Microfiber Flat Mops all produced by 80% poyester and 20% polyamide microfiber mop fabrics.With finished style with banding edge and stitching edge,and very easy to attached with mop frmae with loop and hook velcro.Washable more than hundreds times.Commercial than tradional cotton mop.You can clean al kinds of floor surface with only water.
1 Mid-stage wastewater treatment technology Mid-stream wastewater is mainly generated during the washing, screening and bleaching processes in the papermaking process.
Under the precondition that the black liquor is treated by alkali recovery (black liquor extraction rate> 80%), the COD of middle-stage or plant-wide integrated wastewater is controlled at 1500~1800mg/L, and it can reach 5 papermaking industry through primary sedimentation and secondary biochemical treatment. The secondary emission requirements for water pollutant discharge standard 6 (GB3544) 2001) are only slightly different. For example: Oxidation ditch process system based on American Amko company's technical equipment, strong surface aeration process system based on Oslo's technical equipment from Finland, based on Pracker's technology equipment from Sweden, adopting selector technology As the core of deep well aeration process system (well depth is 9m) and so on. Introduced here is the LRP+ multistage A/O process system.
1.1 LRP process
According to the analysis and research on wastewater discharged to meet the standards, the main components are lignin and other difficult-to-biodegrade substances, so for companies in the process of changing production, to ensure compliance with standards, it is necessary to ensure that biodegradable substances are basically removed, and thus it is necessary to prolong the biochemical process. Stay time or increase the dosage, but the result is to increase operating costs.
Through the study of the source of lignin, it can be found that the bleaching process using chlorine-containing compounds is the main reason for production, so treating this part of the water alone can improve the treatment efficiency and reduce the processing cost. Hynniuen proposed the Lignin removal process (LRP). The basic principle is based on the ability of acidified fiber sludge to promote organic precipitation. The main components of fiber sludge are the degradation products of cellulose and hemicellulose (called fibers). When water comes into contact with fibers, water molecules associate with the hydroxyl groups on the surface of the fibers under the effect of hydrogen bonds, and water molecules are negatively charged. One end of the fiber protrudes outward from the surface of the fiber (negative charge generated by the ionization of the hydroxyl group can also promote the arrangement of water molecules), which results in strong solvation and a certain degree of hydrophilicity [2] . The lignin molecules have a network structure in space. The hydrophobic part of the lignin molecules converges to the inside of the rubber core. Negatively charged functional groups such as hydroxyl groups, phenolic hydroxyl groups and the like are distributed on the surface. Na+ forms a solvation shell around the rubber core, thus forming a stable Polymer hydrophilic colloids. When the pH value of the solution is reduced, the electronegativity of the negatively charged functional group decreases, the shell of the solvate becomes thinner, and the acidified fiber sludge reduces the repulsion between the lignin particles after adding the LRP system, making it easy to destabilize and precipitate [3] , thereby reducing the amount of acid added, and at the same time can give full play to the advantages of high degree of fiber polymerization, high molecular weight, adsorption points and advantages of linear structural characteristics, not only can be a large number of adsorption and adhesion of lignin in the wastewater has been precipitated and Fine fibers, but also reduce the dosage of coagulant.
The LRP process can be roughly divided into three stages: acidification, mixing and precipitation of fiber sludge, pH adjustment and sludge separation treatment.
From the actual operation point of view, the main advantages of LRP technology are the following: Compared with the traditional physicochemical method (such as aluminum salt precipitation method), the consumption of chemical drugs is low, and thus the operating cost is relatively low; easy to stain Mud treatment, and the use of excess sludge as a cardboard raw material, to achieve the comprehensive utilization of sludge; For users who already have mechanical processing or biological treatment equipment, it is very convenient to combine the LRP process with the original process, so it is a kind of The adaptability is very strong; the operation and management are simple, and the processing system has strong impact load capacity.
1.2 Multistage A/O Process
The content of lignin in the bleached water treated by the LRP system is greatly reduced, which is favorable for the subsequent biochemical treatment. The biochemical treatment section adopts a multi-stage A/O biochemical treatment system centered on a suspension chain moving aeration device to ensure that the effluent meets the emission standards.
The system consists of anaerobic tank, hydrolytic acidification tank and multi-stage A/O tanks. The wastewater enters the sedimentation tank through anaerobic tank, hydrolysis acidification tank and multi-stage A/ tank, and the effluent after the precipitation enters the stable tank stable treatment. After the discharge; part of the sludge in the sedimentation tank flows back to the front of the aeration tank and is mixed with the influent water before entering the anaerobic tank, and the other part is discharged as excess sludge into the sludge concentration tank.
