NEW BIOFILTER MEDIA FOR HEAVY METALS REMOVAL FROM AQUACULTURE WASTEWATER

Abstract

It will be necessary to provide about 40 million additional tons of fish by 2030 to keep the per capita share constant. Fish from aquaculture contribute about 50% of the total fish production around the world. It has become common to treat water from fish farms using the biological method, because it is one of the best methods comparinet to the physical and chemical methods. Although ammonia (NH3) is one of the most important pollutants produced by fish farms, several heavy metals have serious effects on fish and the environment. In this experiment, a treatment unit consisting of two stages was designed, the mechanical filter stage as a primary treatment and then the biological filter as the main treatment stage. Gravel was used as a mechanical filter medium, while activated carbon (AC) and rice straw (RS) were used as biofilter media. The AC and RS effects on the heavy metals removal from the water were studied. Changing the pH value on ammonia removal efficiency was also produced to determine its effect. The concentrations of lead (Pb), tin (Sn), iron (Fe), arsenic (As), copper (Cu), nickel (Ni), boron (B), zinc (Zn) and cadmium (Cd) were measured for wastewater and treated water. The best efficiency of AC and RS was to remove copper (Cu) by 65.80 and 84.68%, respectively, and the lowest efficiency was to remove lead (Pb) by 31.50 and 43.20%, respectively. The best pH of AC and RS was 8 with ammonia removal efficiency of 85 and 68%, respectively.