Microbial remediation method for basic chromium pollution soil

A chromium-contaminated soil and microbial remediation technology, applied in the field of chromium-contaminated soil remediation, can solve the problems of less research on remediation, and achieve the effect of reducing bioavailability and good remediation effect

Active Publication Date: 2013-04-03
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, relatively little research has been done on the practical remediation of alkaline-contaminated soils using the isolated microbial strains

Method used

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  • Microbial remediation method for basic chromium pollution soil
  • Microbial remediation method for basic chromium pollution soil
  • Microbial remediation method for basic chromium pollution soil

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Embodiment 1: Screening, isolation and identification of bacterial strains of the present invention

[0024] 1. Enrichment: Collect contaminated soil from the chromium slag yard of the former Hongxing Chemical Plant in Hangzhou, weigh 5g of the soil in 50mL of sterilized liquid LB medium (sodium chloride 5gL -1 , yeast extract 5gL -1 , Tryptone 10gL -1 , pH7.0~7.5), 28°C, 160rpm shaking culture.

[0025] 2. Domestication: When the soil suspension changes from the original yellow (Cr(VI) is yellow) to gray-green (Cr(III) is green), take the supernatant and inoculate it into the newly prepared liquid containing Cr(VI) In LB medium, shake culture at 28°C at 160rpm. When the culture medium turns gray-green again, inoculate it into a liquid medium containing a higher Cr(VI) concentration, thereby gradually increasing the Cr(VI) concentration in the medium. VI) concentration, thereby acclimating the target bacterial strain. The Cr(VI) used in the acclimatization process w...

Embodiment 2

[0029] Embodiment 2: the determination of the culture of thalline and inoculum concentration

[0030] The strain P. saccharolyticum LY10 was cultivated overnight to the logarithmic growth phase, and inoculated in different proportions to contain 100mgL -1 In the liquid LB medium of Cr(VI), the final concentration of bacteria was 8.34×10 5 , 5.68×10 6 , 9.22×10 7 , 6.76×10 8 , 1.47×109cellsmL -1 , 28°C, shaking culture at 160rpm. Samples were taken at different times, and the supernatant was taken after centrifugation at 10,000 rpm for 10 min to determine the content of Cr(VI).

[0031] The test results show that: when the cell concentration is from 8.34×10 5 cells mL -1 increased to 9.22×10 7 cells mL -1 , with the increase of bacterial concentration, the reduction rate of Cr(VI) gradually accelerated. However, as the cell concentration increased from 6.76×10 8 increased to 1.47×10 9 cells mL -1 , the improvement of Cr(VI) reduction rate is not obvious, the result...

Embodiment 3

[0032] Embodiment 3: Microbiological remediation of chromium-contaminated soil

[0033] The alkaline chromium-contaminated soil in the chromium slag yard of the former Hongxing Chemical Plant in Hangzhou was collected. The pH of the contaminated soil was 11.3, and the concentration of water-soluble Cr(VI) was 443.9mg kg -1 . The samples were air-dried and ground and passed through a 100-mesh sieve. Take 5g of sieved soil in a 250mL Erlenmeyer flask, add 15mL to pre-culture, and the cell concentration is 10 7 ~10 8 cells mL -1 cultured at 28°C. Supplement 2 mL of fresh liquid LB medium every 5 days to supplement the water evaporated and the nutrients consumed during the restoration process, so as to ensure the nutritional requirements for bacterial growth and maintain the metabolic activity of cells. Samples were taken at different times to determine the Cr(VI) concentration in the soil. After repairing for 22 days, the soil samples were air-dried and finely ground, and p...

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Abstract

The invention discloses a microbial remediation method for basic chromium pollution soil. The method comprises the following steps of: adding a bacteria solution according to mass-to-volume ratio (g:mL) of the soil to the bacteria solution of 1:3 by taking Pseudochrobactrumsaccharolyticum LY10 as a mediation strain and taking 10<7>-10<8> cellsmL<1> as the bacteria inoculation concentration, culturing at the temperature of 28 DEG C, and supplementing a culture medium for 5 days at intervals, so that the growth and metabolism activity of the bacteria is maintained. After remediation is realized within 22 days, the Cr(VI) removal rate in the soil is 95.9 percent, and the content of the exchangeable chromium can be obviously reduced; and after remediation, the occurrence form of chromium in the polluted soil is obviously changed, the bio-availability is reduced, and a good remediation effect is achieved. The method is easy to operate, economic, effective and environment-friendly and can provide a technical support for promotion of the bioremediation of the chromium pollution soil.

Description

technical field [0001] The invention relates to a restoration method for chromium-contaminated soil, in particular to a microbial restoration method for alkaline chromium-contaminated soil. Background technique [0002] According to preliminary investigations, the total stockpiles of chromium slag in my country currently exceed 6 million tons, scattered in more than 80 places in more than 20 provinces and cities. After decades of rainwater washing and infiltration, the chromium slag storage site has been seriously polluted. According to estimates by relevant experts, the amount of soil that has been seriously polluted by chromium slag and must be treated is estimated to be between 4 million tons and 10 million tons, and the resulting water pollution cannot be ignored. "The Outline of the Eleventh Five-Year Plan for National Economic and Social Development of the People's Republic of China" has listed chromium slag pollution control as a key project of environmental governan...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/10
Inventor 龙冬艳陈英旭
Owner ZHEJIANG UNIV
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