farmland drainage. There are many sources of ammonia nitrogen pollution, large emissions, and large changes in the concentration of emissions. A large amount of ammonia nitrogen wastewater discharged into the water body not only causes eutrophication of the water body and causes the water body to be black and smelly, but also increases the difficulty and cost of water treatment, and even has a toxic effect on people and organisms. The general formation of ammonia nitrogen wastewater is caused by the coexistence of ammonia water and inorganic ammonia. Generally, the main source of ammonia nitrogen in wastewater with a pH above neutral is the joint action of inorganic ammonia and ammonia water. Under acidic pH conditions, ammonia nitrogen in wastewater is mainly caused by inorganic ammonia. There are two main components of ammonia nitrogen in wastewater, one is ammonia nitrogen formed by ammonia water, and the other is ammonia nitrogen formed by inorganic ammonia, mainly ammonium sulfate, ammonium chloride, etc.

[0007] The hazards of high ammonia nitrogen wastewater are mainly as follows:

[0008] On the one hand, ammonia nitrogen in wastewater is an important substance for eutrophication of water bodies and environmental pollution. It can easily cause algae and other microorganisms to multiply in the water, making it difficult for water treatment plants to operate and causing unpleasant odors in drinking water. In severe cases, it can cause a decrease in dissolved oxygen in the water, leading to the death of large numbers of fish and even the drying up of lakes.

[0009] On the other hand, ammonia nitrogen will also increase the amount of chlorine used in water disinfection and industrial circulating water sterilization; it is corrosive to certain metals (copper); when sewage is reused, ammonia nitrogen in the recycled water can promote the reproduction of microorganisms in water pipes and water-using equipment, forming bioscaling, clogging pipes and water-using equipment, and affecting heat exchange efficiency.

[0010] Secondly, ammonia is oxidized into nitrite and nitrate by nitrifying bacteria. Nitrate in drinking water can induce methemoglobinemia in infants, while nitrite hydrolysis generates nitrosamines, which are highly carcinogenic and directly threaten human health.

[0011] The Chinese patent with application number CN201910470536.2 and invention name "A composite bacterial agent for degrading high-ammonia-nitrogen sewage and its application in sewage treatment" discloses a composite bacterial agent for degrading high-ammonia-nitrogen sewage. The composite bacterial agent for degrading high-ammonia-nitrogen sewage is obtained by mixing capsular red bacterium 3Z, spherical red bacterium fermentation broth, palustris red pseudomonas fermentation broth, Rhodobacter johrii fermentation broth and Bacillus subtilis fermentation broth, which can efficiently convert inorganic nitrogen into organic nitrogen.

[0012] The Chinese patent with application number CN201911111327.5 and invention name "A sewage treatment agent for removing ammonia nitrogen and total nitrogen and its preparation method" discloses a sewage treatment agent for removing ammonia nitrogen and total nitrogen and its preparation method. The treatment agent is composed of nitrite bacteria, nitrate bacteria, yeast, lactic acid bacteria and additives. During the treatment process, the treatment agent fully exerts the synergistic effects of catalytic oxidation, flocculation, adsorption, co-precipitation, etc. to enhance the treatment of sewage.

[0013] Application No. 202311744026.2, a composite treatment agent for high-concentration ammonia nitrogen sewage and its preparation method, belong to the field of sewage treatment. The composite treatment agent for high-concentration ammonia nitrogen sewage of the present invention contains the following components by weight: 10-20 parts of microbial agents, 100-150 parts of sodium alginate, 20-30 parts of strawberry straw activated carbon, 30-50 parts of modified chitosan, and 10-20 parts of modified coal gangue. The composite treatment agent of the present invention has a good purification effect on high-concentration ammonia nitrogen sewage. By screening and proportioning the bacterial strains, an effective bacterial community is formed to achieve the decomposition of ammonia nitrogen compounds; the components cooperate with each other to achieve effective dynamic adsorption of ammonia nitrogen compounds, improve the treatment effect of sewage, and achieve the effect of purifying high-ammonia nitrogen sewage.

