Method for treatig waste water containing chromium with aquatic plant

A technology for aquatic plants and chromium wastewater, applied in the field of treatment of chromium-containing wastewater, can solve the problems of aggravating water eutrophication, no water hyacinth treatment, wild growth of plants, etc., and achieves the effects of easy management, low cost, and easy availability of plants

Inactive Publication Date: 2005-07-27
NANJING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Trivalent chromium is a trace element in human and animal foods, but ingesting large amounts of trivalent chromium may cause lung cancer
There have been patent application documents disclosing that water hyacinth is used to treat nitrogen, phosphorus nutrient salts and organic polluted wastewater (biological treatment technology for factory organic wastewater and organic pollution of rivers and lakes, application number 99103548.8, publication number CN 1269332A), and for the treatment of rich Cyanobacteria in nutrient-rich waters (Cyanobacteria control cyanobacteria in eutrophic waters, application number 01108743.9, publication number CN 1406880A), but there is no report of heavy metal chromium in water treatment by water hyacinth
In Dianchi Lake, Yunnan, water hyacinth was used to control the nitrogen and phosphorus nutrients in the lake, but due to the large lake surface, the plant grew wildly and was difficult to control, which aggravated the eutrophication of the water body

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] The plastic basin used in the laboratory has a diameter of 1m, a height of 0.20m, and a volume of 150L. The water hyacinth is cultivated. The water sample is prepared from tap water with heavy metal salts (analytical pure potassium dichromate, chromium trichloride) to prepare chromium-containing wastewater, and the pH value is 4~ 9. 100 water hyacinths were stocked in it, and the water temperature was 25°C. After several days of cultivation, the plants grew normally. The time taken for the initial concentration to decrease to the fifth-class surface water standard was recorded. The detailed results are shown in the table below. The water hyacinth enriched in chromium was mixed with the soil in a ratio of 1 to 1, and the compost products were analyzed, and no hexavalent chromium was detected.

[0020] No. Initial concentration of hexavalent chromium Initial concentration of trivalent chromium Time taken for the concentration to drop to 0.1mg / L

[0021] Wastewater 1 2mg / ...

Embodiment 2

[0028] A sewage sample was taken from a sewage outlet of a steel company in Nanjing. The chromium content was 7mg / L and the pH was 5.0.

[0029] Water samples were placed in plastic pots with a diameter of 0.50m and a height of 0.15m, and 10 hyacinths were stocked in them. The temperature of the water body was 28°C, and the sunlight was simulated. There were 3 parallel experiments. After 14 days of cultivation, the biomass of chromium increased. 60%, the chromium in the water is reduced to 0.1mg / L. The water hyacinth enriched in chromium was mixed with the soil in a ratio of 1 to 1, and the compost products were analyzed, and no hexavalent chromium was detected.

Embodiment 3

[0031] The waste water from the outlet of a small electroplating factory in a certain town was collected. The chromium content of the waste water reached 15 mg / L, zinc 5 mg / L, copper 7 mg / L, nickel 0.5 mg / L, and the pH was 4.5. Collect water samples to the laboratory, pour them into plastic basins with a diameter of 0.50m and a height of 0.15m, and put 15 water hyacinth plants in them. After 20 days, the chromium content was reduced to below 0.1mg / L. Zinc, copper, nickel dropped to 0.6, 0.2, 0.08mg / L respectively. The chromium-enriched water hyacinth was mixed with the soil in a ratio of 1 to 1 for composting. After the composting was over, the compost products were analyzed and no hexavalent chromium was detected.

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Abstract

A method for treating waste water containing chromium by aquatic plant achieves simple operation, low cost and consumption. The water hyacinth is bred in Spring water body discharged, the breeding area <= water surface area 70%, fishing 1 time / 10-20 days during production period, fishing 1 time / 6-8 days during vigorous period, the collected water hyacinth is used for composting. It advantages include to eliminate residual chromium of river waste water and improve water quality for agricultural and landscape water.

Description

1. Technical field [0001] The invention relates to a method for treating chromium-containing wastewater, in particular to treating chromium-containing wastewater with aquatic plants such as water hyacinth. 2. Background technology [0002] The common forms of chromium in the environment are trivalent chromium and hexavalent chromium. Trivalent chromium is a trace element in human and animal foods, but intake of large amounts of trivalent chromium may cause lung cancer. Hexavalent chromium is highly toxic and a strong carcinogen. It is generally believed that its toxicity is 100 times higher than that of trivalent chromium. The main source of chromium pollution is the processing of chromium-containing ore, metal surface treatment, leather tanning, paint, coating, pigment, wood preservation, printing and dyeing and other industries. In my country, the chromium-containing ore processing industry alone discharges 350,000 to 420,000 tons of chromium slag every year. 6+ The sol...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F3/32
Inventor 刘华良王晓蓉王联红林仁章蒋佳良
Owner NANJING UNIV
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