CN-121975905-A - Method for enriching alkali-resistant mineralized solution and modifying cement mortar by sludge mixed bacteria

CN121975905ACN 121975905 ACN121975905 ACN 121975905ACN-121975905-A

Abstract

The application belongs to the technical field of microbial reinforced building materials, and in particular relates to a method for enriching an alkali-resistant mineralized solution of sludge mixed bacteria and modifying cement mortar, which comprises the following steps of selecting activated sludge of a sewage treatment plant and garden soil as separate inoculation sources, adding the activated sludge and garden soil into a selected culture solution containing carbon sources, nitrogen sources, trace elements and mineral substances, adjusting the pH value of the system to a high-alkali condition under the action of an alkaline regulator, realizing the screening and enrichment of mixed bacteria by multi-period culture, collecting thalli after solid-liquid separation and performing expansion culture in an expansion culture medium to obtain the alkali-resistant mineralized solution of sludge mixed bacteria with mineralized capacity and adapting to the high-alkali environment; the solution is inoculated into mineralized nutrient solution containing inorganic calcium source to prepare microorganism mineralized solution, and the microorganism mineralized solution is used as mixing solution to prepare cement mortar, so that calcium carbonate is deposited in situ in mortar pores, the compactness, compressive strength and durability of the cement mortar are obviously improved, and the mineralized modified effect of the cement mortar is greatly better than that of a single strain.

Inventors

Guan Ta
JIA ZHIYI
Hao Xingdong
SUN JIA
Ge Kaixin

Assignees

西安科技大学
中国电建集团西北勘测设计研究院有限公司

Dates

Publication Date: 20260505
Application Date: 20251212

Claims (10)

1. The enrichment method of the alkali-resistant mineralized solution for the sludge mixed bacteria is characterized by comprising the following steps of: activated sludge and garden soil of a sewage treatment plant are selected as separated inoculation sources, and the separated inoculation sources are added into a selective culture solution to form an inoculation system; The selective culture solution at least comprises a carbon source, a nitrogen source, a trace element solution, a mineral solution and water, wherein the total mass of all components in the selective culture solution is 100 parts by mass, the carbon source is 0.5-10 parts by mass, the nitrogen source is 0.001-1 part by mass, the trace element solution is 0.5-10 parts by mass, the mineral solution is 0.5-10 parts by mass, and the balance is water; adding an alkaline regulator into the inoculation system, regulating the pH of the system to 10-12, performing aerobic culture under the oscillation conditions of 30+/-5 ℃ and 50-150 r/min, replacing the selected culture solution at intervals of 1-3 d, continuously culturing for 1-4 periods, wherein the culture time of each period is 10-30 d, and screening and enriching the sludge mixed flora in a high-alkaline environment to obtain an enriched bacterial solution suitable for the high-alkaline environment; and (3) carrying out solid-liquid separation on the enriched bacterial liquid, collecting bacterial bodies, and carrying out expansion culture in an expansion culture medium containing a carbon source, a nitrogen source and inorganic salt to obtain the sludge mixed bacteria alkali-resistant mineralized solution which has mineralization capability and is suitable for a high-alkali environment.
2. The method for enriching an alkali-resistant mineralized solution according to claim 1, characterized in that in the alkali-resistant mineralized solution, the total relative abundance of all bacteria is 100%, the relative abundance of bacteria belonging to Halomonas is 40-80%, the relative abundance of bacteria belonging to Alkaliphilus-30%, the relative abundance of bacteria belonging to Alidiomarina haloalkalitolerans is 1-15%, the relative abundance of bacteria belonging to Salipaludibacillus is 1-10%, the relative abundance of bacteria belonging to Nitrincola is 1-10%, the relative abundance of bacteria belonging to Rhodobacteraceae is 1-10%, the relative abundance of bacteria belonging to Anaerobacillus is 1-10%, the relative abundance of bacteria belonging to Alidiomarina is 1-10%, and the relative abundance of bacteria belonging to Bacillus is less than 10%.
3. The enrichment method of the alkali-resistant mineralized solution for sludge mixed bacteria of claim 1, wherein the addition amount of the activated sludge and garden soil is 1 (0.5-2) in terms of mass ratio.
4. The enrichment method of the sludge mixed bacteria alkali-resistant mineralized solution is characterized in that a carbon source in the selected culture solution is glucose and/or lactic acid, a nitrogen source is ammonium chloride and/or ammonium nitrate, and the mineral solution comprises 1-5 parts by mass of calcium chloride, 1-5 parts by mass of magnesium sulfate and 0.5-3 parts by mass of potassium chloride.
5. The method for enriching an alkali-resistant mineralized solution with sludge mixed bacteria according to claim 1, wherein the microelement solution comprises ethylenediamine tetraacetic acid and at least one of salts containing iron, zinc, cobalt, manganese, copper, molybdenum, nickel, selenium and boron.
6. The method for enriching an alkali-resistant mineralized solution by sludge mixed bacteria according to claim 1, wherein the alkaline regulator is trisodium phosphate.
7. The method for modifying cement mortar by using the alkali-resistant mineralization solution for sludge mixing is characterized by comprising the following steps: The alkaline-resistant mineralized solution of the sludge mixed bacteria obtained by the enrichment method of the alkaline-resistant mineralized solution of the sludge mixed bacteria is inoculated into mineralized nutrient solution according to the volume ratio of 1 (0.5-2), so as to obtain the mineralized solution of microorganisms; The mineralized nutrient solution comprises 8-12 parts by mass of inorganic calcium source, 4-6 parts by mass of yeast powder, 4-6 parts by mass of sodium chloride, 0.8-1.2 parts by mass of glucose and 18-22 parts by mass of urea; And taking the microbial mineralization solution as a mixing solution of the cement mortar, enabling the microbial mineralization solution to replace all or part of mixing water, cement and aggregate to be mixed together for molding, and curing, so that mixed microbial flora in the sludge mixed bacteria alkali-resistant mineralization solution induces calcium carbonate mineral to be deposited in situ in the mortar under the high alkali environment of the cement mortar.
8. The method for modifying cement mortar by using the alkali-resistant mineralized solution for sludge mixing according to claim 7, wherein the usage amount of the microbial mineralized solution for replacing mixing water is 40-100% of the total mixing water volume of the cement mortar, the mass ratio of cement to sand is 1:2-1:3, and the water-cement ratio is 0.35-0.50.
9. The method for modifying cement mortar by using the alkali-resistant mineralized solution for sludge mixing according to claim 7, wherein the inorganic calcium source is calcium acetate, and the weight of the calcium acetate is 15-25 parts.
10. The method for modifying cement mortar by using the alkali-resistant mineralized solution for sludge mixing according to claim 7, wherein the cement is 42.5-grade Portland cement, the aggregate is standard sand conforming to the ISO standard, and the cement mortar is cured under the conditions of 20+/-2 ℃ and relative humidity of not less than 95% after stirring and molding.