[0014] Although there are many methods to treat wastewater containing ammonia nitrogen, the treatment process for high-concentration ammonia nitrogen wastewater is relatively complicated and generally requires multiple steps. Therefore, a treatment method with simple process, cost saving, easy control and no secondary pollution is very necessary for the treatment of high-concentration ammonia nitrogen wastewater. Summary of the invention

[0015] The purpose of the present invention is to provide a preparation process of a sewage treatment agent to solve the problems raised in the above background technology.

[0016] To achieve the above object, the present invention provides the following technical solution: a sewage treatment agent, comprising, by weight:

[0017] 20-50 parts of microbial agent, 40-60 parts of modified diatomaceous earth, 5-10 parts of silicic acid, 80-120 parts of sodium alginate and 40-60 parts of modified soluble starch.

[0018] Preferably, the microbial agent includes Aerobacterium, Zoogloea, Leaf Bacillus, and Paracoccus.

[0019] Preferably, in any of the above schemes, the Aerobacter, Zooglobacter, Leaf Bacillus, and Paracoccus are cultured to a bacterial solution with a bacterial concentration of OD600≈3, and then mixed in a bacterial solution volume ratio of 1:2:3:2 to obtain a mixed bacterial solution, and then the mixed bacterial solution is heated at 20°C and 100 r·min -1 The culture is continued for 48-60 hours under the conditions to prepare freeze-dried powder, which is a microbial agent.

[0020] Preferably, in any of the above schemes, the preparation method of the modified diatomite comprises: adding chitosan to a 5% by mass acetic acid solution, stirring at a speed of 200-400 rpm for 40-60 min, then adding diatomite, continuing to stir at a speed of 400-500 rpm for 60-120 min, and then standing for 30-60 min, placing it in an electrically heated constant temperature forced air drying furnace to dry to constant weight, and grinding to obtain modified diatomite.

[0021] Preferably, in any of the above schemes, the content of chitosan in the modified diatomaceous earth is 80-100 mg / g.

[0022] Preferably, in any of the above schemes, the method for preparing the modified soluble starch comprises:

[0023] S1: mixing raw starch with water to obtain a starch emulsion with a starch mass percentage concentration of 20-30wt%;

[0024] S2: adjusting the pH of the starch emulsion to 8.0-11.0 with an acid-base regulator, then mixing with 2,3-epoxypropyltrimethylammonium chloride, heating to 45-55° C. for reaction, and the reaction time is 24-30 hours;

[0025] S3: adjusting the pH of the product of the above step to 5.0-7.0, and then washing and drying to obtain modified soluble starch.

[0026] In any of the above schemes, it is preferred that the raw starch includes a combination of one or more of potato starch, corn starch and cassava starch.

[0027] Preferably, in any of the above schemes, the added amount of the 2,3-epoxypropyltrimethylammonium chloride is 11-13 wt % of the mass of the raw starch.

[0028] A preparation process of a sewage treatment agent comprises the following steps:

[0029] S1: adding the microbial agent to the modified diatomite aqueous solution, stirring evenly to make the microbial agent evenly loaded inside and on the surface of the modified diatomite, and drying to a moisture content of ≤4%, to obtain material 1;

[0030] S2: Add the above-obtained material 1, silicic acid, and modified soluble starch into a reactor with a stirring magnet and a sodium alginate aqueous solution, set the stirring speed to 400-600rpm, the temperature to 30-40°C, the pH to 7.0, the reaction time to 40-100min, and finally dry to a moisture content of ≤3% to obtain a sewage treatment agent.

[0031] The sewage treatment agent disclosed by the invention has wide application in sewage treatment.

[0032] The technical effects and advantages of the present invention are as follows: the present invention uses microbial degradation to degrade ammonia nitrogen compounds in sewage, and can perform preliminary flocculation and sedimentation on suspended matter in water. Through reasonable microbial ratio, maximum flocculation and sedimentation and degradation of ammonia nitrogen compounds are achieved. The microorganisms cooperate with each other and coexist in a coordinated manner. When they are put into sewage, a dominant bacterial community can be formed, and the ammonia nitrogen index in the sewage can be rapidly reduced. The effect is rapid and significant, and it is not affected by other components in the sewage. It can continuously degrade ammonia nitrogen compounds in the sewage. At the same time, the microbial agent is loaded on the inside of the modified diatomaceous earth and the modified soluble starch is wrapped on the outside, which can effectively avoid the death of microorganisms caused by direct exposure of the microbial agent to a high concentration of ammonia nitrogen environment, thereby resulting in a decrease in degradation ability. The stability of the microorganisms can be effectively maintained, and a certain protective effect on the microorganisms can be provided, thereby ensuring the effective number of microorganisms and significantly enhancing the ammonia nitrogen degradation ability of the microorganisms.

