Abstract
Porous concrete has been used for promotion of self-purification at the river and the waterway as an attached growth medium for microorganisms. Recently, porous concrete with zeolite is developed. Zeolite has cation exchange ability and adsorption function which can increase water purification ability. However, the effects of porous concrete with zeolite is not understood in detail.
In this study, ammonia removal and biological nitrification using porous concrete with zeolite were focused. Effects of porous concrete characteristics such as the porosity, the mixing rate of the zeolite, and the zeolite type(supported cation type) on ammonia adsorption, attached growth of microorganisms including nitrifying bacteria, and ammonium nitrogen removal were investigated.
It was shown that porous surface can increase both specific surface area and microbial amount attaching to the media, which resulted in the increase of ammonia removal rate up to around double and the removal ability. It was also understood that the ammonia adsorption by zeolite showed similar positive effect for nitrogen removal to biological nitrification. Adsorption and biological reaction can happen at the same time, which suggests the multiple function for ammonia removal by the porous concrete with zeolite. It is suggested that zeolite type can affect on the nitrification, whereas there was not clear relationship between nitrifying activity and the amount of nitrifying microorganisms.
