| A research of an Integrated Circuit Package Company in Jiangmen analyzed its used water and wastewater. The mixture of all the effluent is difficult to treat. Therefore,separating collection of different wastewater is a better method. Coagulant sedimentation was used to treat grinding and dicing waste water. Ion exchange combined with Fenton oxidation method was used to treat immersion waste water. Water-saving and emission reduction plan was carried out based on the results, which will support the cleaner production of this enterprise.1. The total amount of waste water in this company is 292 m3/d, which can be divided into three categories:(1)Grinding and dicing waste water, which contains a large amount of suspended solids, is stable and the output is about 25m3/d;(2)Immersion waste water contains a small amount of cupric ion with high COD and total nitrogen. The output is about 33m3/d;(3)Electroplating waste water contains a small amount of cupric, tin ion and organic matters. The output is about 234m3/d.Various types of waste water from the enterprises are usually transported to the waste water stations, and discharged after chemical precipitation treatment.2.Experimental study on grinding and dicing wastewater and immersion wastewater.(1)Coagulation-sedimentation method was carried out to treat grinding and dicing waste water. The results show that turbidity of waste water reduced from 231.6NTU to0.8NTU when p H was adjusted to 9.0, 8% poly aluminum chloride was 150μL/L.Quality of the outlet water is better than tap-water with p H=7~8, EC=77.1μS/cm.(2)Ion exchange combined with Fenton oxidant method got satisfactory results based on the experiments carried out.A. Static experiments were carried out to select the resin with better performance.Results show that resin OD5 had a greater adsorption capacity of organic matters among six resins, and its COD adsorption capacity was about 180 mg /g. Kinetics experiments of resin OD5 declare that resin OD5 followed the internal diffusion model with adsorption rate k=7.6×10-3min-1. Recovery experiments demonstrate that resin OD5 had a goodregeneration performance, and the regeneration rate was above 99% under the optimum condition that the regenerant concentration was 8%, and the volume was twice larger than the resin.B. The results of dynamic experiments declare that there were two platforms of the treated water COD when exchange flow was 9.0BV/h. On first platform, treated water was about 90 BV and COD was about 220-270mg/L. On second platform, treated water was about 160 BV and COD was about 270-320mg/L. The average adsorption capacity of the resin was about 160mg/g before the breakthrough point. Regeneration experiments were carried out under the optimum conditions selected by static experiments, results show that the average adsorption capacity of the resin was about 170mg/g before the breakthrough point when the flow of regenerant was 2.4BV/hC. On first platform of Fenton oxidant with ion exchange method, the COD of oxidized water was about 60mg/L under the conditions that p H=5.0, 3.0m L/L H2O2,[H2O2]/[Fe2+]=5.0. On second platform, the COD of oxidized water was about 77mg/L under the conditions that p H=5.0, 4.0m L/L H2O2,[H2O2]/[Fe2+]=5, which both meet the national emission standards.Immersion waste water was treated by ion exchange method combined with Fenton oxidation, the TN from 114.1mg/L down to 20mg/L and the copper content from 6.7mg/L to less than 0.2mg/L and Ammonia is reduced to less than 8.0mg/L.3. Quality of treated grinding and dicing waste water was good enough to reuse into immersion process and high pressure rinsing process. While the outlet water in high pressure rinsing process can also reuse in immersion process. The excess water will use in electroplate process with electroplate rinse pure water as rinse water. In this way, we can save approximately 74m3/d water, and the rate of water-saving is about 25.2%. The reduction of waste water emission is about 74m3/d, and the emission reduction rate is25.3%. |
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