Description

Method for enriching alkali-resistant mineralized solution and modifying cement mortar by sludge mixed bacteria Technical Field The application belongs to the technical field of microbial reinforced building materials, and particularly relates to a method for enriching an alkali-resistant mineralized solution for sludge mixing and modifying cement mortar. Background Sludge is a necessary byproduct in the sewage treatment process, the yield is huge, the components are complex, and the disposal and the digestion of the sludge are all the problems in the field of environmental engineering. The accumulation of a large amount of sludge occupies land, and pathogens, organic pollutants, heavy metals and the like contained in the sludge are more likely to cause secondary pollution to surrounding soil, water and atmosphere, and if the sludge is improperly treated, the ecological environment and public health are seriously threatened. Conventional sludge disposal methods mainly include sanitary landfill, land utilization, incineration, and the like, however, these methods have significant limitations. Landfill needs to occupy a large amount of land resources and has long-term environmental risks, direct land utilization is limited by the components and stability of pollutants in sludge, and incineration is high in cost and easy to produce harmful gases. On the other hand, in the field of building materials, the common glue sand block has the problems of large brittleness, poor cracking resistance, insufficient durability and the like, and the performance of the common glue sand block needs to be further improved. In recent years, with the deep concept of 'abolished city city' and resource circulation, the recycling way of sludge becomes a research hot spot. Under the background, the microorganism mineralization technology provides a new idea for simultaneously solving sludge recycling and material modification due to the characteristics of green, economical and remarkable efficiency. The mixed bacteria system with high-efficiency mineralization capacity can be obtained by culturing and domesticating the diversified microbial flora rich in the sludge. The microorganism-induced calcium carbonate deposition technique (MICP) can utilize such a mixed bacteria, which is incorporated into the gum sand matrix, creating calcium carbonate precipitates at internal pores and microcracks. The deposition can not only effectively solidify the rubber sand block body and improve the mechanical strength of the rubber sand block body, but also can realize the sealing and storage of partial harmful substances in the sludge, and shows the dual environmental and engineering benefits of 'treating waste with waste'. However, the research of mixing bacteria liquid cultured by sludge and garden soil into the gum sand block is still under the exploring stage, and a plurality of technical bottlenecks and challenges are faced. Firstly, the mixed bacterial liquid derived from sludge has essential differences from a single bacterial strain purely cultured in a laboratory in bacterial composition, activity and metabolic products, the components are more complex, the activity fluctuation of the bacterial strain is large, the mineralization efficiency and stability of the bacterial liquid in a gel sand system are directly affected, meanwhile, compared with the bacterial liquid used for soil solidification or restoration directly, the gel sand block is used as a compact cement-based material, the internal pore structure is fine, and more importantly, the high-alkali environment (pH is usually higher than 12) formed by cement hydration is strictly tested on the survival, migration and mineralization behaviors of microorganisms, and most microorganisms are easy to inactivate or block metabolism under the conditions, so that the existing microorganism reinforcement technology aiming at porous media or loose bodies is difficult to be directly applied. In the prior art, a conventional mode of simply mixing bacterial liquid with mixing water and then injecting the bacterial liquid at one time is adopted, and the method has obvious defects that firstly, a rigid structure formed rapidly in the mixing and condensing process of the colloidal sand can prevent bacterial strains and nutrients thereof from further diffusing and distributing in the interior, so that the mineralization of microorganisms is only concentrated on a surface layer or a specific area, and secondly, a large number of microorganisms are rapidly deactivated due to the fact that strong alkalinity is difficult to be tolerated and mineral cannot be continuously generated in the high alkalinity environment of early hardening of the colloidal sand, so that the modification effect is greatly reduced, and long-term and stable performance improvement is difficult to realize. In addition, the existing method lacks systematic research in the aspects of fungus liquid adding time, compatibility with addi