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Treatment method for synchronously removing COD (Chemical Oxygen Demand) and rigidity of waste water

A treatment method and technology for wastewater, applied in neutralized water/sewage treatment, oxidized water/sewage treatment, flocculation/sedimentation water/sewage treatment, etc. effect and other issues, to achieve the effect of reuse, complete precipitation, and reduction of hardness

Active Publication Date: 2013-09-18
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of conventional Fenton are: (1) After the Fenton reaction, the pH of the wastewater is adjusted to neutral, and a large amount of alkaline substances need to be injected; (2) Fenton chemical oxidation is effective in removing COD and chroma, but the efficiency of COD removal It can still be further improved, and basically has no effect on the removal of hardness
The treatment process is relatively complicated, the dosage of acid and alkali is large, and the operating cost is high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Treatment of reverse osmosis concentrated water in a printing and dyeing factory, sewage properties: pH, COD, hardness (as CaCO 3 meter), conductivity were 8.23, 106.8mg / L, 116.9mg / L, 20.6ms / cm.

[0031] Take part of the high-concentration wastewater and put it into the oxidation tank, add H 2 o 2 and FeCl 2 , H 2 o 2 / Fe 2+ The molar ratio is 0.5:1, FeCl 2 The dosage is 0.3g / L. After adding the above reagents, it is necessary to add a small amount of sulfuric acid to adjust the pH to 3-4. Under the above conditions, carry out the Fenton reaction, and the reaction time is 30min. After the reaction, add Ca(OH) at the ratio of 1g / L waste water 2 , the measured pH value was 10.08, then adding Na 2 CO 3 , the dosage is 2g / L waste water, after stirring, the water with COD and hardness removed is obtained, and the treatment effect is shown in Table 1.

[0032] Table 1 Treatment effect of reverse osmosis concentrated water in a factory

[0033] indicators ...

Embodiment 2

[0036] Treatment of oil extraction wastewater from an oilfield, the nature of the wastewater: CaCl with high salinity and high iron content 2 Water type, with strong corrosiveness and scaling, COD and hardness are 400-500mg / L and 250-300mg / L respectively.

[0037] Take part of the high-concentration wastewater and put it into the oxidation tank, add H 2 o 2 and FeSO 4 , H 2 o 2 / Fe 2+ The molar ratio is 1:1, FeSO 4 The dosage is 2.0g / L waste water, after adding the above reagents, add a small amount of hydrochloric acid to adjust the pH to 3-4, carry out Fenton reaction under the above conditions, and the reaction time is 60min. After the Fenton reaction is completed, add Ca(OH) at a ratio of 3.5g / L to waste water 2 , the measured pH value was 10.58, then adding Na 2 CO 3 , the dosage is 4.5g / L waste water, after stirring, the water with COD and hardness removed is obtained, and the treatment effect is shown in Table 2.

[0038]In this embodiment, there is no need to...

Embodiment 3

[0042] Treatment of landfill leachate MBR effluent, sewage properties: COD and hardness are 1000-1100mg / L and 500-700mg / L respectively.

[0043] Take part of the high-concentration wastewater and put it into the oxidation tank, add H 2 o 2 and FeSO 4 , H 2 o 2 / Fe 2+ The molar ratio is 2.5:1, FeSO 4 The dosage is 2.4g / L wastewater. After adding the above reagents, add a small amount of sulfuric acid to adjust the pH to 3-4. Under the above conditions, carry out Fenton reaction, and the reaction time is 90min. After the Fenton reaction is completed, add Ca(OH) in the proportion of 6g / L waste water 2 , the measured pH value was 11.23, then adding Na 2 CO 3 , the dosage is 7g / L waste water, the water with COD and hardness removed is obtained after stirring, and the treatment effect is shown in Table 3.

[0044] Table 3 Treatment effect of MBR effluent in a landfill

[0045] indicators

[0046] In this embodiment, there is no need to add additional alkali to ad...

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Abstract

The invention belongs to the field of waste water treatment, and discloses a treatment method for synchronously removing the COD (Chemical Oxygen Demand) and rigidity of waste water. The treatment method particularly comprises the following steps of: adding ferrous salt and hydrogen peroxide to the waste water, and adding acid for controlling pH to 3-4 and having reaction; adding calcium hydroxide so that the pH is more than 10, then adding sodium carbonate, and stirring to obtain water with COD and the rigidity removed. The treatment method disclosed by the invention can be used for removing COD out of the waste water through a Fenton method and removing the rigidity by adopting a precipitation method, improves the removal ratio of the COD to 86% which is higher than the removal efficiency of the conventional Fenton oxidation by utilizing the absorption synergistic action of the precipitation method on COD removal and increases the removal ratio of the rigidity to 96%.

Description

technical field [0001] The invention belongs to the field of waste water treatment, in particular to a treatment method for synchronously removing COD and hardness of waste water. Background technique [0002] Fenton is a kind of advanced oxidation technology in water treatment, which refers to H 2 o 2 in Fe 2+ Under the catalytic action of catalysis, strong oxidizing hydroxyl radical OH is generated. ·OH attacks the C-H bond, C-C bond or C≡C bond to cause chain scission or ring opening of organic matter, and is rapidly oxidized and decomposed. This method is highly efficient and non-toxic, especially has outstanding advantages in the treatment of refractory biodegradable organic matter in wastewater, which can completely oxidize refractory biodegradable organic matter into CO 2 and H 2 O, so as to reduce the COD of sewage; it can also partially oxidize the refractory organic matter into biodegradable small molecules, oxygen-containing organic matter (such as alcohol, a...

Claims

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Application Information

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IPC IPC(8): C02F1/72C02F1/66C02F1/52
Inventor 汪晓军袁延磊崔家琪顾晓扬
Owner SOUTH CHINA UNIV OF TECH
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