[0033] The present invention modifies soluble starch, uses 2,3-epoxypropyltrimethylammonium chloride as a cationic etherifying agent, and a nucleophilic substitution reaction occurs between hydroxyl 2,3-epoxypropyltrimethylammonium chloride on starch molecules, so that the soluble starch is a quaternary ammonium salt type cationic starch. The flocculation ability of the prepared sewage treatment agent is greatly improved, and the COD removal rate is good.

[0034] The present invention modifies diatomite, which has the characteristics of light texture, small porosity, large specific surface area and high chemical stability. After being modified with chitosan by the modification method of the present invention, chitosan will generate substances with positive charge after being dissolved in an acidic solution. By utilizing this principle, diatomite and chitosan acidic solution are mixed and stirred to load chitosan onto the surface of diatomite. The sewage treatment agent prepared by the invention has strong flocculation ability and can produce bridging and electrical neutralization effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention is a flow chart of the preparation process. DETAILED DESCRIPTION

[0036] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] Embodiment 1:

[0038] A sewage treatment agent, comprising, by weight,

[0039] 20 parts of microbial agents, 40 parts of modified diatomaceous earth, 5 parts of silicic acid, 80 parts of sodium alginate and 40 parts of modified soluble starch.

[0040] The microbial agents include Aerobacterium, Zoogloea, Leaf Bacillus, and Paracoccus.

[0041] The Aerobacterium, the Zooglobium, the Leaf Bacillus, and the Paracoccus are cultured to a bacterial solution with a bacterial concentration of OD600≈3, and then mixed according to a bacterial solution volume ratio of 1:2:3:2 to obtain a mixed bacterial solution, and then the mixed bacterial solution is heated at 20°C and 100 r·min -1 The culture was continued for 48 hours under the conditions and freeze-dried powder was prepared as a microbial agent.

[0042] The preparation method of the modified diatomite comprises: adding chitosan to an acetic acid solution with a mass fraction of 5%, stirring at a speed of 200 rpm for 40 minutes, then adding diatomite, continuing to stir at a speed of 400 rpm for 60 minutes, and then standing for 30 minutes, placing it in an electrically heated constant temperature forced air drying furnace to dry to constant weight, and grinding to obtain the modified diatomite.

[0043] The content of chitosan in the modified diatomaceous earth is 80 mg / g.

[0044] The preparation method of the modified soluble starch comprises:

[0045] S1: mixing raw starch with water to obtain a starch emulsion with a starch mass percentage concentration of 20wt%;

[0046] S2: adjusting the pH of the starch emulsion to 8.0 with an acid-base regulator, then mixing with 2,3-epoxypropyltrimethylammonium chloride, heating to 45° C. for reaction, and the reaction time is 24 hours;

[0047] S3: adjusting the pH of the product of the above step to 5.0, and then washing and drying to obtain modified soluble starch.

[0048] The raw material starch is potato starch.

[0049] The added amount of the 2,3-epoxypropyltrimethylammonium chloride is 11 wt % of the mass of the raw starch.

[0050] A preparation process of a sewage treatment agent comprises the following steps:

[0051] S1: adding the microbial agent to the modified diatomite aqueous solution, stirring evenly to make the microbial agent evenly loaded inside and on the surface of the modified diatomite, and drying to a moisture content of ≤4%, to obtain material 1;

[0052] S2: Add the above-obtained material 1, silicic acid, and modified soluble starch into a reactor with a stirring magnet and a sodium alginate aqueous solution, set the stirring speed to 400 rpm, the temperature to 30°C, the pH to 7.0, the reaction time to 40 min, and finally dry to a moisture content of ≤3% to obtain a sewage treatment agent.

