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CN-121651626-B - Pretreatment process for improving compatibility of river and lake sludge in saline-alkali soil

CN121651626BCN 121651626 BCN121651626 BCN 121651626BCN-121651626-B

Abstract

The invention relates to the technical field of sludge treatment, in particular to a pretreatment process for improving the compatibility of river and lake sludge in saline-alkali soil, wherein the pretreatment process is carried out on the river and lake sludge through salt washing, alkali reduction, structural solidification and nutrient activation, so that the river and lake sludge with good compatibility with the saline-alkali soil is finally obtained; in the structure solidification, the sludge is deodorized by a sludge modifier, the water retention and the air permeability are improved, so that the sludge has a stable internal structure, in the process of nutrient activation, various saline-alkali resistant microorganisms are adopted to further decompose organic matters in the sludge, the fertility of the sludge is improved, and harmful bacteria in the sludge are improved, so that the pretreated sludge is rich in various beneficial microorganisms and has sufficient nutrients, the compatibility with saline-alkali soil is further enhanced, and the method has wide application prospect.

Inventors

  • CHENG YU
  • GU LU
  • Jiang Cidong
  • Xia Zhuyuan
  • ZHANG SONGWEI
  • DENG CHENGPING
  • ZHOU XIN
  • LIU QIANG
  • JIANG XIAYE
  • GE YUN

Assignees

  • 江苏省海洋地质调查院

Dates

Publication Date
20260508
Application Date
20260206

Claims (9)

  1. 1. A pretreatment process for improving compatibility of river and lake sludge in saline-alkali soil, which is characterized by comprising the following steps: S1, dehydrating and crushing dredged sludge, wherein the water content of the dehydrated sludge is less than or equal to 55%, washing once by using citric acid solution with the mass fraction of 0.1% -0.2%, washing 2-3 times by using deionized water, draining, adding an acidity regulator, and regulating the pH value of the system to 7-7.2 to obtain pretreated sludge A; S2, adding a sludge modifier into the pretreated sludge A, fully and uniformly mixing, and piling and aging for 5-7 days to obtain pretreated sludge B; S3, inoculating a microbial composite microbial agent into the pretreated sludge B, turning over and piling uniformly, fermenting, naturally cooling to 25-30 ℃ after the fermentation is finished, standing and ageing for 15-20 days to obtain river and lake sludge with good compatibility with saline-alkali soil; The sludge modifier in the step S2 is obtained by mixing a sludge modifier A and a sludge modifier B according to a mass ratio of 9-13.6:4.3-7.5; The acidity regulator in the step S1 comprises an acidity regulator A and an acidity regulator B; The acidity regulator A is prepared from straw, vinasse and wood chips; The acidity regulator B is phosphogypsum; The preparation method of the acidity regulator A comprises the following steps: step A1, sun drying and crushing straw, vinasse and wood dust, mixing with sodium hydroxide solution, adding into a reaction kettle, heating, stirring and centrifuging to obtain an extracting solution; A2, adding citric acid into the extracting solution while stirring to adjust the pH of the system, and standing to obtain a supernatant A and solid waste B, wherein the supernatant A is an acidity regulator A; The sludge modifier A is obtained by mixing solid waste B, coconut husk, sodium alginate and xanthan gum; The sludge modifier B is obtained by mixing red brick powder, bentonite and bacillus cereus.
  2. 2. The pretreatment process for improving the compatibility of river and lake sludge in saline-alkali soil according to claim 1, wherein the preparation method of the acidity regulator A is as follows: Step A1, sun drying straw, distiller's grains and wood dust until the water content is less than or equal to 12%, pulverizing to 1-3mm with a pulverizer, mixing with 0.2-0.3mol/L sodium hydroxide solution, adding into a reaction kettle, heating, stirring, and centrifuging to obtain extractive solution; A2, adding citric acid into the extracting solution while stirring to adjust the pH of the system to 6-6.5, standing for 12-15h, and collecting supernatant A and solid waste B, wherein the supernatant A is the acidity regulator A.
  3. 3. The pretreatment process for improving the compatibility of river and lake sludge in saline-alkali soil according to claim 1, wherein the dosage ratio of straw, vinasse, wood chips and sodium hydroxide solution in the step A1 is 2-5g:2-5g:60-160mL; The temperature during heating and stirring is 70-75 ℃ and the time is 5-6h.
  4. 4. The pretreatment process for improving the compatibility of river and lake sludge in saline-alkali soil according to claim 1, wherein the mass ratio of the solid waste B to the coco coir to the sodium alginate to the xanthan gum is 3-6:3-6:5.5-8:4-6.
  5. 5. The pretreatment process for improving the compatibility of river and lake sludge in saline-alkali soil according to claim 1, wherein the mass ratio of the red brick powder to the bentonite to the bacillus cereus is 13.9-17:3.5-7:2-5; The total iron content of the red brick powder is more than or equal to 3 percent, and the particle size is 100-150 meshes.
  6. 6. The pretreatment process for improving the compatibility of river and lake sludge in saline-alkali soil according to claim 1, wherein the microbial composite inoculant in the step S3 is prepared from bacillus proteolyticus, bacillus subtilis and klebsiella.
  7. 7. The pretreatment process for improving the compatibility of river and lake sludge in saline-alkali soil according to claim 6, wherein the bacillus proteolyticus, the bacillus subtilis and the klebsiella are formed into a microbial composite microbial agent in the form of bacillus proteolyticus bacterial suspension, bacillus subtilis bacterial suspension and klebsiella bacterial suspension; the mass ratio of the bacillus deproteinized bacterial suspension to the bacillus subtilis bacterial suspension to the klebsiella bacterial suspension is 3-7:2-5:2-5; The viable count of bacillus proteolyticus in the microbial composite microbial agent is 4 multiplied by 10 7 -4×10 9 CFU/mL, the viable count of bacillus subtilis is 2 multiplied by 10 8 -2×10 10 CFU/mL, and the viable count of klebsiella is 5 multiplied by 10 6 -5×10 7 CFU/mL.
  8. 8. The pretreatment process for improving the compatibility of river and lake sludge in saline-alkali soil according to claim 1, wherein the fermentation temperature in the step S3 is 50-55 ℃ and the fermentation time is 9-12 days, and the pile is turned 3-4 times during the fermentation.
  9. 9. The pretreatment process for improving the compatibility of river and lake sludge in saline-alkali soil according to claim 1, wherein the mass ratio of the pretreated sludge A to the sludge modifier in the step S2 is 100-180:35-55; and in the step S3, the mass ratio of the pretreated sludge B to the microbial composite microbial agent is 75-100:18-30.

