Reclaiming Clean Water from Optoelectronics Manufacturing Wastewater

Background

Due to recent droughts in Taiwan, the government began enforcing water conservation policies to regulate water intensive
industrial end-users to reuse 70–85% of their wastewater. To comply and remain commercially viable, global optoelectronic company in Taiwan (TFT-LCD panel production) implemented a zero liquid discharge (ZLD) process to maximize water recovery. Using an advanced MBR-RO-EDR* membrane treatment system, the company has successfully recycled an average of 91% of its process water in recent years.

System Information

The wastewater influent is a mixture of waste streams collected from various stages of the panel production line. The water quality, as a result, is a complex makeup of contaminants (Table 1) and creates a challenging scenario for treatment. However, once the MBR reduces suspended solid levels, the RO and EDR ensure ultrapure water quality for reuse.

LG BW 400 R G2, LG Chem’s highest rejection brackish water membrane with the new L feed spacer for reducing differential pressure, was selected as part of the optoelectronic company’s technology procurement strategy to deliver long-term stable production of high-quality permeate with minimal fouling, cleaning requirements, and energy consumption. The operating conditions are listed in Table 2.

Membrane Performance

Compared to the alternative RO (non-TFN membrane) product operated at the plant, NanoH₂O™ membranes showed better and more reliable normalized permeate flow (Figure 1) and salt passage (Figure 2). Furthermore, NanoH₂O™ membranes required more than half fewer cleaning frequencies versus the non-TFN membrane, leading to notable savings in labor, chemical use, and plant downtime (Figure 1). Despite the complex ionic species composition of the wastewater, NanoH₂O™ membranes achieved high-quality permeate requirements for reuse (Table 3). LG BW 400 R G2 is a robust RO membrane element that helped lower the O&M costs of the wastewater recycling facility and realize the water conservation goals of the optoelectronic company.