[0053] Embodiment 2:

[0054] A sewage treatment agent, comprising, by weight,

[0055] 40 parts of microbial agents, 50 parts of modified diatomaceous earth, 7 parts of silicic acid, 100 parts of sodium alginate and 50 parts of modified soluble starch.

[0056] The microbial agents include Aerobacterium, Zoogloea, Leaf Bacillus, and Paracoccus.

[0057] The Aerobacterium, the Zooglobium, the Leaf Bacillus, and the Paracoccus are cultured to a bacterial solution with a bacterial concentration of OD600≈3, and then mixed according to a bacterial solution volume ratio of 1:2:3:2 to obtain a mixed bacterial solution, and then the mixed bacterial solution is heated at 20°C and 100 r·min -1 The culture was continued for 55 hours under the conditions to prepare freeze-dried powder, which was a microbial agent.

[0058] The preparation method of the modified diatomite comprises: adding chitosan to an acetic acid solution with a mass fraction of 5%, stirring at a speed of 300 rpm for 50 minutes, then adding diatomite, continuing to stir at a speed of 450 rpm for 80 minutes, and then standing for 45 minutes, placing it in an electrically heated constant temperature forced air drying furnace to dry to constant weight, and grinding to obtain the modified diatomite.

[0059] The content of chitosan in the modified diatomaceous earth is 90 mg / g.

[0060] The preparation method of the modified soluble starch comprises:

[0061] S1: mixing raw starch with water to obtain a starch emulsion with a starch mass percentage concentration of 25wt%;

[0062] S2: adjusting the pH of the starch emulsion to 9.0 with an acid-base regulator, then mixing with 2,3-epoxypropyltrimethylammonium chloride, heating to 50° C. for reaction, and the reaction time is 28 hours;

[0063] S3: adjusting the pH of the product of the above step to 6.0, and then washing and drying to obtain modified soluble starch.

[0064] The raw starch includes a combination of potato starch and corn starch.

[0065] The added amount of the 2,3-epoxypropyltrimethylammonium chloride is 12 wt % of the mass of the raw starch.

[0066] A preparation process of a sewage treatment agent comprises the following steps:

[0067] S1: adding the microbial agent to the modified diatomite aqueous solution, stirring evenly to make the microbial agent evenly loaded inside and on the surface of the modified diatomite, and drying to a moisture content of ≤4%, to obtain material 1;

[0068] S2: Add the above-obtained material 1, silicic acid, and modified soluble starch into a reactor with a stirring magnet and a sodium alginate aqueous solution, set the stirring speed to 500 rpm, the temperature to 35°C, the pH to 7.0, the reaction time to 60 min, and finally dry to a moisture content of ≤3% to obtain a sewage treatment agent.

[0069] Embodiment 3:

[0070] A sewage treatment agent, comprising, by weight,

[0071] 50 parts of microbial agents, 60 parts of modified diatomaceous earth, 10 parts of silicic acid, 120 parts of sodium alginate and 60 parts of modified soluble starch.

[0072] The microbial agents include Aerobacterium, Zoogloea, Leaf Bacillus, and Paracoccus.

[0073] The Aerobacterium, the Zooglobium, the Leaf Bacillus, and the Paracoccus are cultured to a bacterial solution with a bacterial concentration of OD600≈3, and then mixed according to a bacterial solution volume ratio of 1:2:3:2 to obtain a mixed bacterial solution, and then the mixed bacterial solution is heated at 20°C and 100 r·min -1 The culture was continued for 60 hours under the conditions and freeze-dried powder was prepared as a microbial agent.

[0074] The preparation method of the modified diatomite comprises: adding chitosan to an acetic acid solution with a mass fraction of 5%, stirring at a speed of 400 rpm for 60 minutes, then adding diatomite, continuing to stir at a speed of 500 rpm for 120 minutes, and then standing for 60 minutes, placing it in an electrically heated constant temperature forced air drying furnace to dry to constant weight, and grinding to obtain the modified diatomite.

[0075] The content of chitosan in the modified diatomaceous earth is 100 mg / g.

