Comparison of activated carbon and zeolites' filtering efficiency in freshwater

Abstract

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 4mg/L to 1mg/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 (150g each) was found to be able to maintain suitable water quality (1mg/L ammonia, 0mg/L nitrite, <50mg/L nitrate, 6.8-8.0pH) for fish.