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Multi-stage a/o-mbr treatment method of oil shale retort wastewater

A segmented water inlet and treatment method technology, applied in the field of sewage treatment, can solve the problems of high treatment cost, unstable treatment effect, low removal rate, etc., and achieve the goal of reducing the reflux ratio of mixed liquid, saving aeration cost, and reducing dosage Effect

Active Publication Date: 2017-08-11
NORTHEASTERN UNIV LIAONING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The treatment methods for oil shale retort wastewater at home and abroad mainly include physical and chemical methods, chemical methods, and biological methods; among them, physical and chemical methods and chemical methods are mainly used to remove petroleum and phenols in oil shale retort wastewater and improve the biodegradability of wastewater (pretreatment) and advanced treatment of wastewater; biological methods are mainly delayed aeration method, sequencing batch activated sludge method (SBR), membrane bioreactor method (MBR), anoxic / aerobic method (A / O), anaerobic / anoxic / aerobic method (A / A / O), contact oxidation method, etc., these processes have effectively improved the removal effect of organic matter and ammonia nitrogen in wastewater, but in the treatment of COD, ammonia nitrogen, total nitrogen content High oil shale mainstream wastewater often has disadvantages such as low removal rate, complicated operation and management, unstable treatment effect, and high treatment cost.
As the relevant national environmental protection standards have increased the control of total nitrogen indicators, it is difficult for existing technologies to meet the requirements of the new standards. For this reason, some oil shale refineries have begun to continuously add high-efficiency microorganisms; or adopt large reflux ratio and Extend the hydraulic retention time, strengthen aeration and other methods to improve the removal efficiency of COD, ammonia nitrogen and total nitrogen
However, these methods have greatly increased the operating costs of sewage treatment projects.

Method used

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  • Multi-stage a/o-mbr treatment method of oil shale retort wastewater

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] The pretreated oil shale retort wastewater is introduced into the multi-stage A / O-MBR treatment system with water inflow; the multi-stage A / O-MBR treatment system with water inflow is composed of the first anoxic pool, the first aerobic pool, The second anoxic pool, the second aerobic pool, the third anoxic pool, the third aerobic pool and the membrane bioreactor are connected in series, and each anoxic pool is equipped with a stirring device or a submersible propeller. The tanks are equipped with aeration devices, and the membrane bioreactor is connected to the first anoxic tank through the return pipe; the oil shale carbonization wastewater is divided into the first part, the second part and the third part, and enters the first anoxic tank, the second part and the third part respectively. The second anoxic pond and the third anoxic pond; wherein the first part accounts for 35% of the total volume of all oil shale retort wastewater, and the second part accounts for 35% ...

Embodiment 2

[0043] Method is with embodiment 1, and difference is:

[0044] (1) The ammonia nitrogen concentration of pretreated oil shale dry distillation wastewater is 2000mg / L, the total nitrogen content is 2100mg / L, and the COD concentration is 1900mg / L; the activated sludge concentration in each aerobic pool and anoxic pool is 2000mg / L; The first part accounts for 45% of the total volume of all oil shale retort wastewater, and the second part accounts for 30% of the total volume of all oil shale retort wastewater;

[0045] (2) The temperature during the nitrification reaction is 10°C;

[0046] (3) Control the reflux ratio of the whole system to 300%;

[0047] (4) The ammonia nitrogen concentration of the discharged clear water is 4.8mg / L, the total nitrogen content is 170mg / L, and the COD is 240mg / L;

[0048] (5)V 1 The selected value is 0.08, the total hydraulic retention time of the anoxic pool is t 1 =24×(2100-200) / (3000×V 1 ), t 1 =190 hours; the hydraulic retention time t ...

Embodiment 3

[0051] Method is with embodiment 1, and difference is:

[0052] (1) The ammonia nitrogen concentration of pretreated oil shale dry distillation wastewater is 3000mg / L, the total nitrogen content is 3100mg / L, and the COD concentration is 4000mg / L; the activated sludge concentration in each aerobic pool and anoxic pool is 5000mg / L; The first part accounts for 45% of the total volume of all oil shale retort wastewater, and the second part accounts for 35% of the total volume of all oil shale retort wastewater;

[0053] (2) The temperature during the nitrification reaction is 30°C;

[0054] (3) Control the reflux ratio of the whole system to 400%;

[0055] (4) The ammonia nitrogen concentration of the discharged clear water is 8.2mg / L, the total nitrogen content is 230mg / L, and the COD is 260mg / L;

[0056] (5)V 1 The selected value is 0.2, the total hydraulic retention time of the anoxic pool is t 1 =24×(3100-200) / (5000×V 1 ), t 1 =70 hours; the hydraulic retention time t of...

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Abstract

The invention provides a step-feed multistage A / O-MBR processing method for oil shale retorting waste water, and comprises the following steps: (1) the oil shale retorting waste water is introduced with a step-feed multistage A / O-MBR processing system; the waste water is divided into three portions and enters into three anoxic pools respectively; (2) denitrification reactions are carried out in each anoxic pool; (3) waste water enter into each aerobic pool, and nitrosation reactions and nitrification reactions are carried out in each aerobic pool; (4) the waste water enters into a membrane bioreactor; (5) clear water generated after filtering by the membrane module is discharged, and a retained sludge mixed liquor returns to the first anoxic pool. According to the invention, oxygen-limited aeration is carried out in the first aerobic pool and the second aerobic pool, thereby realizing short distance nitrification; by means of step-feed, COD in the original water can be fully utilized for denitrification, thereby reducing external carbon source adding amount and mixed liquor reflux ratio, and reducing aeration cost and denitrification required carbon source.

Description

technical field [0001] The invention belongs to the technical field of sewage treatment, in particular to a segmented water-inflow multi-stage A / O-MBR treatment method for oil shale carbonization wastewater. Background technique [0002] Oil shale is an important alternative energy source that can be used to refine shale oil. China's shale oil production has risen from about 700,000 tons in 2012 to 800,000 tons in 2014, ranking first in the world in terms of oil production. first place. During the shale oil production process, a large amount of oil shale dry distillation wastewater will be produced. The wastewater contains a large amount of COD, ammonia nitrogen, volatile phenol, petroleum and other pollutants. It is a kind of high ammonia nitrogen, high organic pollutants, and difficult to treat. waste water. [0003] The treatment methods for oil shale retort wastewater at home and abroad mainly include physical and chemical methods, chemical methods, and biological meth...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F3/30
Inventor 李亮胡筱敏于鑫钱光升姜彬慧
Owner NORTHEASTERN UNIV LIAONING
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