Method for removing heavy metals in urban waste incineration flying ash through bioleaching technology

A technology of urban waste and incineration fly ash, which is applied in the field of environmental engineering, can solve the problems of high extraction cost, waste of inorganic salt culture solution, etc., and achieve the effect of increasing cycle extraction times and improving regeneration performance

Inactive Publication Date: 2016-08-31
BEIJING INSTITUTE OF TECHNOLOGYGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, autotrophic bioleaching is usually only performed once, resulting in a great waste of inorganic salt culture solution and still high leaching costs

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Use tap water to prepare inorganic salt culture solution, and its components are as follows: KNO 3 , 0.5g / L; (NH 4 ) 2 SO 4 , 2.0g / L; KH 2 PO 4 , 1.0g / L; Na 3 PO 4 , 0.5g / L; FeSO 4 , 0.2g / L; MgSO 4 , 0.1g / L; CaCl 2 , 0.2g / L; Na 2 S 12g / L; Sulfur, 10g / L; Pyrite 12g / L; Natural pH. Inoculate the basic working bacteria agent at a concentration of 8% (V / V), cultivate it for 8 days at a culture temperature of 32°C, aerated dissolved oxygen at 80% saturation, and a stirring speed of 80 rpm, until the pH value of the system is reduced to 1.0 , Fe 2+ Concentration rose to 400mg / L, Fe 3+ After the concentration rose to 500mg / L, the solid matter was removed by suction filtration, and the extract was collected for the extraction of washed fly ash (3 washes, single gray-water ratio 1:3, total gray-water ratio 1:9). After the solid-to-liquid ratio is 6%, the stirring speed is 60 rpm, and the leaching time is 4 hours, the pH of the system rises to 4.6, and the fly ash lea...

Embodiment 2

[0033] The inorganic salt culture solution was prepared with tap water and placed in a membrane bioreactor (the membrane module is a 0.45 micron polytetrafluoroethylene microfiltration flat membrane). The composition of the inorganic salt culture solution is as follows: KNO 3 , 0.8g / L; (NH 4 ) 2 SO 4 , 2.2g / L; KH 2 PO 4 , 1.0g / L; Na 3 PO 4 , 0.7g / L; FeSO 4 , 0.2g / L; MgSO 4 , 0.1g / L; CaCl 2 , 0.2g / L; Na 2 S 12g / L; Sulfur, 10g / L; Pyrite 6.0g / L; Natural pH. Inoculate the basic working bacteria agent at a concentration of 10% (V / V), cultivate it for 7 days at a culture temperature of 33°C, aerated dissolved oxygen at 90% saturation, and a stirring speed of 60 rpm, until the pH value of the system is reduced to 1.0 , Fe 2+ Concentration rose to 200mg / L, Fe 3+ After the concentration rises to 350mg / L, turn on the inlet and outlet water to maintain balance and adjust the speed of the inlet and outlet water to control the pH of the outlet water to stabilize at 1.0. The e...

Embodiment 3

[0035] Use tap water to prepare inorganic salt culture solution, and its components are as follows: KNO 3 , 0.8g / L; (NH 4 ) 2 SO 4 , 1.8g / L; KH 2 PO 4 , 1.2g / L; Na 3 PO 4 , 0.8g / L; FeSO 4 , 0.1g / L; MgSO 4 , 0.1g / L; CaCl 2 , 0.2g / L; Na 2 S, 10g / L; sulfur, 15g / L; pyrite, 10g / L; natural pH. Inoculate the compound bacterial agent at a concentration of 10% (V / V), cultivate it for 9 days at a culture temperature of 33°C, aerated dissolved oxygen at 85% saturation, and a stirring speed of 75 rpm, until the pH value of the system is reduced to 0.8 , Fe 2+ Concentration rose to 300mg / L, Fe 3+ After the concentration rose to 400mg / L, the solid matter was removed by suction filtration and the extract was collected for the extraction of washed fly ash (3 washes, single gray-water ratio 1:4, total gray-water ratio 1:12). After the solid-to-liquid ratio is 5%, the stirring speed is 60 rpm, and the leaching time is 5 hours, the pH of the system rises to 4.8, and the fly ash leac...

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PUM

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Abstract

Flying ash is hazardous waste which is produced during household garbage incineration power generation and contains various toxic metals, the stabilization / solidification landfill cost of the mainstream disposal process of the flying ash is 2000-3000 yuan / ton, and the environmental risk of the toxic metals still exists. Removal of the toxic metals from the flying ash is the premise of low-limit / non-limit resource utilization of the flying ash. Low-price inorganic energy substrates such as sulphur are used as working media, and efficient, environment-friendly and safe extraction of the toxic metals in the flying ash is achieved under the conditions of normal temperature and pressure through the direct / indirect action of autotrophy leaching inocula. Besides, through desalting and dealkalization with water scrubbing, bacterial strain compounding and breeding of high-salt-tolerance bacterial strains, the regeneration performance of leachate organisms is obviously improved, the circulation leaching frequency is greatly increased, and thus the consumption of inorganic salt culture solutions in the leaching process is greatly lowered, and the bioleaching cost is further reduced. The detoxified flying ash is used for resource utilization such as manufacturing of bricks, roadbeds and concrete, the high cost of the traditional landfill process is saved, and the potential environmental risk is eliminated.

Description

technical field [0001] The invention relates to a method for removing heavy metals in urban waste incineration fly ash by using biological leaching technology, and belongs to the technical field of environmental engineering. Background technique [0002] At present, the problem of urban garbage in my country is becoming more and more prominent. Two-thirds of the cities in the country are surrounded by garbage, and one quarter of them has no landfill sites. In 2015, the output of urban waste reached 260 million tons, and the annual growth rate is 8%-10%. Waste incineration power generation has become the best way to reduce the amount of municipal mixed waste due to its thorough harmlessness, efficient reduction and considerable energy conversion. During the 13th Five-Year Plan period, the proportion of waste incineration power generation will increase from the current 25% to 50%. [0003] Fly ash is a hazardous waste collected from domestic waste incineration power generati...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B7/02C22B3/18
CPCC22B3/18C22B7/006C22B7/02Y02P10/20
Inventor 辛宝平王佳田炳阳
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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