Design And Engineering For Treatment Of PCB Wastewater And Reclaimed Water

Since entering in twenty-first Century, the PCB (printed circuit board) industry in the rapid development of China, China has become the world’s first PCB producer. With the rapid development of PCB industry, environmental problems, especially water pollution problems, become the bottleneck of restricting the sustainable development of the industry. PCB wastewater treatment technology in our country is not mature industrial wastewater treatment technology, units and companies specializing in PCB wastewater research are less. Although, with the large-scale development of the industry and development, PCB wastewater treatment technology get mature, the PCB wastewater treatment on the technology still has difficulty. In addition, the environmental protection departments around the wastewater discharge standards of PCB enterprises also are inconsistent, treatment technology and engineering configuration is uneven. In particular, PCB wastewater treatment is not up to standard, because there is no reasonable classified collection for production line drainage; no reasonable classified collection, because no understanding of the production process, and the characteristics of the production line of sewage, therefore cannot be effectively classified PCB waste reasonably. PCB wastewater treatment method also experienced a process, from the initial focus on heavy metal pollutants removal, so far all the factors of standard monitoring, ammonia nitrogen and CODCr, pollutant removal is the focus of PCB wastewater treatment. How to effectively remove harmful substances, to make waste water discharge meet the national standard, this is the current PCB industry facing a major issue.Printed circuit board according to different main pollutants of waste water generally can be divided into cleaning wastewater, printing ink wastewater, and complex wastewater, such as strong acid, strong alkali wastewater types. At present the craft of PCB wastewater treatment mainly include:oxidation; Biological treatment; Adsorption method; Chemical precipitation; REDOX process; Electrolytic process, etc.This paper presents the characteristics of wastewater treatment in PCB industry, and puts forward the combined treatment of heavy metal wastewater treatment system with the combination of water reuse, wastewater treatment, chemical coagulation, chemical coagulation, sand filtration and carbon filtration, and the combined treatment of BAF and A/O. Based on the technological transformation project of wastewater treatment facilities in Zhuhai, Guangdong Province, the design calculation and equipment selection of main structures of PCB wastewater treatment were carried out. Through engineering practice, to ensure the discharge of waste-water and the system is stable operation.The main conclusions of this paper are as follows:(1) Using the combined process of "hydroxide precipitation, sulfide precipitation, chemical coagulation, sand filtration and carbon filter", the integrated technology for treating heavy metal wastewater, UF-RO membrane separation technology is the core of the integrated technology, A/O-BAF process.(2) Combined with engineering practice, the main pollutants in wastewater treatment process, such as SS, NH3-N, COD, TP and petroleum, were evaluated. After monitoring, according to the results of PCB waste water treatment, main pollutants removal rate were over 80%, among them, the removal rate of TP is 98%.(3) after the operation of the PCB wastewater treatment project, the pharmaceutical cost, the electric charge and the labor cost of the treatment unit are 21095.5 yuan Id (6.80 yuan /t water),2206.4 yuan /d (0.13 yuan/t water) and 400 yuan /d (0.13 yuan /t water). Therefore, the comprehensive operating cost of the project is 7.64 yuan/t water.(4) after the completion of the PCB wastewater treatment project, the monitoring results showed that the main pollutants of the wastewater were 66.03 SS, COD was 411.99 t/a, NH3-N was 43.70 t/a, TN was 106.86t/a, TP was 35.56 t/a, oil was 11.14t/a, and the oil was t/a. After the wastewater is treated to achieve the standard discharge, the annual reduction of the sewage charges to 850840 yuan/a, can also generate considerable indirect economic benefits. Thus, the treatment process has a remarkable comprehensive benefit. Not only has realized the discharging standard wastewater, and the main water pollutants were slashing, thus effectively protect the water body, shows good environmental benefits.(5) The successful application of the process in the treatment of PCB wastewater can provide reference and reference for the engineering practice of similar wastewater treatment.