[0076] The preparation method of the modified soluble starch comprises:

[0077] S1: mixing raw starch with water to obtain a starch emulsion with a starch mass percentage concentration of 30wt%;

[0078] S2: adjusting the pH of the starch emulsion to 11.0 with an acid-base regulator, then mixing with 2,3-epoxypropyltrimethylammonium chloride, heating to 55° C. for reaction, and the reaction time is 30 hours;

[0079] S3: adjusting the pH of the product of the above step to 7.0, and then washing and drying to obtain modified soluble starch.

[0080] The raw starch includes a combination of potato starch and tapioca starch.

[0081] The added amount of the 2,3-epoxypropyltrimethylammonium chloride is 13 wt % of the mass of the raw starch.

[0082] A preparation process of a sewage treatment agent comprises the following steps:

[0083] S1: adding the microbial agent to the modified diatomite aqueous solution, stirring evenly to make the microbial agent evenly loaded inside and on the surface of the modified diatomite, and drying to a moisture content of ≤4%, to obtain material 1;

[0084] S2: Add the above-obtained material 1, silicic acid, and modified soluble starch into a reactor with a stirring magnet and a sodium alginate aqueous solution, set the stirring speed to 600 rpm, the temperature to 40°C, the pH to 7.0, the reaction time to 100 min, and finally dry to a moisture content of ≤3% to obtain a sewage treatment agent.

[0085] Embodiment 4:

[0086] A sewage treatment agent, comprising, by weight,

[0087] 50 parts of microbial agents, 60 parts of modified diatomaceous earth, 10 parts of silicic acid, 120 parts of sodium alginate and 60 parts of modified soluble starch.

[0088] The microbial agents include Aerobacterium, Zoogloea, Leaf Bacillus, and Paracoccus.

[0089] The Aerobacterium, the Zooglobium, the Leaf Bacillus, and the Paracoccus are cultured to a bacterial solution with a bacterial concentration of OD600≈3, and then mixed according to a bacterial solution volume ratio of 1:2:3:2 to obtain a mixed bacterial solution, and then the mixed bacterial solution is heated at 20°C and 100 r·min -1 The culture was continued for 60 hours under the conditions and freeze-dried powder was prepared as a microbial agent.

[0090] The preparation method of the modified diatomite comprises: adding chitosan to an acetic acid solution with a mass fraction of 5%, stirring at a speed of 400 rpm for 60 minutes, then adding diatomite, continuing to stir at a speed of 500 rpm for 120 minutes, and then standing for 60 minutes, placing it in an electrically heated constant temperature forced air drying furnace to dry to constant weight, and grinding to obtain the modified diatomite.

[0091] The content of chitosan in the modified diatomaceous earth is 100 mg / g.

[0092] The preparation method of the modified soluble starch comprises:

[0093] S1: mixing raw starch with water to obtain a starch emulsion with a starch mass percentage concentration of 30wt%;

[0094] S2: adjusting the pH of the starch emulsion to 11.0 with an acid-base regulator, then mixing with 2,3-epoxypropyltrimethylammonium chloride, heating to 55° C. for reaction, and the reaction time is 30 hours;

[0095] S3: adjusting the pH of the product of the above step to 7.0, and then washing and drying to obtain modified soluble starch.

[0096] The raw starch includes a combination of potato starch, corn starch and tapioca starch.

[0097] The added amount of the 2,3-epoxypropyltrimethylammonium chloride is 13 wt % of the mass of the raw starch.

[0098] A preparation process of a sewage treatment agent comprises the following steps:

[0099] S1: adding the microbial agent to the modified diatomite aqueous solution, stirring evenly to make the microbial agent evenly loaded inside and on the surface of the modified diatomite, and drying to a moisture content of ≤4%, to obtain material 1;

[0100] S2: Add the above-obtained material 1, silicic acid, and modified soluble starch into a reactor with a stirring magnet and a sodium alginate aqueous solution, set the stirring speed to 600 rpm, the temperature to 40°C, the pH to 7.0, the reaction time to 100 min, and finally dry to a moisture content of ≤3% to obtain a sewage treatment agent.

