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An air monitoring program is in place at a wafer fab to characterize outdoor air quality and its potential impact on manufacturing processes. Airborne molecular contamination (AMC), and specifically acid contamination, was of particular concern as the facility incorporated 90-nanometer (nm) manufacturing technology. Impinger ionic analysis, passive and real-time reactivity monitoring, and litmus paper hue readings were among the techniques used to assess air quality. Historical data for each monitoring technique was evaluated and compared to determine the applicability of each monitoring technique for these purposes. Data from this monitoring program also offered an opportunity to evaluate the performance of chemical filters installed in makeup air handling units for their ability to remove AMC. This study presents the results of air monitoring, detailing outdoor air quality and how that air quality compares to established specifications; comparison of different monitoring techniques used in the study; performance of installed chemical filter systems; recommendations for improving acid contamination control and evaluation of selected options; and recommendations for overall AMC monitoring and control programs. [ABSTRACT FROM AUTHOR]

Water quality plays an important role in ensuring the healthy growth of aquatic living. Fish in ponds release nitrogen, phosphorus, ammonia, nitrates and organic waste. The presence of these chemicals in water leads to an increment in the pH level of the pond water, which could affect the growth of the fish. Therefore, it is vital to have an effective filter system for pond water to remove the unwanted waste. At current literature, the filtering effectiveness of activated carbon and zeolite in fresh water pond systems are remained inexplicit. In this work, a lab-scale filtering system was set up to study the ammonia removal efficiency of activated carbon and zeolite. The efficiency of these two types of filtering media was first studied separately and then combined as a hybrid filter with a weight ratio of 1:1. The effectiveness of the single filter media and hybrid media filter were evaluated based on the measurement of the concentration of ammonia, nitrite and nitrate, and the pH level. It was found that the hybrid filter – a combination of activated carbon and zeolite – tended to have higher efficiency in maintaining good water quality compared to the single media system; the ammonia level was reduced from 4 mg/L to 1 mg/L in 2.5 days. The greater the amount of the hybrid filter media presents in the system, the better the conversion rate of ammonia to nitrate. A combination of activated carbon and zeolite (150 g each) was found to be able to maintain suitable water quality (1 mg/L ammonia, 0 mg/L nitrite, <50 mg/L nitrate, 6.8–8.0 pH) for fish. [ABSTRACT FROM AUTHOR]