Abstract: Disclosed is a method for treating wastewater containing at least one copper complex, comprising: 1) providing the wastewater containing the at least one copper complex, wherein the at least one copper complex is chosen from EDTA-Cu2+ complex and ammonia-Cu2+ complex; 2) adjusting pH of the wastewater containing the at least one copper complex to be within a range from 2.0 to 3.0, and adding ferrous sulfate to convert copper in the wastewater into a form of cuprous ions; and 3) adjusting pH of the wastewater obtained in step 2) to be within a range from 8.0 to 10.5, so that the cuprous ions in the wastewater are converted into precipitates of cuprous hydroxide and/or precipitates of cuprous oxide.

Abstract: A method of fabricating a printed circuit board is disclosed. The method includes opening a first window in a first base board and opening a second window in a second base board and a resin layer. The resin layer is between the second base board and the first base board. The method further includes bonding the first base board and the second base board through the resin layer; placing a heat dissipating conductor in the first window in the first base board through the second window; placing a resin portion on the first base board in the second window; embedding a sub-board in the second window of the second base board; and bonding the sub-board with the first base board through the resin portion.