The treatment process of printing and dyeing wastewater
Wastewater treatment process
Hydrolysis acidification - biological contact oxidation - coagulation sedimentation: Hydrolysis acidification decomposes benzene ring or long-chain macromolecular substances that are difficult to degrade, such as dyes, auxiliaries, fibers, etc. in the sewage into small molecular substances, and effectively degrades the surfactant in the sewage, so as to better control the foam problem generated in the subsequent aerobic process. The effluent treated by hydrolysis acidifier enters into the contact oxidation tank. The contact oxidation tank is equipped with fillers.
Some microorganisms grow firmly on the surface of the fillers in the form of biofilm, and some grow in suspension in water, which has the characteristics of both activated sludge and biofilter. After hydrolysis and contact oxidation treatment of wastewater, the coagulation sedimentation process is adopted to further remove chromaticity and reduce COD value in wastewater. Delayed aeration - coagulation sedimentation: high-quality effluent can be obtained. The coagulant dosage is small, the equipment is simple, and the sludge volume is small, but the process is complex, the floor area is large, and the capital construction and operation costs are high.
Process Flow Chart of Printing and Dyeing Wastewater Treatment
The printing and dyeing wastewater enters the regulating tank after removing large suspended solids and floating solids through the grid and screen, where the water quantity is regulated and the water quality is balanced, and at the same time, acid is added for neutralization, and then it is pumped to the hydrolysis acidification tank, which is only controlled in the acid fermentation stage to improve the biodegradability of the wastewater.
The acidified effluent flows into the contact oxidation tank, where most of the organics and chroma are removed by microorganisms, and then flows into the sedimentation tank. Part of the sludge in the sedimentation tank returns to the hydrolysis acidification tank, where solubilization and volume shrinkage reactions are carried out to greatly reduce the excess sludge.
Application of Electromagnetic Flowmeter in the Printing and Dyeing Industry
The excess sludge can be directly dehydrated after thickening. In order to obtain better water quality, the biochemical effluent is further treated by coagulation sedimentation and discharged up to standard. The excess sludge in the secondary sedimentation tank is concentrated and then digested. The thickened sludge is concentrated and dehydrated. The sludge cake is transported outside. The supernatant and dehydrated filtrate of the thickener return to the sewage treatment system.
Alkali liquor is often used for desizing, bleaching, and mercerizing in printing and dyeing pretreatment. The pH controller of the Bleaching Meter can control the pH between 9-10 to ensure the quality of the fabric.
An electromagnetic flowmeter is used in the water inlet link plant to accurately control the water volume. The use demand can be met by selecting the split electromagnetic flowmeter with a 316L electrode and PTFE lining configuration of Supmea.
An integrated electromagnetic flowmeter is often used for the measurement and transmission of dyes. High-frequency excitation, fast response, and precise control are customized to achieve automatic dye filling.
In the dyeing process, it is crucial to ensure temperature control. It is necessary to pay attention to the temperature change at all times to keep the temperature within range. The combination of the temperature sensor and recorder of Supmea can realize the measurement and control of temperature, improve the automation level and reduce the labor cost.
Steam is usually used in the printing process for steaming and color fixation. The vortex flowmeter of Supmea is selected for convenient installation and accurate measurement. With pressure and temperature sensors and a flow totalizer, the flow can be remotely displayed. Steam is often used in drying and shaping.The temperature and pressure integration vortex flowmeter of Supmea makes an accurate measurement, which is convenient for enterprises to control costs. The pH controller and flowmeter of Supmea are selected to realize wastewater treatment and re-discharge and save the production cost of the enterprise. We will fully combine professional instrument experience with printing and dyeing technology to provide more professional services for printing and dyeing enterprises.