【Removal of COD from high - difficulty industrial wastewater by high molecular cationic polymer】
2015-09-24
Removal of COD from high - difficulty industrial wastewater by high molecular cationic polymer
Song Chengzhang, Chen Mengmeng
(Guangzhou Environmental Protection Technology Co., Ltd., Guangzhou Guangdong 511458)
Abstract: the high concentration of refractory industrial wastewater is complex, COD content is high, high concentration, high toxicity, difficult degradation, the environmental hazard. This paper introduces the application cases of the independent research and development of our company in various kinds of high difficulty industrial wastewater treatment. The practical application results show that the removal rate of COD is 91% and the effluent is lower than the national emission standard, which is the way out for the high concentration and difficult to degrade industrial wastewater.
Key words: high difficulty industrial wastewater, high efficiency COD removal agent
High concentrations of refractory industrial wastewater from petrochemical, coal chemical, mechanical cutting, printing and dyeing, food processing industries, the type of wastewater is usually a high, high concentration of COD, high concentration, high toxicity, high emissions, and other characteristics, if it is directly discharged into the environment, will cause serious damage to the ecological environment [1]. However, there is a lack of technology is feasible, economical and reasonable solution, causing businesses to invest in high, difficult to control, water pollution and serious a series of outstanding problems, especially the recent containing high concentration of salt mother liquor wastewater pollution incidents, serious threat to the local environment, and is not conducive to the survival and development of enterprises has become highly concerned by society, the public and the government [2]. So it is necessary to make a reasonable treatment to the discharge, because of its stable state and complex organic matter, which makes it difficult to deal with the single physical, chemical or biological methods. Therefore, it is very important to find a new and efficient method for industrial wastewater treatment.
Aiming at the characteristics of high concentration and high COD content in industrial wastewater, the new high efficiency COD removal agent, which is independently developed by our company, has been applied to various industries, especially in the COD removal effect of petroleum chemical, steel, coal tar chemical, machining, printing and dyeing, etc.. The product specializes in the removal of COD, mainly G series, D series, M series and other models, including different types of COD removal agent, applied to different types of industrial wastewater treatment. Our company is highly efficient COD removal agent should be used for different types of high concentration of refractory industrial wastewater operations case.
1 iron and steel industrial wastewater
Iron and steel enterprises are mostly set sintering, coking, iron, steel, Lian Zhu, steel and other production processes and machinery, power, refractories and other auxiliary processes as one of the integrated enterprise, the production process in the production process
Produce and emit a large amount of waste water [3]. The general discharge of one or more of the processes of the enterprise's external
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Received date: 2015-09-08
Author: Chen Mengmeng (1988-), female, Luohe Henan, graduated from Guangdong Ocean University, master's graduate students, technical engineers, mainly engaged in wastewater treatment.
Known as the iron and steel enterprise total drainage, iron and steel enterprise total drainage has a large amount of drainage, containing a variety of pollutants and pollution load characteristics.
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1.1 coking wastewater
Coking wastewater is one of the main wastewater discharged by iron and steel enterprises. Coking wastewater is a high concentration of organic wastewater, which is produced during the process of coal coke, gas purification and coking product recovery. Coking wastewater is mainly composed of gas at the beginning of the cold phase gas condensate and gas end cooling water, gas washing water and gas occurrence station of gas washing water, refined benzene separation of water and gas holder wastewater, coke oven seal water and other occasions of sewage [4]. Coking wastewater is complex, containing a large number of toxic and harmful substances, is a typical refractory organic wastewater. Conventional treatment methods for the removal of the difficult degradation of the compound, resulting in higher effluent COD and color, can not reach the standard. Therefore, in the process of seeking treatment of coking wastewater, our company independently developed a new type of pharmaceutical efficient COD removal agent not only can remove most of COD, and can be used to make water quality change, so that not only improve the quality of the environment, but also realize the recycling of water resources.
1.1.1 Hebei XXX large iron and Steel Co., Ltd. coking wastewater operation case
At present, the coking wastewater is generally treated by pre - treatment, two - level and deep treatment to meet the standard discharge, the COD series of our company G series is mainly used in the pretreatment stage, as the best choice for COD removal. According to the process and product of coking wastewater, the content of oil in PPM 100-1000 is high, which is high in organic content, which is high in COD content, which leads to high biochemical stage. Therefore, it is necessary to remove oil in the pretreatment stage. The removal efficiency of COD series of high efficiency G removal agent COD is more than 95%. The product is a composite polymer water treatment agent, and the molecular chain has a large number of positive charge groups.
