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Chromium-containing sludge treatment method and system based on supercritical water oxidation reaction

A supercritical water oxidation and sludge treatment technology, applied in water/sludge/sewage treatment, sludge treatment, dehydration/drying/thickened sludge treatment, etc., to reduce leaching toxicity, simple process, and large resource utilization Effect

Inactive Publication Date: 2019-06-11
SHAANXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] At present, supercritical water oxidation technology is mainly used to treat various organic polluted wastewater, and no scholars have used supercritical water oxidation technology to conduct some in-depth research on Cr

Method used

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  • Chromium-containing sludge treatment method and system based on supercritical water oxidation reaction
  • Chromium-containing sludge treatment method and system based on supercritical water oxidation reaction
  • Chromium-containing sludge treatment method and system based on supercritical water oxidation reaction

Examples

Experimental program
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Effect test

Embodiment 1

[0049] A method for treating chromium-containing sludge, comprising the following steps:

[0050] 1) Pretreatment: Before the experiment, the sludge was dried in a high-temperature oven at 105°C for 24 hours to ensure that the water was completely lost. Then use a planetary ball mill to grind the solid sludge into powder, use a vibrating sieve to divide the sludge into different particle sizes, and use the sludge powder under a 300-mesh sieve as the original sludge.

[0051] Take 1g of raw sludge and weigh it, put it into a muffle furnace and burn it at 600°C until it reaches a constant weight, then weigh it and subtract it from the initial value to get the organic matter content, which is 49.9%.

[0052] Take 0.1000g of raw sludge, add 2mL of ultrapure water to wet it in a polytetrafluoroethylene crucible, and then add 5mL of 98% HNO 3 and 2mL HF, heated on a hot plate (temperature 150-200°C) until nearly dry, then removed and cooled to room temperature. Add 5mL HF and cont...

Embodiment 2

[0058] Compared with Example 1, the difference is that the temperature of the supercritical water oxidation reaction is adjusted to 470°C.

[0059] Test Results:

[0060] The removal rate of TOC in sludge can reach 98.9%, the lowest is 16.92mg / L. The supernatant Cr is 1074.8mg / L, and 67.2% of the Cr in the sludge will be transferred to the liquid phase, and the sludge cannot meet the national discharge requirements.

Embodiment 3

[0062] Compared with Example 1, the difference is that the temperature of the supercritical water oxidation reaction is adjusted to 520°C.

[0063] Test Results:

[0064] At 520°C, the supernatant TOC is 15.7mg / L, and the removal rate can still reach 99%. The supernatant Cr reaches 1219.1mg / L, and the Cr mobility is 73.0%. The sludge does not meet the national discharge requirements.

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Abstract

The invention discloses a chromium-containing sludge treatment method based on a supercritical water oxidation reaction. After heating, drying and grinding the sludge, the sludge is then diluted intoa diluted sludge with a certain moisture content; after the combined treatment of ultrasonic treatment and supercritical water oxidation, the treated solid-liquid organic matter is completely degraded; Cr ions are oxidized into hexavalent chromium and transferred to a liquid phase; solid-phase residue basically does not contain heavy metal chromium, so safe landfill can be conducted, while chromium in a supernatant can be recycled. A chromium-containing sludge treatment system based on the supercritical water oxidation reaction is also disclosed, including a pretreatment unit, an ultrasonic treatment unit and a supercritical water oxidation unit. The pretreatment unit includes a material storage tank, a heater and a grinder. The ultrasonic treatment unit uses an ultrasonic processor. The supercritical water oxidation unit includes a reactor, an oxygen tank, a temperature controller and a pressure controller.

Description

technical field [0001] The invention belongs to the field of environmental protection, and in particular relates to a method and system for treating chromium-containing sludge based on supercritical water oxidation reaction. Background technique [0002] With the development of tannery industrialization, tannery sludge has become a major pollution source that threatens the environment. In addition to organic pollutants, the main toxicity of tannery sludge comes from heavy metal chromium. Chromium in tannery sludge is mainly combined with compounds such as calcium salt minerals, crystalline iron oxides and crystalline chromium oxides, and belongs to a strongly bound state. Chromium in these bound states presents a high risk of ecological hazard. The trivalent chromium in the sludge will be oxidized and converted into hexavalent chromium during the reaction process. The toxicity of hexavalent chromium is about 100 times that of trivalent chromium. It is a strong mutation sub...

Claims

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Application Information

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IPC IPC(8): C02F11/00C02F11/13C02F11/06C02F101/22
Inventor 马宏瑞李晓洁朱超杨永林陈丰羽吴昕
Owner SHAANXI UNIV OF SCI & TECH
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