Sharp developed a non-dilution technology to remove at least 90% of the nitrogen contained in wastewater discharged from its semiconductor facilities. It combines the company's own system*¹ for treating spent developer using microorganisms with micro-nano bubble technology*². At the Fukuyama Plant, a facility was constructed to put this technology into practical use, and it has been in operation since July 2006.

Conventional methods for treating wastewater containing nitrogen consist in vaporizing the water by raising its temperature and using catalysts to break down the nitrogen, or in concentrating the wastewater and disposing of it as industrial waste. Such methods, however, present problems in terms of added costs and energy consumption. Also, conventional treatment methods using microorganisms require diluting such wastewater with 10 times its volume of fresh water to activate the microorganisms, and that demands large amounts of water and large areas for treatment facilities.

In June 2005 Sharp developed a technology that treats wastewater containing nitrogen by combining micro-nano bubble technology with a proprietary technology already used by the company to treat spent developer employing microorganisms. This new composite technology boosts treatment capacity by optimizing the material and the configuration of the microbial culture substrate, and thereby eliminating the need to dilute the wastewater. It also generates no sludge, thus reducing the amounts of solid waste.

*1 Proprietary methods, including the use of microorganisms, to purify spent developer. In 1999, Sharp received the Minister of International Trade and Industry Prize, Recycling Promotion Achievement Award for them.

*2 Micro-nano bubble technology: Developed in the early 1980s by Professor Hirofumi Ohnari and others at the Tokuyama College of Technology, it shrinks bubbles that are normally several millimeters in diameter to just a few micrometers or nanometers. The technology is mainly used for purifying water in dam reservoirs and in aquaculture.

The Mie Plant, working together with Tokuyama Corporation, has developed material recycling technology for waste development chemicals solution used in the LCD production process.
This system uses special recycling equipment inside the plant to collect and concentrate the development chemicals solution used in photolithography processes for LCDs. The liquid is trucked to Tokuyama's facilities, where it is treated and purified to a level indistinguishable from virgin development chemicals solution, and returned to the Mie Plant for re-use. The system became operational in April 2005.

Closed-Loop Recycling System for Waste LCD Development Chemicals at the Mie Plant

* The photolithography process uses a special light-sensitive resist and development chemicals solution used to form a layer of thin film in a specified pattern on a glass substrate to create TFTs (thin-film transistors) for an LCD panel.