(1) water quality survey
A. design treatment capacity of 300 m3/h;
B. design process flow:
Figure 1 coking wastewater treatment process flow chart
(2) system issues
After the wastewater treatment process, the water quality of the effluent is more serious, the taste is bigger, the COD is high, the preliminary judgment is the pretreatment process and the equipment is not perfect.
(3) pre - processing scheme
On the company's actual situation, we suggest in the flotation tank at the entrance, the metering pump with frequency of 200 kg / h cast and COD removal agent G series; at the same time with metering pump with frequency of 30 kg / h investment plus 1 per thousand PAM aqueous solution, to strengthen the effect of pretreatment.
A. modification process
Fig. 2 modification process flow chart of coking wastewater treatment
B. process description
Wastewater into the oil tank, the suspended solids and heavy oil in the pool in the separation of the oil, so that the light oil beads to rise to the surface, so that the oil particles separated from the water. Level reaches a certain level the oil scraper discharge scum pool, vibration oil wastewater to the regulating pond, water quality regulation, then enters the air floatation pool by COD removal agent G series for further separation of oil and water; and after mixing coagulation reaction removal in coking wastewater containing fine suspended particles, to enter the biological system to create the conditions. After the completion of the pretreatment, two biochemical treatment, the removal of COD, ammonia nitrogen and other difficult degradation of pollutants. Finally, the effluent from the sedimentation tank.
C. operation effect
My company COD G series series cast a little at the entrance, COD removal agent and waste water after full mixing, after the air flotation, the oil content from 300 ppm will be around 20 ppm, after biochemical treatment, reached 10 ppm, reached the standard of pollutant discharge in the iron and steel industry (GB13456-2012) standards. Among them, through experiments in the laboratory, adding COD removal agent G series and PAM, the COD by 9820mg/L fell to 540 mg / L, COD removal rate increased by 95%, which is the subsequent biochemical treatment laid the foundation.
1.1.2 Wuhan XXX large iron and Steel Co., Ltd. coking wastewater running instance
This waste water is a coking circulating water, and the water consumption per hour is 100 t, and the treatment process is separated oil pool + oil / water separation tank, and the G series of COD remover is applied to oil / water separation tank. After the oil tank, the oil content is reduced to about 200ppm, and then added COD removal agent G series, the oil content can be 10 ppm, COD removal rate reached 90%.
1.2 Guangdong XXX large steel plate Co., Ltd. hot dip galvanized wastewater
The company electro galvanized unit production process, in order to improve the quality of the products, production process was improved lead to large amounts of Zn2 + with wastewater discharge, so that the treatment of acid and alkaline waste water system discharge water Zn2 + standard: standard discharge is less than or equal to 4 mg / L, with an average of 14.26 to 9.71mg/L, resulting in monthly pay sewage charges 20 to 30 million yuan; on the other hand resulting in a waste of resources. The water content of the wastewater is mainly derived from the dissolved zinc and waste water in the unit. Therefore, it is necessary to strengthen the management of the process control, the hot zinc plating wastewater treatment, while trying to recover the zinc.
The company's hot dip galvanized steel mill wastewater treatment process in the pretreatment, biochemical treatment phase are used in the process of environmental protection and a series of products, which is used in the pre process of COD removal agent G series products; biochemical treatment stage is the use of our company HHB biological technology. After the operation of our company to undertake all the indicators are lower than the national level emission standards. The average value of 30mg/L is COD, which can be directly used in the environment of green water, can raise the ornamental fish. The project has been recognized by the local government, Guangzhou JFE Steel Co., Ltd. is a beautiful scenery.
2 Petrochemical Wastewater
Petrochemical wastewater is a series of organic material processing process, which is based on petroleum as raw material, cracking, refining, fractionation, reforming, synthesis and so on. The wastewater usually have higher organic matter concentration and ammonia nitrogen concentration, and wastewater often contain large aromatic difficult degradation of organic pollutants and toxic and harmful substances, such as sulphide, volatile phenol. And the use of conventional treatment, the effect is not good. Such as Ling Wenhua [6] UASB reactor for high concentration of petrochemical wastewater treatment, the reactor uses the temperature range of 30~38, in the influent COD 8000 COD, mg/L removal rate reached 63%, and the system load is high.
