Feasibility Study on Reuse of Washed Water in Electronic Industry: Case Study for Flexible Printed Circuit Board Manufacturing in Thailand

Water reuse for final cleaning process in electronic industry is evaluated. The target factory produces flexible printed circuit boards, which are washed with purified deep-well water as a final process before packaging. Survey of water consumption and its quality was conducted. Feasibility study aims to find the suitable schemes the factory can apply to the real practice when the water consumption rate for final cleaning process increases, with a few conditions that need to be concerned. Material flux analysis and economical evaluation are also performed. It is found that the water needs to be treated before reusing due to the conductivity and LPC that are too high. It is, therefore, suggested that the reused water recharged to both RO unit and ion- exchanger at a suitable ratio. The most attractive alternative in term of both technical and economical aspects is when the recharged ration is 30:70. Raw water consumption can be saved up to 19,760 m3 per year and the investment can be paid off within 2 years.