[0101] Comparative Example 1:

[0102] The difference between this comparative example and Example 1 is that no microbial agent is added, specifically:

[0103] A sewage treatment agent, comprising, by weight,

[0104] 20 parts of microbial agents, 40 parts of modified diatomaceous earth, 5 parts of silicic acid, 80 parts of sodium alginate and 40 parts of modified soluble starch.

[0105] The microbial agents include Aerobacterium, Zoogloea, Leaf Bacillus, and Paracoccus.

[0106] The Aerobacterium, the Zooglobium, the Leaf Bacillus, and the Paracoccus are cultured to a bacterial solution with a bacterial concentration of OD600≈3, and then mixed according to a bacterial solution volume ratio of 1:2:3:2 to obtain a mixed bacterial solution, and then the mixed bacterial solution is heated at 20°C and 100 r·min -1 The culture was continued for 48 hours under the conditions and freeze-dried powder was prepared as a microbial agent.

[0107] The preparation method of the modified diatomite comprises: adding chitosan to an acetic acid solution with a mass fraction of 5%, stirring at a speed of 200 rpm for 40 minutes, then adding diatomite, continuing to stir at a speed of 400 rpm for 60 minutes, and then standing for 30 minutes, placing it in an electrically heated constant temperature forced air drying furnace to dry to constant weight, and grinding to obtain the modified diatomite.

[0108] The content of chitosan in the modified diatomaceous earth is 80 mg / g.

[0109] The preparation method of the modified soluble starch comprises:

[0110] S1: mixing raw starch with water to obtain a starch emulsion with a starch mass percentage concentration of 20wt%;

[0111] S2: adjusting the pH of the starch emulsion to 8.0 with an acid-base regulator, then mixing with 2,3-epoxypropyltrimethylammonium chloride, heating to 45° C. for reaction, and the reaction time is 24 hours;

[0112] S3: adjusting the pH of the product of the above step to 5.0, and then washing and drying to obtain modified soluble starch.

[0113] The raw material starch is potato starch.

[0114] The added amount of the 2,3-epoxypropyltrimethylammonium chloride is 11 wt % of the mass of the raw starch.

[0115] A preparation process of a sewage treatment agent comprises the following steps:

[0116] S1: adding the microbial agent to the modified diatomite aqueous solution, stirring evenly to make the microbial agent evenly loaded inside and on the surface of the modified diatomite, and drying to a moisture content of ≤4%, to obtain material 1;

[0117] S2: Add the above-obtained material 1, silicic acid, and modified soluble starch into a reactor with a stirring magnet and a sodium alginate aqueous solution, set the stirring speed to 400 rpm, the temperature to 30°C, the pH to 7.0, the reaction time to 40 min, and finally dry to a moisture content of ≤3% to obtain a sewage treatment agent.

[0118] Comparative Example 2:

[0119] The difference between this comparative example and Example 2 is that the diatomaceous earth is not modified, specifically:

[0120] A sewage treatment agent, comprising, by weight,

[0121] 40 parts of microbial agents, 50 parts of diatomaceous earth, 7 parts of silicic acid, 100 parts of sodium alginate and 50 parts of modified soluble starch.

[0122] The microbial agents include Aerobacterium, Zoogloea, Leaf Bacillus, and Paracoccus.

[0123] The Aerobacterium, the Zooglobium, the Leaf Bacillus, and the Paracoccus are cultured to a bacterial solution with a bacterial concentration of OD600≈3, and then mixed according to a bacterial solution volume ratio of 1:2:3:2 to obtain a mixed bacterial solution, and then the mixed bacterial solution is heated at 20°C and 100 r·min -1 The culture was continued for 55 hours under the conditions to prepare freeze-dried powder, which was a microbial agent.

[0124] The preparation method of the modified diatomite comprises: adding chitosan to an acetic acid solution with a mass fraction of 5%, stirring at a speed of 300 rpm for 50 minutes, then adding diatomite, continuing to stir at a speed of 450 rpm for 80 minutes, and then standing for 45 minutes, placing it in an electrically heated constant temperature forced air drying furnace to dry to constant weight, and grinding to obtain the modified diatomite.

[0125] The content of chitosan in the modified diatomaceous earth is 90 mg / g.