2.1 XXX large branch of Sinopec oil refining wastewater operation case
At present, we have done a lot of research on the treatment of high concentration and difficult degradation of petrochemical wastewater by the technical staff of our company. COD series of high efficiency M removal agent series products have the advantages of high COD removal rate and low cost, so it is more and more popular in petrochemical industry.
(1) the amount of waste water treatment: 500 m3/h;
(2) treatment process flow: water - oil - oil - gas - water - oil - > - > - > - > - > - > - > BAF - > - > effluent;
(3) the result of the operation: my company is recommended in the flotation cell in front of a reaction tank, used to add COD M removal agent series of chemicals, strengthen the pretreatment effect. After COD removal agent M series treatment, COD from the original 4826 mg/L to 436 mg/L removal rate reached more than 91%.
2.2 large branch of Sinopec XXX alkaline wastewater
The method of alkali washing is often used to refine the fuel oil. The lye and oil containing s, N, O and other compounds react, so as to effectively remove affects the stability of the oil material and some sulfur compounds, such as naphthenic acid, phenol, hydrogen sulfide and mercaptan therefore alkali washing refining process be improved oil traits and improve oil quality important link, resulting a lot of spent caustic wastewater. Spent caustic wastewater contains a large number of pollutants, the COD content reached thousands mg / L or even hundreds of thousands of mg / L and alkaline residue wastewater contains higher salt.
For the treatment of high salt, high concentration, refractory alkaline wastewater is always the difficult problem in petrochemical industry. Our company's research and development personnel and Chemical Experiment Research Institute, will be highly efficient COD removalM series used in the treatment of alkaline wastewater of high concentration. It is found that the COD removal rate reached 80%, the decolorization effect better, the water is clear, so the products in petrochemical spent caustic wastewater processing industry is paid more and more attention.
(1) wastewater treatment capacity: 300 m3/h;
(2) modification of process flow:
Figure 3 alkaline wastewater treatment process flow diagram
(3) process description: because the company has no specific process, our company according to the company's waste water treatment, do a process flow. Because of the alkaline wastewater is strongly alkaline, need to adjust the pH biochemical treatment before, so you need pH regulation pool.
(4) operation effect: alkaline residue wastewater by COD removal agent M series after treatment, COD by 20050mg/L fell 40.4 mg / L, COD removal rate increased by about 80%, which is the subsequent biochemical treatment laid the foundation.
2.2 propylene oxide wastewater from XXX large branch of Sinopec
A large amount of wastewater is produced in the process of producing propylene oxide. The wastewater has the characteristics of high temperature, high alkalinity, high salt, high COD, etc.. Therefore, the sewage treatment in the production of propylene oxide is a worldwide problem, which has recently been solved by Chinese enterprises. Our company COD M series of high concentration of epoxy propane wastewater treatment, found that COD removal rate reached 89%, the decolorization effect is good, the water quality is clear, marking the environmental protection enterprises in this field has achieved a breakthrough.
(1) wastewater treatment capacity: 400 m3/h;
(2) modification of process flow:
Fig. 4 process flow chart of epoxy propane wastewater treatment
(3) the operating effect: after the mg/L series of COD removal agent M, the COD is reduced to 2709 18350mg/L, the removal rate of COD is increased by 86%, which is the basis for the subsequent biochemical treatment.
3 machining cutting fluid industrial wastewater
Machining cutting fluid wastewater because of its high concentration of COD, complex composition and poor biodegradability, has become a headache in the water treatment industry. In recent years, the production of cutting fluid wastewater is increasing and the processing difficulty is increasing. Therefore, it is urgent to find a feasible method to deal with the wastewater. COD series of our company, G series, M series of chemicals with strong oxidation ability, COD removal efficiency, good decolorization effect, etc., in high concentration machining of cutting fluid wastewater treatment has more application case.
3.1 Jiangsu XXX large stainless steel machining cutting fluid wastewater operation case
(1) the amount of waste water treatment: 100 m3/h;
(2) treatment process flow: the influent - > - > - > - > - > - > - > - > - > - > - > - > - > - > - > - > - > -;
The process is to deal with the sewage system of another kind of waste water, and it is planned at the same time to deal with the cutting fluid wastewater, which is used for the treatment of the waste water. There are two ponds as the storage use.