Description

Pretreatment process for improving compatibility of river and lake sludge in saline-alkali soil Technical Field The invention relates to the technical field of sludge treatment, in particular to a pretreatment process for improving compatibility of river and lake sludge in saline-alkali soil. Background Saline-alkali soil is a generic term for saline-alkali soil and alkaline earth, and various salinized and alkalinized soil. The saline soil is soil which contains a large amount of soluble salts and can not grow most plants, the salt content of the saline soil is generally more than 0.6%, and the alkaline earth is strong alkaline soil with the percentage of the substitution amount of the substituted sodium ion cations (ESP) exceeding 20%. The salinized soil has poor physical and chemical properties, and is mainly characterized by too high salinity or alkalinity, so that plant roots are lack of water or are poisoned, the soil is sticky and heavy in texture, aggregates are less, the soil is hardened during drought, water permeability and air permeability are poor, and the salinized soil is extremely unfavorable for agricultural production. At present, measures for treating the saline-alkali soil can be roughly classified into engineering improvement, chemical improvement, biological improvement and the like. The engineering improvement measures mainly comprise the cultivation measures of leveling the land, digging a drainage ditch, turning over the land, rotary tillage, soaking the field and the like, and the water level is reduced by using open ditch drainage or vertical drainage to reduce the rising of saline and alkaline, or the improvement is carried out by irrigating and washing the saline and alkaline and the like, or a salt discharging pipeline and a salt discharging hole are constructed, so that the salt in the saline and alkaline land is discharged out of the field through the salt discharging hole and the salt discharging pipe. The silt mainly exists in the channel, mainly exists in the river course that velocity of flow is slow even still, forms through the biochemical action, and the production of silt can make the shipping of river course influenced, quality of water and river course environment. The dredging sludge contains more organic matters and contains elements such as nitrogen, phosphorus, potassium and the like in the plant growth process. The sludge subjected to recycling treatment must meet the requirements that heavy metals cannot exceed standards, toxic and harmful organic matters cannot exceed standards, peculiar smell is eliminated and nutrient elements are reserved. The treated sludge is used as fertilizer to improve soil structure and avoid soil hardening. At present, dredging sludge is used as a soil conditioner for improving saline-alkali soil, but the problems of pH value conflict, salinity conflict and insufficient nutrients exist in the mixing of the dredging sludge and saline-alkali soil. Therefore, according to the related art in the above, there is a need to develop a pretreatment process for improving the compatibility of river and lake sludge in saline-alkali soil. Disclosure of Invention In view of the above, the invention aims to provide a pretreatment process for improving the compatibility of river and lake sludge in saline-alkali soil, so as to solve the problem of poor compatibility of saline-alkali soil and river and lake sludge in the prior art. Based on the above objects, the present invention provides a pretreatment process for improving the compatibility of river and lake sludge in saline-alkali soil. A pretreatment process for improving compatibility of river and lake sludge in saline-alkali soil comprises the following steps: S1, dehydrating and crushing dredged sludge, wherein the water content of the dehydrated sludge is less than or equal to 55%, washing once by using citric acid solution with the mass fraction of 0.1% -0.2%, washing 2-3 times by using deionized water, draining, adding an acidity regulator, and regulating the pH value of the system to 7-7.2 to obtain pretreated sludge A; S2, adding a sludge modifier into the pretreated sludge A, fully and uniformly mixing, and piling and aging for 5-7 days to obtain pretreated sludge B; S3, inoculating a microbial composite microbial agent into the pretreated sludge B, turning over and piling uniformly, fermenting, naturally cooling to 25-30 ℃ after the fermentation is finished, standing and ageing for 15-20 days to obtain river and lake sludge with good compatibility with saline-alkali soil; the sludge modifier in the step S2 is obtained by mixing a sludge modifier A and a sludge modifier B in a mass ratio of 9-13.6:4.3-7.5. Preferably, the acidity regulator in step S1 includes acidity regulator a and acidity regulator B; The acidity regulator A is prepared from straw, vinasse and wood chips; the acidity regulator B is phosphogypsum. Preferably, the preparation method of the acidity regulator A comprises