[0126] The preparation method of the modified soluble starch comprises:

[0127] S1: mixing raw starch with water to obtain a starch emulsion with a starch mass percentage concentration of 25wt%;

[0128] S2: adjusting the pH of the starch emulsion to 9.0 with an acid-base regulator, then mixing with 2,3-epoxypropyltrimethylammonium chloride, heating to 50° C. for reaction, and the reaction time is 28 hours;

[0129] S3: adjusting the pH of the product of the above step to 6.0, and then washing and drying to obtain modified soluble starch.

[0130] The raw starch includes a combination of potato starch and corn starch.

[0131] The added amount of the 2,3-epoxypropyltrimethylammonium chloride is 12 wt % of the mass of the raw starch.

[0132] A preparation process of a sewage treatment agent comprises the following steps:

[0133] S1: adding the microbial agent to the modified diatomite aqueous solution, stirring evenly to make the microbial agent evenly loaded inside and on the surface of the modified diatomite, and drying to a moisture content of ≤4%, to obtain material 1;

[0134] S2: Add the above-obtained material 1, silicic acid, and modified soluble starch into a reactor with a stirring magnet and a sodium alginate aqueous solution, set the stirring speed to 500 rpm, the temperature to 35°C, the pH to 7.0, the reaction time to 60 min, and finally dry to a moisture content of ≤3% to obtain a sewage treatment agent.

[0135] Comparative Example 3:

[0136] The difference between this comparative example and Example 3 is that the soluble starch is not modified, specifically:

[0137] A sewage treatment agent, comprising, by weight,

[0138] 50 parts of microbial agents, 60 parts of modified diatomaceous earth, 10 parts of silicic acid, 120 parts of sodium alginate and 60 parts of modified soluble starch.

[0139] The microbial agents include Aerobacterium, Zoogloea, Leaf Bacillus, and Paracoccus.

[0140] The Aerobacterium, the Zooglobium, the Leaf Bacillus, and the Paracoccus are cultured to a bacterial solution with a bacterial concentration of OD600≈3, and then mixed according to a bacterial solution volume ratio of 1:2:3:2 to obtain a mixed bacterial solution, and then the mixed bacterial solution is heated at 20°C and 100 r·min -1 The culture was continued for 60 hours under the conditions and freeze-dried powder was prepared as a microbial agent.

[0141] The preparation method of the modified diatomite comprises: adding chitosan to an acetic acid solution with a mass fraction of 5%, stirring at a speed of 400 rpm for 60 minutes, then adding diatomite, continuing to stir at a speed of 500 rpm for 120 minutes, and then standing for 60 minutes, placing it in an electrically heated constant temperature forced air drying furnace to dry to constant weight, and grinding to obtain the modified diatomite.

[0142] The content of chitosan in the modified diatomaceous earth is 100 mg / g.

[0143] The preparation method of the modified soluble starch comprises:

[0144] S1: mixing raw starch with water to obtain a starch emulsion with a starch mass percentage concentration of 30wt%;

[0145] S2: adjusting the pH of the starch emulsion to 11.0 with an acid-base regulator, then mixing with 2,3-epoxypropyltrimethylammonium chloride, heating to 55° C. for reaction, and the reaction time is 30 hours;

[0146] S3: adjusting the pH of the product of the above step to 7.0, and then washing and drying to obtain modified soluble starch.

[0147] The raw starch includes a combination of potato starch and tapioca starch.

[0148] The added amount of the 2,3-epoxypropyltrimethylammonium chloride is 13 wt % of the mass of the raw starch.

[0149] A preparation process of a sewage treatment agent comprises the following steps:

[0150] S1: adding the microbial agent to the modified diatomite aqueous solution, stirring evenly to make the microbial agent evenly loaded inside and on the surface of the modified diatomite, and drying to a moisture content of ≤4%, to obtain material 1;

[0151] S2: Add the above-obtained material 1, silicic acid, and modified soluble starch into a reactor with a stirring magnet and a sodium alginate aqueous solution, set the stirring speed to 600 rpm, the temperature to 40°C, the pH to 7.0, the reaction time to 100 min, and finally dry to a moisture content of ≤3% to obtain a sewage treatment agent.

