Nomoto Naoki, Ali Muntjeer, Jayaswal Komal, Iguchi Akinori, Hatamoto Masashi, Okubo Tsutomu, Takahashi Masanobu, Kubota Kengo, Tagawa Tadashi, Uemura Shigeki, Yamaguchi Takashi, Harada Hideki
a Department of Energy and Environment Science , Nagaoka University of Technology , Niigata , Japan.
b New Industry Creation Hatchery Center , Tohoku University , Sendai , Japan.
Environ Technol. 2018 Apr;39(7):907-916. doi: 10.1080/09593330.2017.1316319. Epub 2017 Apr 20.
Profile analysis of the down-flow hanging sponge (DHS) reactor was conducted under various temperature and organic load conditions to understand the organic removal and nitrification process for sewage treatment. Under high organic load conditions (3.21-7.89 kg-COD mday), dissolved oxygen (DO) on the upper layer of the reactor was affected by organic matter concentration and water temperature, and sometimes reaches around zero. Almost half of the COD was removed by the first layer, which could be attributed to the adsorption of organic matter on sponge media. After the first layer, organic removal proceeded along the first-order reaction equation from the second to the fourth layers. The ammoniacal nitrogen removal ratio decreased under high organic matter concentration (above 100 mg L) and low DO (less than 1 mg L) condition. Ammoniacal nitrogen removal proceeded via a zero-order reaction equation along the reactor height. In addition, the profile results of DO, COD, and NH-N were different in the horizontal direction. Thus, it is thought the concentration of these items and microbial activities were not in a uniform state even in the same sponge layer of the DHS reactor.
