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A sludge pretreatment process with desalination effect

A sludge treatment and pretreatment technology, which is applied in sludge treatment, water/sludge/sewage treatment, chemical instruments and methods, etc., can solve the problems of reduced efficiency of anaerobic digestion and aerobic composting, sludge drying and incineration Increased costs, reduced organic matter components, etc., to reduce the risk of heavy metal pollution, facilitate subsequent treatment, and increase the calorific value

Active Publication Date: 2017-08-01
TIANJIN ENEW ENVIRONMENTAL PROTECTION ENGCO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] With the improvement of sewage treatment and discharge standards in recent years, the traditional biochemical treatment process of sewage plants has been unable to meet the discharge requirements of total phosphorus. At the same time, considering the cost factor, most water plants use chemical phosphorus removal methods and add a large amount of iron to the treatment process. Salt or aluminum salt flocculants mix a large amount of inorganic metal salts into the activated sludge of water plants, thereby reducing the organic components in the mixed sludge, and finally lead to the fact that inorganic salts account for dry sewage in the sludge of sewage plants. 35% or even more of the sludge component, which brings many problems to the subsequent treatment and disposal of the sludge
For example, the reduction of organic components in sludge leads to a decrease in the efficiency of anaerobic digestion and aerobic composting, and the large amount of inorganic components in sludge leads to a decrease in the calorific value of sludge, which also greatly increases the cost of sludge drying and incineration, etc.
In addition, for urban water supply plants, because of the need to remove suspended solids in the water during the treatment process, a large amount of flocculants will also be invested, resulting in a large amount of inorganic metal salts in the water supply plant sludge, which is difficult to efficiently recycle in the future

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  • A sludge pretreatment process with desalination effect
  • A sludge pretreatment process with desalination effect
  • A sludge pretreatment process with desalination effect

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] as attached figure 1As shown, the water content of the water supply plant sludge is 80-85%, randomly sampled, and after partial drying, the total content of iron salts and aluminum salts in the sludge is measured by a spectrophotometer as 65%, and the sludge is put into the sludge Mud conditioning tank, add water to condition and dilute to 90% water content, put the sludge into the pickling tank, then put 20% hydrochloric acid, fully stir and react for 70 minutes for pickling, after pickling, use gravity concentration method to concentrate , the concentration time is 30 minutes to obtain desalted sludge and pickling solution, the pH of the pickling solution is 6, randomly sample, and use a spectrophotometer to detect the total content of inorganic salts after partial drying is 5%, and the sludge enters the sludge treatment; the washing liquid is discharged into the purification pool, and then poured Put in sodium hydroxide, adjust the pH to 4, obtain the purified liquid...

Embodiment 2

[0047] as attached figure 2 As shown, the municipal sludge of the sewage treatment plant has a moisture content of 85-99.8%. Random sampling is used to detect the organic matter content of 45% by gravimetric method, and the total content of inorganic salts is detected by spectrophotometer and other methods after partial drying. 36%, put the sludge into the pickling tank, then put in 35% sulfuric acid to pickle the sludge, stir and react for 30 minutes, make the pH6. Random sampling, part of the organic matter content was detected by gravimetric method to be 58%, and the total content of inorganic salt was detected by spectrophotometer and other methods after part of drying was 14%, and the inorganic salt was removed by 61%. After the acidity was adjusted, the sludge entered the sludge treatment; The pickling solution enters the purification tank, then puts calcium oxide into the purification tank, adjusts the pH to 7, and obtains the purified solution and the precipitate cont...

Embodiment 3

[0049] as attached image 3 As shown, take the dewatered sludge from the sewage plant, the water content of the sludge is 80-85%, random sampling, part of the organic matter content is 35% by gravimetric method, and the total content of inorganic salts is detected by spectrophotometer and other methods after part of the drying. 40%, put the sludge into the sludge conditioning tank, add water to condition and dilute to a water content of 95%, enter the pickling device, then put in 10% oxalic acid and 20% sulfuric acid, and fully stir the reaction for 120 minutes to make the pH 6.5, take random samples, partly use the gravimetric method to detect the organic matter content of 55%, and partly use spectrophotometer and other methods to detect after drying The total content of inorganic salts is 4%, and 90% of inorganic salts are removed, and the second washing sludge enters the sludge treatment; the washing liquid is discharged into the purification pool, and then magnesium oxide ...

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Abstract

The invention provides a sludge pretreatment technology with a desalting effect. The sludge pretreatment technology with the desalting effect comprises the following steps of (1) placing sludge in an acid pickling device, feeding acid to perform acid pickling, and separating after stirring reaction to obtain desalted sludge and acid pickling liquid which contains inorganic salt and has pH value smaller than 2; (2) feeding the acid pickling liquid obtained in the step (1) in a purification pond, adding moderately strong alkali to regulate the pH value to 4-8 so as to obtain purified liquid and precipitates, and feeding the purified liquid to a sewage treatment device; (3) feeding the precipitates obtained in the step (2) in a regulating pond and adding inorganic acid to obtain flocculating agents; and (4) feeding the desalted sludge obtained in the step (1) in an acidity returning pond, adding moderately strong alkali until the pH value is greater than 6, and feeding obtained reactant to the sewage treatment device. The sludge pretreatment technology is used prior to a conventional sludge treatment technology. After the sludge is treated by the technology, inorganic salts in the sludge are reduced by 50-90%, and the extracted inorganic salts can be prepared into flocculating agents, fertilizer raw materials or building materials. Follow-up sludge treatment efficiency is improved, and treatment facility scale and operating cost are reduced.

Description

technical field [0001] The invention belongs to the field of sludge treatment, in particular to a sludge pretreatment process with desalination effect. Background technique [0002] With the improvement of sewage treatment and discharge standards in recent years, the traditional biochemical treatment process of sewage plants has been unable to meet the discharge requirements of total phosphorus. At the same time, considering the cost factor, most water plants use chemical phosphorus removal methods and add a large amount of iron to the treatment process. Salt or aluminum salt flocculants mix a large amount of inorganic metal salts into the activated sludge of water plants, thereby reducing the organic components in the mixed sludge, and finally lead to the fact that inorganic salts account for dry sewage in the sludge of sewage plants. 35% or even more of the sludge component brings many problems to the subsequent treatment and disposal of the sludge. For example, the reduc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F11/00
Inventor 王学科
Owner TIANJIN ENEW ENVIRONMENTAL PROTECTION ENGCO LTD
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