[0152] The application of the sewage treatment agent prepared by the present invention in treating sewage is specifically as follows: sewage from a refinery is taken and placed in 8 water tanks for testing, numbered as water tanks 1-7, wherein no treatment agent is placed in water tank 1, which serves as a blank control group, and the sewage composite treatment agents prepared according to Examples 1-4 and Comparative Examples 1-3 are placed in water tanks 2-7, respectively, at a dosage of 10 g / m 3 , the water quality of all tanks was tested 72 hours after the treatment agent was added.

[0153] The specific detection indicators are shown in the following table:

[0154]

[0155]

[0156] It can be seen from the results in the above table that the sewage treatment agent prepared in the present application has a good purification effect on high-concentration ammonia nitrogen sewage. By screening and proportioning the bacterial strains, an effective bacterial community is formed to achieve efficient decomposition of ammonia nitrogen compounds. Moreover, under the combined action of the flocculant and the modified soluble starch, the flocculation effect is significant.

[0157] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A sewage treatment agent, characterized in that: In parts by weight, including: 20-50 parts of microbial agent, 40-60 parts of modified diatomaceous earth, 5-10 parts of silicic acid, 80-120 parts of sodium alginate and 40-60 parts of modified soluble starch.

2. A sewage treatment agent according to claim 1, characterized in that: The microbial agents include Aerobacterium, Zoogloea, Leaf Bacillus, and Paracoccus.

3. A sewage treatment agent according to claim 2, characterized in that: The Aerobacter, Zooglobium, Leaf Bacillus, and Paracoccus are cultured to a bacterial solution with a bacterial concentration of OD600≈3, and then mixed according to a bacterial solution volume ratio of 1:2:3:2 to obtain a mixed bacterial solution, and then the mixed bacterial solution is continuously cultured for 48-60 hours at 20°C and 100 r·min-1 to prepare a freeze-dried powder, which is a microbial agent.

4. A sewage treatment agent according to claim 1, characterized in that: The preparation method of the modified diatomite comprises: adding chitosan to an acetic acid solution with a mass fraction of 5%, stirring at a speed of 200-400 rpm for 40-60 minutes, then adding diatomite, continuing to stir at a speed of 400-500 rpm for 60-120 minutes, and then standing for 30-60 minutes, placing it in an electrically heated constant temperature forced air drying furnace to dry to constant weight, and grinding to obtain the modified diatomite.

5. A sewage treatment agent according to claim 4, characterized in that: The content of chitosan in the modified diatomaceous earth is 80-100 mg / g.

6. A sewage treatment agent according to claim 1, characterized in that: The preparation method of the modified soluble starch comprises: S1: mixing raw starch with water to obtain a starch emulsion with a starch mass percentage concentration of 20-30wt%; S2: adjusting the pH of the starch emulsion to 8.0-11.0 with an acid-base regulator, then mixing with 2,3-epoxypropyltrimethylammonium chloride, heating to 45-55° C. for reaction, and the reaction time is 24-30 hours; S3: adjusting the pH of the product of the above step to 5.0-7.0, and then washing and drying to obtain modified soluble starch.

7. A sewage treatment agent according to claim 6, characterized in that: The raw starch includes one or more of potato starch, corn starch and tapioca starch.

8. A sewage treatment agent according to claim 6, characterized in that: The added amount of the 2,3-epoxypropyltrimethylammonium chloride is 11-13 wt % of the mass of the raw starch.

9. A process for preparing the sewage treatment agent according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: adding the microbial agent to the modified diatomite aqueous solution, stirring evenly to make the microbial agent evenly loaded inside and on the surface of the modified diatomite, and drying to a moisture content of ≤4%, to obtain material 1; S2: Add the above-obtained material 1, silicic acid, and modified soluble starch into a reactor with a stirring magnet and a sodium alginate aqueous solution, set the stirring speed to 400-600rpm, the temperature to 30-40°C, the pH to 7.0, the reaction time to 40-100min, and finally dry to a moisture content of ≤3% to obtain a sewage treatment agent.

10. Use of the sewage treatment agent according to any one of claims 1 to 8 in sewage treatment.

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