(3) operation effect: after repeated experiments, the use of highly efficient COD remover G series, M series, and in the PAC, PAM with the use of a better effect. The G dosage was 6%, M dosage was 9 per thousand, while the G removal rate of COD is 83%, the removal rate of COD was 92% M. Therefore, the comprehensive comparison between the amount of investment and the use of the results, I recommend the use of COD M removal agent series.
3.2 Guangdong XXX metal plate with the company machining cutting fluid wastewater
(1) the amount of waste water treatment: 150 m3/h;
(2) process flow: the influent - > - > - > - > - > - > - > - > - > - > - > - > - > - > - > - > - > - > - > - > - >;
(3) operating results: my company proposed in the flotation tank or demulsification pool continuously and uniformly adding COD removal agent D series, and then cast PAM solution add the prepared, uniform mixing of flocculation reaction, the COD removal rate reached 87%.
4 printing and dyeing industrial wastewater
Textile printing and dyeing is one of the key industries of industrial pollution control and water conservation. Printing and dyeing wastewater is processed cotton, hemp, chemical fiber and its blending products mainly in the printing and dyeing factory discharge of wastewater [7]. Printing and dyeing wastewater is larger, each printing and dyeing processing 1 tons of textile waste water 100~200 tons, of which 80~90% become [8]. Textile printing and dyeing wastewater has the characteristics of large amount of water, high COD, high alkalinity, high water quality and so on. Printing and dyeing wastewater treatment is difficult to focus on two aspects, such as difficulty of COD and high chroma, so, for the above problems, the COD series, M series, G Series in the field of printing and dyeing wastewater treatment have better effect.
4.1 Guangdong XXX Textile Co., Ltd. printing and dyeing wastewater treatment running instance
The wastewater of the company is a dye wastewater, which has the characteristics of high chroma, high content of organic pollutants, high water quality and so on.
4.1.1 wastewater treatment capacity: 100 m3/h;
4.1.2 process flow:
Fig. 5 process flow chart of printing and dyeing wastewater treatment
4.1.3 system problem
(1) 110mg/L COD or so, not up to the discharge standards.
(2) the color of the 130mg/L or so, the effluent requirements of the following 50mg/L, not up to the discharge standards.
(3) the suspended material is about 200mg/L, and the effluent is less than 70mg/L, which can not reach the discharge standard.
(4) the treatment effect of the biochemical pool is not ideal: the removal rate of COD is about 56%, and the removal rate is low.
4.1.4 preprocessing scheme
According to the company's site specific circumstances, the requirements of the hope to improve the quality of the treated water standards, increase the processing capacity. After understanding the process improvement proposal and suggestion, the solution is mainly divided into two aspects: (1) to strengthen the pretreatment, reduce the biochemical pool water load, improve the biochemical pool treatment capacity; (2) to enhance the biochemical pool treatment effect, improve CODIn the pre treatment stage, we use the COD removal agent M series products; the biochemical treatment stage is the HHB of our company.
4.1.5 operation effect
COD in 5037mg/L, after my company COD M series, COD is 278 mg/L; and after my company's HHB bio enhancement technology, COD for 90 mg/L, to meet the country's first level emission standards. Moreover, the water color, suspended material indicators also meet national emission standards.
5 Conclusion
Environmental pollution is one of the biggest threat facing mankind today, especially the development of industrial production, the discharge of a large number of various types of high concentration refractory wastewater, if the wastewater is discharged directly or not handled properly, will affect the water self purification, thus the water quality deterioration. We should recognize the high concentration of refractory wastewater from a new point of view. Waste water and resources is the opposite of unity, waste water can be considered to be the development of the resources, as long as the technical clearance, measures properly, waste water can be transformed into resources.
It is feasible to treat high concentration refractory industrial wastewater with high concentration of COD removal agent. The removal rate of COD is more than 90%, which provides favorable conditions for the subsequent biochemical treatment of wastewater. In particular, the following biochemical treatment for the use of the HHB of our company, the effluent of the indicators are lower than the national emission standards, is the most direct, the most economic, the most realistic and most reliable technology to solve the high concentration of refractory industrial wastewater.
Reference
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