For papermaking wastewater, multi-stage A/O biochemical treatment system has three characteristics:
Low sludge load Most papermaking wastewater treatment projects have high sludge load values ​​and provide a small amount of microorganisms. Microbes only decompose the most nutritious part of the pollutants and do not make full use of the whole process of biological metabolism, resulting in purification efficiency. Lower; and low sludge load can make full use of the whole process of microbial and microbial metabolism provided by the sludge, completely absorb and decompose the pollutants in the wastewater, make the effluent water quality better, and under the condition of low sludge load, activated sludge Fully involved in the reaction, the amount of remaining sludge to be treated is small, and the contained organic matter has been well decomposed and mineralized, so the sludge is stable without odor.
High oxygenation efficiency
Microporous aerators are currently the most efficient equipment for oxygenation, but for the treatment of papermaking wastewater with high suspended solids content and poor operating conditions, maintenance and repairs are more difficult. All the fasteners on the surface of the water after the suspension chain movement aeration device can be used to maintain the aeration pipe directly without stopping the air and without emptying the structure. This not only has a fixed microporous exposure. The gasifier features high oxygen transfer efficiency and has its own convenient and quick maintenance mode.
No sludge swelling
The most direct manifestation of sludge swelling is the increase in SVI. The main causes of sludge swelling are: first, water temperature, and the possibility of occurrence in summer and autumn is relatively high; second, water quality. In general, a large amount of waste water containing soluble organic matter containing carbohydrates is prone to sludge expansion, especially if water quality suddenly deteriorates. when. In terms of the aeration tank itself, high sludge load, high sludge concentration, and single operation mode are liable to cause sludge expansion when the water quality suddenly deteriorates. The main solutions are: changing the air volume; reducing the sludge load, usually Reduce the amount of influent water or dilute the influent water; change the operation process; add chlorination; slight sludge expansion can increase the amount of sludge discharged and reduce the concentration of the mixture; set the carrier in the aeration tank to cultivate biofilm; use A/O process. The multi-stage A/O process mixture undergoes multiple alternating effects of an aerobic zone and an anoxic zone, effectively reducing the SVI value and avoiding sludge swelling.
2 Sludge resource and comprehensive utilization technology
Sludge production from papermaking wastewater is generally 5 to 10 times that of municipal wastewater treatment plants of the same size. Therefore, the disposal of sludge is very important. The organic matter content in the paper sludge is about 30%, and it does not contain heavy metals. It is an ideal raw material for fertilizer production. Sludge fertilizer production process shown in Figure 4. Specifically, after the sludge is mixed with other additives after mechanical dewatering, aerobic fermentation is used as the main method for the production of fertilizer. The aerobic fermentation process utilizes the metabolism of aerobic microorganisms to convert the organic matters in the sludge into rich substances. Humic substances of plant nutrients, the final metabolites of the reaction are CO2, H2O and heat, and the large amount of heat generated maintains the material at a sustained high temperature to reduce the moisture content of the material and effectively remove pathogens, parasite eggs, and sludge. Weed seeds allow the disposal of sludge to be reduced, stabilized, harmless, and resourced.
3 Project Example
Shandong Quanlin Paper Co., Ltd. (1997) invested in the first phase of the pollution control project (materialization of papermaking wastewater) and the second phase project (oxidation pond) in 1999. With the changes in the company's production scale and product structure, the company has established pollution control facilities. Facilities gradually exposed the lack of processing technology and processing capacity. After the demonstration, a multi-stage A/O process running after the original oxidation pond was installed with a suspension chain mobile aeration device was adopted. The main technical parameters of the project are as follows: the treated water volume is 4.5×104m3/d (first phase), 10×104m3/d (second phase); the influent COD is 1500mg/L, the effluent is 200mg/L; the influent BOD5 is 500mg/L , The water is 60mg/L. This project was approved by the Environmental Protection Bureau of Shandong Province in April 2002.
4 Conclusion
The middle-stage wastewater treatment adopts a combination of physical and chemical methods for different water quality, so as to achieve the goal of reducing the treatment cost. For the characteristics of bleached wastewater containing a large amount of lignin, the use of LRP physicochemical system can effectively remove the material that is not easily biodegradable, thus greatly reducing the difficulty and pressure of biochemical treatment.
The production of sludge from papermaking wastewater treatment is large. How to achieve the final reduction, stabilization, harmlessness, and resource utilization of sludge disposal is very important. Sludge production provides an effective way to this end.
Microfiber Flat Mop,Flat Squeeze Mop,Flat Mop Pads,Flat Squeeze Mop And Bucket
jiangsu qiyun cleaning knitting product co.,ltd , https://www.jarfrry.com