Laboratory experiments were carried out on water quality purification with EcoBio-Block (EBB). EBB is a porous concrete block including Bacillus subtilis natto group. In this study, we examined experimentally denitrification effect of EBB by letting it live together with denitrification bacteria in soil. The time variations of TN, ON, DIN, NH4-N, NO2-N, and NO3-N were obtained under the aerated condition by changing the weight ratio of EBB to water. On the basis of those data, the denitrification rate, the mineralization rate, and the decreasing rate of DIN were obtained. As a result, we confirmed that the processes of organic matter decomposition, nitrification, and denitification were performed effectively by the symbiosis of useful microbial group and denitrifying bacteria.
